# Pediatric Critical Care Review Hasan Pappas

1. Regarding the interaction between respirations and circulation, all of the following are true except: A. The Mueller maneuver decreases afterload B. The hemodynamic effects of changing intrathoracic pressure dominates over changing intrathoracic volume C. Hypoxic pulmonary vasoconstriction is noted when alveolar PaO2 drops to < 60 Torr D. The single most important cardiopulmonary interaction of all is the effect that ventilator induced changes in intrathoracic pressure have on right ventricular preload E. Venous return parallels transmural pressure of the right atrium Click here for answer 2. Ventricular afterload is best approximated by: A. Ventricular end-diastolic pressure B. Ventricular end-diastolic volume C. Systolic blood pressure D. Mean blood pressure E. Ventricular wall stress Click here for answer 3. Mechanism(s) operative in ventricular interdependence is/are: A. Right to left shift of the interventricular septum B. Constraint of left ventricular expansion by stretch of common ventricular myofibrils C. Restriction of left ventricular filling by the stretched pericardium D. All of the above Click here for answer 4. A true statement pertaining to cardiopulmonary interaction is: A. The cardiopulmonary interaction is of greatest clinical importance for the failing left ventricle B. In the failing heart, the effect of changes in intrathoracic pressure on preload will dominate over the effects on afterload C. In young infants with less compliant ventricles with a limited contractile reserve, positive pressure ventilation with increased intrathoracic pressure may be a detrimental D. Afterload is best approximated by left ventricle preload Click here for answer 5. Regarding the fetal circulation, all of the following statements are true except: A. The foramen ovale allows equalization of preload of the right and left ventricles B. The right ventricle ejects more highly oxygenated blood than the left ventricle since it receives the umbilical vein blood C. The right ventricle sees a low afterload D. The left ventricle sees a high afterload E. The right ventricle ejects more blood than the left ventricle due to the difference in afterload Click here for answer 6. Regarding the fetal and newborn myocardium: A. A low contractile element concentration is present in the newborn myocardium B. Because fetal heart functions at the peak of the ventricular function curve, combined ventricular output is maximum at a resting atrial pressure of 3-5 mm Hg C. Compared to the adult, the newborn heart has higher indices of myocardial performance at rest, but is unable to significantly improve ventricular performance D. Small increases in afterload decrease cardiac output more significantly in the fetus and the newborn compared to the adult, and nitroglycerin increases cardiac output more in adult compared to the newborn E. All of the above Click here for answer 7. Changes in afterload contribute to an increase in cardiac output at birth because: A. Right ventricular afterload decreases and left ventricular afterload decreases B. Right ventricular afterload decreases and left ventricular afterload increases C. Both right ventricular and left ventricular afterload increase D. Right ventricular afterload increases and left ventricular afterload decreases E. None of the above Click here for answer 8. Which one of the following contribute the most to the total peripheral resistance: A. Aorta and large arteries B. Small arteries C. Arterioles D. Capillaries Click here for answer 9. The major portion of cardiac O2 consumption is used to support: A. Myocardial wall tension B. The product of stroke volume and mean arterial pressure C. Electrical activation of the myocardium D. None of the above Click here for answer 10. Regarding myocardial O2 consumption and myocardial wall tension, which of the following situations is considered to be least efficient: A. Poor myocardial compliance B. A heart with left ventricular hypertrophy C. A dilated heart with a small preload D. A dilated heart with a large preload and a thin left ventricular wall Click here for answer 11. Ischemia of the myocardium with associated symptoms and signs is rarely seen with aortic regurgitation, but is commonly seen with aortic stenosis. The underlying pathophysiologic phenomena related to these clinical entities is/are: A. Maintaining blood pressure by increasing stroke volume rather than vasoconstriction is more O2 efficient B. The O2 cost of isometric contraction (pressure work) is much greater than isotonic contraction (volume work) C. Increasing cardiac output by afterload reduction which increases stroke volume but decreases pressure greatly improves the efficiency of the heart D. All of the above statements are true Click here for answer 12. Regarding the above diagram, which of the following statement(s) represent(s) myocardial O2 supply: A. Area A B. Area B C. Both D. Neither Click here for answer 13. Ischemic heart disease (IHD) should be sought as a diagnosis in neonates who are critically ill. Risk factors for IHD in neonates include: A. Increased intracavity pressure B. Variable aortic pressure C. Ductal run-off D. Global hypoxia and episodes of arterial desaturation E. All of the above Click here for answer 14. Which of the following statements is true regarding ischemic heart disease in critically ill neonates: A. Is almost unheard of B. Is treated with O2, positive pressure ventilation and inotropes C. Symptoms resolve in 48 hours with supportive care and the EKG and radiographic changes resolve in two weeks D. The clinical picture is that of hypoxemia, cardiomegaly, cardiogenic shock and tricuspid insufficiency E. All except A are true Click here for answer 15. Clinical situations in which myocardial ischemia and infarction are recognized in children with congenital heart disease include: A. Right ventricular infarction in total anomalous pulmonary venous drainage B. Left ventricular infarction in aortic stenosis C. Biventricular infarction in transposition of the great arteries D. All of the above E. None of the above Click here for answer 16. True statement(s) about anomalous left coronary artery include: A. By four months of age, the majority of infants will have developed a coronary fistula B. Without treatment, 80% will survive to adulthood C. There is frequently a history of cyanosis at birth D. May mimic gastroschisis E. All of the above Click here for answer 17. The leading cause of ischemic heart disease in children is: A. Kawasaki Syndrome B. Left anomalous coronary artery C. Severe aortic stenosis D. Atherosclerotic disease E. None of the above Click here for answer 18. Coronary artery involvement and cardiac abnormalities are more common in children with Kawasaki Syndrome who: A. Are female older than 8 years of age B. Have associated torus fracture C. Have had a fever less than two days D. Have an ESR of < 20 mm/hr E. None of the above Click here for answer 19. A 13-year-old male, victim of a motor vehicle accident with multiple trauma and closed head injury, is in the PICU with elevated intracranial pressure. Poor peripheral perfusion and low urine output is noted with a central venous pressure of 18 mm Hg. True statements pertaining to this patient include: A. Impaired left and right ventricular function have been reported in patient with closed head injury B. Head injury causes an enhanced autonomic response with direct sympathetic cardiac stimulation and an enhanced level of circulating catecholamines C. ST-T changes on the EKG are seen in head injury patients D. Myocardial injury is seen frequently in the setting of thoracic trauma E. All of the above Click here for answer 20. During high permeability pulmonary edema: A. The ratio of extravascular lung water to dry lung weight is decreased B. The blood-free dry weight of the lung is increased C. The dry weight of the lung is decreased D. None of the above is true Click here for answer 21. A true statement pertaining to the equation Q = K¦ (Pc-Pi) – s (P c - P i ) is which of the following: A. K¦ is the reflection co-efficient B. s is the filtration co-efficient C. When s = 1, there is no restriction to passage of protein across the capillary membrane D. When s = 0 there is absolute restriction to the passage of protein across the capillary membrane E. None of the above Click here for answer 22. Of the various causes of heart failure that produce pulmonary edema not related to congenital heart disease, anthracyclin cardiotoxicity is an important type. Factor(s) that potentiate the incidence of heart failure due to anthracyclin is/are: A. Administration of bleomycin B. Administration of cyclophosphamide C. Mediastinal radiotherapy D. All of the above E. None of the above Click here for answer 23. A 13-year-old boy with a previous history of acute lymphoblastic leukemia treated with chemotherapy including doxorubicin presents to the Pediatric ICU in florid pulmonary edema. The chest radiograph shows an enlarged heart with evidence of alveolar edema. True statements regarding this clinical scenario include all of the following except: A. Symptoms of congestive cardiac failure due to doxorubicin toxicity may appear years after the last dose of doxorubicin B. The mortality rate for this patient is at least 50-60% C. Cardiotoxicity due to doxorubicin is dose independent D. Cardiac enzyme assay and serial chest radiographs have not been useful in the prediction of cardiomyopathy E. Because anthracyclin cardiomyopathy may be reversible in children, intensive cardiac support with tracheal intubation and positive pressure ventilation may be warranted to treat an acute episode of pulmonary edema Click here for answer 24. Which of the following is not a cause of high permeability pulmonary edema: A. Salicylate intoxication B. Prolonged exposure to high FiO2 C. Anaphylaxis associated with pulmonary edema D. A combination of doxorubicin and cyclophosphamide E. Heroin overdose Click here for answer 25. Which of the following organ systems is most frequently affected by heroin overdose: A. Kidney B. Heart C. Brain D. Lung E. Skeletal muscle Click here for answer 26. Which of the following statement(s) describing pulmonary vascular tree physiology is/are true: A. Normal matching of ventilation to perfusion is achieved by local hypoxic pulmonary vasoconstriction B. Hypoxic pulmonary vasoconstriction is usually localized and reversible C. In neonates, hypoxic pulmonary vasoconstriction may persist even after the hypoxia has been corrected D. Potential anatomic shunts that are present inside the lungs can open up and may account for the cyanosis noted during conditions of elevated pulmonary pressure E. All of the above Click here for answer 27. Which of the following physiologic changes in response to hypoxia is not likely: A. Impairment of short term memory occurs at approximately PaO2 of 60 torr B. When the PaO2 falls to < 60 torr, carotid and aortic bodies are activated leading to tachycardia and hyperventilation C. Levels of 2,3 – DPG increase in 20 minutes D. Tubular re-absorption of Na+ is impaired at a low PaO2 E. PaO2 of < 40 torr produces twitching and seizures Click here for answer 28. A 2-1/2 month old baby with Tetralogy of Fallot is brought to the emergency department and subsequently to the PICU for progressively turning blue soon after waking up at 7:00 a.m. when his mother began to feed him. He became fussy, began to cry and since then has been getting progressively more cyanotic and limp. True statements regarding this clinical scenario include all of the following except: A. The onset of these symptoms in early morning and with feeding is characteristic B. The peak incidence is seen at this age C. There is a strong negative correlation between PaO2 and the incidence of attacks D. Squatting or knee-chest position redistributes systemic blood flow to the upper body, improves pulmonary blood flow but does not affect arterial oxygen saturation E. Propranolol can abort the attack and may decrease the frequency of these episodes when used chronically Click here for answer 29. Cyanosis in the face of a normal PaO2 occurs in: A. A victim of smoke inhalation B. A child overdosed on shoe dye C. A patient with a hematocrit of 75% D. All of the above Click here for answer 30. In the post-operative period, a right to left shunt helps preserve cardiac output and decreases post-operative complications in children with the following: A. Repair of Tetrology of Fallot B. Repair of truncus arteriosis C. Fontan procedure D. All of the above E. None of the above Click here for answer 31. A 6-month-old child with Down’s Syndrome who underwent repair of an atrioventricular canal defect canal was admitted to the PICU 6 hours ago. High pulmonary artery pressure is noted along with a decreased O2 saturation to the 80’s and evidence of low cardiac output. The first priority after stabilization of the patient is: A. Adjust the vent settings B. Increase FiO2 C. Obtain a chest radiograph D. Obtain an echocardiogram to rule out any residual abnormality E. None of the above Click here for answer 32. Regarding pulmonary circulation in this patient, all of the following statements are true except: A. O2 is a very strong pulmonary vasodilator after cardiopulmonary bypass B. The effect of hyperventilation on pulmonary vascular resistance is mediated by changes in pH rather than PCO2 C. Pulmonary vascular resistance increases with increasing post-operative hematocrit D. Pulmonary vascular resistance increases in the post-operative night as pulmonary artery pressure is maintained or increases, thus cardiac output decreases E. Pulmonary vascular endothelial dysfunction after cardiopulmonary bypass is common Click here for answer 33. A 5-day-old who presented with rapid onset of shock a few hours ago is found to have hyoplastic left heart syndrome and is on a Prostaglandin-E2 infusion. The patient is being mechanically ventilated. You notice that the O2 saturation on pulse oximetry is 92%. You anticipate all of the following except: A. Pulmonary congestion B. Right ventricle may suffer from diastolic overload C. Use of hyperventilation and tolazoline will improve saturation and the patient’s overall condition D. Pulmonary blood flow is increased Click here for answer 34. Regarding chylothorax, all of the following are true except: A. Malnutrition is a recognized complication B. Most frequently seen with intrapericardial procedures C. May occur without damage to the thoracic duct D. Pleural fluid may appear serosanguinous and will not clot E. Pleural effusion may develop as late as one month after surgery Click here for answer 35. Regarding treatment of chylothorax: A. Pleural drainage is required to improve ventilation and prevent atelectasis B. To decrease lymph flow, a high carbohydrate, high protein, medium chain triglyceride diet with reduced fat is recommended C. Malnutrition is an important complication D. All of the above Click here for answer 36. The indications for surgical ligation of the thoracic duct for chylothorax is/are: A. Average daily chyle loss of > 100 ml/year of the patient’s age, after five days of medical therapy B. A flow of chyle that does not diminish after two weeks C. Nutritional complications that are severe D. All of the above Click here for answer A. The modified Fontan procedure B. Stage I Norwood procedure C. Both D. Neither 37. ____ Increased pulmonary vascular resistance results in hypoxemia ____ Increased pulmonary vascular resistance results in cardiogenic shock ____ Improve(s) systemic oxygenation and reduces the obligatory diastolic overload Click here for answer 38. Which of the following statements is not true regarding fenestrated Fontan procedure: A. Maintains the systemic perfusion when pulmonary vascular resistance is elevated B. Decreases the incidence of pleural effusion C. Increases the mortality rate in patients undergoing the procedure D. Can be closed in the cardiac catheterization laboratory later during hospitalization Click here for answer 39. When an infant with transposition of the great arteries and an intact ventricular septum presents for repair at 3 months of age, the best approach is: A. Senning procedure B. Mustard procedure C. Immediate correction by arterial switch D. Pulmonary artery banding and a Blalock-Taussig shunt E. None of the above Click here for answer 40. The two issues of paramount importance after arterial switch are: A. Mustard vs Senning’s procedures B. Presence of atrial septal defect and patent ductus arteriosus C. Global performance of left ventricle and focal myocardial ischemia D. None of the above Click here for answer 41. Chylothorax is least likely to occur with repair of: A. Aortic or pulmonary valve surgery or ventricular septal defect B. Patent ductus arteriosus ligation C. Repair of coarctation D. Glenn anastomosis E. Shunt procedure (Blalock-Taussig, Waterston, Pott) Click here for answer 42. Postoperatively, patients with transposition of the great arteries undergoing arterial switch are characterized by all of the following except: A. Unrecognized left to right shunts or overzealous volume administration can precipitate sudden hemodynamic compromise B. Focal ischemia is a recognized complication C. Compromised cardiac output responds favorably to afterload reduction D. Global left ventricular systolic dysfunction is not seen E. The left ventricle is typically dilated and tolerates any further load poorly Click here for answer 43. Following a Blalock-Taussig shunt, true statements include all of the following except: A. The ipsilateral arm may be cold and pulseless for 48-72 hours B. Blalock-Taussig shunt is generally performed on the side opposite the aortic arch C. Ipsilateral pulmonary edema is a recognized complication D. Flow is determined by the size of the subclavian artery; size of the graft itself is not critical E. Diuretics should be avoided if possible Click here for answer 44. Regarding cardiac transplantation, which of the following statements is inaccurate: A. A major cause of early post-operative failure is right ventricular failure from increased pulmonary vascular resistance B. Matching is based on ABO compatibility C. Systemic hypertension is frequently seen post-operatively due to Cyclosporin-A D. Endomyocardial biopsy is the best way to diagnose rejection when done weekly post-operatively E. Ketamine will enhance myocardial function Click here for answer 45. A 5-month-old underwent repair of Tetralogy of Fallot through a ventriculotomy with a transannular patch. Central venous pressure is 10 mm Hg. Poor perfusion of the extremities is noted with low urine output. A bolus of colloid 15ml/kg is given over 20 minutes. It is noted that the central venous pressure has decreased to 7 mm Hg. This suggests that: A. Ventricular compliance has improved B. Afterload has decreased following volume expansion C. Myocardial perfusion has improved D. This clinical scenario is not possible E. A, B, and C Click here for answer 46. A 12-year-old is admitted to the Pediatric ICU with septic shock. A pulmonary artery catheter is inserted for hemodynamic monitoring. Left ventricular stroke work index was 30 g/min/m2 four hours ago. Now left ventricular stroke work index is 55 g/min/m2. This indicates that: A. Afterload has increased B. Afterload has decreased C. Contractility has improved D. None of the above Click here for answer 47. Regarding shock, the compensatory state is least likely with: A. Cardiogenic shock B. Septic shock C. Hypovolemic shock D. Obstructive shock Click here for answer A. An adolescent with extensive orthopedic injury receiving positive mechanical ventilation B. An infant with critical aortic stenosis receiving positive pressure ventilation C. Both D. Neither 48. ____ With inspiration, there is a decrease in pulse pressure without a phase lag and diastolic pressure falls ____ With inspiration, there is an increase in pulse pressure without a phase lag and diastolic pressure increases Click here for answer 49. Mechanisms responsible for pulmonary edema associated with upper airway obstruction does not include which of the following: A. Increased right ventricular afterload B. Ventricular interdependence C. Increased left ventricular afterload D. Decreased left ventricular afterload Click here for answer 50. An infant with congestive cardiac failure is admitted to the Pediatric ICU. Intermittent “grunting” is noted. True statements regarding this clinical scenario include all of the following except: A. Grunting is a form of the Valsalva maneuver B. Grunting decreases left ventricular afterload C. Grunting is a form of the Mueller maneuver D. A decrease in left ventricular preload may shift the Starling curve to a more favorable position, thus decreasing myocardial O2 consumption E. This patient is likely to benefit from inotropic drugs Click here for answer 51. Nitroprusside would be least effective for: A. Congestive heart failure due to cardiomyopathy B. Mitral regurgitation C. Ventricular septal defect with congestive cardiac failure due to significant left to right shunt D. Myocardial dysfunction following cardiopulmonary bypass E. Hypotensive anesthesia Click here for answer 52. Which of the following statements is least accurate regarding the toxicity of nitroprusside: A. Neuroexcitatory symptoms of delirium, confusion and convulsions are due to thiocyanate accumulation B. Thiocyanate tends to accumulate in patients with renal dysfunction C. Thiocyanate is not removed by either hemo or peritoneal dialysis D. Measurement of thiocyanate concentration does not have relevance to detecting cyanide toxicity E. Methemoglobin levels should be determined during prolonged infusion of nitroprusside Click here for answer 53. Match the selections listed below with their appropriate descriptions: A. Nitroprusside B. Nitroglycerin C. Both D. Neither ____ The preferred drug when treating a child with congestive cardiac failure, pulmonary edema, and marginal blood pressure ____ The preferred drug for the treatment of congestive cardiac failure induced by mitral or aortic regurgitation ____ The preferred drug for congestive cardiac failure with preserved blood pressure, because it produces a greater increase in cardiac output in this setting Click here for answer 54. Regarding volume resuscitation in shock states, which of the following is true: A. Isotonic solutions may be administered safely up to an amount equivalent to 200% of the patient’s circulating blood volume B. Hetastarch and Dextran administration should not exceed 200 ml/kg/dose because of concerns about hemostasis C. Rapid fluid resuscitation in excess of 40 ml/kg in 1 hour is associated with improved survival and no increased risk of pulmonary edema in patients with septic shock D. Plasma catecholamines increase only marginally in shock states E. None of the above Click here for answer 55. In the USA, trauma is the leading cause of death in children older than one year. The major contributor to mortality is: A. Hypovolemic shock B. Cardiogenic shock C. Septic shock D. Head injury E. Infection Click here for answer 56. In the Pediatric ICU, the major cause of cardiogenic shock is: A. Myocarditis B. Kawasaki Syndrome C. Anomalous left coronary artery D. Post-operative repair of congenital cardiac lesions E. Isoproterenol treated asthmatics Click here for answer 57. Impaired cellular metabolism occurs earliest during the clinical course of which type of shock: A. Cardiogenic shock B. Septic shock C. Hypovolemic shock D. Obstructive shock E. Anaphylactic shock Click here for answer 58. In a child who presents with a temperature of 42o C, poor peripheral circulatory status, altered mental status, and acidosis: A. Heat shock protein is released in excessive amounts B. Anhydrosis results from cellular sweat gland damage C. DIC is a recognized complication D. Riley-Day Syndrome is a possibility E. All of the above Click here for answer 59. A 14-year-old who sustained a fractured femur suddenly develops chest pain and dyspnea. Pathophysiologic changes likely leading to this clinical picture include: A. Sudden right ventricular failure leading to shock B. Pulmonary vasoconstriction and pulmonary capillary endothelial damage with resulting shock C. Massive release of vaso-active mediators from pulmonary circulation leading to circulatory failure D. Total blockage of main pulmonary artery leading to impaired venous return E. All of the above Click here for answer 60. Useful diagnostic work-ups include: A. Microscopic urinalysis B. Ventilation-perfusion scan C. Pulmonary angiography D. All of the above Click here for answer 61. Therapy for the patient referenced in Question #62 would include all except: A. Optimizing hemodynamics B. Optimizing oxygenation C. Prevention of further episodes D. Removal of emboli Click here for answer 62. Air embolism with fatal cerebral complications occurs with: A. Laceration of a large vessel following trauma B. Spinal surgery C. Cranial surgery D. All of the above Click here for answer QUESTIONS 63-65: A 12-year-old child who has had renal transplantation presents with sudden onset of acute severe abdominal pain with prostration. He has been receiving azathioprine and prednisone for the last 4 months. He is hypotensive, poorly perfused and pale with marked abdominal rigidity. No hematemesis or melena are noted. Urinalysis is unremarkable. Amylase and lipase are 850 IU/dl and 500 IU/dl respectively. 63. The most likely diagnosis is: A. Pyelonephritis B. Chronic rejection C. Pancreatic shock D. Perforated duodenal ulcer preceded by hemorrhage E. None of the above Click here for answer 64. Anticipated complications in this patient include: A. Hypercalcemia B. Hyperuricemia C. Acute respiratory distress syndrome D. Hypervolemia E. Appendicitis Click here for answer 65. Appropriate interventions in the patient would include which of the following: A. Volume restriction B. Appropriate management of hypercalcemia C. Surgical exploration D. Appropriate management of respiratory dysfunction Click here for answer 66. When managing children at risk of developing shock states, all of the following are true except: A. Urine output in children is normally 2-3 ml/kg/hr B. It is usual for oliguria to occur before the alterations in blood pressure or the development of significant tachycardia C. Central filling pressure always reflects intravascular volume accurately D. Intravascular volume expansion by as much as 30% may not alter right atrial pressure significantly E. The major determinants of cardiac filling pressure are ventricular function and compliance Click here for answer 67. A 3-year-old with a 2-day history of frequent episodes of diarrhea is admitted to the Pediatric ICU with a diagnosis of hypovolemic shock. There is no evidence of systemic infection and chest radiograph shows a normal size heart and normal lung fields. Which of the following statements regarding management of this patient is least accurate: A. It is unlikely that monitoring of central venous pressure adds significantly to careful, repeated physical exams and monitoring of urine output B. Every attempt should be made to elevate central venous pressure to the upper limit of normal (@ 10 mm Hg) C. The concept that central filling pressure always reflects intravascular volume accurately is misleading D. If this patient develops oliguria or anuria, central venous pressure monitoring becomes essential to avoid fluid overload Click here for answer 68. Regarding metabolic acidosis in the shock state, all of the following are true except: A. Base deficits > 10 mEq/l in cardiogenic and septic shock are associated with a worse outcome than a similar situation in hypovolemic shock B. Hepatic conversion of lactate or acetate to correct acidosis is impaired in most shock states C. Severe metabolic acidosis associated with organic acidemia can be treated with peritoneal dialysis D. With correction of acidosis, serious hypercalcemia and hyperkalemia may occur Click here for answer 69. Regarding hemodynamic management of shock states: A. When volume resuscitation > 50-70 ml/kg is administered in the first 4-6 hours, invasive monitoring should be considered B. In patients with acute respiratory distress syndrome, central filling pressures should be maintained at a lower levels (£ 10 mm Hg) C. In patients with increased intracranial pressure, inotropic support may be warranted before preload is fully augmented D. Application of pneumatic anti-shock garments in the field does not alter survival E. All of the above Click here for answer 70. The functional reserve of the cardiovascular system in the newborn is limited due to: A. Abundance of contractile elements in the neonatal myocardium B. Sarcoplasmic reticulum is more abundant C. Less compliant myocardium leading to increased myocardial wall stress D. Pulmonary vascular bed is minimally recruited under basal conditions Click here for answer 71. The Bezold-Jarisch Reflex refers to: A. Under basal conditions, sympathetic tone to the heart is relatively low while parasympathetic tone is dominant B. Stretching of the carotid sinus triggers a parasympathetic-efferent activity resulting in bradycardia and vasodilation C. Hypovolemia with a decreased stretching of aortic arch baroreceptors causes a sympathetic output with tachycardia and vasoconstriction D. Activation of cardiopulmonary baroreceptors localized in the atrial and ventricular wall result in vagal stimulation with bradycardia and vasodilation E. None of the above Click here for answer 72. Risk factors for infection following radial artery cannulation include: A. Insertion by surgical cut down B. Inflammation at the insertion site C. Cannulation for > 4 days D. All of the above Click here for answer 73. The most serious complication of axillary artery cannulation is: A. Thrombosis B. Distal ischemia C. Embolism D. Brachial plexus injury E. Infection Click here for answer 74. Precautions to be taken during pulmonary artery catheter insertion include all except: A. When withdrawing the catheter, always deflate the balloon by disconnecting the syringe and opening the valve to the atmosphere B. Dysrhythmias occur most commonly during insertion into the right atrium, probably due to irritation of the AV mode C. The catheter should not be advanced more than 10 cm without seeing a change in waveform after entering the right atrium D. Balloon rupture is more commonly seen in pediatric patients E. Risk of infection is minimized if the catheter is repositioned < 3 times and/or left in for < 3 days Click here for answer 75. The graph below shows various curves that represent cardiac output as measured by the thermodilution technique. Which of the following statements is most accurate: A. Curve “A” represents a patient with a ventricular septal defect B. Curve “C” is likely to give a falsely high cardiac output C. Cardiac output obtained by Curve “B” will be higher than that obtained by Curve “A” D. Curve “A” will correspond to a higher cardiac output than Curve “B” E. All of the above Click here for answer QUESTIONS 76-79: Please reference the diagram below. Loop A-B-C-D is the normal pressure volume loop of the cardiac cycle. 76. In the normal loop, the point at which the aortic valve opens is: A. Point B B. Point C C. Point A D. Point E E. Point D Click here for answer 77. An intervention is performed which results in Loop A-B1-C1-D. The most likely explanation for this change is: A. A bolus of intravenous fluid B. An increase in afterload C. An increase in contractility D. All of the above Click here for answer 78. Provided there is no change in pressure, loop A1-B-C-D1 is most likely due to: A. Increased preload B. Increased contractility D. Decreased contractility E. None of the above Click here for answer 79. Provided the contractility is unchanged, loop A2-B-C2-D2 is most likely due to: A. Increased end-diastolic pressure B. Increased afterload C. Increased contractility D. Decreased afterload E. None of the above Click here for answer Answers 1. A The Mueller maneuver (inspiration against closed glottis) increases afterload similar to phenylephrine. The valsalva maneuver has the opposite effect. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 369-380) 2. E The ventricular afterload is best approximated by ventricular wall stress, or the degree of stretching of the ventricular muscle. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 369-380) 3. D All three mechanisms described are operative in the process of ventricular interdependence. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 369-380) 4. A In the failing heart, or congestive cardiac failure, the effect of changes in intrathoracic pressure on afterload is predominant. Afterload is best approximated by ventricular wall stress. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 390-391) 5-6. B, E The right ventricle does not receive more highly oxygenated blood than the left ventricle because of the phenomenon of “streaming,” wherein the blood that is returning from the umbilical vein, through the inferior vena cava, is directed to the left atrium due to the presence of a flap in the inferior vena cava. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 17-23) 7. A After birth, due to expansion of the lungs and separation of the placenta, both right ventricular and left ventricular afterloads decrease. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 397-411) 8. C Arterioles contribute the most to the total peripheral resistance. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 409-413) 9. A The major portion of oxygen consumption by the heart is directed towards the myocardial wall tension. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 420-422) 10-11. D, D Myocardial wall tension is directly proportional to intraventricular pressure and also directly proportional to the intraventricular volume. However, myocardial wall tension is inversely proportional to the myocardial wall thickness. Therefore, in a situation where the wall of the myocardium is thin, there is an increase in myocardial wall tension, and this is likely to lead to increased myocardial oxygen consumption, since the majority of oxygen consumed by the heart is utilized by myocardial wall tension. A heart that is dilated, (which means that there is increased intraventricular volume associated with a large preload) in the presence of a thin left ventricular wall is a heart that would be considered least efficient. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 420-422) 12. B The diagram represents the following: Area A is referred to as systolic time index; and Area B is referred to as diastolic time index. Since an increase of heart rate increases myocardial oxygen consumption, tachycardia would adversely affect both of these variables, as does hypotension. Area B represents a time where the myocardium receives its blood supply and oxygen. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 420-421) 13-15. E, E, D Ischemic heart disease in infants and children should be sought whenever there are risk factors such as those mentioned in Question #13. In the presence of these risk factors, ischemic heart disease in infants in children is not uncommon. Some of the clinical situations are enumerated in Question #15. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 422-424) 16. A Eighty percent (80%) of infants with anomalous left coronary artery, if untreated, will die before their 1st birthday. There is frequently a history of screaming with feeding. History of cyanosis at birth is not a recognized feature. This condition may mimic endocardial fibroelastosis or myocarditis. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 424-425) 17. A Kawasaki Syndrome is a leading cause of ischemic heart disease in children. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 426-428) 18. E Coronary artery involvement and cardiac abnormality are more commonly seen in children with Kawasaki Syndrome, who are male, less than 1 year of age, have had a fever of longer than 2 weeks duration, and who have an ESR of more than 100 mm/hr. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 426-428) 19. E These are recognized cardiac abnormalities in a setting of trauma. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; p 431) 20. B With high permeability pulmonary edema, the ratio of extra vascular lung water to total lung weight increases, and the blood-free dry weight of the lung is increased because of the presence of protein in the extravascular fluid. The total dry weight of the lung is also increased. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 432-435) 21. E Kf is the filtration co-efficient. s is the reflection co-efficient. When s is equal to 1, there is complete restriction to passage of protein across the capillary membrane. On the other hand, when it is equal to 0, there is no restriction to passage of protein across the capillary membrane. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 432-435) 22. D Administration of bleomycin and cyclophosphamide as well as radiation therapy are known to potentiate the cardiotoxicity of anthracyclin. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 436-438) 23. C Cardiotoxicity due to doxorubicin is indeed dose-dependent and is usually seen at doses higher than 450 mg/M2. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 436-438) 24. D The combination of doxorubicin and cyclophosphamide leads to cardiomyopathy with subsequent cardiac failure, which can present with pulmonary edema. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 436-438) 25. D The lungs are the most frequently affected organs with heroin overdose. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 440-441) 26. E All of the pulmonary vascular physiologic changes listed are true. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 441-454) 27. C It will take at least 24 hours for the levels of 2,3-DPG to increase in response to hypoxia. All of the other physiologic responses to hypoxia are true. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 445-448) 28. C There does not seem to be a strong correlation between the level of PaO2 and incidence of Tet spells. All other options are true. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 454-458) 29. D Cyanosis in the face of a normal PaO2 occurs with smoke inhalation which is particularly associated with carbon monoxide poisoning. An overdose on shoe dye leads to Met hemoglobinemia. Both these clinical conditions are characterized by a normal arterial oxygen tension but a decreased measured oxygen saturation. Patients with a very high hematocrit also may present with cyanosis which is usually a peripheral cyanosis in the presence of a normal PaO2. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 456-458) 30. D All of the three conditions mentioned benefit from a right to left shunt in preserving the cardiac output. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 101-112, pp 755-763, pp 804-805) 31. D The first priority in these patients is to obtain an echocardiogram in order to rule out any residual abnormalities that might be contributing to the abnormal cardiac output and oxygenation. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 618-620) 32. A Due to pulmonary vascular endothelial dysfunction after cardiopulmonary bypass, oxygen is often not a very strong pulmonary vasodilator. With a pH greater than 7.45, it appears that the pulmonary vascular resistance decreases independent of the arterial carbon dioxide tension (PaCO2). The other options are true. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 618-620) 33. C These findings suggest that there is increased pulmonary blood flow which is likely to lead to pulmonary congestion and also a diastolic overload on the right ventricle. Use of hyperventilation and tolazoline will lead to further pulmonary congestion and may lead to deterioration of the patient’s overall condition. Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 863-868) 34-36. B, D, D Most thoracic duct injuries occur following an extrapericardial procedure, usually a palliative procedure such as a systemic to pulmonary shunt. Prior to enteral feeding, the pleural fluid may be serosanguinous. It turns into a milky color following enteral feeding. Malnutrition due to loss of protein and fat is a recognized complication which must be managed appropriately. All are indications for surgical ligation of the thoracic duct for persistent cholothorax. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 481-482) 37. B, A, A The purpose of the modified Fontan procedure, is to eliminate the obligatory diastolic overload on the single ventricle and also to improve oxygenation. Following the Norwood procedure, a systemic to pulmonary shunt is created and any situation that increases pulmonary vascular resistance leads to a decreased pulmonary blood flow, with subsequent hypoxemia. On the other hand, an increase in pulmonary vascular resistance in a patient with a modified Fontan procedure will lead to cardiogenic shock. This is due to the fact that blood flow from the right side of the heart to the lungs is gravity-dependent because of absence of a contractile right heart. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 868-874) 38. C The creation of a fenestration between the upper chambers of the heart will allow shunting of the blood from the right side to the left side of the heart in a setting of increased pulmonary vascular resistance, which in turn will maintain cardiac output. It has also been shown to decrease incidence of pleural effusion and mortality. The fenestration can be closed in a cardiac catheterization laboratory at a later date. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 881-883) 39-40. D, C To allow reconditioning of the left ventricle. Focal myocardial ischemia may occur and this may affect the left ventricular function, either focally or globally. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 825-836) 41. A Refer to Question #34. 42. D Myocardial ischemia can occur with resultant ventricular dysfunction (refer to Question #40). 43. B It is usually done on the same side as the arch or the side in which the arch descends. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; p 746) 44. E Ketamine is a myocardial depressant in a denervated heart. It is likely to depress the myocardial function in this setting. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 1563-1564) 45. E A stiff myocardium with poor myocardial compliance is a recognized problem in the post-operative period following repair of Tetralogy of Fallot. Adequate volume expansion with subsequent decrease in afterload is likely to improve myocardial perfusion and myocardial compliance. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 856-857) 46. C Left ventricular stroke work index reflects contractility. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 482-486) 47. A Compensatory mechanisms are least efficient with shock that is cardiogenic in origin. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 577-589; Perkin RM, Levin DL. Shocking Pediatric Patients; J Pediatr, 1982; 101:163) 48. A, B In a setting of myocardial dysfunction, the effects of positive pressure ventilation on afterload predominates over the effect on preload. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 390-391) 49. D An increased negative intrathoracic pressure would increase the left ventricular afterload. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 390-391) 50. C Mueller maneuver is inspiration against the partially closed glottis. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 369-380) 51. C It may increase the shunt. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; p 202) 52. C Thiocyanate is removed by dialysis. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; p 202) 53. B, A, A Nitroglycerin tends to decrease central venous pressure and pulmonary artery occlusion pressure without significantly lowering blood pressure. Therefore, it is the preferred drug in patients with marginal blood pressure. Sodium nitroprusside, on the other hand, is the preferred drug for patients who have a preserved blood pressure. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 202-205) 54-57. C, A, D, B In the US, trauma is the leading cause of death in children beyond infancy. Shock is the major contributor to mortality in these cases. Cases of hypovolemic shock can be successfully treated with crystalloid solutions when sufficient volumes are administered. It has been shown that replacement of up to 50% of the total blood volume of the patient with crystalloids is not associated significant expansion of the interstital space. Fluid administration equivalent to 200% of blood volume will result in edema fluid accumulation particularly if administered rapidly. Metastarch is available as 6% solution in 0.9 saline. Therapeutically it is equivalent to albumin but the cost is much less. The administration should not exceed 10-20 mi/kg/day because of the concern about derangement in hemostasis. Carcillo, et al (JAMA 1991) found that fluid resuscitation rapidly in excess of 40 mi/kg in the first hour was associated with improved survival in children with septic shock. The risk of pulmonary edema was not increased. Plasma catecholamines are significantly elevated in shock states and impaired cellular metabolism occurs early with septic shock. (Carcillo JA, Davis AL, Zoritsky A. Role of Early Fluid Resuscitation in Pediatric Septic Shock. JAMA 1991; 266:1242; Martex AJ, et al. The High Oncotic Pressure of Dextran. Arch Surg, 1970; 101:421; Hauser CJ, et al. Volume Therapy – Treatment of Hypovolemia. Hosp Physician, 1980; 16:38) 58. E 59-62. E, D, D, D Fat embolism is a recognized complication of any orthopedic procedure and fracture. It also occurs in sickle cell disease. The treatment is supportive. Microscopic urine analysis may reveal fat globules. Removal of these emboli are not technically possible. Air embolism is in the clinical setting referred to in the question. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 224-225) 63-65. C, C, D This is a patient with acute hemorrhagic pancreatitis. Potential complications are hypocalcemia, hyperglycemia, ARDS, and septic shock. Appropriate interventions would include volume resuscitation, management of the hypocalcemia, and appropriate management of the respiratory dysfunction. Surgical exploration is not indicated at this time. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 1175-1178) 66-69. C, B, D, E In a patient with a pure hypovolemia and in the absence of any other complications such as infection or myocardial dysfunction, a careful repeated physical examination and monitoring of the peripheral perfusion and urine output is usually adequate for fluid management. However, if the patient’s condition becomes complicated then central venous catheter insertion for monitoring should be a consideration. Hypokalemia and hypocalcemia may develop following vigorous correction of metabolic acidosis. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 588-597) 70. C The newborn myocardium is indeed less compliant and this leads to increased myocardial wall stress with increased myocardial oxygen consumption. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 18-26) 71. D Nerve fibers representing baroceptors located in the atrial and ventricular wall primarily in the distribution of left coronary artery mediate this reflux. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; p 513) 72-73. D, C Self explanatory. 74-75. B, C Dysrhythmias are more often seen during catheter insertion into the right ventricle and include PVC and ventricular tachycardia. Cardiac output is inversely proportional to the area under the curve. Prolonging the upstroke/downstroke of the curve leads to false elevation of the area under the curve, which would lead to false under estimation of the cardiac output. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 481-488) 76-79. B, A, B, B Point B is end-diastolic volume. B-C is an isovolemic contraction; aortic valve opens at Point C. C-D is the period of systole; a fluid bolus increases end diastolic volume (B-B1). Increased contractility leads to a lower end systolic volume (A-A1). Increased afterload is associated with higher systolic pressure (C2-D2) but smaller stroke volume. (Nichols DG, et al. Critical Heart Disease in Infants and Children. Mosby, 1995; pp 25-32)