• Question 1: • A patient with a known hypertrophic cardiomyopathy and dynamic left ventricular outflow tract obstruction is intubated for community-acquired pneumonia Urine output is minimal, with no response to a fluid bolus The patient is tachycardic with HR of 120/min and BP of 118/74 mm Hg Which of the following therapies is most appropriate as part of the treatment? A)Furosemide B)Enalaprilat C)Metoprolol D)Nitroglycerin E)Nicardipine • Correct Answer: C • Rationale Therapy for hypertrophic cardiomyopathy is directed at the dynamic left ventricular outflow tract obstruction The obstruction causes an increase in left ventricular systolic pressure, which leads to a complex interplay of abnormalities that decrease cardiac output In the intensive care setting, this condition often deteriorates with volume depletion, and with the institution of inotropic agents In that circumstance, the infusion of fluids and the discontinuation of inotropic agents is the initial therapy A beta-blocker should also be added; however, if hypotension is present, a vasoconstrictor such as phenylephrine should be administered first Acute onset of atrial fibrillation may result in severe hemodynamic compromise due to the loss of atrial contractions Prompt cardioversion should occur in this circumstance • The first-line approach to the relief of symptoms is to block the effects of catecholamines that exacerbate the outflow tract obstruction, and to slow that heart rate to enhance diastolic feeling Beta-blockers are generally the initial choice to accomplish these goals Verapamil, the calcium channel blocker, can also be used Sudden death has been reported in patients with severe pulmonary hypertension and severe outflow obstruction who are given verapamil This drug should be given with caution in patients with this combination of findings Nitroglycerin would decrease cardiac filling and is problematic • Question 2: • A 5-day-old infant presents to the emergency department with RR of 84/min, oxygen saturation of 88%, HR of 170/min, and BP of 55/20 mm Hg Physical examination findings are notable for severe retractions; cool, mottled extremities with weak peripheral pulses; and lethargy After intubation, establishment of peripheral IV access, and an initial bolus of 20 mL/kg of normal saline, the patient has not improved Laboratory values are as follows: sodium, 144 mEq/L; potassium, 5.0 mEq/L; chloride, 105 mEq/L; carbon dioxide, 13 mEq/L; blood urea nitrogen, 35 mg/dL; creatinine, 1.2 mg/dL; glucose, 105 mg/dL; ionized calcium, 4.7 mg/dL; lactate, mmol/L In addition to providing broad-spectrum antibiotics and fluid, the most appropriate next step in resuscitation is: A)Dopamine to start at µg/kg/min B)Prostaglandin infusion C)Milrinone D)Calcium gluconate, 100-mg/kg bolus E)Cardiology consultation • Correct Answer: B • Rationale Neonatal shock has a broad differential diagnosis Infection, congenital heart disease, arrhythmia, and inborn errors of metabolism can all present with shock Much as with pediatric and adult shock patients, the initial minutes of the resuscitation are spent establishing means to stabilize the patient and supporting intravascular volume For the neonate with evidence of poor cardiac output, ductal dependent congenital heart disease must be considered Current recommendations include the initiation of prostaglandin infusion to maintain ductal patency until the diagnosis of congenital heart disease can be excluded If the patient does not improve with fluids and prostaglandins, a dopamine infusion is the next step While neonates are more dependent on extracellular calcium for myocardial contractility than adults, this child has a normal ionized calcium level and would not benefit from higher levels Pulmonary hypertension is frequently seen in septic neonates and can be treated with inhaled nitric oxide, but this is not the next appropriate step for this patient • Question 3: • Which of the following measures would result in an immediate increase in right ventricular stroke volume? • A)Exhalation during positive pressure ventilation • B)Relief of inferior vena cava compression • C)Relief of intra-abdominal pressure • D)Sustained right lateral decubitus positioning • E)Sustaining a Valsalva maneuver while sitting • Correct Answer: A • Rationale It has long been recognized that positive airway pressure in lung inflation can have distinct effects on heart loading conditions and performance Other direct and indirect effects on the heart have been suspected as well Sustained increased intrathoracic pressure produces a net decrease in venous return and a decrease in stroke volume and cardiac output This clinical effect needs to be differentiated from the dynamic immediate effects of intrathoracic pressure variations Lung inflation with positive airway pressure may have dynamic effects on myocardial contractile status that can have rapid onset, even during a single breath Positive-pressure inspiration, inferior vena cava constriction, and release of abdominal compression have all been reported to decrease right ventricular (RV) inflow RV inflow is increased with positive pressure expiration, the release of inspiratory hold, the constriction of the inferior vena cava, and abdominal compression Decrease of the RV end flow during positive pressure inspiration and vena cava constriction transiently decreases RV end-diastolic volume and increases the transseptal pressure gradient, causing the septum to shift to the right • Correct Answer: D • Rationale Severe burn injury results in the massive release of catecholamines, which doubles the metabolic rate in burns covering more than 40% total body surface area The hypermetabolic state is associated with an elevated temperature, tachycardia, tachypnea, and profound weight loss despite appropriate enteral nutrition The white blood cell count is elevated for several days after injury and subsequently drops precipitously and is not an indicator of infection The hypermetabolic state persists for years after injury Wound sepsis does not occur within 24 hours of injury The patient has appropriate urine output, vital signs, and laboratory results, making hypovolemia or hypervolemia unlikely While missed injuries occur, they so at a low rate of about 4%—a rate that is much less common than the well-characterized hypermetabolism of thermal injury • Question 146: • A 73-year-old woman is admitted to the ICU after a motor vehicle collision in which she sustained fractures of her femur and hip She has a history of angina and documented 2-vessel coronary artery disease managed medically She has no underlying pulmonary disease Three days later she undergoes surgery for her fractures, and after returning from the operating room is noted to be hypotensive (78/50 mm Hg), cyanotic (SaO2 of 80% on room air), and tachycardic (112/min) A pulmonary artery catheter is inserted revealing the pulmonary artery/pulmonary artery occlusion pressure tracing shown in the Figure Cardiac output is 2.4 L/min, cardiac index is 1.5 L/min/m2, right atrial pressure is 21 mm Hg, pulmonary artery pressure is 38/26/29 mm Hg, and pulmonary artery occlusion pressure is 14 mm Hg Based on the clinical and hemodynamic data, which of the following best explains the hypotension and hypoxemia? A)Acute pulmonary or fat embolism B)Postoperative hemorrhage C)Right ventricular infarction D)Abdominal compartment syndrome E)Thoracic compartment syndrome • Correct Answer: A • Rationale The patient is hypotensive and has a very low cardiac output The key findings are a very high right atrial pressure that is greater than the pulmonary artery occlusion pressure (PAOP) and a large pulmonary artery end-diastolic pressure–PAOP gradient, indicating high pulmonary vascular resistance This picture indicates acute right heart failure due to increased pulmonary vascular resistance (The fact that there is only a modest increase in the pulmonary artery pressure may be explained by the very low cardiac output) Acute pulmonary thromboembolism or fat embolism could produce this picture A right ventricle infarction can result in a low cardiac output, with the right atrial pressure higher than the PAOP, and severe hypoxemia due to a patent foramen ovale and low SvO2 However, with a right ventricular infarct, this marked increase in pulmonary vascular resistance would not be expected Abdominal compartment syndrome may produce hypotension, low cardiac output and index but a low right atrial pressure from impeded venous return Thoracic compartment syndrome generally produces similar findings with impeded venous return but has equalized right atrial, pulmonary artery, and pulmonary artery occlusion pressures due to the uniformly distributed increase in intrathoracic pressure • Question 147: • A patient is brought to the ICU after ingesting cocaine by the nasal route He is agitated, with BP of 190/110 mm Hg, HR of 120/min, RR of 20/min, and temperature of 39°C (102.1°F) Which of the following interventions would be most appropriate for this patient? A)IV propranolol by infusion B)IV lorazepam C)Activated charcoal via nasogastric tube D)Intramuscular haloperidol E)Clonidine by transdermal patch • Correct Answer: B • Rationale The first line of treatment for agitation in acute cocaine intoxication is benzodiazepines, which should be delivered by an IV route Haloperidol, which can lower seizure threshold, should be avoided An ECG should be obtained to evaluate for potential myocardial ischemia Fluids should be administered in light of the tachycardia, hyperthermia, and excessive muscular activity with agitation, which predisposes to the development of rhabdomyolysis Cocaine is rapidly absorbed from all mucosal surfaces and activated charcoal is unlikely to have any benefit after the first hour following ingestion Significant hypertension associated with cocaine intoxication often responds to control of agitation For sustained hypertension, an agent with alpha- and betablocking activity (such as labetalol) is preferred Use of a relatively selective beta-blocker (such as metoprolol) alone may result in unopposed alpha-adrenergic-mediated vasoconstriction and worsening of hypertension • Question 148: • A 50-year-old man is transferred to the ICU after rescue from a house fire On exam, he is unresponsive and comatose Arterial blood gas results on 10-L nasal cannula oxygen are as follows: pH, 7.16; PaCO2, 30 mm Hg; PaO2, 214 mm Hg The most important next step in management is to: A)Check the arterial blood gas carboxyhemoglobin level B)Place the patient on a 100% nonrebreather mask C)Transfer the patient to a hyperbaric chamber D)Intubate and ventilate the patient with 100% FIO2 E)Treat the patient with IV sodium bicarbonate • Correct Answer: D • Rationale The patient is presenting with severe carbon monoxide poisoning Carbon monoxide poisoning is a major cause of death following smoke inhalation The correct answer is D, intubation and ventilation The patient is comatose and unresponsive and thus immediate intervention must include securing the airway Options A, C, and E a e all p o a l i di ated i the patie t’s t eat e t pla but should follow intubation Option B would be the correct initial management if the patient did not have severe altered mental status or impending respiratory failure requiring intubation • Question 149: • A 50-year-old man is transferred to the ICU after rescue from a house fire On exam, he is confused and tachypneic with RR of 38/min Carbon monoxide poisoning is associated with increased minute ventilation via which of the following mechanisms? A)Increased dead space ventilation B)Shift of hemoglobin dissociation curve C)Induction of systemic lactic acidosis D)Decreased pulmonary capillary exchange of carbon dioxide E)Increased tissue oxygen content • Correct Answer: C • Rationale Carbon monoxide rapidly diffuses across the pulmonary capillary membrane and has more than 200 times greater affinity for binding to hemoglobin than does oxygen Once bound, carbon monoxide impairs the ability of hemoglobin to offload bound oxygen and thus impairs tissue oxygen delivery, rather than increasing it (option E) This impaired delivery can lead to anaerobic metabolism and severe lactic acidosis This metabolic acidosis triggers compensatory hyperventilation, and thus the answer is C The shift of the hemoglobin dissociation curve in option B does occur, but does not trigger significant hyperventilation Options A and D are incorrect as they have nothing to with carbon monoxide intoxication • Question 150: • You are consulted by the emergency department for a 50-year-old man brought by ambulance after exposure to an office fire He has previous medical history of chronic alcohol abuse, cigarette smoking, hypertension, and diabetes mellitus He is asymptomatic and physical exam reveals no signs of burn injury Arterial blood gas (ABG) results on room air show pH of 7.37, PaCO2 of 50 mm Hg, and a PaO2 of 78 mm Hg Carboxyhemoglobin level is 10% • Which of the following is the most appropriate next step in management? A)Discharge the patient to home after completion of emergency department evaluation B)Admit to a floor bed on 100% nonrebreather with repeat carboxyhemoglobin in 24 hours C)Admit to the ICU on a 100% nonrebreather with serial carboxyhemoglobin levels D)Intubate and oxygenate with 100% oxygen; admit to ICU with serial carboxyhemoglobin levels E)Intubate and ventilate the patient with 100% oxygen; transfer urgently for hyperbaric oxygen therapy • Correct Answer: A • Rationale The patient is being evaluated for possible carbon monoxide poisoning given exposure to smoke inhalation Carboxyhemoglobin level is 10% on arterial blood gas studies A normal carboxyhemoglobin level in a nonsmoker is less than 5%; however, cigarette smokers can have a baseline carboxyhemoglobin level of 10%- % Gi e the patie t’s histo of s oki g a d negative workup, he can be safely discharged home after a thorough evaluation