Cardiothoracic Surgery US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Cardiothoracic Surgery. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Cardiothoracic Surgery US Medical PG Question 1: A 27-year-old male arrives in the emergency department with a stab wound over the precordial chest wall. The patient is in distress and is cold, sweaty, and pale. Initial physical examination is significant for muffled heart sounds, distended neck veins, and a 3 cm stab wound near the left sternal border. Breath sounds are present bilaterally without evidence of tracheal deviation. Which of the following additional findings would be expected on further evaluation?
- A. Decrease in central venous pressure by 5 mmHg with inspiration
- B. 15 mmHg decrease in systolic blood pressure with inspiration (Correct Answer)
- C. Decrease in the patient's heart rate by 15 beats per minute with inspiration
- D. Steadily decreasing heart rate to 60 beats per minute
- E. Elevated blood pressure to 170/110
Cardiothoracic Surgery Explanation: ***15 mmHg decrease in systolic blood pressure with inspiration***
- The constellation of muffled heart sounds, distended neck veins, and hypotension (implied by cold, sweaty, and pale appearance) following a precordial stab wound points to **cardiac tamponade**, an acutely life-threatening condition.
- A significant drop in systolic blood pressure (>10 mmHg) during inspiration, known as **pulsus paradoxus**, is a classic sign of cardiac tamponade as the increased venous return to the right heart during inspiration bows the interventricular septum, impinging on left ventricular filling.
*Decrease in central venous pressure by 5 mmHg with inspiration*
- In cardiac tamponade, the **central venous pressure (CVP) is typically elevated** and would not decrease significantly with inspiration due to impaired right ventricular filling.
- The elevated CVP contributes to the observed **distended neck veins**.
*Decrease in the patient's heart rate by 15 beats per minute with inspiration*
- In cardiac tamponade, the body attempts to compensate for reduced cardiac output with **reflex tachycardia**, so a decrease in heart rate is unexpected.
- Heart rate usually remains elevated or variable as the heart struggles to maintain perfusion.
*Steadily decreasing heart rate to 60 beats per minute*
- A steadily decreasing heart rate to 60 bpm (bradycardia) is contrary to the expected physiological response of **tachycardia** in cardiac tamponade as the body compensates for hypoperfusion.
- Bradycardia in this context would indicate severe decompensation and imminent cardiac arrest rather than a compensatory mechanism.
*Elevated blood pressure to 170/110*
- This patient is in **obstructive shock** due to cardiac tamponade; therefore, their blood pressure would be **hypotensive**, not hypertensive.
- **Hypotension** is a key component of Beck's triad (muffled heart sounds, distended neck veins, hypotension) which strongly suggests cardiac tamponade.
Cardiothoracic Surgery US Medical PG Question 2: A 64-year-old woman is brought to the emergency department 1 hour after the onset of acute shortness of breath and chest pain. The chest pain is retrosternal in nature and does not radiate. She feels nauseated but has not vomited. She has type 2 diabetes mellitus, hypertension, and chronic kidney disease. Current medications include insulin, aspirin, metoprolol, and hydrochlorothiazide. She is pale and diaphoretic. Her temperature is 37°C (98°F), pulse is 136/min, and blood pressure is 80/60 mm Hg. Examination shows jugular venous distention and absence of a radial pulse during inspiration. Crackles are heard at the lung bases bilaterally. Cardiac examination shows distant heart sounds. Laboratory studies show:
Hemoglobin 8.3 g/dL
Serum
Glucose 313 mg/dL
Urea nitrogen 130 mg/dL
Creatinine 6.0 mg/dL
Which of the following is the most appropriate next step in management?
- A. Furosemide therapy
- B. Pericardiocentesis (Correct Answer)
- C. Aspirin therapy
- D. Hemodialysis
- E. Norepinephrine infusion
Cardiothoracic Surgery Explanation: ***Pericardiocentesis***
* The patient presents with classic signs of **cardiac tamponade**, including **Beck's triad** (hypotension, jugular venous distension, distant heart sounds), **pulsus paradoxus** (absence of radial pulse during inspiration), and acute onset of shortness of breath and chest pain.
* Given her history of **chronic kidney disease** and elevated urea/creatinine levels, uremic pericarditis is a likely cause, leading to significant pericardial effusion and tamponade. **Pericardiocentesis** is the definitive treatment to relieve pressure on the heart.
*Furosemide therapy*
* While **crackles** suggest pulmonary congestion, this patient is severely hypotensive with signs of cardiogenic shock due to tamponade. Administering a diuretic like **furosemide** would further reduce preload, worsening her already compromised cardiac output and hypotension.
* The primary issue is extrinsic compression of the heart by pericardial fluid, not left ventricular failure responsive to diuresis.
*Aspirin therapy*
* The patient's chest pain and other symptoms could potentially point to an acute coronary syndrome, which would warrant **aspirin**. However, her profound hypotension and clear signs of cardiac tamponade (Beck's triad, pulsus paradoxus) make **cardiac tamponade** the more immediate and life-threatening concern.
* Addressing the tamponade takes priority as its hemodynamic compromise is more acute and direct.
*Hemodialysis*
* The patient has severe **acute-on-chronic kidney disease** and likely **uremic pericarditis**. While **hemodialysis** is indicated for uremia, it is not the immediate life-saving intervention for **cardiac tamponade**.
* **Pericardiocentesis** is required first to stabilize her hemodynamics; hemodialysis can be performed afterward to address the underlying uremia.
*Norepinephrine infusion*
* **Norepinephrine** is a powerful vasopressor that would increase systemic vascular resistance and blood pressure. While the patient is hypotensive, the underlying cause is **cardiac tamponade**, which mechanically obstructs cardiac filling and output.
* **Vasopressors** alone will not resolve the mechanical obstruction and may even increase myocardial oxygen demand without increasing cardiac output, potentially worsening the situation. The tamponade must be relieved first.
Cardiothoracic Surgery US Medical PG Question 3: A 32-year-old man is brought to the emergency department 10 minutes after he sustained a stab wound to the left chest just below the clavicle. On arrival, he is hypotensive with rapid and shallow breathing and appears anxious and agitated. He is intubated and mechanically ventilated. Infusion of 0.9% saline is begun. Five minutes later, his pulse is 137/min and blood pressure is 84/47 mm Hg. Examination shows a 3-cm single stab wound to the left chest at the 4th intercostal space at the midclavicular line without active external bleeding. Cardiovascular examination shows muffled heart sounds and jugular venous distention. Breath sounds are normal bilaterally. Further evaluation of this patient is most likely to show which of the following findings?
- A. Inward collapse of part of the chest with inspiration
- B. Subcutaneous crepitus on palpation of the chest wall
- C. Cough productive of frank blood
- D. Lateral shift of the trachea toward the right side
- E. A 15 mm Hg decrease in systolic blood pressure during inspiration (Correct Answer)
Cardiothoracic Surgery Explanation: ***A 15 mm Hg decrease in systolic blood pressure during inspiration***
- The patient's presentation with **hypotension**, **tachycardia**, **muffled heart sounds**, and **jugular venous distention** following a chest stab wound is characteristic of **cardiac tamponade**, a component of **Beck's triad**.
- **Pulsus paradoxus**, defined as an inspiratory drop in systolic blood pressure greater than 10 mmHg, is a classic finding in cardiac tamponade due to increased right ventricular filling and bowing of the interventricular septum into the left ventricle during inspiration.
*Inward collapse of part of the chest with inspiration*
- This finding, known as a **flail chest**, occurs when three or more adjacent ribs are fractured in two or more places, leading to a segment of the chest wall paradoxically moving inward with inspiration.
- While it indicates significant chest trauma, it doesn't align with the present signs of **cardiac tamponade**, which is primarily a pericardial issue.
*Subcutaneous crepitus on palpation of the chest wall*
- **Subcutaneous crepitus** suggests the presence of air in the subcutaneous tissues, typically from a **pneumothorax** or **ruptured bronchus**.
- Although possible with chest trauma, the patient's normal breath sounds bilaterally and the specific symptoms pointing to cardiac tamponade make this a less likely primary finding compared to pulsus paradoxus.
*Cough productive of frank blood*
- **Hemoptysis** (coughing up blood) is indicative of airway or lung parenchymal injury, such as a **tracheobronchial tear** or **pulmonary contusion**.
- This symptom does not directly explain the classic triad of cardiac tamponade (hypotension, muffled heart sounds, JVD) observed in this patient.
*Lateral shift of the trachea toward the right side*
- A **tracheal shift** to the contralateral side is a hallmark sign of a **tension pneumothorax**, where air accumulates in the pleural space, compressing the lung and mediastinum.
- The patient's breath sounds are described as normal bilaterally, which makes a tension pneumothorax with tracheal deviation highly unlikely in this scenario.
Cardiothoracic Surgery US Medical PG Question 4: A 45-year-old male is brought into the emergency room by emergency medical services due to a stab wound in the chest. The wound is located superior and medial to the left nipple. Upon entry, the patient appears alert and is conversational, but soon becomes confused and loses consciousness. The patient's blood pressure is 80/40 mmHg, pulse 110/min, respirations 26/min, and temperature 97.0 deg F (36.1 deg C). On exam, the patient has distended neck veins with distant heart sounds. What is the next best step to increase this patient's survival?
- A. Heparin
- B. Intravenous fluids
- C. Aspirin
- D. Intravenous colloids
- E. Pericardiocentesis (Correct Answer)
Cardiothoracic Surgery Explanation: ***Pericardiocentesis***
- The patient's presentation with **hypotension**, **tachycardia**, **distended neck veins**, and **distant heart sounds** after a chest stab wound is classic for **cardiac tamponade** (Beck's triad).
- **Pericardiocentesis** is the immediate life-saving procedure to drain the pericardial fluid and relieve pressure on the heart, improving cardiac output.
- In penetrating trauma, this serves as a **bridge to definitive surgical management** (thoracotomy or sternotomy).
*Heparin*
- **Heparin** is an anticoagulant and would worsen the situation by increasing bleeding into the pericardial space due to the stab wound.
- It is contraindicated in active bleeding and traumatic injury.
*Intravenous fluids*
- While **IV fluid resuscitation is recommended** in cardiac tamponade to maintain preload and support cardiac output, fluids alone **do not address the underlying mechanical obstruction**.
- The primary issue is **extrinsic compression of the heart** requiring drainage, not hypovolemia alone.
- Fluids are supportive but not definitive—**pericardiocentesis is the life-saving intervention**.
*Aspirin*
- **Aspirin** is an antiplatelet agent and would increase the risk of bleeding, exacerbating the patient's condition.
- It is used for conditions like myocardial infarction or stroke prevention, not for acute traumatic bleeding.
*Intravenous colloids*
- Similar to crystalloid fluids, **colloids** may provide temporary hemodynamic support but do not relieve the mechanical compression of the heart.
- They are supportive measures that **do not substitute for definitive pericardial drainage**.
Cardiothoracic Surgery US Medical PG Question 5: A 54-year-old man presents to the emergency department complaining of shortness of breath and fatigue for 1 day. He reports feeling increasingly tired. The medical records show a long history of intravenous drug abuse, and a past hospitalization for infective endocarditis 2 years ago. The echocardiography performed at that time showed vegetations on the tricuspid valve. The patient has not regularly attended his follow-up appointments. The visual inspection of the neck shows distension of the neck veins. What finding would you expect to see on this patient’s jugular venous pulse tracing?
- A. Obliterated x descent
- B. Absent a waves
- C. Large a waves
- D. Decreased c waves
- E. Prominent y descent (Correct Answer)
Cardiothoracic Surgery Explanation: ***Prominent y descent***
- A prominent y descent in the **jugular venous pulse (JVP)** tracing is characteristic of **tricuspid regurgitation**, which is highly probable given the patient's history of **intravenous drug abuse** and previous **infective endocarditis** affecting the tricuspid valve.
- The **y descent** reflects the rapid emptying of the right atrium into the right ventricle during early diastole; in tricuspid regurgitation, the increased right atrial volume due to regurgitant flow leads to a more rapid and pronounced fall in right atrial pressure once the tricuspid valve opens.
*Obliterated x descent*
- An obliterated or absent **x descent** is more typically seen in conditions like **cardiac tamponade** or severe **right ventricular failure**, where there's impaired right atrial filling during ventricular systole.
- While the patient has heart issues, the clinical picture strongly points to tricuspid regurgitation, which would not typically cause an obliterated x descent.
*Absent a waves*
- **Absent a waves** in the JVP tracing most commonly suggest **atrial fibrillation**, where there is no organized atrial contraction.
- The case description does not provide information to suggest atrial fibrillation as the primary issue.
*Large a waves*
- **Large a waves** (cannon a waves) are indicative of conditions where there is increased resistance to right atrial emptying during atrial contraction, such as **tricuspid stenosis**, **pulmonary hypertension**, or certain types of **atrial-ventricular dissociation**.
- While the history of endocarditis could theoretically lead to tricuspid stenosis, tricuspid regurgitation is a more common sequela in IV drug users and better fits the overall clinical picture, and stenosis would not cause a prominent y descent.
*Decreased c waves*
- The **c wave** in the JVP is caused by the bulging of the tricuspid valve into the right atrium during early ventricular systole.
- A decreased c wave is not a typical finding in the context of tricuspid regurgitation; rather, a more prominent c-v wave is expected due to the regurgitant flow.
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