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ABEM ACCM practice questions

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Question 1Cardiovascular Disorders

Which hemodynamic profile best defines cardiogenic shock in a patient whose volume status has already been optimized?

  1. Cardiac index below 2.2 L/min/m² with a wedge pressure below 8 mm Hg and flat neck veins
  2. Cardiac index below 2.2 L/min/m² with wedge pressure above 15 mm Hg Correct answer.
  3. Elevated cardiac index with a mixed venous oxygen saturation above 75%
  4. Cardiac index above 4.0 L/min/m² with low systemic vascular resistance

Explanation

Cardiogenic shock is defined by a low cardiac index (generally under 2.2 L/min/m²) together with elevated filling pressures (wedge pressure above 15 mm Hg) once volume status has been optimized. The combination identifies pump failure rather than hypovolemia or vasodilation as the cause of hypoperfusion.

Question 2Cardiovascular Disorders

Which finding is an absolute contraindication to fibrinolytic therapy in acute ST-elevation myocardial infarction?

  1. Age of 74 years
  2. ST-segment elevation in two contiguous leads
  3. Any prior intracranial hemorrhage Correct answer.
  4. Blood pressure of 158/94 mm Hg

Explanation

A history of intracranial hemorrhage at any time is an absolute contraindication to fibrinolysis because of the risk of catastrophic intracranial bleeding. Advanced age and moderate hypertension are relative considerations at most and do not by themselves preclude reperfusion therapy.

Question 3Cardiovascular Disorders

A patient with acute decompensated heart failure is dyspneic, hypertensive, and has diffuse pulmonary crackles and frothy sputum. Which initial therapy is most appropriate?

  1. Nitroglycerin infusion plus noninvasive ventilation Correct answer.
  2. Emergent pericardiocentesis with catheter drainage
  3. Intravenous furosemide alone with strict fluid restriction and no ventilatory support
  4. Rapid infusion of 2 L of crystalloid

Explanation

Hypertensive acute pulmonary edema is driven by elevated filling pressures and afterload, so intravenous nitroglycerin combined with noninvasive positive-pressure ventilation reduces both, improves oxygenation, and lowers work of breathing. Diuretics are adjunctive and should not delay vasodilator and ventilatory support.

Question 4Cardiovascular Disorders

Which echocardiographic finding is most consistent with cardiac tamponade?

  1. Global left ventricular hypokinesis with a reduced ejection fraction
  2. Severe mitral regurgitation from a flail leaflet
  3. Right ventricular diastolic collapse Correct answer.
  4. A left ventricular outflow tract gradient above 30 mm Hg

Explanation

Tamponade physiology produces diastolic compression of the right-sided chambers, along with a dilated, non-collapsing inferior vena cava from elevated pericardial pressure. Left ventricular dysfunction or isolated valvular lesions do not produce these findings.

Question 5Cardiovascular Disorders

A patient with a wide-complex tachycardia at 190 beats/min has a blood pressure of 78/40 mm Hg and is confused and diaphoretic. What is the most appropriate immediate management?

  1. Carotid sinus massage and Valsalva maneuvers
  2. Procainamide infusion at 20 mg/min
  3. Immediate synchronized cardioversion Correct answer.
  4. Adenosine 6 mg rapid IV push

Explanation

Any tachyarrhythmia with a pulse that causes hypotension, altered mentation, or shock should be treated with immediate synchronized cardioversion. Pharmacologic or vagal maneuvers are reserved for patients who are hemodynamically stable.

Question 6Cardiovascular Disorders

For a comatose patient resuscitated from out-of-hospital cardiac arrest, which post-arrest measure best improves the chance of neurologically intact survival?

  1. Routine hyperventilation to a PaCO2 of 25 mm Hg
  2. Targeted temperature management with fever avoidance Correct answer.
  3. Prophylactic broad-spectrum antibiotics for one week
  4. Immediate extubation and early mobilization

Explanation

Guidelines recommend targeted temperature management, generally in the 32 to 37.5 °C range, with active avoidance of fever in comatose survivors of cardiac arrest. Hyperthermia and hyperventilation both worsen secondary neurologic injury.

Question 7Cardiovascular Disorders

A patient with sudden tearing chest pain has a blood pressure of 190/110 mm Hg, and imaging shows a dissection involving the ascending aorta. Which initial pharmacologic strategy is correct?

  1. Norepinephrine infusion to raise systemic vascular resistance
  2. Systemic thrombolysis with tenecteplase
  3. Intravenous hydralazine titrated to a diastolic pressure below 60 mm Hg
  4. Beta-blockade to a heart rate near 60, then a vasodilator Correct answer.

Explanation

In acute type A dissection the immediate goal is to reduce aortic wall stress, so beta-blockade is given first to lower heart rate and dP/dt, followed by a vasodilator to control systolic pressure. Vasodilator monotherapy can provoke reflex tachycardia and increase shear forces.

Question 8Cardiovascular Disorders

Which finding best supports the use of systemic thrombolysis in acute pulmonary embolism?

  1. Hypoxemia requiring 4 L/min of nasal cannula
  2. Right ventricular to left ventricular ratio of 1.1 with normal vital signs
  3. Saddle embolus on CT in a normotensive patient with normal troponin
  4. Persistent hypotension despite fluid resuscitation Correct answer.

Explanation

Systemic thrombolysis is indicated for high-risk pulmonary embolism with sustained hypotension or shock after initial resuscitation. Normotensive patients with right ventricular strain are intermediate-risk and are generally managed with anticoagulation and close monitoring.

Question 9Cardiovascular Disorders

A patient with known Wolff-Parkinson-White syndrome presents with an irregular wide-complex tachycardia at 200 beats/min and a blood pressure of 132/84 mm Hg. Which therapy is most appropriate?

  1. Intravenous adenosine
  2. Intravenous diltiazem
  3. Intravenous digoxin
  4. Intravenous procainamide Correct answer.

Explanation

Pre-excited atrial fibrillation should be treated with a drug that slows conduction in the accessory pathway, such as procainamide; unstable patients require immediate cardioversion. Atrioventricular nodal blockers are dangerous because they can enhance antegrade conduction over the pathway and precipitate ventricular fibrillation.

Question 10Cardiovascular Disorders

A patient with aortic dissection develops acute severe aortic regurgitation and cardiogenic shock while awaiting surgery. Which intervention is contraindicated?

  1. Sodium nitroprusside with invasive arterial monitoring
  2. Immediate cardiothoracic surgical consultation
  3. Intra-aortic balloon pump counterpulsation Correct answer.
  4. Esmolol infusion titrated to heart rate

Explanation

Intra-aortic balloon counterpulsation augments diastolic aortic pressure and thereby increases the regurgitant fraction in acute severe aortic regurgitation, worsening forward flow. Afterload reduction and emergent surgical repair are the appropriate priorities.

Question 11Cardiovascular Disorders

Which measure best predicts fluid responsiveness in a patient with septic shock who is deeply sedated and mechanically ventilated in a controlled mode?

  1. Central venous pressure of 8 mm Hg
  2. A single inferior vena cava diameter measurement
  3. Pulse pressure variation above 13% Correct answer.
  4. Hourly urine output trending upward

Explanation

Dynamic indices such as pulse pressure variation above 13% during controlled mechanical ventilation predict fluid responsiveness far better than static pressures or a single caval measurement. These indices depend on heart-lung interaction and become unreliable with spontaneous breathing, arrhythmias, or low tidal volumes.

Question 12Cardiovascular Disorders

A patient taking digoxin presents with nausea and visual disturbance, a heart rate of 40 beats/min, and a potassium of 6.2 mEq/L. Which therapy is most specific?

  1. Intravenous calcium chloride bolus
  2. Emergent hemodialysis with a high-flux filter
  3. Digoxin-specific Fab fragments Correct answer.
  4. Amiodarone infusion at 1 mg/min

Explanation

Digoxin-specific antibody fragments bind and neutralize digoxin and are the definitive therapy for life-threatening toxicity, including malignant arrhythmias and hyperkalemia. Calcium administration is traditionally avoided in digoxin toxicity, and the drug is not effectively removed by dialysis because of its large volume of distribution.

Question 13Cardiovascular Disorders

A patient remains bradycardic at 38 beats/min and hypotensive after a large metoprolol overdose despite atropine and transcutaneous pacing. Which therapy is most appropriate?

  1. Flumazenil bolus followed by a continuous infusion
  2. Sodium bicarbonate 1 mEq/kg boluses
  3. High-dose insulin with glucose plus glucagon Correct answer.
  4. Naloxone bolus followed by infusion

Explanation

Beta-blocker poisoning refractory to atropine and pacing is treated with high-dose insulin euglycemia therapy together with glucagon, which enhance myocardial carbohydrate uptake and cyclic AMP generation respectively. Vasopressors and pacing remain supportive measures.

Question 14Cardiovascular Disorders

A patient in cardiogenic shock has a cardiac index of 1.7 L/min/m², wedge pressure of 22 mm Hg, high systemic vascular resistance, and central venous oxygen saturation of 48%. Which explanation best accounts for the low venous oxygen saturation?

  1. Oxygen delivery that exceeds systemic oxygen consumption
  2. Cyanide toxicity from prolonged nitroprusside
  3. Arteriovenous shunting from early sepsis
  4. Cardiac output inadequate for the prevailing oxygen demand Correct answer.

Explanation

A low mixed or central venous oxygen saturation in the presence of a low cardiac index and high filling pressures indicates that oxygen delivery is insufficient for metabolic demand, the hallmark of cardiogenic shock. A high-output state with low saturation instead suggests increased demand or shunting.

Question 15Cardiovascular Disorders

Which statement describes a recognized limitation of peripheral venoarterial extracorporeal membrane oxygenation in cardiogenic shock?

  1. It requires a median sternotomy for cannulation
  2. It is limited to femoral arterial cannulation
  3. It raises left ventricular afterload Correct answer.
  4. It cannot provide gas exchange

Explanation

Peripheral venoarterial ECMO returns blood retrogradely into the aorta, which increases left ventricular afterload; without venting this can cause left ventricular distension, pulmonary edema, and impaired recovery. The circuit does provide gas exchange and can be placed percutaneously at several sites.

Question 16Cardiovascular Disorders

A patient with Staphylococcus aureus endocarditis has a 1.8 cm mitral vegetation and new moderate-to-severe heart failure. Which is the best next step?

  1. Urgent surgical consultation for valve replacement Correct answer.
  2. Repeat echocardiography in one week
  3. Complete the planned 6-week antibiotic course before surgical evaluation
  4. Add gentamicin for synergy

Explanation

Heart failure and large vegetations are established indications for early surgery in infective endocarditis, and delaying operation until antibiotics are finished increases mortality. Management should involve urgent multidisciplinary evaluation rather than watchful waiting.

Question 17Cardiovascular Disorders

A patient with severe aortic stenosis (valve area 0.6 cm²) becomes hypotensive at 82/50 mm Hg with a rising lactate after receiving intravenous nitroglycerin for chest pain. The lungs are clear. Which is the most appropriate next step?

  1. Continue nitroglycerin at a lower dose and add furosemide
  2. Stop the vasodilator and support preload and vascular tone Correct answer.
  3. Start dobutamine to increase output across the fixed orifice
  4. Begin esmolol to slow the heart rate and improve filling

Explanation

In severe aortic stenosis the fixed obstruction makes stroke volume dependent on preload and systemic vascular resistance, so vasodilators can cause abrupt hypotension and coronary hypoperfusion. Management is to restore preload and vascular tone while arranging urgent valve replacement.

Question 18Cardiovascular Disorders

A patient on peripheral femorofemoral venoarterial ECMO has a well-perfused lower body, but the right arm is mottled and the right radial arterial PaO2 is 55 mm Hg while the post-oxygenator PaO2 is 400 mm Hg. Which mechanism best explains this?

  1. Recirculation of oxygenated blood within the ECMO circuit
  2. Native ejection of deoxygenated blood into the aortic arch Correct answer.
  3. Cannula malposition with near-complete drainage failure
  4. Oxygenator failure with a rising transmembrane pressure gradient

Explanation

When the native left ventricle resumes ejecting, poorly oxygenated blood entering the aortic root can supply the coronary and brachiocephalic circulation while ECMO flow perfuses the descending aorta, producing upper-body hypoxemia known as north-south or Harlequin syndrome. Improving native lung function, increasing ECMO flow, or revising cannulation addresses the problem.

Question 19Cardiovascular Disorders

A mechanically ventilated patient with a large pericardial effusion has no measurable pulsus paradoxus but remains hypotensive with a central venous pressure of 20 mm Hg. Which is the best interpretation?

  1. The absence of pulsus paradoxus confirms hypovolemia instead
  2. Pulsus paradoxus is reliable only in spontaneously breathing patients without lung disease
  3. Positive-pressure ventilation can blunt pulsus paradoxus; obtain echocardiography Correct answer.
  4. Tamponade is excluded because pulsus paradoxus is absent

Explanation

Positive-pressure ventilation, along with severe obstructive lung disease, right ventricular hypertrophy, or right heart failure, can attenuate or abolish pulsus paradoxus, so its absence never excludes tamponade. Echocardiography with Doppler and chamber-collapse assessment is required to confirm the diagnosis.

Question 20Cardiovascular Disorders

A patient with acute severe mitral regurgitation from papillary muscle rupture is in shock with a blood pressure of 78/45 mm Hg and a wedge pressure of 30 mm Hg while awaiting surgery. Which intervention best reduces the regurgitant fraction?

  1. Esmolol infusion to slow the heart rate
  2. Rapid crystalloid loading to raise left ventricular filling pressure
  3. Phenylephrine infusion to raise systemic vascular resistance
  4. Intra-aortic balloon pump counterpulsation Correct answer.

Explanation

In acute severe mitral regurgitation, lowering left ventricular afterload reduces the regurgitant fraction and increases forward stroke volume, and intra-aortic balloon counterpulsation accomplishes this while improving coronary perfusion. Definitive treatment remains urgent surgical repair or replacement.

Question 21Thoracic and Respiratory Disorders

A 24-year-old man is brought in after a motorcycle crash. He is anxious and hypotensive with distended neck veins, absent breath sounds on the right, and hyperresonance to percussion. What is the most appropriate immediate intervention?

  1. Immediate needle decompression followed by tube thoracostomy Correct answer.
  2. Rapid sequence intubation and positive-pressure ventilation
  3. Pericardiocentesis in the emergency department
  4. Chest radiograph to confirm the diagnosis before any procedure

Explanation

Tension pneumothorax is a clinical diagnosis, and decompression must never wait for imaging in an unstable patient. Needle or finger decompression relieves the obstructive shock and is followed by tube thoracostomy. Positive-pressure ventilation without decompression worsens intrathoracic pressure and can precipitate arrest.

Question 22Thoracic and Respiratory Disorders

In a patient with acute severe asthma, which finding is a sign of impending respiratory arrest?

  1. PaCO2 of 32 mm Hg
  2. Respiratory rate of 30 breaths per minute
  3. A quiet chest with minimal air movement Correct answer.
  4. Prolonged expiratory phase with diffuse wheezing

Explanation

A silent chest means airflow is so limited that wheezing can no longer be generated, which signals impending respiratory failure. Tachypnea and a low PaCO2 reflect early hyperventilation, and a rising or normalizing PaCO2 is the later ominous trend.

Question 23Thoracic and Respiratory Disorders

A 68-year-old man with a COPD exacerbation has a pH of 7.28, PaCO2 of 68 mm Hg, and PaO2 of 55 mm Hg while receiving supplemental oxygen. What is the best next step?

  1. Nebulized bronchodilators alone
  2. Immediate endotracheal intubation and mechanical ventilation
  3. Noninvasive positive-pressure ventilation Correct answer.
  4. High-flow nasal oxygen at 60% FiO2

Explanation

Acute hypercapnic respiratory acidosis in a COPD exacerbation is a strong indication for noninvasive ventilation, which reduces intubation and mortality. The pH below 7.35 with hypercapnia identifies the patients who benefit most. Intubation is reserved for failure of NIV or contraindications such as altered mentation or hemodynamic instability.

Question 24Thoracic and Respiratory Disorders

Which initial tidal volume strategy is recommended for mechanical ventilation in ARDS?

  1. 12 mL/kg of predicted body weight
  2. 10 mL/kg of actual body weight
  3. 6 mL/kg of predicted body weight Correct answer.
  4. 8 mL/kg of actual body weight

Explanation

Lung-protective ventilation in ARDS targets 4 to 8 mL/kg of predicted body weight, starting near 6 mL/kg and keeping plateau pressure at or below 30 cm H2O. Predicted body weight based on height is used because actual weight overestimates lung size. This strategy reduces mortality and ventilator-induced lung injury.

Question 25Thoracic and Respiratory Disorders

A 55-year-old woman presents with sudden dyspnea and hypotension (blood pressure 78/50 mm Hg). Bedside echocardiography shows a dilated, hypokinetic right ventricle. What is the most appropriate management?

  1. Rapid infusion of 2 L of crystalloid
  2. CT pulmonary angiography before any treatment
  3. Intravenous furosemide for right heart failure
  4. Urgent reperfusion with a thrombolytic agent Correct answer.

Explanation

Hemodynamic instability plus right ventricular dysfunction defines high-risk pulmonary embolism, which warrants emergent reperfusion, typically systemic thrombolysis when no contraindication exists. Imaging must not delay treatment in an unstable patient. Large fluid boluses can further distend the failing right ventricle and worsen shock.

Question 26Thoracic and Respiratory Disorders

A patient is coughing up large volumes of blood with worsening hypoxemia. Which action is the immediate priority?

  1. Endotracheal intubation with the bleeding side down Correct answer.
  2. Immediate rigid bronchoscopy with suctioning
  3. Upright positioning with nebulized racemic epinephrine
  4. Emergent CT angiography before airway control

Explanation

Massive hemoptysis kills through asphyxiation, so securing the airway takes precedence over diagnosis. Intubating with the bleeding lung in the dependent position protects the unaffected lung from blood, and bronchoscopy or angiography follows once the airway is controlled.

Question 27Thoracic and Respiratory Disorders

A patient with flail chest and an underlying pulmonary contusion is hemodynamically stable. Which intervention most improves outcome?

  1. Prophylactic broad-spectrum antibiotics
  2. Immediate operative fixation of all fractured ribs
  3. Prolonged paralysis and high tidal volume ventilation
  4. Multimodal analgesia and early pulmonary hygiene Correct answer.

Explanation

Outcomes in flail chest and contusion depend on pain control, clearance of secretions, early mobilization, and noninvasive ventilatory support when needed. Rib fixation is reserved for selected patients with failure to wean or severe deformity. Antibiotics are not given prophylactically because they do not prevent pneumonia.

Question 28Thoracic and Respiratory Disorders

A patient on volume-control ventilation suddenly develops a peak airway pressure of 45 cm H2O and a plateau pressure of 32 cm H2O, up from a plateau of 20 cm H2O. What is the most likely cause?

  1. Bronchospasm from inadequate bronchodilator therapy
  2. Pneumothorax with reduced lung compliance Correct answer.
  3. Partial obstruction from the patient biting the tube
  4. Retained secretions in the large airways

Explanation

Peak pressure reflects resistance plus compliance, whereas plateau pressure reflects alveolar pressure alone. A simultaneous rise in peak and plateau pressure indicates reduced compliance, as seen with pneumothorax, worsening ARDS, abdominal distension, or mainstem intubation. An isolated peak pressure rise points instead to increased airway resistance.

Question 29Thoracic and Respiratory Disorders

Which finding classifies pleural fluid as an exudate by Light's criteria?

  1. Pleural fluid protein to serum protein ratio of 0.6 Correct answer.
  2. Pleural fluid white blood cell count of 200 cells per microliter
  3. Pleural fluid glucose of 80 mg/dL
  4. Pleural fluid pH of 7.45

Explanation

Light's criteria identify an exudate when the pleural-to-serum protein ratio exceeds 0.5, the pleural-to-serum lactate dehydrogenase ratio exceeds 0.6, or the pleural lactate dehydrogenase exceeds two-thirds of the upper normal serum value. A protein ratio of 0.6 meets the first criterion. Glucose, pH, and cell count help characterize an effusion but are not part of the classification.

Question 30Thoracic and Respiratory Disorders

Which condition typically produces type 2 (hypercapnic) respiratory failure?

  1. Idiopathic pulmonary fibrosis
  2. Severe iron-deficiency anemia
  3. Myasthenia gravis Correct answer.
  4. Acute pulmonary embolism

Explanation

Type 2 respiratory failure results from alveolar hypoventilation, which occurs when the respiratory pump fails, as in neuromuscular disease. Pulmonary embolism, fibrosis, and anemia impair oxygenation and typically cause type 1 failure with a normal or low PaCO2.

Question 31Thoracic and Respiratory Disorders

A patient with pneumonia has acute hypoxemic respiratory failure, a respiratory rate of 30 breaths per minute, and an SpO2 of 88% on a 10 L/min reservoir mask, with normal PaCO2 and stable hemodynamics. Which is the preferred initial support?

  1. Venturi mask at 40% inspired oxygen
  2. High-flow nasal cannula oxygen Correct answer.
  3. Simple face mask at 5 L/min
  4. Immediate endotracheal intubation

Explanation

High-flow nasal cannula delivers a high, stable FiO2 with a modest positive pressure effect and is first-line support for acute hypoxemic respiratory failure without hypercapnia. It reduces the need for intubation compared with conventional oxygen. Escalation to noninvasive ventilation or intubation occurs if the work of breathing or oxygenation fails to improve.

Question 32Thoracic and Respiratory Disorders

A fire victim has hoarseness, singed nasal hairs, and carbonaceous sputum. What is the most appropriate next step?

  1. Observation with repeat examination in 6 hours
  2. Nebulized albuterol alone
  3. Early endotracheal intubation Correct answer.
  4. Nasal cannula oxygen at 2 L/min and discharge

Explanation

Hoarseness, facial burns, and carbonaceous sputum indicate inhalation injury with progressive airway edema that can rapidly make intubation impossible. The airway should be secured early, before swelling worsens. Observation and discharge are unsafe in this setting.

Question 33Thoracic and Respiratory Disorders

What is the most appropriate initial management of aspiration pneumonitis in a patient with a witnessed aspiration and new hypoxemia?

  1. Immediate broad-spectrum intravenous antibiotics for 7 days
  2. Supportive oxygen therapy with airway protection Correct answer.
  3. High-dose intravenous corticosteroids
  4. Prophylactic tube thoracostomy

Explanation

Chemical aspiration pneumonitis is managed supportively with oxygen, airway protection, and lung-protective ventilation if needed. Antibiotics are not indicated at onset because the injury is chemical; they are reserved for patients who later develop infection. Corticosteroids have not been shown to improve outcomes.

Question 34Thoracic and Respiratory Disorders

A mechanically ventilated patient with COPD becomes hypotensive. Peak pressure is 40 cm H2O, plateau 25 cm H2O, and the flow-time curve shows expiratory flow that does not return to zero before the next breath. What is the best immediate action?

  1. Add extrinsic positive end-expiratory pressure
  2. Disconnect the circuit and allow full exhalation Correct answer.
  3. Increase the tidal volume to overcome resistance
  4. Increase the respiratory rate to improve minute ventilation

Explanation

Failure of expiratory flow to reach zero indicates air trapping and auto-PEEP, which raises intrathoracic pressure and impairs venous return, causing hypotension. Disconnecting the circuit allows complete exhalation and rapid hemodynamic improvement. The ventilator rate and inspiratory time are then reduced and airflow obstruction is treated.

Question 35Thoracic and Respiratory Disorders

A hemodynamically stable patient has a pulmonary embolism with right ventricular strain on echocardiography and normal blood pressure. What is the most appropriate management?

  1. Placement of an inferior vena cava filter
  2. Systemic thrombolysis for all patients with right ventricular strain
  3. Emergent surgical pulmonary embolectomy
  4. Anticoagulation with rescue reperfusion if instability develops Correct answer.

Explanation

Right ventricular strain with normal blood pressure defines intermediate-risk pulmonary embolism, for which anticoagulation is standard and routine thrombolysis is not recommended. Reperfusion is reserved for hemodynamic deterioration. IVC filters are limited to patients who cannot be anticoagulated.

Question 36Thoracic and Respiratory Disorders

A patient with pneumonia has a loculated parapneumonic effusion with pleural fluid pH 7.0, glucose 30 mg/dL, and lactate dehydrogenase 900 U/L. What is the best management?

  1. Tube thoracostomy drainage plus antibiotics Correct answer.
  2. Antibiotics alone with repeat imaging in 72 hours
  3. Intrapleural fibrinolytics without drainage
  4. Repeat thoracentesis without drainage

Explanation

A low pleural pH, low glucose, and high lactate dehydrogenase identify a complicated parapneumonic effusion that requires pleural drainage in addition to antibiotics. Delay leads to loculation and empyema. Fibrinolytics are considered as adjuncts when drainage is inadequate, not as a substitute for drainage.

Question 37Thoracic and Respiratory Disorders

What oxygen saturation target is recommended for a patient with COPD and chronic hypercapnia who is receiving supplemental oxygen?

  1. Above 98%
  2. 94% to 98%
  3. 88% to 92% Correct answer.
  4. 95% to 100%

Explanation

Oxygen is titrated to an SpO2 of 88% to 92% in patients with COPD at risk for hypercapnia, which meets oxygenation needs while limiting worsening CO2 retention. Higher saturations increase the risk of hyperoxia-related hypercapnia. Oxygen is still given when hypoxemia is present; the target is simply lower.

Question 38Thoracic and Respiratory Disorders

A patient with myasthenic crisis has worsening weakness and shallow breathing. Which finding best indicates that intubation is needed?

  1. SpO2 of 94% on 2 L/min
  2. PaO2 of 60 mm Hg on room air
  3. Respiratory rate of 24 breaths per minute
  4. Vital capacity of 12 mL/kg Correct answer.

Explanation

A vital capacity below roughly 15 to 20 mL/kg, a negative inspiratory force weaker than about -20 to -25 cm H2O, or a rising PaCO2 signals impending ventilatory failure in neuromuscular disease. Oxygenation is preserved until late, so gas exchange measures are insensitive early indicators. Waiting for hypoxemia risks sudden decompensation.

Question 39Thoracic and Respiratory Disorders

Which condition makes permissive hypercapnia hazardous?

  1. Status asthmaticus with severe dynamic air trapping
  2. COPD exacerbation with auto-PEEP
  3. Raised intracranial pressure from head trauma Correct answer.
  4. ARDS with a plateau pressure of 28 cm H2O

Explanation

Permissive hypercapnia causes cerebral vasodilation and raises intracranial pressure, so it is avoided in acute brain injury. It is generally tolerated in severe asthma, ARDS, and COPD when needed to respect lung-protective pressure limits.

Question 40Thoracic and Respiratory Disorders

A patient with a chest tube placed for traumatic hemothorax drains 1600 mL of blood immediately and remains hypotensive. What is the best next step?

  1. Continued observation with serial hemoglobin
  2. Emergent operative thoracotomy Correct answer.
  3. Repeat chest radiograph before any decision
  4. Clamping the chest tube to slow the output

Explanation

Immediate drainage of more than 1500 mL of blood, or ongoing loss of more than 200 mL per hour for 2 to 4 hours, indicates continued intrathoracic hemorrhage and is an indication for thoracotomy. Clamping the tube allows blood and air to accumulate, producing tension physiology.

Question 41Abdominal and Gastrointestinal Disorders

A 48-year-old man presents with severe epigastric pain radiating to the back, nausea, and vomiting. Serum lipase is six times the upper limit of normal. Which diagnosis is most likely?

  1. Acute cholecystitis
  2. Acute pancreatitis Correct answer.
  3. Mesenteric ischemia
  4. Perforated duodenal ulcer

Explanation

Acute pancreatitis is diagnosed when at least two of three criteria are present: characteristic epigastric pain, serum lipase or amylase greater than three times the upper limit of normal, and imaging consistent with pancreatitis. This patient meets the first two criteria.

Question 42Abdominal and Gastrointestinal Disorders

Which imaging study is the preferred initial test for suspected acute cholecystitis?

  1. Hepatobiliary iminodiacetic acid scan
  2. Contrast-enhanced CT of the abdomen
  3. Right upper quadrant ultrasonography Correct answer.
  4. Magnetic resonance cholangiopancreatography

Explanation

Right upper quadrant ultrasonography is the preferred initial imaging test for acute cholecystitis because it is rapid, portable, and highly sensitive for gallstones, gallbladder wall thickening, and pericholecystic fluid. CT is reserved for equivocal cases or suspected complications.

Question 43Abdominal and Gastrointestinal Disorders

A patient with cholangitis and septic shock remains hypotensive despite fluids and antibiotics. Which intervention is most urgently indicated?

  1. Laparoscopic cholecystectomy
  2. Endoscopic biliary drainage Correct answer.
  3. Diagnostic magnetic resonance cholangiopancreatography
  4. Percutaneous cholecystostomy

Explanation

In acute cholangitis with septic shock, urgent source control by endoscopic biliary drainage is indicated and should not be delayed for surgery or further imaging. Antibiotics and resuscitation alone are insufficient when the biliary tree is obstructed.

Question 44Abdominal and Gastrointestinal Disorders

Which is the most common cause of small bowel obstruction in a patient with prior abdominal surgery?

  1. Incarcerated hernia
  2. Crohn disease stricture
  3. Postoperative adhesions Correct answer.
  4. Small bowel malignancy

Explanation

Postoperative adhesions are the most common cause of small bowel obstruction in adults, especially those with prior abdominal surgery. Hernia is the second most common cause overall and is more likely in a patient without prior surgery.

Question 45Abdominal and Gastrointestinal Disorders

An upright chest radiograph in a patient with sudden severe epigastric pain shows a crescent of air beneath the diaphragm. What does this finding indicate?

  1. Perforation of a hollow viscus Correct answer.
  2. Pneumatosis intestinalis
  3. Gastric outlet obstruction
  4. Acute pancreatitis

Explanation

Free subdiaphragmatic air on an upright radiograph indicates pneumoperitoneum, most often from perforation of a hollow viscus such as a peptic ulcer. It is an indication for urgent surgical evaluation.

Question 46Abdominal and Gastrointestinal Disorders

Which test is most appropriate to confirm suspected Clostridioides difficile infection in a hospitalized patient with watery diarrhea?

  1. Colonoscopy with biopsy
  2. Stool nucleic acid amplification testing Correct answer.
  3. Stool culture for C. difficile
  4. Serum lactate dehydrogenase

Explanation

Stool nucleic acid amplification testing detects toxigenic C. difficile and is the preferred confirmatory test in symptomatic patients. Stool culture is slower and less practical, and colonoscopy is not required for diagnosis.

Question 47Abdominal and Gastrointestinal Disorders

A 72-year-old with atrial fibrillation has sudden severe abdominal pain out of proportion to examination and an elevated lactate. Which artery is most commonly occluded in this condition?

  1. Internal iliac artery
  2. Superior mesenteric artery Correct answer.
  3. Inferior mesenteric artery
  4. Celiac trunk

Explanation

The superior mesenteric artery supplies most of the small bowel and is the most common site of acute arterial mesenteric ischemia. Emboli from atrial fibrillation frequently lodge distal to the origin of the middle colic artery.

Question 48Abdominal and Gastrointestinal Disorders

Which computed tomography finding in acute mesenteric ischemia most strongly suggests transmural bowel infarction?

  1. Pneumatosis intestinalis Correct answer.
  2. Bowel wall thickening
  3. Mesenteric fat stranding
  4. Target sign of the bowel wall

Explanation

Pneumatosis intestinalis, especially with portal venous gas, indicates gas within the bowel wall and strongly suggests transmural infarction requiring urgent surgery. Wall thickening and fat stranding are nonspecific and may occur earlier in ischemia.

Question 49Abdominal and Gastrointestinal Disorders

A patient with cirrhosis and ascites has fever and abdominal pain. Ascitic fluid analysis shows 450 polymorphonuclear cells per microliter. Which treatment is indicated?

  1. Oral vancomycin
  2. Intravenous cefotaxime Correct answer.
  3. Intravenous acyclovir
  4. Observation without antibiotics

Explanation

Spontaneous bacterial peritonitis is diagnosed when the ascitic fluid polymorphonuclear cell count is at least 250 cells per microliter. Third-generation cephalosporins such as cefotaxime are first-line therapy.

Question 50Abdominal and Gastrointestinal Disorders

A patient with cirrhosis and hepatic encephalopathy develops confusion after a gastrointestinal bleed. Which medication is the first-line treatment?

  1. Rifaximin alone
  2. Flumazenil
  3. Lactulose Correct answer.
  4. Neomycin

Explanation

Lactulose is first-line therapy for hepatic encephalopathy because it acidifies the colon and traps ammonia. Rifaximin is typically added for secondary prophylaxis rather than used as initial monotherapy.