Review of Critical Care Medicine

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Archive for the ‘Medical’ Category

Opsoclonus Myoclonus syndrome in Chikungunya Virus Infection

Posted by Dr KAMAL DEEP on August 14, 2018

Int J Med Rev Case Rep. Online First

http://mdpub.net/?mno=315

doi: 10.5455/IJMRCR.Opsoclonus-Myoclonus-Chikungunya

Posted in Medical | Leave a Comment »

Ultrasound of Chest in ICU

Posted by Dr KAMAL DEEP on March 31, 2017

Indications for Chest ultrasound include:

1.To differentiate white out of pleural effusion from consolidation

2. Bedside detection of anomalies to avoid transporting critically Ill patient and faster ,dynamic picture

3.Guidance for diagnostic and therapeutic thoracentesis.

 A 3.5 to 5.0 MHz transducer.

Cardiac transducers are particularly effective allowing scanning between rib interspaces.

Typical Position in Critically Ill patient:- Supine with the ipsilateral arm held across the chest towards the opposite side.

Method :-The transducer is oriented to scan between the ribs. The A lines and B lines are shown below:-

A lines:- A lines are horizontal lines that are brightly echogenic and located between the rib shadows when the probe is positioned longitudinally

B lines:- Pleural ultrasound image depicting B lines (“comet tail artifact”), which are seen in acute pulmonary edema and acute respiratory distress syndrome. The presence of B lines would provide an alternate explanation for increased density seen on the chest radiograph, other than pleural fluid.

Lung sliding — The sonographic effect of lung sliding (also known as lung gliding or the lung sliding sign) is created by movement of the lung relative to the chest wall during respiration . The sonographic appearance is that of a thin, bright line moving horizontally along the pleural line with a wave-like pattern located above (towards the chest wall) and a granular pattern below. Lung sliding is an indirect sign indicating adherence of the visceral pleura to the parietal pleura. When air separates the two pleural layers as in a pneumothorax, the movement disappears.

In addition the Blue Protocol can be downloaded from this link https://com-anest.sites.medinfo.ufl.edu/files/2015/06/2015-BLUELung.pdf which can be summarized as below:-

  • Predominant A lines + lung sliding = Asthma/COPD
  • Multiple predominant B lines anteriorly with lung sliding = Pulmonary Edema
  • Normal anterior profile + DVT= PE
  • Anterior absent lung sliding + A lines + lung point = Pneumothorax (PTX)
  • Anterior alveolar consolidations, anterior diffuse B lines with abolished lung sliding, anterior asymmetric interstitial patterns, posterior consolidations or effusions with out anterior diffuse B lines = Pneumonia
  • A lines:
    • Appear as horizontal lines
    • Indicate dry interlobular septa.
    • Predominance of A lines has 90% sensitivity, 67% specificity for pulmonary artery wedge pressure <= 13mm Hg
    • A line predominance suggests that intravenous fluids may be safely given without concern for pulmonary edema
  • B lines (“comets”):
    • White lines from the pleura to the bottom of the screen
    • Highly sensitive for pulmonary edema, but can be present at low wedge pressuresThe  hypothesized  physical  and  anatomic  basis  of  echocardiographic  lung  comet  tails.  Reflections  of  the  ultrasound  beam  between  thickened  interlobular  septa  and  the  pleura  generate  a  resonance  signal  over  a  prolonged time.  The  increased  return  over  time  is  interpreted  by  the  ultrasound  machine  as  a  hyperechoic  structure  originating deeper  in  the  tissue  and  is  displayed  as  a  comet-tail  on  the  ultrasound  screen.  (Illustrations  and  images  from  Jambrik et  al.  Usefulness  of  ultrasound  lung  comets  as  a  nonradiologic  sign  of  extravascular  lung  water. 
    • Lung Abscess 

 This video shows a small pleural effusion and adjacent alveolar consolidation of the lung. With each inspiration, aerated lung is interposed into the imaging window with loss of visualization of the underlying structures. This is termed the curtain sign. The 3.5 MHz transducer is in longitudinal orientation and placed perpendicular to the chest wall to scan through the 8th intercostal space in the left mid-axillary line.















      Posted in Medical | 1 Comment »

      Hemodynamic Monitoring MCQs

      Posted by Dr KAMAL DEEP on May 5, 2016

      Cardiac output (CO) monitoring using oesophageal Doppler monitoring (ODM):

      A.Uses frequency shifts in reflected sound waves to estimate flow velocity

      B.Will overestimate values of stroke volume (SV) and CO if the probe is poorly positioned

      C.Can be used in children

      D.Does not measure blood flow to the head or arms

      E. Requires measurement or estimation of aortic cross-sectional area.

      All are true except B.

      image

      An animation illustrating how the Doppler effect causes a car engine or siren to sound higher in pitch when it is approaching than when it is receding. The pink circles represent sound waves.
      The Doppler effect (or the Doppler shift) is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is named after the Austrian physicist Christian Doppler, who proposed it in 1842 in Prague.

      To understand what happens, consider the following analogy. Someone throws one ball every second at a man. Assume that balls travel with constant velocity. If the thrower is stationary, the man will receive one ball every second. However, if the thrower is moving towards the man, he will receive balls more frequently because the balls will be less spaced out. The inverse is true if the thrower is moving away from the man. So it is actually the wavelength which is affected; as a consequence, the received frequency is also affected. It may also be said that the velocity of the wave remains constant whereas wavelength changes; hence frequency also changes.

      image

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      image

      When the probe has been placed and focused , blood f low velocity can be calculated based on the Doppler principle. Emitted ultrasound is scattered by erythrocytes travelling in the descending aorta and partially reflected back to the probe.When ultrasound is reflected by a moving object such as erythrocytes, the frequency of reflected ultrasound is higher than the emitted frequency when erythrocytes move towards the probe and lower when they move away from the probe . Erythrocyte velocity is directly proportional to the Doppler frequency shift (Df), i.e. the discrepancy between transmitted frequency (fT) and received frequency. This relationship is described by the Doppler equation : Blood flow velocity (v) can now be calculated from the frequency shift, because other factors that determine velocity are basically known and constant (c is the velocity of ultrasound waves in body tissue, fT the transmitted frequency and θ is the angle between ultrasound beam and blood flow). The angle θ is not precisely known, however, it closely approximates the angle with which the ultrasound transducer is mounted to the central axis of the probe (i.e. 45° with the CardioQ device), because the oesophagus and aorta run nearly parallel at mid-thoracic level.
      image

      image

      Technical limitations derive from the blood flow velocity measurement itself as well as the assumptions needed to translate velocity into CO. The intensivist needs to be aware of these limitations, as there are conditions in which TED derived measurements may not necessarily be reliable. The measurement of blood flow velocity assumes that all erythrocytes travel in the same direction and at the same speed. Indeed, in healthy subjects, descending aortic blood flow is usually laminar with a relative uniform velocity profile over the aortic cross section . However, skewed velocity profiles and rotational blood flow in the descending aorta has also been described. Non-laminar f low is likely to occur in patients with pathology of the aorta or aortic valve. Another important aspect in velocity measurement is the angle with which ultrasound is insonated into the aorta, because the cosine of this angle makes part of the Doppler equation. As described earlier this angle is not precisely known .but is assumed to equal the angle with which the ultrasound transducer is mounted to the central axis of the probe. However, this assumption may not hold true in those patients who have an altered relationship between the aorta and oesophagus, e.g. because of previous surgery, tumour mass or severe scoliosis. Due to the non-linear character of the cosine function, deviations in the actual angle from the assumed angle will result in relatively small errors at small degrees but become unacceptably high when the angle of insonation exceeds 60°. With the angle of 45°, which the CardioQ uses, a deviation of 1°, 5° and 10° in the actual from the assumed angle results in measurement errors of approximately 2%, 8% and 16%, respectively. Translation of blood flow velocity into CO requires estimations of the aortic cross sectional area as well as the distribution of blood flow between the descending aorta and supraaortic arteries. However, neither of the above measurements is actually taken. Rather, the CardioQ uses a nomogram and provides a calibration factor to translate descending aortic blood flow velocity to total left ventricular cardiac output over a wide range of patient conditions. However, a nomogram derived from average values in a population does not always accurately predict individual values. Moreover, the nomogram neither accounts for changes in aortic diameter nor in changes of blood f low distribution. Aortic diameter may change due to changes in blood volume and blood pressure.Furthermore, blood f low distribution may also change, e.g. due to changes in vascular tone caused by pharmacologic action, sympathetic blockade, blood loss, sepsis or anaphylaxis.Despite these limitations, trend monitoring should generally be possible if the basic conditions remain constant. However, it is important to realize that changes in the basic condition, e.g. sudden changes of aortic diameter and blood flow distribution due to acute haemorrhage, may lead to inconsistent or even misleading CO readings . Thus, the intensivist needs to be aware of the technical limitations of TED to avoid misinterpretation of displayed data.. If θ is 0, cos θ is 1, but as θ gets progressively closer to 90° the velocity of blood flow becomes more and more underestimated. At 90° cos θ = 0 (velocity is not measured).
      image

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      Oesophageal Doppler:
      a.Utilises the Doppler shift to measure blood velocity.
      B.Velocity of blood (m/s) in the descending aorta can be calculated provided the aortic cross-sectional area is known.
      C.It is assumed 70% of cardiac output is distributed caudally to the descending aorta.
      D. Doppler probes must be removed after 1 week.
      E. Is accurate when used with a working epidural.

      A & C are True only.

      Oesophageal Doppler:
      A.Peak velocity is a good estimate of myocardial contractility.
      B.By age 70 peak velocity falls to less than 50cm/second.
      C. Stroke distance (SD) is the area under the velocity-time curve and provides an estimate of stroke volume.
      D .An increase in stroke volume of less than 5-10% with a fluid bolus suggests hypovolaemia.
      E. A corrected flow time (FTc) greater than 400ms is due to hypovolaemia.

      A & C are true only
      Peak velocity declines with age, with normal values of 90-120cm/s at the age of 20, falling to 50-80cm/s by the age of 70.

      Concerning corrected flow time (FTc) measured by oesophageal Doppler:

      A.An FTc less than 330ms may be due to excessive metaraminol use.
      B.An FTc of up to 400ms may be normal in anaesthetised patients.
      C.A normal FTc is 230 to 260ms.
      D.A low peak velocity and FTc less than 330ms may be due to increased preload.
      E.Goal-directed therapy using oesophageal Doppler protocols may improve outcomes for surgical patients.

      A,B and E are true
      FTc is prolonged by vasodilatation, and therefore an FTc of up to 400ms may be considered normal in anaesthetised patients, in particular, in those with a working epidural in situ, due to the vasodilatation that is encountered.
      Increased afterload may result in a low peak velocity and low FTc.

      A 74-year-old lady with a history of ischaemic heart disease and severe congestive cardiac failure is admitted to the ICU with hypotension and presumed sepsis. She is sedated and ventilated in pressure support mode. On examination she is confused, BP is 85/35mmHg, HR is 115bpm (sinus tachycardia), Sp02 is 95% on 60% oxygen. Arterial blood gas analysis shows a lactate of 4.3mmol/L (39mg/dL). Which is the BEST guide to the need for further intravenous fluid replacement?

      A.Response of oesophageal Doppler to passive leg raising. B.Insertion of a pulmonary artery catheter and pulmonary artery occlusion pressure measurement.
      C.Titrate fluid resuscitation against repeated blood lactate measurements.
      D.Assess pulse pressure variation.
      E.Urine output measurement.

      The following assumptions are made when determining stroke volume using an oesophageal Doppler probe:
      a. 70% of total cardiac output passes the probe.
      B. The ascending aorta runs parallel to the oesophagus.
      C.The diameter of the aorta is constant throughout systole.
      D.Haematocrit is unchanged between measurements.

      A 58-year-old man is ventilated on the ICU following a Whipple’s pancreatoduodenectomy. He is hypotensive (BP 85/65mmHg) and tachycardic (HR 120bpm). Initial oesophageal Doppler measurements include a flow time corrected (FTc) of 290ms, which rises to 310ms following a 250ml fluid challenge. Which statement is TRUE?
      a. A low FTc invariably means more fluid is required.
      B.This patient has normal cardiac contractility.
      C. FTc is a marker of afterload. D. Fluid should be titrated to an FTc of 340ms.
      E. Dobutamine should be started at this point.

      A 42-year-old woman is admitted to the ICU generally unwell 1 week following abdominal surgery. She is oliguric, hypotensive (BP 80/35mmHg) and tachycardic (HR 130bpm). An oesophageal Doppler probe is sited, showing: flow time (corrected) 380ms, peak velocity 110cm/s, stroke volume 90m1. Which of the following statements is TRUE? a. A fluid challenge should be administered.
      B.Cardiac contractility is impaired.
      C.A cautious dose of frusemide should be given.
      D.The measured (uncorrected) flow time will be greater than 380ms.
      E.The data are consistent with massive pulmonary embolism

      Posted in Medical | 2 Comments »

      MCQs in Respiratory Critical Care

      Posted by Dr KAMAL DEEP on March 19, 2015

      Transpulmonary pressure (TPP) and ventilator-associated lung injury:

      a At end-inspiration, the TPP is the principal force maintaining inflation.
      b TPP is calculated from the alveolar pressure minus the pleural pressure.
      c The use of oesophageal TPP monitoring to set positive end-expiratory pressure (PEEP), to achieve an end-expiratory TPP of 0-10cmH20, may be associated with improved outcomes in acute respiratory distress syndrome (ARDS).
      d During non-invasive ventilation (NIV), TPPs may be dangerously high, despite low delivered airway pressures.
      e Barotrauma is directly due to high airway pressures.

      True a,b,c,d
      At end-inspiration, the TPP is the principal force maintaining inflation of lung units and thus is an important factor in the genesis of ventilator-induced lung injury (VILI).
      TPP is calculated from alveolar pressure minus the pleural pressure, and thus alveolar and pleural pressure differences may both play an important role in the pathophysiology of VILI.
      In a study by Talmor et al, where PEEP was set to achieve an end-expiratory pressure of 0-10cmH20 and end-inspiratory TPP was limited to 25cmH20 using oesophageal TPP monitoring, a trend towards reduced 28-day mortality in ARDS was noted.
      In patients receiving NIV who generate high negative pleural pressures, TPP may be extremely high despite low delivered pressures, thus increasing the risk of barotrauma.
      Barotrauma occurs due to regional lung over-distension leading to lung damage, air leaks and pneumothoraces. It is not directly caused by high airway pressures. Volutrauma occurs due to high absolute lung ventilatory volumes leading to alveolar rupture and air leaks.
      1. Talmor D, Sarge T, Malhotra A, et al. Mechanical ventilation guided by esophageal pressure in acute lung injury. New Engl J Med 2008; 359: 2095-104.
      2. Slutsky AS, Ranieri VM. Ventilator-induced lung injury. New Engi 1 Med 2013; 369: 2126-36.

      In volume-controlled ventilation
      A. Tidal volume is given according to a pre-set volume target
      B. If the inspiratory time is fixed, the peak and mean airway pressure is
      independent of pulmonary compliance
      C. If the minute volume and frequency is set, it is not possible to adjust the tidal
      volume
      D. If tidal volume and minute volume is set, the ventilator frequency must be set
      between 10 and 20 breaths per minute

      A. T
      B. F
      C. T
      D. F

       

      Regarding the Berlin definition for acute respiratory distress’syndfame (ARDS):
      a The timing of ARDS must occur within 5 days of a known clinical insult and new or worsening respiratory symptoms.
      b Bilateral opacities are evident on chest imaging, which are not attributable to effusions, lobar collapse or pulmonary nodules.
      c The respiratory failure seen cannot be fully explained by cardiac failure or fluid overload.
      d ARDS is classified into mild and severe according to the PaO2/FiO2 ratio.
      e Severe ARDS is defined by a Pa02/Fi02 ratio of <150mmHg with a positive end-expiratory pressure (PEEP) >5cmH2O.

      True b & c
      The timing of ARDS must occur within 1 week of a known clinical insult and new or worsening respiratory symptoms.
      The definition requires bilateral opacities to be evident on chest imaging — either chest X-ray or CT scan — which is not attributable to effusions, lobar collapse or pulmonary nodules.
      ARDS exists where respiratory failure cannot be fully explained by cardiac failure or fluid overload. Objective assessment with ultrasound may be required to exclude hydrostatic oedema if no risk factors are present.
      The Berlin definition classifies ARDS into mild, moderate and severe. This is determined by the Pa02/Fi02 ratio: mild: a Pa02/Fi02 ratio of less than 300mmHg (39.9kPa) with positive end-expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) >5cmH2O (may be delivered non-invasively); moderate: a Pa02/Fi02 ratio of less than 200mmHg (26.6kPa) with PEEP >5cmH2O; severe: a
      a Pa02/Fi02 ratio of less than 100mmHg with PEEP >5cmH2O.

      Severe ARDS is defined as a Pa02/Fi02 ratio of less than 100mmHg (13.3kPa) with PEEP >5cmH2O.
      1. The ARDS Definition Task Force. Acute respiratory distress syndrome. The Berlin definition. JAMA 2012; 307(23): 2526-33.
      2. Ferguson ND, Fan E, Camporota L, etal. The Berlin definition of ARDS: an expanded rationale, justification, and supplementary material. Intensive Care Med 2012; 38: 1573-82.

      Which is/are correct statements regarding the inspiratory time (Ti)
      A. At the end-inspiratory time, the expiration phase always starts
      B. If Ti is set by the Inspiration:Expiration ratio, the Ti is independent of
      ventilator frequency
      C. If Ti is directly set, the expiratory time decreases with increasing ventilator
      frequency
      D. Normal Ti is in the range of 3–4 seconds

      A. F
      B. F
      C. T
      D. F

       

       

      Causes of right ventricle (RV) failure include:
      a Acute pulmonary embolus.
      b Protamine.
      c Extensive lung resection.
      d Acute respiratory distress syndrome (ARDS).
      e Obstructive sleep apnoea.

      All True
      Causes of RV failure can be divided into: intrinsic RV failure in the absence of pulmonary hypertension, usually due to RV infarction; RV failure secondary to increased RV afterload and pulmonary hypertension; and RV failure due to volume overload. Acute pulmonary emboli may cause an increase in pulmonary vascular resistance and thus RV afterload and therefore may cause RV failure.
      Protamine is used to reverse the effects of heparin and results in the production of protamine-heparin complexes. The complexes stimulate complement activation and the production of thromboxane, which can in turn lead to pulmonary arterial vasoconstriction, increased pulmonary afterload and RV failure.
      Extensive lung resection may result in increased pulmonary artery pressures — due to several different mechanisms — and this can potentially result in increased RV afterload and RV failure.
      The extensive alveolar and capillary lesions seen in acute respiratory distress syndrome (ARDS) have deleterious effects on pulmonary circulation and may result in increased pulmonary vascular resistance, increased RV afterload and RV failure.
      Obstructive sleep apnoea may cause raised pulmonary artery pressures and subsequently RV failure.
      1. Kevin LG, Barnard M. Right ventricular failure. Contin Educ Anaesth Crit Care Pain
      2007; 7(3): 89-94.

      Regarding prone position ventilation:
      a.The PROSEVA study group showed no mortality benefit at 28 days
      in severe acute respiratory distress syndrome (ARDS).
      b.Alveolar recruitment is improved with better drainage of secretions.
      c.A more homogenous ventilation distribution is achieved, due to
      favourable changes in thoraco-abdominal compliance.
      d.Proning increases extravascular lung water.
      e.The optimal duration of prone positioning is 24 hours.

      True b & C
      The PROSEVA study group found improved 28-day mortality (16% prone vs. 32.8% supine [p=0.001]) and 90-day mortality (23.6%
      prone and 41% supine [p<0.001]) in severe ARDS (Pa02/Fi02 ratio <150mmHg).
      The prone position improves alveolar recruitment and allows better drainage of chest secretions.
      With proning a more homogenous ventilation distribution is achieved, due to favourable changes in thoraco-abdominal compliance.
      Extravascular lung water is reduced following proning.
      The optimal duration of proning is currently unknown. The PROSEVA study proned patients for at least 16 hours. The average number of proning sessions was 4+/-4 per patient.
      1. Guerin C, Re gnier J, Richard JC, etal. Prone positioning in severe acute respiratory distress syndrome. New Engl J Med 2013; 368(2):159-68.
      2. Waldmann C, Soni N, Rhodes A. Oxford Desk Reference Critical Care. Oxford, UK: Oxford University Press, 2008.
      3. Edgcombe H, Carter K, Yarrow S. Anaesthesia in the prone position. Br .1 Anaesth 2008; 100(2): 165-83

      In biphasic positive airway pressure (BIPAP):
      A. The ventilator generates a dual CPAP level with an upper and lower pressure
      set by the user
      B. Patients may freely generate spontaneous breaths in the low pressure phase
      only
      C. Patients are allowed to exhale even during the high pressure phase
      D. Airway Pressure Release Ventilation is an extreme concept of BIPAP with a
      very short low pressure phase

      A. T
      B. F
      C. T
      D. T

       

       

      Positive end-expiratory pressure (PEEP):
      a In severe acute respiratory distress syndrome (ARDS), a PEEP >15cmH20 improves mortality.
      b PEEP increases functional residual capacity.
      c Hepatic and renal blood flow is increased with higher levels of PEEP.
      d PEEP application increases intrathoracic pressure, diminishing venous return to the right heart.
      e An observed increase in lung compliance suggests alveolar recruitment.

      True b, d & e

      In severe ARDS, high PEEP (>15cmH20) does not improve mortality. Some PEEP (around 5-10cmH20) is associated with improved oxygenation.
      Application of PEEP increases functional residual capacity.
      Decreased renal blood flow and reduced splanchnic and hepatic perfusion can occur with higher levels of PEEP.
      PEEP application increases intrathoracic pressure, diminishing venous return to the right heart.
      Following PEEP application, an observed increase in lung compliance is suggestive of alveolar recruitment.

      The National Heart, Lung and Blood Institute ARDS Clinical Trials Network. Higher versus lower positive end-expiratory pressures in patients with the acute respiratory distress syndrome. New Engl J Med 2004; 351: 327-36
      2. Waldmann C. Soni N, Rhodes A. Oxford Desk Reference Critical Care. Oxford, UK: Oxford University Press, 2008.

       

       

      Regarding the I:E ratio
      A. Is normal set between 1:3 and 1:4
      B. Should be lowered to decrease intrinsic PEEP
      C. Increase I:E ratio may improve alveolar recruitment and oxygenation in ARDS
      D. Adjustment of I:E ratio must be matched with respiratory frequency

      A. F
      B. T
      C. T
      D. T

       

       

      The following have been shown to improve mortality in acute respiratory distress syndrome (ARDS):
      a Inhaled (b-agonists.
      b Prone ventilation.
      c Treatment with intravenous glucocorticoids.
      d Use of high-frequency oscillatory ventilation (HFOV).
      e Ventilation at tidal volumes of 6ml per kg.

      True b & e 
      The BALTI-2 trial suggested (b agonists may increase mortality in ARDS. 
      The PROSEVA study demonstrated a mortality benefit in patients with ARDS. A total of 237 patients were assigned to the prone group, and 229 patients were assigned to the supine group. 28-day 
      mortality was 16.0% in the prone group and 32.8% in the supine group (p<0.001).
      The use of steroids in ARDS is controversial; methylprednisolone given at least 7 days after the onset of ARDS has been suggested to reduce time spent on mechanical ventilation, but has not shown conclusively to reduce mortality.
      HFOV does not improve mortality in ARDS, and has been demonstrated to increase mortality compared to current best practice.
      As initially described in the ARDSNET study, low tidal volume ventilation (6-7m1/kg) reduces mortality in ARDS. This is now considered a standard of practice in patients with ARDS.
      Smith FG, Perkins GD, Gates S, et al, for the BALTI-2 study investigators. Effect of intravenous 13-2 agonist treatment on clinical outcomes in acute respiratory distress syndrome (BALTI-2): a multicentre, randomised controlled trial. Lancet 2012; 379: 21.7. 
      Guerin C, Reignier J, Richard JO; et al. Prone’ [)ositioning in severe acute respiratory distress syndrome. New Engl J Med 2013;.3,58(2): 159-68.
      The National Heart, Lung and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network. Efficacy and safety of corticosteroids for persistent acute respiratory distress syndrome. The National Heart, Lung and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network. N Engl J Med 2006; 354: 1671-84. 
      Ferguson ND, Cook DJ, Guyatt GH, et al, for the OSCILLATE Trial Investigators and the Canadian Critical Care Trials Group. High:Oequency oscillation in early acute respiratory distreQs syndrome. New Engl J Med 2013; 368(9): 795-805.
      Young D, Lamb SE, Shah S, et al. High-frequency oscillation for acute respiratory distress syndrome. New Engl .1 Med 2013; 368: 80-6-13.
      The Acute Respiratory Distress Syndrome Network. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress:yndrome. New Engl J Med 2000; 342(18): 1301-8.

       

      Various methods to set optimal PEEP at the bedside include:
      A. Arterial PaO2
      B. Analysis of the pressure-volume curve (lower inflection point)
      C. Recording of the oesophageal pressure to estimate transpulmonary pressure
      D. Measurement of end-expiratory lung volume variations

      A. T
      B. T
      C. T
      D. T

       

       

      The following are recognised strategies in the prevention of ventilator-associated pneumonia (VAP):
      a Daily sedation holds.
      b Head-up positioning of 30 to 45°.
      c Prone positioning.
      d Chlorhexidine mouthcare.
      e Daily ventilator tubing changes.

      True a, b & d
      Daily sedation holds have been demonstrated to reduce patient time spent on the ventilator, and thus reduce the incidence of VAP
      Head-up positioning of 30 to 45° reduces micro-aspiration, and thus the incidence of VAR
      Prone positioning improves mortality in severe ARDS, but its impact on VAP rates per se is as yet unclear.
      Chlorhexidine mouthcare has been demonstrated to reduce the incidence of VAP
      Daily changes of ventilator tubing may increase the VAP risk due to cross-contamination from excess handling of equipment.
      1. Hunter JD. Ventilator-associated pneumonia. Br Med J 2012; 344: e3325.
      2. Guerin C, Reignier J, Richard JC, et al. Prone positioning in severe acute respiratory distress syndrome. Now Engl J Med 2013: 368(2): 159-68.

      Disadvantages of endotracheal intubation includes all of the
      following, EXCEPT

      A. Loss of the protective function of the upper airway
      B. Loss of phonation
      C. Decreased airway resistance
      D. Damage to the subglottic area
      E. Need for sedation and or analgesia

      Answer C is correct

       

      During the 2009 H1N1 influenza A pandemic:
      a Zanamivir (Relenza) is administered via the oral route.
      b Oseltamivir is an M2 channel blocker and given in a dose 75rng twice a day.
      c The Sequential Organ Failure Assessment (SOFA) score was suggested by the UK Government as a critical care admission triage tool.
      d Pregnancy was an independent predictor of mortality.
      e Transfer to an extracorporeal membrane oxygenation (ECMO) centre, in patients with H1N1-related acute respiratory distress syndrome (ARDS) was associated with lower hospital mortality.

      True c & e
      Zanamivir is given intravenously and is used when the enteral absorption of oral oseltamivir is poor or in cases of resistant virus. Oseltamivir is an oral neuraminidase inhibitor, which is active against both influenza A and B. It is dosed at 75mg bd for 5 days, doubled in severe infection (150mg bd for 10 days). Ribavirin may also be used in conjunction. M2 channel blockers (rimantadine) are not routinely used to treat influenza, due to neurotoxicity.Hemagglutinin (HA) and neuraminidase (NA) are the two large glycoproteins on the outside of the viral particles. HA is a lectin that mediates binding of the virus to target cells and entry of the viral genome into the target cell, while NA is involved in the release of progeny virus from infected cells, by cleaving sugars that bind the mature viral particles.Thus, these proteins are targets for antiviral drugs.

      Once inside the cell, the acidic conditions in the endosome cause two events to happen: First, part of the hemagglutinin protein fuses the viral envelope with the vacuole’s membrane, then the M2 ion channel allows protons to move through the viral envelope and acidify the core of the virus, which causes the core to disassemble and release the viral RNA and core proteins.The viral RNA (vRNA) molecules, accessory proteins and RNA-dependent RNA polymerase are then released into the cytoplasm (Stage 2). The M2 ion channel is blocked by amantadine drugs, preventing infection
      The SOFA score was suggested by the UK Department of Health as a critical care triage tool. Triage suggested included patients with a SOFA score >11 and certain inclusion/exclusion criteria would not be admitted to critical care, and also withdrawal of care would be considered at 48 hours and on subsequent days for patients with SOFA scores >11. Retrospective survey data post-pandemic suggested if this approach had been undertaken, withdrawal of care would have potentially occurred in several patients who subsequently survived after a short period of ventilation.
      Influenza infection whilst pregnant (particularly during the 3rd trimester) carries a high rate of complications and increased need for hospitalisation (4-7 x risk).
      Referral and transfer of H1N1-related ARDS to an ECMO centre was associated with a lower hospital mortality compared with non-ECMO referred patients, even if the referred patients did not ultimately receive ECMO.
      Gwavava C, Lynch G. Intensive care management of pandemic (H1N1) influenza. Anaesthesia Tutorial of the Week 2009, 2011. http://www.aagbi.org/education/educational -resources/tutorial-week.
      2, Noah MA, Peek GJ, Finney SJ, et al. Referral to an extracorporeal membrane oxygenation center and mortality among patients with severe 2009 influenza A JAMA 2011; 306(15): 1659-68,
      3 Zangrillo A, Zoccai GB, Landoni G, et al. Extracorporeal membrane oxygenation (ECMO) in patients with HI NI influenza infection: a systemic review and meta-analysis including B studies and 266 patients receiving ECMO. Crit Care 2013; 17: R30.

      To increase oxygenation during IPPV all of the following are useful
      EXCEPT:

      A. Increase FiO2
      B. Increase PEEP
      C. Decrease I:E ratio
      D. Increase peak inspiratory pressure
      E. Alveolar recruitment

      Answer C is correct

      Influenza A:
      a Influenza A is a DNA virus.
      b Neuraminidase facilitates the release of newly replicated viruses
      from infected cells.

      c Haemagglutinin allows attachment of the virus to host respiratory
      epithelium.
      d Influenza A is characterised by cough, fever, myalgia and sore
      throat.
      e It is best detected using PCR (polymerase chain reaction)
      techniques.

      True b c d and e
      Influenza A is an RNA virus.
      Influenza A is described by surface glycoproteins, haemagglutinin (H) and neuraminidase (N). 16 types of haemagglutinin and 9 types of neuraminidase exist. Influenza B is the second type of influenza virus (i.e. A or B).
      Haemagglutinin allows attachment of the virus to-host respiratory epithelium.
      Influenza A is characterised by cough, fever, myalgia and sore throat.Reverse transcriptase polymerase chain reaction RT-PCR testing,
      from nasopharyngeal swabs or aspirates, is the best method of diagnosis.
      1. Gwavava C, Lynch G. Intensive care management of pandemic (H1N1) influenza. Anaesthesia Tutorial of the Week 2009, 2011, http://www.aagbi.org/education/educational -resources/tutorial-week.
      2. Parsons PE, Wiener-Kronish JP. Critical Care Secrets, 5th ed. Missouri, USA: Elsevier Mosby, 2013.

      Effective methods to decrease an elevated PaCO2 may include all of
      the following EXCEPT:

      A. Increase tidal volume
      B. Increase frequency
      C. Decrease circuit dead space
      D. Increase PEEP
      E. Increase inspiratory pressure

      Answer D is correct

       

       

      Critical care ventilation:
      a During volume-controlled ventilation, the difference in peak and plateau pressures reflects the pressure required to overcome resistive forces.
      b The plateau pressure during pressure-controlled ventilation reflects the pressure required to overcome elastic forces during inspiration.
      c Auto-triggering describes the ventilator incorrectly cycling to inspiration.
      d Desirable tidal volume should be based on the patient’s actual body weight.
      e A lung protective strategy employs tidal volumes of 8-10m1/kg.

      True a & c
      During volume-controlled ventilation, the difference in peak and plateau pressures reflects the pressure required to overcome resistive forces.
      During pressure-controlled ventilation (PCV), inspiratory pressures are constant, therefore, it is not possible to differentiate the elastic and resistive properties of the patient’s lungs from observation of the airway trace.
      Auto-triggering describes the ventilator incorrectly cycling to inspiration.
      Tidal volumes generated should be based on ideal body weight.
      The ARDS network termed ‘lung protective ventilation’ to be 6-7m1/kg tidal volumes. Lung protective ventilation has been shown to reduce mortality in acute lung injury, with possible benefits also seen in patients with normal lungs.

      Adverse effects of PEEP include the following EXCEPT:
      A. Over distension of normal alveoli

      B. Barotrauma
      C. Decreased cardiac output
      D. Increased intracranial pressure
      E. Increased cyclic collapse of unstable alveoli

      Answer E is correct

       

       

      In relation to a potential ‘can’t intubate, can’t
      ventilate (CICV) scenario’ in anaesthesia practice:

      a It is estimated to occur in 0.01 to 2.0 per 100,000 cases.
      b Jet ventilation is required for cricothyroidotomy with a cannula of >4mm diameter.
      c Over 90% of CICV situations are preventable.
      d Fixation error may lead to loss of situational awareness and poor decision making.
      e Cricothyroidotomy skills are retained for only a short period.

      True c, d & e
      The CICV or can’t intubate, can’t oxygenate (CICO) scenario is an inability to secure the patient’s airway with an endotracheal tube and an inability to ventilate a patient’s lungs by conventional non-invasive means. This is a rare complication, estimated to occur in 0.01 to 2.0 per 10.000 cases.
      Cannula cricothyroidotomy requires jet ventilation to ventilate a patient’s lungs when a narrow-bore cannula (e.g. 2mm diameter) is
      used. A dedicated wide-bore proprietary cannula (>4mm) fits a
      standard 15mm connector and does not require jet ventilation.
      Data from the United States suggest that >90% of CICV situations are preventable with adequate pre-operative airway assessment and preparation.
      The fixation in trying to ‘achieve endotracheal intubation at all costs’, and the persistence in trying an airway method that has already failed, results in significant human error, loss of situational awareness and poor decision making.
      Skills in any cricothyroidotomy technique are retained for a short period of time only. It is recommended that chosen techniques should be practised every 3-6 months for optimal performance and skill retention.
      1. Popat M. The unanticipated difficult airway: the can’t intubate, can’t ventilate scenario. Johnston I, Harrop-Griffiths W, Gemmell L, Eds. in: AAGB1 Core Topics in Anaesthesia 2012; 4: 44-55.
      2. The Difficult Airway Society (DAS). http://das.uk.com/files/ddl-Jul04-A4.pdf

       

      Regarding intensive care unit ventilation:
      a Prolonging the expiratory time will increase the mean airway pressure.
      b Increasing positive end-expiratory pressure (PEEP) may directly increase arterial oxygen tension.
      c Decreased inspiratory time may cause gas trapping due to increased expiratory time.
      d Morbid obesity may increase chest wall compliance.
      e Auto-PEEP can be selected during controlled ventilation.

      True b
      The mean airway pressure is increased by prolonging the ventilator inspiratory time. This may increase arterial oxygen tension but it may also reduce venous return.
      Increasing PEEP may directly increase arterial 02 tension.
      Increased inspiratory time may cause gas trapping due to decreased expiratory time.
      Generally, morbid obesity reduces chest wall compliance.
      Auto-PEEP or intrinsic PEEP due to inadequate patient expiration may impair ventilator triggering.

       

      During controlled ventilation:
      a Airway pressure generated depends on the compliance and resistance of the respiratory system and circuit.
      b The inspiratory pressure waveform is constant during volume ventilation.
      c In time triggering, breaths are delivered according to a pre-set frequency.
      d Triggering is when the ventilator incorrectly cycles to inspiration.
      e Cycling is used to dictate when the inspiratory phase is complete.

      True a, c & e
      T Airway pressure generated during controlled ventilation depends on the compliance and resistance of the respiratory system and circuit.
      F Inspiratory flow is constant (square wave) during volume-controlled ventilation.
      T In time triggering, breaths are delivered according to a pre-set frequency.
      F Triggering is when the ventilator detects a drop in airway pressure or flow that occurs when a patient makes a spontaneous breath, instigating the ventilator to deliver a positive pressure inspiratory breath.
      T Volume, time and flow can be used to cycle the ventilator.

      Waldmann C, Soni N, Rhodes A. Oxford Desk Reference Critical Care. Oxford, UK: Oxford University Press, 2008.

       

       

      Weaning from mechanical ventilation:
      a Weaning is the process of liberation from mechanical ventilation.
      b Delay in weaning prolongs critical care stay, increases costs and is associated with a higher mortality.
      c Synchronised intermittent mandatory ventilation (SIMV) alone is considered a poor weaning strategy.
      d The ongoing need for inotropes precludes weaning.
      e No universal consensus exists for weaning.

      True a, b, c & e
      T Weaning is the process of liberation from mechanical ventilation.
      T Delay in weaning prolongs critical care stay, increases costs and is associated with a higher mortality.
      T The use of synchronised intermittent mandatory ventilation (SIMV) alone from recent weaning trials is deemed the least efficient method for weaning. Combining SIMV with spontaneous breathing/pressure support may improve efficiency.
      F The ongoing need for inotropes does not preclude weaning. There is no universal strategy or consensus currently for weaning critical care patients from mechanical ventilation. Further research and international collaboration is needed.
      1. Waldmann C, Soni N, Rhodes A. Oxford Desk Reference eriticaf Care. Oxford, UK: Oxford University Press, 2008.
      2. Lermitte J, Garfield MJ. Weaning from mechanical ventilation. Contin Educ Anaesth Crit Care Pain 2005; 5(4): 113-7.

       

      Regarding surgical resection of the oesophagus:
      a A lumbar epidural is likely to be beneficial.
      b A fibre-optic scope should be available to confirm correct double-lumen tube (DLT) placement.
      c Respiratory morbidity is high postoperatively.
      d Non-invasive ventilation in the early postoperative period is absolutely contraindicated.
      e Acute onset of fast atrial fibrillation at 3-7 days postoperatively may herald the development of an anastomotic leak.

      True b, c & e
      F A thoracic epidural will aid effective postoperative analgesia, improving mobility and cough. It should be considered in all patients if not contraindicated.
      T There is a significant morbidity/mortality associated following double-lumen endotracheal tube displacement and/or incorrect positioning. Respiratory failure post-oesophagectomy is common and may affect up to 25% of patients. There should be a low threshold for using a fibre-optic scope to confirm initial DLT placement and subsequent intra-operative tube position checks.
      T Respiratory morbidity following oesophagectomy is common with respiratory complications occurring in approximately 25% of patients. These patients may require critical care re-admission and early intervention with potential re-intubation. Cardiovascular complications (12%) and anastomotic leak (16%) may also complicate the postoperative period.
      F The use of non-invasive positive pressure ventilation (NPPV) for respiratory failure in the immediate postoperative period following oseophagectomy is controversial, but not absolutely contraindicated. High inspiratory (IPAP) and expiratory (EPAP,

      CPAP) pressures may hypothetically cause anastomotic distension and subsequent leak. However, there is increasing evidence that these concerns may be overstated and that NPPV use for postoperative respiratory failure may decrease re-intubation need and acute respiratory distress syndrome (ARDS), without increasing the risk of anastomotic leakage. Although, gastric distension is unlikely below inspiratory pressures of 25cmH20, the use of nasogastric drainage is advocated by many, as this would reduce the risk of distension. Further studies are warranted.
      Anastomotic leak may occur typically between 3-7 days and may present with non-specific signs such as pyrexia, general malaise, respiratory infection and cardiac arrhythmias (often atrial fibrillation is seen).
      1. Rucklidge M, Sanders D, Martin A. Anaesthesia for minimally invasive oesophagectomy. Contin Educ Anaesth Crit Care Pain 2010; 10(2): 43-7.
      2. Sherry KM, Smith FG. Anaesthesia for oesophagectomy. Contin Ethic Anaesth Crit Care Pain 2003; 3(3): 67-90
      3. Michelet P, D’Journo XB, Seinaye F, et al. Non-invasive ventilation for the treatment of postoperative respiratory failure after oesophagectomy. Br J Surg 2009; 96: 54-60.

       

      Management of tracheostomy and laryngectomy emergencies:
      a If the patient is making spontaneous breathing efforts, hand ventilation using a Mapleson C circuit should be used initially to assess the tracheostomy patency.
      b High-flow oxygen should be applied to the face and tracheostomy.
      c A suction catheter should be used to assess tracheostomy patency.
      d A laryngeal mask over the stoma site is inappropriate for ventilation.
      e A size 7.0 cuffed endotracheal tube should be used to intubate the stoma

      True b & c

      Initial manual or hand ventilation of a potentially displaced tracheostomy may cause massive surgical emphysema and impede resuscitative efforts and so is not advised. Attaching the Mapleson C or Water’s circuit with capnography to the tracheostomy tube, whilst the patient is making spontaneous ventilatory effort, is extremely useful as it can quickly establish that the tracheostomy is indeed in the airway and is patent/semi-patent through lung ventilation and CO2 exhalation.
      This should be done even in laryngectomy patients as the distinction between a patient with a tracheostomy and a patent upper airway and a patient with a laryngectomy with no patent upper airway, may not be known at the time of resuscitative efforts and initial assessment.
      Use of a soft suction catheter is an effective way of assessing tracheostomy patency.
      During primary emergency oxygenation, a laryngeal mask or supraglottic airway device over the tracheostomy/laryngectomy stoma site may prove life-saving and should be considered early.
      For secondary emergency oxygenation, intubation of the stoma can be undertaken in adults with a size 6.0 endotracheal tube or small tracheostomy tube. A size 7.0 endotracheal tube is not advised in the first instance as this may be too large. The priority here is to obtain a patent airway for oxygenation and ventilation, with success being more likely with a size 6.0 tube. An Aintree catheter may be very useful as one can oxygenate and even ventilate down it. A fibre-optic scope, bougie and/or airway exchange catheter may be considered in this drastic situation. 1. htto://www,tracheostomy.org.uk.
      2. McGrath BA, Bates L, Atkinson D, Moore JA. Multidisciplinary guidelines for the management of tracheostomy and laryngectomy airway emergencies. Anaesthesia 2012; 67: 1025-41.

       

       

      High-frequency ventilation:
      a A high-pressure jet (10-50psi) is used in high-frequency oscillatory ventilation (HFOV).
      b Lung compliance is improved by maintaining the lung on its deflation limb on the dynamic pressure-volume curve.

      C Peak airway pressures are increased.
      d Oxygenation and carbon dioxide elimination are decoupled in HFOV.
      e The OSCILLATE trial found a higher mortality associated with HFOV use.

      True d & e
      In high-frequency jet ventilation (HFJV), a high-frequency, high-pressure jet (10-50 pound/square inch, psi or 68.9-344.5kPa) is delivered via a small-bore cannula into the airway. Air is entrained into the airway by the high-pressure jet. Exhalation occurs passively.
      During high-frequency ventilation the lung is maintained on its deflation limb on the static pressure-volume curve, improving lung compliance and alveoli recruitment.
      Peak airway pressures are reduced with high-frequency ventilation, minimising barotrauma.
      Oxygenation and carbon dioxide elimination are decoupled in high-frequency oscillatory ventilation (HFOV).
      In the OSCILLATE trial, 548 patients from 39 centres were recruited. Mortality was 47% in HFOV vs. 35% receiving conventional ventilation. Increased sedative and muscle relaxant use was required in the HFOV group. In another trial conducted around the same time, the OSCAR trial found an identical 41 % 30-day mortality. Increased sedative and muscle relaxant use was also found in the HFOV group.
      1. Waldmann C, Soni N, Rhodes A. Oxford Desk Reference Critical Care. Oxford, UK: Oxford University Press, 2008.
      2. Ferguson N, Cook DJ, Guyatt GH, et al; the OSCILLATE Trial Investigators. High-frequency oscillation in early acute respiratory distress syndrome. New Eng! J Med 2013; 368(9): 795-805.
      3. Young 0, Lamb SE, Shah S, et a!; the OSCAR Study Group. High-frequency oscillation for acute respiratory distress syndrome. New Eng! .1 Med 2013; 368: 806-13.

       

       

      Non-invasive ventilation (NIV):
      a Decreases work of breathing and may aid weaning from mechanical ventilation.
      b Can reduce the need for intubation and hospital morbidity.
      c Failure is associated with a higher mortality in respiratory failure.
      d Greatest benefit is seen in acute hypercapnic chronic obstructive pulmonary disease (COPD) exacerbation or cardiogenic pulmonary oedema.
      e Severe acidosis is a contraindication.

      True a b c d
      NIV decreases the work of breathing and may aid weaning from
      mechanical ventilation.
      Can reduce the need for intubation and hospital morbidity.
      Failure of NIV is associated with a higher mortality in respiratory failure.
      The greatest benefit of NIV use is seen in patients with respiratory failure caused by acute COPD exacerbation or cardiogenic pulmonary oedema.
      Severe respiratory acidosis (<pH 7.25) is not a contraindication for a short trial of NIV (1-2 hours) in a monitored environment, where prompt intubation and ventilation may be undertaken as rescue, if NIV fails. Coexistent severe metabolic with respiratory acidosis, may suggest a mixed aetiology and other organ dysfunction, resulting in a greater incidence of NIV failure.

       

      Non-invasive ventilation (continuous positive airway pressure [CPAP]/bilevel positive airway pressure [BiPAP]) is contraindicated in:
      a Coma.
      b Mechanical bowel obstruction.
      c Recent upper GI surgery.
      d Cardiogenic pulmonary oedema.
      e Chest wall trauma.

      True a & b
      Coma (GCS <8/15) of any cause, the patient is unable to protect their airway and is at risk of aspiration. This is particularly true if non-invasive ventilation is used.
      Mechanical bowel obstruction poses a significant aspiration risk which may be exacerbated with non-invasive ventilation.
      There is a hypothetical risk of aspiration and strain of suture lines post-oesophagectomy with non-invasive ventilation. However, there is increasing evidence that CPAP with nasogastric tube decompression is safe and may prevent the need for re-intubation post-oesophagectomy. Further studies are warranted to investigate further.
      There is a significant mortality benefit with non-invasive ventilation use in cardiogenic pulmonary oedema.
      Non-invasive ventilation may be beneficial in chest trauma with persistent hypoxaemia, as it may establish and maintain lung recruitment, improving overall gas exchange.
      1. Waldmann C, Soni N, Rhodes A. Oxford Desk Reference Critical Care. Oxford,UK: Oxford University Press, 2006.
      2. Michelet P, D’Journo XB, Seinaye F, et al Non-invasive ventilation for the treatment of postoperative respiratory failure after oesophagectomy. Br J Surg 2009; 96: 54-60.

       

      High-frequency ventilation (HFV):
      a When compared to HFV, tidal volume must exceed dead space for effective ventilation during conventional ventilation.
      b During HFV, tidal volumes are near to or less than anatomical dead space.
      c Pendelluft is the principal mechanism of gas transport in HFV.
      d Taylor dispersion is the exchange of gas between adjacent lung units due to differing time constants.
      e Molecular diffusion is not important in HFV.

      True a & b
      T Tidal volume must exceed dead space for effective ventilation during conventional ventilation: VA=f(VT-VD).
      T Tidal volumes are near to or less than anatomical dead space during H FV.
      F Pendelluft is the exchange of gas between adjacent lung units due to their differing time constants. Gas flows from fast- to slow-filling units at the end of inspiration and the reverse occurs at the end of expiration.
      F Taylor dispersion is the interplay between convective forces and molecular diffusion causing laminar and radial gas dispersion.
      F Molecular diffusion is the principal mechanism of gas transport in the terminal airways.

       

      Ventilator-induced lung injury (VILI):
      a Gross barotrauma manifesting as pneumothorax is a frequent complication of mechanical ventilation.
      b Atelectrauma occurs due to direct injury to the alveoli from over-distension.

      c Biotrauma occurs due to shearing injury to the alveoli, caused by repetitive collapse and opening.
      d Development of extra-alveolar air due to perivascular alveoli disruption is thought to be an initial mechanism of barotrauma.
      e Biotrauma in the lung increases leucocytes, tumour necrosis factor (TNF), IL-6 and IL-8 release.

      True a, d & e
      Gross barotrauma manifesting as pneumothorax is a frequent complication of mechanical ventilation. Other complications include: pulmonary interstitial emphysema or subcutaneous emphysema, progression of pneumothorax to tension pneumothorax and cardiac arrest.
      Direct injury to alveoli from over-distension is volutrauma.
      Atelectrauma occurs due to the repetitive collapse and opening during mechanical ventilation causing shearing injury to alveoli. Biotrauma results from inflammatory mediators in the airspace and circulation.
      Development of extra-alveolar air due to perivascular alveoli disruption is thought to be an initial mechanism of barotrauma.
      Biotrauma in the lung increases leucocytes, TNF, IL-6 and IL-8 release.
      1. Waldmann C, Soni N, Rhodes A. Oxford Desk Reference Critical Care. Oxford. UK: Oxford University Press, 2008.
      Answer 87: Regarding hepatic encephalopathy: True a, c &
      d
      T The West Haven system is used to stage hepatic encephalopathy from 0 to IV: Grade 0 is when no abnormality is detected; Grade I is lack of awareness, euphoria, agitation, reduced attention span; Grade II is intermittent disorientation, drowsiness, inappropriate

       

      Pulmonary function tests:
      a The Fowler method can be used to determine functional residual capacity (FRC).
      b Vital capacity (VC) monitoring is useful in all critically ill patients when predicting the need for intubation.
      c The ratio of respiratory frequency to tidal volume (f/VT) is not a reliable predictor of weaning outcome.
      d Intrinsic positive end-expiratory pressure (PEEPi) may develop during mechanical ventilation if the expiratory time is too short or expiratory resistance is increased.
      e Respiratory drive can be assessed by measuring airway pressure 0.1 sec after occluding the airway against inspiratory effort.

       

       

      in relation to pregnancy and critical care the
      following are true:
      a Alveolar ventilation is increased during pregnancy.
      b There is increased glomerular filtration in pregnancy.
      c Major obstetric haemorrhage is the leading cause of maternal mortality worldwide and is the most frequent indication for pregnancy-related critical care admission.
      d Anaemia seen in the HELLP syndrome is non-haemolytic in nature.
      e The majority of survivors of amniotic fluid embolus syndrome suffer chronic neurological deficits.

      True a-c & e

      Respiratory
      Increased alveolar ventilation (70%), relative hypocarbia (PaCO2 of 25-32mmHg), reduced functional residual capacity (20%), increased 02 consumption and reduced venous oxygen saturation (Sv02)
      Cardiovascular Increased cardiac output (40%), increased stroke volume (25%), increased heart rate (25%), reduced total peripheral resistance, normal CVP in superior vena cava distribution, elevated CVP in inferior vena cava distribution, aorto-caval compression, increased circulating volume, increased plasma volume (40-50%), increased red cell mass (20%) and physiologic anaemia
      Gastrointestinal Reduced lower oesophageal sphincter tone, elevated risk of gastro-pulmonary aspiration, increased metabolism of carbohydrate +++, protein ++ and fat +, and hyperglycaemia (due to insulin resistance)
      Haematopoietic Reduced haemoglobin concentration (functional anaemia despite elevated red cell mass), slightly elevated leucocyte count, slightly reduced platelet count, increased clotting tendency
      Renal Increased renal blood and plasma flow (5Q-60%), increased glomerular filtration (50-60%), reduced serum urea and creatinine, glycosuria and mild proteinuria

       

      Indications for intubation and ventilation
      after traumatic brain injury prior to transfer include:
      a Glasgow Coma Scale (GCS) score <12.
      b Decrease in motor response score >2 points.
      c Bilateral mandibular fractures.
      d Spontaneous hyperventilation.
      e Seizures.

      All True

      Traumatic brain injury is a formal indication for intubation and ventilation. The Association of Anaesthetists of Great Britain and Ireland (AAGBI) in their 2006 document state that: "Tracheal  intubation during transfer is difficult and dangerous. All patients with a GCS of 8 or less require intubation prior to transfer. In addition, whatever the baseline GCS, intubation should be considered if the GCS has fallen by 2 or more points. Intubation is essential if there is a fall of 2 or more points in the motor score. Intubation requires adequate sedation and muscle relaxation to avoid an increase in [ICP], and measures to prevent aspiration of gastric contents. This will normally involve rapid sequence induction with in-line stabilisation of the cervical spine". If the GCS has fallen from a baseline of 15 to 12, this is an indication for intubation, particularly if transfer is being considered.
      A decrease in motor response score of >2 points indicates a deteriorating conscious level and a likely need for intubation prior to transfer.
      Bilateral mandibular fractures pose a bleeding risk to the airway and potential difficult airway.
      If spontaneous hyperventilation reduces PaCO2 to less than 4.0kPa, the subsequent vasoconstriction may worsen cerebral perfusion. This warrants intubation and ventilation for neuroprotection.
      Seizures are an indication for intubation and ventilation.
      1. Dinsmore .1. Traumatic brain injury: an evidence-based review of management. Contin Educ Anaesth Crit Care Pain 2013; 13(6): 189-95.
      2. The Association of Anaesthetists of Great Britain and Ireland (AAGBI). Recommendations for the safe transfer of patients with brain injury, 2006. http://www.aagbi.orgisitesidefault/filesibraininjury.odf.

       

      The following have been demonstrated to reduce the incidence of ventilator-associated pneumonia (VAP):
      a Prophylactic antibiotics in ventilated patients.
      b Head-up patient positioning.
      c Daily sedation holds.
      d Subglottic irrigation devices.
      e Low tidal volume ventilation.

       

      Regarding the Berlin definition for acute respiratory distress’syndfame (ARDS):
      a The timing of ARDS must occur within 5 days of a known clinical insult and new or worsening respiratory symptoms.
      b Bilateral opacities are evident on chest imaging, which are not attributable to effusions, lobar collapse or pulmonary nodules.
      c The respiratory failure seen cannot be fully explained by cardiac failure or fluid overload.
      d ARDS is classified into mild and severe according to the PaO2/FiO2 ratio.
      e Severe ARDS is defined by a Pa02/Fi02 ratio of <150mmHg with a positive end-expiratory pressure (PEEP) >5cmH2O.

       

      Non-invasive ventilation (NIV):
      a Decreases the work of breathing and may aid weaning from mechanical ventilation.
      b Can reduce the need for intubation and hospital morbidity.
      c Failure is associated with a higher mortality in respiratory failure.
      d Greatest benefit is seen in acute hypercapnic chronic obstructive pulmonary disease (COPD) exacerbation or cardiogenic pulmonary oedema.
      e Severe acidosis is a contraindication.

       

      True a-d
      NIV decreases the work of breathing and may aid weaning from
      mechanical ventilation.
      Can reduce the need for intubation and hospital morbidity.
      Failure of NIV is associated with a higher mortality in respiratory
      failure.
      The greatest benefit of NIV use is seen in patients with respiratory failure caused by acute COPD exacerbation or cardiogenic pulmonary oedema.
      Severe respiratory acidosis (<pH 7.25) is not a contraindication for a short trial of NIV (1-2 hours) in a monitored environment, where prompt intubation and ventilation may be undertaken as rescue, if

      NIV fails. Coexistent severe metabolic with respiratory acidosis may suggest a mixed aetiology and other organ dysfunction, resulting in a greater incidence of NIV failure.
      1. Waidmann C. Soni N, Rhodes A. Oxford Desk Reference Critical Care. Oxford, UK: Oxford University Press, 2008.
      2. McNeil_GBS, Glossop AJ. Clinical applications of non-invasive ventilation in critical care. Contin Educ Anaesth Crit Care Pain 2012: 12(1): 33-7.

       

       

      Cardiopulmonary exercise testing (CPET):
      a A standard seven-panel plot is used to display physiological results graphically.
      b Peak VO2 (oxygen consumption) is independent of patient motivation.
      c The anaerobic threshold (AT) is the point at which the rate of oxygen consumption (V02) increase exceeds the rate of carbon dioxide output.
      d An AT <14m1/kg/min is associated with worse outcomes following major surgery.
      e Multivariate analysis can be applied to CPET data to predict 5-year survival after major surgery.

       

      True E
      A standard nine-panel plot is used to graphically present CPET results. Panels 2, 3 and 5 relate to the cardiovascular system; panels 1, 4 and 7 examine ventilation and panels 6, 8 and 9 examine ventilation perfusion relationships.
      The anaerobic threshold (AT) is independent from patient motivation and provides a reliable measure of dynamic functional capacity specific to that patient. Peak VO2 represents the maximum VO2 that is measured, usually at the point where exercise is terminated, and therefore may be influenced by patient motivation to continue exercising. Peak VO2 correlates with postoperative cardiopulmonary complications after oesophagectomy and abdominal aneurysm surgery.
      The anaerobic threshold (AT) is the point at which the rate of increase of carbon dioxide output exceeds the rate of increase in oxygen consumption (V02). It is the point where aerobic metabolism alone is no longer adequate and is supplemented by anaerobic production of adenosine triphosphate (ATP).
      Patients with a peak VO2 less than 14m1/kg/min have a worse overall prognosis than those with a peak VO2 above 14m1/kg/min in patients with heart failure. Patients with an anaerobic threshold (AT) <11m1/min/kg are considered high risk, as there is a higher associated morbidity and mortality following major abdominal surgery. Patients with a pre-operative AT <11m1/kg/min should be admitted to critical care following major surgery.
      Multivariate analysis and model generation techniques can be applied to CPET data to predict 5-year survival after major surgery.
      1. Agnew N. Preoperative cardiopulmonary exercise testing. Contin Ethic Anaesth Crit Care Pain 2010; 10(2): 33-7.
      2. Drury N, Carlisle J. Cardiopulmonary exercise testing. Anaesthesia Tutorial of the Week 217, 2011. http://www.aagbi.org/educationleducational-resources/tutorial-week.
      3. Older P, Hall A, Hader R. Cardiopulmonary exercise testing as a screening test for perioperative management of major surgery in the elderly. Chest 1999; 116: 355-62.

      4. Colson M, Baglin J, Bolsin S, Grocott MPW. Cardiopulmonary exercise testing predicts 5-year survival after major surgery. Br) Anaesth 2012; 109(5): 735-41.

       

      image

      If this man requires invasive ventilation, what problem would you anticipate:-

      a. Difficult Bag Mask Ventilation

      b.Difficult Tracheal intubation

      C.High risk of aspiration

      D. Corneal Damage

      Ans is B.

      Small mandible/ and decrease Thyromental distance

      Posted in Medical | Tagged: , | 1 Comment »

      KIDNEY PHYSIOLOGY

      Posted by Dr KAMAL DEEP on November 8, 2013

      Which one of the following is the correct sequence
      in increasing order of their basal blood supply
      (ml/min/100g of tissue) – (ICS 98)
      a) Heart, brain, kidney
      b) Brain, Kidney, Heart
      c) Kidney, heart, brain
      d) Brain, Heart, Kidney

      Liver has the maximum 02 consumption (51m1
      mt)the next organ to have the maximum 0 2
      oxygen(ml/mt) is – (AIIMS 85)
      a) Heart b) Brain
      c) Skeletal muscle d) Kidney

      Capillaries with tight junctions allowing the
      passage of only small molecules are found in –
      a) Brain b) Skin (Delhi 96)
      c) Kidney d) Muscle

      Most permeable capillaries – (JIPMER 99)
      a) Post pituitary b) Liver
      c) Kidney d) Small intestine

      True about blood flow in various organs –
      a) Liver > Kidney > brain > heart (PGI 99)
      b) Liver > brain > Kidney > heart
      c) Kidney > brain > heart > . liver
      d) Liver > heart > brain > kidney

      In metabolic acidosis, true about urinary change
      is – (UPSC 83, Delhi 84)
      a) Increase in ammonia
      b) Decrease in ammonia
      c) Decrease in lactic acid
      d) HCO3

      Normal filtration fraction is — (PGI 84)
      a) 0.9 b) 0.2
      c) 0.6 d) 1.0

      Posted in Medical | 5 Comments »

      Lung Volumes

      Posted by Dr KAMAL DEEP on June 19, 2013

      image 

      Lung volumes and capacity measurements.Top left: A cartoon figure representing lung space divided into lung volumes. Dead space refers to areas where gas exchange does not occur; all other spaces are defined in the accompanying table. Top right: Spirometer recordings are shown with marked lung volumes and capacities. Table at bottom defines individual measurements and values from the top graphs. Note that residual volume, total lung capacity, and function residual capacity cannot be measure with a spirometer.[Widmaier EP, Raff H, Strang KT: Vander’s Human Physiology: The Mechanisms of Body Function, 11th ed. McGraw-Hill, 2008]

       

       

       

      image 

      Pressure-volume curves of the isolated lung, isolated chest wall, combined respiratory system, inspiratory muscles, and expiratory muscles. FRC, functional residual capacity; RV, residual volume; TLC, total lung capacity

       

       

       

       

      image

       

       

       

      image

      Flow-volume curves in different conditions: O, obstructive disease; R(P), parenchymal restrictive disease; R(E), extraparenchymal restrictive disease with limitation in inspiration and expiration. Forced expiration is plotted in all conditions; forced inspiration is shown only for the normal curve. TLC, total lung capacity; RV, residual volume. By convention, lung volume increases to the left on the abscissa. The arrow alongside the normal curve indicates the direction of expiration from TLC to RV.

       

      Questions:-

      Which tends to decrease with increasing
      age – (AIIMS 85)
      a) Vital capacity b) Systolic B.P.
      c) Pulse pressure d) Residiial volume

      All of following tend to increase in old age
      except – (Delhi 96)
      a) Residual volume b) Systolic BP
      c) Pulse pressure d) Vital capacity

      The hall mark of generalised obstructive lung
      disease is- (PGI 80, AIIMS 81)
      a) Reduced tidal volume
      b) Reduced residual volume
      c) Reduced timed vital capacity
      d) Reduced vital capacity

      For diagnosis of obstructive airway disease which
      of the following measurement is usuala)
      Vital capacity (PGI 81, UPSC 86)
      b) Timed vital capacity
      c) Tidal volume
      d) Blood gas analysis

      The hallmark of generalized obstructive disease
      is reduced (PGI 81, Delhi 84)
      a) Vital capacity
      b) Arterial 02 saturation
      c) Timed vital capacity
      d) Tidal volume

      Spirometry is useful to calculate all the except –
      a) Tidal volume b)FEV (AI 97)
      c) Residual volume d) Vital capacity

      Total vital capacity is decreased but timed vital
      capacity is normal in — (JIPMER 80, UJPSC 87)
      a) Bronchial Asthma b) Scoliosis
      c) Chronic bronchitis d) All of the above

      In diffuse pulmonary fibrosis all are decresed excepta)
      Vital capacity (AIIMS 97)
      b) Diffusion capacity
      c) Compliance
      d) Alveolar arterial 0 2 gradient

      All are seen in emphysema except – (Kerala 95)
      a) Decreased vital capacity b) Hyper inflation
      c) Rhonchi d) Damage to alveoli

      In COPD all are affected except— (A189)
      a) FEV b) Ratio of FEV to vital capacity
      c) FVC d) None

      Lung function test in emphysema reveals -(PGI 01)
      a) Increased vital capacity
      b) Decreased diffusion capacity for carbon monoxide
      c) Increased diffusion capacity for carbon monoxide
      d) Decreased total lung capacity
      e) FEV, decreased

      Which is not characterstic of interstitial lung
      diseasea)
      Decreased vital capacity
      b) Decreased total lung capacity
      c) Increased diffusion capacity of carbon
      d) All

      Vital capacity of the lung is very low in
      a) prone b) lithotomy c) trendelenberg d) supine

      All of the following differ in males and females except
      (a) Tidal volume (b) vital capacity (c) residual volume (d) Expiratory reserve volume

      Trendelenberg position produces decrease in all of the following except: AIIMS – 04
      a. Vital Capacity b. Functional residual capacity c. Compliance d. Respiratory rate

      Which is not increased in pregnancy UP. 96
      (a) vital capacity (b) blood volume (c) Extracellular fluid (d) weight

      In upper air way obstruction all of the following changes
      are seen except :
      (A) Decreased Maximum breathing capacity
      (B) RV decreased
      (C) Decreased FEV
      (D) Decreased vital capacity

      Tidal volume is calculated by
      A. Inspiratory capacity minus the inspiratory reserve .
      volume
      B. Total lung capacity minus the reserve volume
      C. Functional residual capacity minus residual
      volume
      D. Vital capacity minus expiratory reserve volumes

      A patient presents with decreased vital capacity and
      total lung volume. What is the most probable
      diagnosis ?
      A. Bronchiectasis
      B. Sarcoidosis
      C. Cystic fibrosis
      D. Asthma

      Volume of air taken into the lungs in normal
      respiration is known as – (PGI 88)
      a) Vital capacity
      b) Timed vital capacity
      c) Tidal volume
      d) Inspiratory reserve volume

      The following are acceptable as normal resultsa)
      PO, 100 mm Hg (JIPMER 79, AIIMS 85)
      b) V/Q ration 1.0
      c) Resting tidal ventilation 5L/min
      d) FEVI 60% of vital capacity

      All of the following differ in males and females
      except – (Assam 95)
      a) Tidal volume
      b) Vital capacity
      c) Residual volume
      d) Expiratory reserve volume

      Vital capacity is a measure of (Kerala 91)
      a) Total volume
      b) Inspiratory reserve volume plus expiratory reserve
      volume
      c) Tidal volume plus inspiratory reserve volume plus
      expiratory reserve volume
      d) Expiratory reserve volume plus reserve volume

      The instrument used for measuring the vital
      capacity and FEV is – (JIPMER 78, DNB 90)
      a) Wright peak flow meter
      b) Vitalograph
      c) Carlen’s catheter
      d) None of the above

      Vital capacity is – (ROHATAK 97)
      a) Tidal Volume+Expiratory Reserve Volume
      b) Tidal Volume+Inspiratory Reserve Volume
      c) I.R.V+E.R.V.
      d) T.V.+I.R.V.+E.R.V.
      e) Tidal volume

      Physiological effects of emphysma may include
      all of the following, except – (SGPGI 05)
      a) increased vital capacity
      b) Irregular ventilation
      c) Impaired gas diffuse
      d) Pulmonary hypertension

      Pulmonary function abnormalities in interstitial
      lung diseases include all of the following except –
      a) Reduced vital capacity (AIIMS NOV 05)
      b) Reduced FEV I/FVC ratio
      c) Reduced diffusion capacity
      d) Reduced total lung capacity

      A 12 year old girl presents with acute rheumatic
      fever and carditis with severe mitral insufficiency.
      She is likely to have which of the following functional
      disability ? (AIIMS Nov 07)
      a) Increased residual volume
      b) Increased PEFR
      c) Increased TLC
      d) Decreased functional residual capacity

      In cryptogenic fibrosing alveolitis which is not seena)
      Decreased lung capacity- (PGI 89)
      b) Decreased diffusing capacity
      c) Decreased arteliolar oxygen tension
      d) Decreased FEV I/FVC ratio

      Most common cause of hypoxemia is- (Kerala 2K)
      a) Lowered inspired P0 2
      b) Hypoventilation
      c) Intracardiac shunting
      d) Ventialtion perfusion mismatch
      e) Decreased diffusing capacity

      Total lung capacity depend on – (Al 98)
      a) Size of airway b) Closing tidal volume
      c) Lung compliance d) Residual volume

      True about interstitial lung disease – (PG1 :June 07)
      a) Decreased FVC
      b) Decreased FEV,
      c) Decreased diffusion capacity
      d) Presence of end inspiratory crackles

      Which pulmonary function change is not seen in
      COPD- (Al 92)
      a) Decreased Residual volume
      b) Decreased FEV
      c) Low mid expiratory flow rate
      d) Decreased diffusion capacity

      Regarding pectus Excavatum all are true except –
      a) Gross CVS dysfunction (PGI 9 7)
      b) Depression in chest
      c) Cosmetic defromity
      d) Decrease in lung capacity

      An 18 year old male presents with pectus excavatum.
      He denies history of any dyspnoea or chest pain. On
      examination there is mild pectus excavatum and
      intermittent wheezing on exertion. Surgery in this
      patient is indicated if he has – (AIIMSNov 07)
      a) FEV i/FVC less than 0.60
      b) Limiation of maximum inspiration during exercise
      c) Peak physical work capacity 60% of

      Which muscle is not punctured during a thoracic
      procedure in the mid-axillary line ? (AIIMSNov 07)
      a) Internal intercostal
      b) External intercostal
      c) Transverse thorasis
      d) Innermost intercostals

      All the following are true about Chronic Obstructive
      lung disease except
      A. Decreased FeV i
      B. Decreased MEFR
      C. Increased RV
      D. Decreased diffusion capacity

      Total lung capacity depends upon :
      (A) Size of airway
      (B) Closing volume
      (C) Lung compliance
      (D) Residual volume

      Normal functional Residual capacity is – (Al 93)
      a) 0.5 Litres b) 1.5 Litres
      c) 2.2 Litres d) 4.0 Litres

      Nitrogen washout method is used for estimatinga)
      Dead space volume (PGI 98)
      b) Functional residual capacity
      c) Tidal volume
      d) Diffusion capacity

      Posted in Medical | 3 Comments »

      ANAESTHESIOLOGY MCQs & Notes

      Posted by Dr KAMAL DEEP on April 25, 2013

      Guedels stages of anaesthesia is seen classically with
      a) Ether b) Chloroform c) Morphine d) Nitrous oxide e) halothane

      The term anasthesia was coined by
      a) Guedel b) Morton c) Claude d) Oliver Wendel Holmes.

      Intravenous Regional Anaesthesia was described by
      a) Macintosh b) Magill c) Guedel d) Bains e) Bier

      The first public demonstration of anesthesia was by
      a) John snow b) 1. W magill c) Thomas morton d) H.G. Wells

      First spinal anaesthesia was given by TN 2001
      a) August Bier b) Sicard c) Morton d) Priestly

      Ether was invented by
      a) Morton b) Priestly c) Wells d) Simpson

      Nitrous oxide was discovered by
      a) J.B.Priestly b) Humphry Davy c) I4orace wells d) P.C.Barton e) G.Q. cotton

       

      In 1937, Guedel published his classic description of the clinical signs of ether anesthesia. He used clear physical signs involving somatic muscle tone, respiratory patterns, and ocular signs to define four stages.

      In the first stage, analgesia, characterized by slow, regular breathing with the diaphragm and intercostal muscles and the presence of the lid reflex, the subject experiences complete amnesia, analgesia, and sedation.

      In the second stage (delirium), the subject experiences excitement, unconsciousness, and a dream state with uninhibited activity. Ventilation is irregular and unpredictable. Reflex dilatation of the pupils occurs, the lid reflex is intact, and the risk of clinically important reflex activity (e.g., vomiting, laryngospasm, or arrhythmias) increases.

      The third stage (surgical anesthesia) consists of four progressive planes. Plane 1 is characterized by slight somatic relaxation, regular periodic breathing, and active ocular muscles. During plane 2, breathing changes, inhalation becomes briefer than exhalation, and a slight pause separates inhalation and exhalation. The eyes become immobile. In plane 3, the abdominal muscles are completely relaxed, and diaphragmatic breathing is very prominent. The eyelid reflex is absent. In plane 4, the intercostal muscles are completely paralyzed, and paradoxic rib cage movement occurs. Breathing is irregular, and pupils are dilated.

      In Guedel’s fourth stage (respiratory paralysis), muscles become flaccid, and eyes widely dilate. Cardiovascular and respiratory arrest occurs, as does cardiovascular collapse.
      In 1954, Artusio expanded Guedel’s description of ether analgesia (stage 1) into three planes. In plane 1, the patient has no amnesia or analgesia. In plane 2, the patient has total amnesia and partial analgesia. In plane 3, the patient has complete analgesia and amnesia, but is comfortable and responsive to verbal stimulation; there is little depression of reflexes. Artusio observed that once patients were anesthetized past stage II (delirium) to the deeper anesthesia of stage III, they could be brought back and forth between stage III and plane 3 of stage II without ever exhibiting stage II. The clinical signs of depth of anesthesia defined by Guedel and others had significant practical utility for the administration of ether, cyclopropane, and chloroform anesthesia.

      ana_2_113_conduct_of_inhalational_induction-_07_t2_med

      MUSCLE RELAXANTS

      Succinyl choline is a muscle relaxant which act by
      a) persistent depolarisation b) competitive blockade c) mechanism of action uncertain d) a and b

      Muscle relaxant contra indicated in CRF

      a) Gallamine b) Succinylcholine c) Tubocurare d) Pancuronium

       

      Muscle relaxant not to be used in liver failure is PGI 88
      a) Pancuronium b) DTC c) Suxamethonium d) Decamethonium

      Decamethonium (Syncurine) is a depolarizing muscle relaxant or neuromuscular blocking agent

      Site of-action of anaesthetic muscle relaxants is PGI 88
      a) Myoneural junction b) central c) ascending reticular activating system d) Red nucleus

      Muscle relaxant most commonly implicated in malignant hyperpyrexia a) DTC b) Gallamine c) Succinylcholine d) Decamethanium

      Decamethonium (Syncurine) is a depolarizing muscle relaxant or neuromuscular blocking agent

      The muscle relaxant effect of succinylcholine last for
      a) 1 minute b) 2 minutes c) 3 to 5 minutes d) 10 minutes

      Shortest acting muscle relaxant is a) Curare b) Pancuronium c) Gallamine d) Succinylcholine

      The most effective muscle relaxant is a) Ether b) N20 c) Halothane d) Trilene

      Which of the following are antagonists of non depolarising muscle relaxants PG184
      a) Neostigmine b) Edrophoium c) Pyridostigmine d) Cyclopyronium

      To decrease awareness in general anaesthesia, the following is given PG! 89
      a) increase depth of anesthesia b) more muscle relaxant used c) promedicate with morphine d) premedicate with diazepam

      Which muscle relaxant does not cross the placental barrier in significant concentrations a) Succinyl choline b) D- tubocurare c) Gallamine d) all

      The following are muscle relaxants except
      a) Decamethonium b) Suxamethonium c) hexamethonium d) Pancuronium

      Hexamethonium is a depolarising ganglionic blocker,[1] a nicotinic nACh (NN) receptor antagonist that acts in autonomic ganglia by binding mostly in or on the NN receptor, and not the acetylcholine binding site itself. It does not have any effect on the muscarinic acetylcholine receptors (mAChR) located on target organs of the parasympathetic nervous system but acts as antagonist at the nicotinic acetylcholine receptors located in sympathetic and parasympathetic ganglia (NN)

      It was formerly used to treat disorders, such as chronic hypertension, of the peripheral nervous system, which is innervated only by the sympathetic nervous system. The non-specificity of this treatment led to discontinuing its use.[3]

      The use of inhaled hexamethonium, an unapproved drug, in a normal volunteer during a medical study is believed to have caused or contributed to her death[4][5] in light of the presence of abnormal "ground glass opacities" on her chest X-ray

      Which is not true of Non depolarising skeletal muscle relaxant
      a) causes Histamine release b) Hypothermia
      c) fasciculation of muscle d) ganglion blockade

      In children, which of the following is preferred for intubation: AIIMS 84, 85, 86
      a) Halothane b) Curare c) Muscle relaxant d) None of the above

      Muscle relaxant action of scoline is not prolonged by
      a) ethylene chloride b) chloroform c) enflurane d) halothane.

      Non-depolarising relaxants may be reversed by
      a) atropine b) succinyl choline c) neostigmine d) calcium chloride.

      Shortest acting muscle relaxant
      a) pancuronium b) Atracurium c) Mivacuriun d) Vecuronium

      Muscle relaxant in kidney failure
      a) atracurium b) pancuronium c) Gallamine d) all of the above

      In the immediate post operative period the common cause of respiratory
      insufficiency could be because of the following, EXCEPT AIIMS 2003
      a) Residual effect of muscle relaxant b) Overdose of narcotic analgesic
      c) Mild hypovalemia d) Myocardial infarction

      21 years old lady with a history of hypersensitivity to neostigmine is posted for an elective casearean section under anesthesia. The best muscle relaxant of choice in this patient should be AIIMS 04
      a) Pancuronium b) Atracurium c) Recuronium d) Vecuronium

      Shortest acting on depolarizing muscle relaxant is: SGPGI – 05
      a. Acetylcholine b. Succinylcholine c. Mivacurium d. Pancuronium

      Muscle relaxant in hepatic failure Manipal 2006
      a) Atracurium b) Gallium
      c) Tubocurarine d) Scoline

      Muscle relaxant in hepatic and renal failure Manipal 2006
      a) Atracurium b) Gallium c) Tubocurarine d) Vecuronium

      Which drug is contra indicated in myasthenia gravis Al 88
      a) Succinyl choline b) Tubocurare c) Neostigmine d) Halothane e) Cyclopropane

      Post operative aching of muscles occur with the use of a) succinyl choline b) panc’uronium c) Gallamine d) DTC

      Succinylcholine causes all except a) Muscle pain b) Malignant hyperthermia c) Hyperkalemia d) Hypokalerriia

      Which drug is totally excreted by the kidney a) Gallamine b) DTC c) Succinyl choline d) alcuronium

      Succinylcholine causes intraocular tension TN 90
      a) Decreased b) Normal c) Increased cl) Variable

      Fasciculations with succinylcholine are first seen over PGI 80, Delhi 86, 93
      a) Eyelids b) Limbs c) Neck d) Abdomen

      Uterine tetanic contraction is most rapidly treated with: AIIMS 79, BHU 87
      a) Spinal anesthesia b) Halothane c) D-tubocurarine d) Succinylcholine e) Surgical incision

      Succinyl choline is short acting due to
      a) rapid excretion b) poor absorption c) rapid hydrolysi- d) none.

      A high potassium level with succinyl choline for intubation occurs with AIIMS 99
      a) Renal failure b) Chronic paraplegia c) Fracture femur
      d) Myocardial infarction

      Psuedocholine esterase is acted upon by J&K 2001
      a) Pancuronium b) Succinyl choline c) Choline d) Atracurium

      The administration of succinylocholine to a paraplegic patient led to the
      appearance of dysarrhythmias, conduction abnormalities and finally cardiac
      arrest. The most likely cause is: AIIMS 2003
      a) Hypercalcemia b) Hyperkalemia c) Anaphylaxis d) hypermagnesemia

      Not used to the patient with penetrating eye injury Orissa 2004
      a) Pancuronium b) Succinyl choline c) d IC A:racurium

      Aggravation of myasthenia is a feature of all the
      following drugs except – (MAHE 98)
      a) Gentamic in b) Neomycin
      c) Edrophonium d) Succinyl

      Drug of choice for myaesthenia gravis – (PGI 99)
      a) Gallamine b) Succinylocholine
      c) D. tubocurare d) Pyridostigmine

      Use of succinylcholine in ECT: PGI 78, AllMS 84
      a) Safer than curare b) May cause prolongation of apnoea c) Reduces
      possibility of fractures d) All are true

      Injection of which is followed by pain Burdwan 2K
      a) Succinyl choline b) Neostigmine c)Curare d) Morphine

      A young boy undergoes eye surgery under day case
      anesthesia with succinyl choline and propofol and
      after 8 hours he starts walking and develops muscle
      pain. What is the likely cause?
      A. Early mobilization
      B. Due to the effects of eye surgery
      C. Succinyl choline
      D. Propofol

      Hyperkalemia is a dangerous complication when
      succinyl choline is given to patient with –
      a) Spinal cord injury (PGMCET 07)
      b) Head injury
      c) Thoracic trauma
      d) Abdominal trauma

      True about Pseudocholineesterase
      a) Present in neuromuscular junction
      b) Level is increased in pregnancy
      c) Succinylcholine is metabolized
      d) Organophosphorus inhibit it

      The enzyme pseudocholinesterase acts on
      a) Decamethonium b) Tubocurarine c) Galiamine d) Suxamethonium

      5 year old suffering from Duchenne muscular dystrophy has to undergo
      tendon lengthening procedure. The most appropriate anaesthetic would be: Al 2003
      a) Induction with intravenous thiopentone and N 20; and halothane for maintenance
      b) Induction with intravenous suxamethonim and N 20; and oxygen for maintenance
      c) Induction with intravenous suxamethonium and N 2 0; and halothane for maintenance
      d) Inhalation induction with inhalation halothane and N 2 0; and oxygen for maintenance

      During rapid sequence induction of anesthesia: Al 2003
      a) Sellick’s maneuver is not required b) Pre — oxygenation is mandatory
      c) Suxamethonium is contraindicated
      d) Patient is mechanically ventilated before endotracheal intubation

      Which of the following anesthetic agents doesn’t trigger malignant hyperthermia? All India 2006
      a) Halothane. b) Isoflurane. c) Suxamethonium. d) Thiopentone.
      ( Ref. : Katzung 9th Edition Page 410)

      Which of the following agents is used for the treatment of postoperative shivering? All India 2006
      a) Thiopentone. b) Suxamethonium. c) Atropine. d) Pethidine.

      Rapid termination of the action of Suxamethonium
      is due to – (MAHE 98)
      a) Rapid renal elimination
      b) Enzymatic degradation by pseudocholinesterase
      c) Metabolized by liver to acetyl CoA
      d) Redistribution

      Key Points for IV anesthetic agents:-

      Thiopental:-

      Barbiturates are almost water insoluble.

      Dose:- 3-5 mg/kg

      No analgesic action and may be antanalgesc at low doses.

      Neuroprotection.

      Transient apnoea is common.Centrlly mediated respiratory depression.Laryngeal reflexes remain intact. Larngeal spasm can occur.

      Slow recovery.

      Enzyme inducers.

      C/Ied in pophyria,status asthmaticus,severe shock,pericardial tamponade and uncompensated myocardial disease.

      Etomidate:-

      Two Isomers.

      S-isomer is anesthetic.

      Dose:- 0.3 mg/kg

      Doesn’t release histamine.

      CBF,CBM,CMRO2 and ICP fall.

      Excitatory phenomenon may be seen with induction.Premedicate with Midazolam.

      Induction agent of choice for poor risk patients with cardiorespiraory disease.

      Etomidate doesn’t blunt the sympathetic response to laryngoscopy and inubation unless combined with a potent opioid analgesic.

      The increased mortality in critically ill patients sedated with etomidate infusion due to inhibitory effect on cortisol synthesis even after a single induction dose of etomidate.

      Inspite of its side effect profile,etomidate remains a valuable induction drug for specific indications such as patients with severe cardiovascular and cerebrovascular disease.

      Etomidate is associated with high incidence of postoperative nausea and emesis when used in combination with opioids for short outpatient procedures.

       

      Propofol:-

      Highly Lipid soluble.

      1% or 2% emulsion in 10% soyabean oil with 1.2% egg phosphatide as the emulsifying agent.

      Dose:- 1-2.5 mg/kg for induction.Lower dose should be used in elderly.

      Sedation may be produced with 0.2 mg/kg bolus dose intravenously or infusion of 1 mg/kg/hr.

      Co-induction with either an opioid(3ug/kg) or midazolam(1-3 mg) enables the induction dose to be reduced.

      Rapidly and extensively metabolized.

      Clearance rate exceeds hepatic blodd flow suggesting that an extrahepatic elimination route contributes to its clearance.

      Decreases CBF,CM and CMRO2.

      Analogous to the barbiturates,Children require higher induction and maintenance doses of propofol on a milligram-per kilogram basis as a result of their larger central distribution volume and higher clearance rate.

      Elderly and patients with poor health require lower induction and maintenance doses of propofol.

      Antioxidant Potential.Free radical scavenger.Its neuroprotective effect may be partially related to this antioxidant potential of propofol’s phenol ring structure,which may act as a free radical scavenger,decreasing free-radical induced lipid perodixation.

      Propofol has been reported to inhibit phagocytosis and killing of bacteria in vitro and to reduce proliferative responses when added to lmphocytes from critically ill.

      Anti-Emetic.Nausea and vomiting very uncommon.

      Direct Myocardial Depressant.Arterial and Venodilatation without compensatory tachycardia.Arterial hypotension is more pronounced in the hypertensive patient.Alters the baroreflex resulting in smaller increase in heart rate for a given decrease in arterial pressure.? A central anticholinergic response may be responsible for bradycardia.

      Green colour of urine due to oxidation to quinol derivative.

      PROPOFOL INFUSION SYNDROME:-Identified in pediatric ICU.Metabolic acidosis,acute cardiomyopathy and skeletal myopathy associated with prolonged (>48 hrs) high dose (>5mg/kg/hr) infusion.It appears to be due to failure of FFA metabolism secondary to inhibition of both FFA entry into mitochondia and specific sites in the respiratory chain.

       

      Midazolam:-

      image

      *Propofol Half Life in minutes

      Dose:- 0.15 – 0.3 mg/kg for induction

      Sedation:- Infusion 2-5 ug/kg/min in ICU.Higher maintenance infusion rates and prolonged administration will result in accumulation and prolonged recovery times. Lower infusion rates are sufficient to provide sedation and amnesia during local and regional anesthesia

      Because of its high lipophilicity and short half-life, propofol has a rapid onset of action (1 to 2 minutes) and a short duration of action (10 to 15 minutes) compared with other sedative options. For patients receiving propofol infusions for longer than 72 hours, the wake-up time can extend to 30 to 60 minutes.

      When infused over days for chronic sedation, the mean elimination half-life of 10 hours may increase to 30 hours as peripheral tissue stores release accumulated midazolam..

      Inhibitors of CYP3A4, such as macrolide antibiotics, diltiazem, propofol, and fluconazole, reduce the metabolism of midazolam and prolong its seda-tive actions

      Co-induction with a small IV dose (1-3 mg of midazolam) allows a reduction in the dose of propofol required for induction. and adds to the hypnotic and amnesic effects.

      Two isomers-Open ring (water soluble)and closed ring(lipid-passage across BB barrier).

      Midazolam is a water-soluble benzodiazepine that is available in an acidified (pH 3.5) aqueous formulation that produces minimal local irritation after iv or im injection.25 At physiologic pH, an intramolecular rearrangement changes the physicochemical properties of midazolam such that it becomes more lipid-soluble.

      On IV injection a rise in PH changes it to closed ring form.

      Amnesic effect greater than Diazepam.

      Intranasal Midazolam more effective in terminating seizures than rectal diazepam.

      Active Metabolites.

      Low clearance.

      Short terminal elimination half life.

      Low steady state volume of distribution.

      Confusional state after prolonged infusion in ICU-COMMON

      CVS:- Stable when used in combination with opioid.

      Ketamine:-

      Dose:- 1-2 mg/kg IV for induction

      25-100 ug/kg/min for maintenance of anesthesia.

      Analgesic even at subanaesthetic doses.

      Dissociative Anaesthesia:- Muscle tone maintained

      Spontaneous respiration preserved

      Pharyngeal reflexes preserved

      Profound Analgesia and amnesia

      Eyes open.

      Involuntary movement is common

      Useful in ASTHMATIC

      UNPLEASANT EMERGENCE PHENOMENON RESTRICTS THE USEFULLNESS.

      Increases ICP

      Increases BP,HR,CO and myocardial oxygen demand.It also sensitizes the heart to small doses of epinephrine and can precipitate arrythmias.

      Posted in Medical | 8 Comments »

      Endotracheal Intubation

      Posted by Dr KAMAL DEEP on June 23, 2012

      The author wish to acknowledge the excellent guidance of Dr Kapil Chhabra, Consultant, Deptt. of Critical Care Medicine in this topic

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      Rapid Sequence Intubation

      RSI is the cornerstone of modern emergency airway management and is defined as the virtually simultaneous administration of a potent sedative (induction) agent and an NMBA, usually succinylcholine, for the purpose of endotracheal intubation. This approach provides optimal intubating conditions, while minimizing the risk of aspiration of gastric contents.

      Administration of 100% oxygen for 3 minutes of normal, tidal volume breathing in a normal, healthy adult results in the establishment of an adequate oxygen reservoir to permit 8 minutes of apnea before oxygen desaturation to less than 90% occurs.

      image

      Sample Rapid Sequence Intubation Using Etomidate and Succinylcholine
       
      Time Step
      Zero minus 10 min Preparation
      Zero minus 5 min

          Preoxygenation
          100% oxygen for 3 min or eight vital capacity breaths
      Zero minus 3 min Pretreatment as indicated “LOAD”
      Zero Paralysis with induction  
      Etomidate, 0.3 mg/kg
      Succinylcholine, 1.5 mg/kg
      Zero plus 45 sec Placement  
      Sellick’s maneuver
      Laryngoscopy and intubation
      End-tidal carbon dioxide confirmation
      Zero plus 2 min Post-intubation management  
      Midazolam 0.1 mg/kg, plus
      Pancuronium, 0.1 mg/kg, or
      Vecuronium, 0.1 mg/kg
       
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      FIGURE 1-7 The LEMON airway assessment method

      Table 1-4. Drugs Used to Facilitate Intubation
      Drug IV Dose (mg/kg) Onset of Action (sec) Side Effects
      Induction drugs
      Thiopental 2.5–4.5 20–50 Hypotension
      Propofol 1.0–2.5 <60 Pain on injection
      Hypotension
      Midazolam 0.02–0.20 30–60 Hypotension
      Ketamine 0.5–2.0 30–60 Increases in intracranial pressure
      Increase in secretions
      Emergence reactions
      Etomidate 0.2–0.3 20–50 Adrenal insufficiency
      Pain on injection
      Muscle relaxants
      Succinylcholine 1–2 45–60 Hyperkalemia
      Increased intragastric pressure
      Increased intracranial pressure
      Rocuronium 0.6–1.0 60–90 —

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      Posted in Medical | 6 Comments »

      CENTRAL NERVOUS SYSTEM II Seizures & Epilepsy

      Posted by Dr KAMAL DEEP on June 10, 2012

      A seizure (from the Latin sacire, "to take possession of") is a paroxysmal event due to abnormal excessive or synchronous neuronal activity in the brain.

      The meaning of the term seizure needs to be carefully distinguished from that of epilepsy. Epilepsy describes a condition in which a person has recurrent seizures due to a chronic, underlying process. This definition implies that a person with a single seizure, or recurrent seizures due to correctable or avoidable circumstances, does not necessarily have epilepsy. Epilepsy refers to a clinical phenomenon rather than a single disease entity, since there are many forms and causes of epilepsy.

      Todds paralysis is seen in – (NIMHANS 88)
      a) Head injury
      b) Strokes
      c) Epilepsy
      d) Subarachnoid hemorrhage

      Seen in Partial/Focal Motor Seizures.

      IMPORTANT:-Focal seizures originate within networks limited to one cerebral hemisphere (note that the term partial seizures is no longer used).

      Three additional features of focal motor seizures are worth noting:-

      1.First, in some patients the abnormal motor movements may begin in a very restricted region such as the fingers and gradually progress (over seconds to minutes) to include a larger portion of the extremity. This phenomenon, described by Hughlings Jackson and known as a "Jacksonian march," represents the spread of seizure activity over a progressively larger region of motor cortex.

      2.Second, patients may experience a localized paresis (Todd’s paralysis) for minutes to many hours in the involved region following the seizure.

      3.Third, in rare instances the seizure may continue for hours or days. This condition, termed epilepsia partialis continua, is often refractory to medical therapy.

      Tic douloureux is synonymous with- (Kerala 91)
      a) Trigeminal neuralgia
      b) Temporal lobe epilepsy
      c) Glossopharyngeal neuralgia
      d) Todds paralysis

      The most common physical sign of cerebral
      metastasis- (Karnat 98)
      a) Epilepsy
      b) Focal neurological deficit
      c) Papilloedema
      d) Visual defects

      Bano Begum, 45 year old lady has typical hand and limb movements with abnormal smell sensation. She was not able to recall any of the events afterwards.Her most probable diagnosis? (AI 02)

      a) Temporal lobe epilepsy b) Dislocation disorder
      c) Fugue d) Conversion reaction

      MOST IMPORTANT:-The range of potential clinical behaviors linked to focal seizures is so broad that extreme caution is advised before concluding that stereotypic episodes of bizarre or atypical behavior are not due to seizure activity. In such cases additional, detailed EEG studies may be helpful.

      Stereotypical :- Designating behaviour which is repeated without variation irrespective of the particular circumstances.

       

      Simple partial seizure is diagnosed by –
      a) EEG b) BEAR (NIMHANS 2K)
      c) CT scan d) MRI

      Drug of choice for simple partial seizure is -(A197)
      a) Sodium Valproate b) Carbamazepine
      c) Phenobarbitone , d) Diazepam

      Ethosuximide is used in the treatment of:
      A. Tonic-clonic seizure
      B. Absence seizure
      C. Myoclonic seizure
      D. Simple partial seizure

      The drug carbamazepine is used for all except

      a) MDP (AIIMS 97)
      b) Partial seizures
      c) Trigeminal neuralgia
      d) Migraine

      Carbamazepine (CBZ) is an anticonvulsant and mood-stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder, as well as trigeminal neuralgia. It is also used off-label for a variety of indications, including attention-deficit hyperactivity disorder (ADHD), schizophrenia, phantom limb syndrome, complex regional pain syndrome, paroxysmal extreme pain disorder, neuromyotonia, intermittent explosive disorder, borderline personality disorder and post-traumatic stress disorder.

      It has been seen as safe for pregnant women to use carbamazepine as a mood stabilizer, but, like other anticonvulsants, intrauterine exposure is associated with spina bifida and neurodevelopmental problems.

      Ethosuximide is used in the treatment of- (AI 06)
      a) Tonic-clonic seizure b) Absence seizure
      c) Myoclonic seizure d) Simple partial seizure

      Table 369-8 Selection of Antiepileptic Drugs

      Generalized-onset Tonic-Clonic Focal Typical Absence Atypical Absence, Myoclonic, Atonic
      First-Line

      Valproic acid

      Lamotrigine

      Topiramate

      Lamotrigine

      Carbamazepine

      Oxcarbazepine

      Phenytoin

      Levetiracetam

      Valproic acid

      Ethosuximide

      Valproic acid

      Lamotrigine

      Topiramate

      Alternatives

      Zonisamidea

      Phenytoin

      Carbamazepine

      Oxcarbazepine

      Phenobarbital

      Primidone

      Felbamate

      Topiramate

      Zonisamidea

      Valproic acid

      Tiagabinea

      Gabapentina

      Lacosamidea

      Phenobarbital

      Primidone

      Felbamate

      Lamotrigine

      Clonazepam

      Clonazepam

      Felbamate

       

      image

      Mesial temporal lobe epilepsy. The EEG suggested a right temporal lobe focus. Coronal high-resolution T2-weighted fast spin echo magnetic resonance image obtained through the body of the hippocampus demonstrates abnormal high-signal intensity in the right hippocampus (white arrows; compare with the normal hippocampus on the left, black arrows) consistent with mesial temporal sclerosis.

      In status epilepticus the drug of choice is –
      a) IV Phenytoin (NIMHANS 88)
      b) IV ethosuximide
      c) IV Phenobarbitone
      d) IV diazepam

      The duration of seizure activity sufficient to meet the definition of status epilepticus has traditionally been specified as 15–30 minutes. However, a more practical definition is to consider status epilepticus as a situation in which the duration of seizures prompts the acute use of anticonvulsant therapy. For GCSE, this is typically when seizures last beyond 5 minutes.

      image

      Status epilepticus is a medical emergency. Initial management includes maintenance of the airway and 50% dextrose (25–50 mL) intravenously in case hypoglycemia is responsible. If seizures continue, an intravenous bolus of lorazepam, 4 mg, is given and repeated once after 10 minutes if necessary; alternatively, 10 mg of diazepam is given intravenously over the course of 2 minutes, and the dose is repeated after 10 minutes if necessary. This is usually effective in halting seizures for a brief period but occasionally causes respiratory depression.

      Regardless of the response to lorazepam or diazepam, phenytoin (18–20 mg/kg) is given intravenously at a rate of 50 mg/min; this provides initiation of long-term seizure control. The drug is best injected directly but can also be given in saline; it precipitates, however, if injected into glucose-containing solutions. Because arrhythmias may develop during rapid administration of phenytoin, electrocardiographic monitoring is prudent. Hypotension may complicate phenytoin administration, especially if diazepam has also been given. In many countries, injectable phenytoin has been replaced by fosphenytoin, which is rapidly and completely converted to phenytoin following intravenous administration. No dosing adjustments are necessary because fosphenytoin is expressed in terms of phenytoin equivalents (PE); fosphenytoin is less likely to cause reactions at the infusion site, can be given with all common intravenous solutions, and may be administered at a faster rate (150 mg PE/min). It is also more expensive.

      If seizures continue, phenobarbital is then given in a loading dose of 10–20 mg/kg intravenously by slow or intermittent injection (50 mg/min). Respiratory depression and hypotension are common complications and should be anticipated; they may occur also with diazepam alone, although less commonly. If these measures fail, general anesthesia with ventilatory assistance and neuromuscular junction blockade may be required. Alternatively, intravenous midazolam may provide control of refractory status epilepticus; the suggested loading dose is 0.2 mg/kg, followed by 0.05–0.2 mg/kg/h.

      After status epilepticus is controlled, an oral drug program for the long-term management of seizures is started, and investigations into the cause of the disorder are pursued.

      Diazepam:-Sufficient cerebral levels are reached within one minute of a standard intravenous injection, and rectal administration produces peak levels at about 20 minutes. Diazepam is rapidly redistributed after acute administration, and thus has a relatively short duration of action. After repeated dosing, diazepam accumulates, resulting in higher peak levels, which persist. This can result in sudden and unexpected CNS depression and cardiorespiratory collapse. Diazepam is metabolised by hepatic microsomal enzymes. Respiratory depression, hypotension, and sedation are the principal side effects. Sudden apnoea can occur, especially after repeated injections or if the injection is administered at too fast a rate.

      Bolus intravenous doses of diazepam should be given in an undiluted form at a rate not exceeding 25 mg/minute, using the Diazemuls formulation

      Lorazepam:- has a lesser volume of distribution and is less lipid soluble than diazepam. Its pharmacokinetic characteristics result in a slower onset of action, but a longer duration of action. Lorazepam is indicated in the early stage of status epilepticus only, where its lack of accumulation in lipid stores, strong cerebral binding, and long duration of action due to its distribution half-life are very significant advantages over diazepam.

      Initial injections of lorazepam are effective for about 12 hours (longer than with diazepam), but repeated doses are much less effective, and the drug has no place as long-term therapy.

      Lorazepam is administered by intravenous bolus injection. As distribution is slow, the rate of injection is not critical. In adults, a bolus dose of 0.07 mg/kg (to a maximum of 4 mg) is given, and this can be repeated once after 20 minutes if no effect has been observed. In children under ten years, bolus doses of 0.1 mg/kg are recommended. Long-term infusion of lorazepam should not be used. It is usually available as a 1 ml ampoule containing 4 mg of lorazepam.

      The initial infusion of phenytoin takes 2030 minutes in an adult, and the onset of action is slow. It is therefore often administered in conjunction with a short-acting drug with a rapid onset of action, such as diazepam

      PHENYTOIN:-It is a highly effective anticonvulsant, with the particular advantage of a long duration of action.The usual phenytoin solutions have a pH of 12 and, if added to bags containing large volumes of fluid at lower than physiological pH (for example, 5% glucose), precipitation may occur in the bag or tubing; use in a solution of 0.9% sodium chloride (normal saline) (5-20 mg/ml) is safer. There is also a serious risk of precipitation if other drugs are added to the infusion solution.

      The rate of infusion of phenytoin solution should not exceed 50 mg/minute, and it is prudent to reduce this to 2030 mg/minute in the elderly. The adult dose is 1520 mg/kg; this usually amounts to about 1000 mg and therefore takes at least 20 minutes to administer. Regrettably, a common and potentially serious mistake is to give a lower dose which results in suboptimal cerebral levels.

      PHENOBARBITONE:-Phenobarbitone is a drug of choice for the treatment of established status epilepticus. It is highly effective, has a rapid onset of action, and prolonged anticonvulsant effects. It has stable and non-reactive physical properties, as well as convenient pharmacokinetics. Wide experience has been gained of its use in adults and in children, and few drugs are as well tried in the newborn. It has stronger anticonvulsant properties than most other barbiturates, and may be preferentially concentrated in metabolically active epileptic foci. As well as excellent anticonvulsant properties, it may also have cerebral-protective action. Acute tolerance to the antiepileptic effect is unusual, in contrast to the benzodiazepines and, once controlled, seizures do not tend to recur. Indeed, there is evidence to suggest that given with barbiturate anaesthesia, it can reduce the relapse rate with anaesthetic withdrawal.
      The main disadvantages of phenobarbitone are its potential to cause sedation, respiratory depression, and hypotension; although in practice these effects seem slight except at high levels or with rapidly rising levels, its safety at even high doses is well established. The well-known chronic side effects of phenobarbitone in long-term therapy are of little relevance in the emergency situation of status epilepticus. The drug is eliminated slowly and, although this is of no importance on initial phenobarbitone loading, on prolonged therapy there is a danger of accumulation and blood level monitoring is essential. In the newborn period dosing is more difficult than in adults, as the pharmacokinetics change rapidly during the first weeks and months of life. The drug has a strong tendency to autoinduction. Phenobarbitone is a stable preparation, which does not easily decompose, and the drug is not absorbed by plastic. It should not be used in a solution containing other drugs (for example, phenytoin), as this may result in precipitation.
      The usual recommended adult intravenous loading dose of phenobarbitone is 10 mg/kg (doses of up to 20 mg/kg have been used and recommended), given at a rate of 100 mg/minute (i.e. a total of about 700 mg in seven minutes). This should be followed by daily maintenance doses of 1-4 mg/kg. In neonates, initial phenobarbitone loading doses of between 12 and 20 mg/kg have been recommended to produce therapeutic levels, with subsequent supplementation of 3-4 mg/kg per day, to a maximum dose of 40 mg/kg. In older children, loading doses of between 5 and 20 mg/kg are recommended and maintenance doses of 1-4 mg/kg, although much higher doses have been safely given. After loading, maintenance doses can be given by the oral, intravenous, or intramuscular route. Phenobarbitone is usually presented in 1 ml ampoules containing 200 mg of phenobarbitone sodium.

       

       

      Which of the following is not an adverse effect of
      phenytoin – (AI 90)
      a) Gum hyperplasia
      b) Osteomalacia
      c) Gynecomastia
      d) Megaloblastic anaemia

      In epilepsy, EEG is – (Kerala 90)
      a) Diagnostic
      b) Useless in diagnosis
      c) Complimentary in diagnosis
      d) may or may not be useful

      Investigation of choice to diagnose epilepsy is –
      a) MRI b) EEG (Kerala 94)
      c) CT scan d) Angiogram

      EEG with spike and dome pattern is characteristic
      of…. Epilepsy – (AIIMS 85)
      a) Jacksonian b) Grandmal
      c) Petitmal d) Temporal lobe

      Drug of choice for psychomotor epilepsy is

      a) Valproic acid b) Carbamazepine (AIIMS 87) c) Ethosuximide d) Barbiturate
      e) Phenytoin

      Temporal lobe epilepsy was first recognized in 1881 by John Hughlings Jackson, who described "uncinate fits" seizures arising from the uncal part of temporal lobe and the "dreamy state."

      In the 1940s, Gibbs et al introduced the term psychomotor epilepsy.The international classification of epileptic seizures (1981) replaced the term psychomotor seizures with complex partial seizures. Complex means that there is some alteration of consciouness, versus a simple partial seizure, which means there is no alteration of consciouness. The ILAE classification of the epilepsies uses the term temporal lobe epilepsy and divides the etiologies into cryptogenic (presumed unidentified etiology), idiopathic (genetic), and symptomatic (cause known, eg, tumor).

      Carbamazepine (or a related drug, oxcarbazepine), lamotrigine and phenytoin are currently the drugs of choice approved for the initial treatment of focal seizures, including those that evolve into generalized seizures. Overall they have very similar efficacy, but differences in pharmacokinetics and toxicity are the main determinants for use in a given patient. For example, an advantage of carbamazepine (which is also available in an extended-release form) is that its metabolism follows first-order pharmacokinetics, and the relationship between drug dose, serum levels, and toxicity is linear. Carbamazepine can cause leukopenia, aplastic anemia, or hepatotoxicity and would therefore be contraindicated in patients with predispositions to these problems. Oxcarbazepine has the advantage of being metabolized in a way that avoids an intermediate metabolite associated with some of the side effects of carbamazepine. Oxcarbazepine also has fewer drug interactions than carbamazepine. Lamotrigine tends to be well tolerated in terms of side effects. However, patients need to be particularly vigilant about the possibility of a skin rash during the initiation of therapy. This can be extremely severe and lead to Stevens-Johnson syndrome if unrecognized and if the medication is not discontinued immediately. This risk can be reduced by slow introduction and titration.

      Psychomotor epilepsy is Temporal lobe epilepsy

      True about juvenile mycoclonic epilepsy – (PGI 03)
      a) Focal seizure
      b) Generalised seizure
      c) Myoclonus
      d) Responses to Sodium Valproate
      e) Spike and waves in EEG

      All the following are indications for brain imaging
      in epilepsy, except – (J & k 05)
      a) Epilepsy starts after the age of 5 years
      b) Seizures have focal features clinical
      c) EEG shows a focal seizure source
      d) Control of seizures is difficult

      Gustatory hallucinations are most commonly
      associated with – (Corned 08)
      a) Temporal lobe epilepsy
      b) Grand mal epilepsy
      c) Anxiety disorders
      d) Tobacco dependence

      Cause of death which is common in case of coma –
      a) Tongue falling back and obstructing airway
      b) Secretions obstructing airway (TN 03)
      c) Cardiac arrest
      d) Epilepsy

      1501. Which vitamin deficiency is most commonly seen in a pregnant mother who is on phenytion
      therapy for Epilepsy? All India 2006
      a) Vitamin B6 b) Vitamin B12 c) Vitamin A d) Folic Acid

      In Petit Mal epilepsy all findings are seen except JIPMER ’98
      a) Transient loss of conciousness b) Non specific ECG pattern
      c) No tonic-clonic phase d) Ethosuccamide is Drug of choice

      A 15 year old boy with epilepsy on treatment with
      combination of valproate and phenytoin has good
      control of seizures. Levels of both drugs are in the
      therapeutic range. All of the following adverse effects
      can be attributed to valproate except :
      A. Weight gain of 5 kg
      B. Serum alanine aminotransaminase 150 IU/L
      C. Rise in serum ammonia level by 201.tg/dL
      D. Lymphadenopathy

      Which of the following statements is incorrect in
      relation to pregnant women with epilepsy?
      A. The rate of congenital malformation is increased
      in the offspring of women with epilepsy.
      B. Seizure frequency increases in approximately
      70% of women.
      C. Breast feeding is safe with most anticonvulsants.
      D. Folic acid supplementation may reduce the risk of
      neural tube defect

      An elderly male on ventilator has received atracurium
      infusion for 3 days. He now develops epileptic fits.
      Probable cause for his epilepsy is:
      A. Allergy to drug
      B. Accumulation of Atracurium
      C. Accumulation of Laudanosine
      D. Ventilator failure

      Palatal Myoclonus is seen in – (SGPGI 05)
      a) Epilepsy
      b) Multiple sclerosis
      c) Cerebellar infarction
      d) Guillain Barre syndrome

      Deja Vu is seen in – (Kerala 94)
      a) Normal persons b) Temporal lobe epilepsy
      c) Psychosis d) All of the above

      Arun, diagnosed to have epilepsy recently and put
      on phenytoin. He was previously on
      antidepressents. He has developed fatigue and
      anorexia. His Hb=8.0; TC=7500 ; ESR=30 in first
      hour; SGOT=35; SGPT=35 and B-=0.6. the test
      for diagnosis would be – (AIDE 99)
      a) Chest x-ray b) Urine culture
      •c) MCV d) Blood culture

      All are used in treatment of epilepsy excepta)
      Ethosuximide b) Reserpine (Kerala 94)
      c) Acetazolamide d) Vigabatrine

      Carbamazepine is useful in the following
      conditions EXCEPT- (Kann 95)
      a) Grandmal epilepsy b) Petitmal epilepsy
      c) Psychomotor epilepsy d) Trigeminal neuralgia

      Which is true regarding febrile seizures- (AI 93)
      a) 50% recurrance
      b) Long term phenytoin required
      c) Interictal EEG normal
      d) Status epilepsy is common

      Hypsarrythmia in a child is due to

      a) Grandmal epilepsy (AIIMS 91, Delhi 93)
      b) Petitmal epilepsy
      c) Myoclonic epilepsy
      d) Reflex epilepsy

      All of the following are true of febrile seizures except

      a) Most commonly seen between 9 months and 5 years (AP 97)
      b) Does not last more than 10 minutes
      c) Almost invariably develop into epilepsy
      d) Prognosis is good

      WhIch of the following has the worst
      prognosis – (JIPMER 2001)
      a) Rolandic epilepsy b) Versive epilepsy
      c) Absence epilepsy d) Infantile spasm

      Which one of the following in the characteristic
      feature of juvenile myoclonic epilepsy ? (AIIMS 06)
      a) Myoclonic seizures frequently occur in morning
      b) Complete remission is common
      c) Response to anticonvulsants is poor
      d) Associated absence seizures are present in
      majority of patients

      A 18-month old baby presents with recurrent
      episodes of excessive crying followed by cyanosis,
      uncon sciousness and occassional seizures since 9
      months of age. The most likely diagnosis
      is – (UPSC 98)
      a) Epilepsy b) Anoxic spells
      c) Breath holding spells d) Vasovagal attack

      Posted in Medical | 10 Comments »

      Central Nervous System I MCQs

      Posted by Dr KAMAL DEEP on June 4, 2012

      Action potentials normally are generated by the opening of sodium channels and the inward movement of sodium ions down the intracellular concentration gradient. Depolarization of the neuronal membrane opens potassium channels, resulting in outward movement of potassium ions, repolarization, closure of the sodium channel, and hyperpolarization. Sodium or potassium channel subunit genes have long been considered candidate disease genes in inherited epilepsy syndromes, and recently such mutations were identified. These mutations appear to alter the normal gating function of these channels, increasing the inherent excitability of neuronal membranes in regions where the abnormal channels are expressed.

      All of the following are neurologic channelopathies
      except – (AI 05)
      a) Hypokalemic periodic paralysis
      b) Episodic ataxia type 1
      c) Familial hemiplegic migraine
      d) Spinocerebellar ataxia 1

      Ans is ‘d’ i.e., Sphinocerebellar Ataxia -1 [Ref Harrison 16 1"/e p. 2339 & 15’h/e p. 2321]

      All of the following are calcium channelopathies,
      except – (AIIMS May 05)
      a) Episodic ataxia -1
      b) Spinocerebellar ataxia-6
      c) Familial hemiplegic migraine
      d) Hypokalemic periodic paralysis

      Episode weakness is due to – (PG1 87)
      a) Hypokalaemia b) Dermatomyositis
      c) Paramyotonia congenita d) Myasthenia gravis
      e) Hypophosphatemia

      Cataract is associated with PGI 88
      a) Pseudo muscular hypertrophy b) myotonia congenita c) myotonic dystrophy d) SLE

      In a patient, muscle cramps on exercise, +ve
      myoglobulinemia, the disorder is – (PGI 98)
      a) Pompe’s disease b) Myotonia congenita
      c) Myotonic dystrophy d) Mc ardle’s disease

      Table 366-1 Examples of Neurologic Channelopathies


      Category Disorder Channel Type Mutated Gene Chap. Ref.
      Genetic
      Ataxias

      Episodicataxia-1

      Episodicataxia-2

      Spinocerebellar ataxia-6

      K

      Ca

      Ca

      KCNA1

      CACNL1A

      CACNL1A

      373
      Migraine

      Familial hemiplegic migraine 1

      Familial hemiplegic migraine 3

      Ca

      Na

      CACNL1A

      SCN1A

      14
      Epilepsy

      Benign neonatal familial convulsions

      Generalized epilepsy with febrile convulsions plus

      K

      Na

      KCNQ2, KCNQ3 SCN1B 369
      Periodic paralysis

      Hyperkalemic periodic paralysis

      Hypokalemic periodic paralysis

      Na

      Ca

      SCN4A

      CACNL1A3

      387
      Myotonia

      Myotonia congenita

      Paramyotonia congenita

      Cl

      Na

      CLCN1

      SCN4A

      387
      Deafness Jervell and Lange-Nielsen syndrome (deafness, prolonged QT interval, and arrhythmia) K KCNQ1, KCNE1 30
        Autosomal dominant progressive deafness K KCNQ4  
      Autoimmune
      Paraneoplastic

      Limbic encephalitis

      Acquired neuromyotonia

      Cerebellar ataxia

      Lambert-Eaton syndrome

      Kv1

      Kv1

      Ca (P/Q type)

      Ca (P/Q type)

      101

      101

      101

      101

       

      Whereas the specific clinical manifestations of channelopathies are quite variable, one common feature is that manifestations tend to be intermittent or paroxysmal, as occurs in epilepsy, migraine, ataxia, myotonia, or periodic paralysis. Exceptions are clinically progressive channel disorders such as autosomal dominant hearing impairment.

      Posted in Medical | 1 Comment »