Critical Care Medicine Practice Questions

Q: A 60-year-old man is being weaned from a ventilator in the ICU. Which of the following findings suggests that weaning is likely to fail?

A vital capacity (VC) of 5 mL/kg body weight. **Explanation:** The success of weaning from mechanical ventilation depends on the patient’s ability to maintain adequate gas exchange and respiratory muscle strength. **1. Why Option C is Correct:** Vital Capacity (VC) is a measure of the maximum amount of air a person can exhale after a maximum inhalation. It reflects respiratory muscle reserve. For successful weaning, a **VC of >10–15 mL/kg** is generally required. A value of **5 mL/kg** indicates severe restrictive impairment and inadequate muscle strength to sustain spontaneous breathing, making weaning failure highly likely. **2. Why Incorrect Options are Wrong:** * **Option A (RR 24 breaths/min):** A respiratory rate (RR) 60 mm Hg on FiO2 ≤40% (or P/F ratio >150–200) is a positive predictor. * **Option D (Minute Ventilation 8 L/min):** A minute ventilation (Ve) of **<10 L/min** is a standard criterion for weaning. A value of 8 L/min indicates that the work of breathing is within a manageable range. **High-Yield Clinical Pearls for NEET-PG:** * **Rapid Shallow Breathing Index (RSBI):** The most reliable predictor of weaning success. Calculated as **RR / Tidal Volume (L)**. An **RSBI <105** predicts successful weaning. * **Maximum Inspiratory Pressure (MIP/NIF):** Should be more negative than **–20 to –30 cm H2O**. * **T-Piece Trial:** The gold standard for assessing spontaneous breathing readiness. * **Criteria for Weaning:** PEEP ≤5–8 cm H2O, FiO2 ≤40–50%, Hemodynamic stability (no/minimal vasopressors), and intact airway reflexes.

Q: During cardiac resuscitation, which of the following complications can occur?

Disseminated intravascular coagulation. **Explanation:** The correct answer is **D. Disseminated intravascular coagulation (DIC).** **Why DIC is the correct answer:** Cardiac arrest and subsequent cardiopulmonary resuscitation (CPR) trigger a complex systemic response known as **Post-Cardiac Arrest Syndrome**. During the period of "no-flow" (arrest) and "low-flow" (CPR), there is profound global tissue hypoxia and acidosis. Upon Return of Spontaneous Circulation (ROSC), the **ischemia-reperfusion injury** leads to the release of pro-inflammatory cytokines and tissue factors into the bloodstream. This massive inflammatory surge activates the coagulation cascade systemically, leading to the consumption of clotting factors and platelets, resulting in DIC. Studies indicate that a significant percentage of post-cardiac arrest patients develop laboratory or clinical evidence of DIC within 24 hours. **Why other options are incorrect:** * **A, B, and C (Rupture of lungs, liver, and stomach):** While these are known mechanical complications of CPR, they are classified as **traumatic injuries** resulting from chest compressions or improper airway management (e.g., gastric insufflation). While serious, they are localized mechanical injuries. DIC, conversely, is a systemic pathophysiological complication arising from the metabolic and inflammatory derangements of the arrest state itself. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication of CPR:** Rib fractures (found in >70% of cases). * **Post-Cardiac Arrest Syndrome components:** Brain injury, myocardial dysfunction, systemic ischemia/reperfusion response, and persistent precipitating pathology. * **DIC in CPR:** It is often associated with a poorer prognosis and increased risk of multi-organ failure. * **Gastric Distension:** Common during bag-mask ventilation; it increases the risk of aspiration and can lead to stomach rupture, though it is rarer than DIC in the systemic context.

Q: The best chances of recovery after successful cardiopulmonary resuscitation are seen in which cardiac rhythm?

Ventricular Tachycardia. **Explanation:** The prognosis of cardiac arrest is heavily dependent on the initial presenting rhythm. **Ventricular Tachycardia (VT)**, specifically pulseless VT, carries the best prognosis for recovery and neurologically intact survival. **Why Ventricular Tachycardia is the correct answer:** VT and Ventricular Fibrillation (VF) are "shockable" rhythms. However, VT represents a more organized electrical activity than VF. In VT, the myocardium often retains better metabolic status and a higher likelihood of returning to a perfusing rhythm (ROSC) immediately following defibrillation. Because the heart is often in a "fresher" state of ischemia compared to other rhythms, the chances of successful resuscitation are highest. **Analysis of Incorrect Options:** * **Ventricular Fibrillation (VF):** While also a shockable rhythm with a good prognosis compared to non-shockable rhythms, it represents chaotic electrical activity. The longer a patient stays in VF, the more myocardial energy stores are depleted, eventually deteriorating into asystole. * **Asystole:** This is a "non-shockable" rhythm representing the total absence of electrical and mechanical activity. It usually signifies a prolonged period of ischemia and has the poorest prognosis. * **Electromechanical Dissociation (PEA):** In Pulseless Electrical Activity, there is organized electrical activity but no mechanical contraction. It is often caused by reversible factors (the H’s and T’s), but the survival rates are significantly lower than shockable rhythms like VT. **High-Yield Clinical Pearls for NEET-PG:** * **Chain of Survival:** The most critical factor in VT/VF survival is the **time to defibrillation**. * **Shockable Rhythms:** VT and VF. * **Non-Shockable Rhythms:** Asystole and PEA. * **Drug of Choice:** Epinephrine is the primary vasopressor used in all cardiac arrests; Amiodarone or Lidocaine are used specifically for refractory VT/VF.

Q: In hyperbaric oxygenation, what is the maximum allowed pressure of O2?

3 atm. **Explanation:** Hyperbaric Oxygen Therapy (HBOT) involves breathing 100% oxygen while being in a treatment chamber pressurized to levels greater than sea level atmospheric pressure. **Why 3 atm is the correct answer:** In clinical practice, the maximum pressure used for hyperbaric oxygenation is typically **3 atmospheres absolute (ATA)**. At this pressure, the amount of dissolved oxygen in the plasma increases significantly (based on Henry’s Law), reaching approximately 6.8 volumes percent—enough to support tissue metabolism even in the absence of hemoglobin. Exceeding 3 ATA significantly increases the risk of **Central Nervous System (CNS) Oxygen Toxicity** (the Paul Bert effect), which can manifest as grand mal seizures. **Analysis of Incorrect Options:** * **1 atm (Option B):** This is standard atmospheric pressure at sea level. While breathing 100% oxygen at 1 atm is supplemental oxygen therapy, it does not constitute "hyperbaric" therapy, which by definition requires pressures >1 ATA. * **5 atm and 9 atm (Options C & D):** These pressures are excessively high for medical oxygenation. At these levels, the partial pressure of oxygen becomes acutely toxic to the brain and lungs almost immediately, leading to rapid neurological collapse. **High-Yield Clinical Pearls for NEET-PG:** * **Indications for HBOT:** Carbon monoxide (CO) poisoning, Decompression Sickness (the "Bends"), Gas Gangrene (*Clostridium perfringens*), and non-healing diabetic ulcers. * **Most Common Side Effect:** Middle ear barotrauma (due to failure to equalize pressure across the eustachian tube). * **Absolute Contraindication:** Untreated pneumothorax (as the air pocket will expand during decompression, leading to tension pneumothorax). * **Oxygen Toxicity:** CNS toxicity (seizures) occurs at high pressures (>2-3 ATA), while Pulmonary toxicity (Lorrain Smith effect) occurs with prolonged exposure to lower concentrations of oxygen.

Q: Which statement is true regarding cardiopulmonary resuscitation?

Adrenaline is given if cardioversion fails.. ### Explanation **Correct Option: C. Adrenaline is given if cardioversion fails.** In the management of **Shockable Rhythms** (Ventricular Fibrillation/Pulseless Ventricular Tachycardia), the priority is immediate defibrillation. If the initial shocks (cardioversion/defibrillation) fail to restore a perfusing rhythm, **Adrenaline (1 mg IV/IO every 3–5 minutes)** is administered. It acts via alpha-1 adrenergic receptors to cause vasoconstriction, increasing coronary and cerebral perfusion pressure during CPR, thereby improving the chances of successful subsequent shocks. **Analysis of Incorrect Options:** * **A. Most common presentation:** In adult out-of-hospital cardiac arrests (OHCA), the most common initial rhythm is actually **Ventricular Fibrillation (VF)**, not asystole. Asystole is more common in prolonged arrests or pediatric cases. * **B. Compression to ventilation ratio:** According to the latest AHA/ERC guidelines, the universal ratio for adult CPR (one or two rescuers) is **30:2**. A 5:1 ratio is obsolete and no longer recommended. * **D. Calcium gluconate:** Calcium is **not** recommended for routine use in CPR. It is only indicated in specific scenarios such as hyperkalemia, hypocalcemia, or magnesium/calcium channel blocker toxicity. Routine use may cause cerebral reperfusion injury. **High-Yield Clinical Pearls for NEET-PG:** * **Compression Depth:** 5–6 cm (2–2.4 inches) in adults. * **Compression Rate:** 100–120 compressions per minute. * **Amiodarone:** The antiarrhythmic of choice (300 mg bolus) if VF/pVT persists after the 3rd shock. * **Reversible Causes (5Hs & 5Ts):** Always look for Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, Hypothermia; and Tension pneumothorax, Tamponade, Toxins, Thrombosis (pulmonary/coronary).

Q: High-quality CPR includes all of the following except?

Chest compressions at 200 per minute. This question tests your knowledge of the **AHA (American Heart Association) Guidelines for Cardiopulmonary Resuscitation (CPR)**, which are high-yield for NEET-PG. ### **Analysis of Options** * **Option A (Correct Answer):** The recommended rate for chest compressions is **100–120 per minute**. A rate of 200 per minute is excessive; it prevents adequate ventricular filling and leads to rescuer fatigue, significantly decreasing the quality of CPR and coronary perfusion pressure. * **Option B:** For adults, the depth of compressions should be **at least 2 inches (5 cm)** but should not exceed 2.4 inches (6 cm). This depth is necessary to create enough intrathoracic pressure to circulate blood to vital organs. * **Option C:** Allowing **complete chest recoil** is critical. It allows the heart to refill with blood (diastolic filling) between compressions. Leaning on the chest prevents this and reduces cardiac output. * **Option D:** **Avoiding excessive ventilation** is vital because over-ventilation increases intrathoracic pressure, which decreases venous return to the heart and lowers survival rates. ### **High-Yield Clinical Pearls for NEET-PG** * **Compression-to-Ventilation Ratio:** 30:2 for adults (single or dual rescuer). For children/infants, it is 30:2 (single) or 15:2 (two-rescuer). * **Minimize Interruptions:** Keep pauses in compressions to less than 10 seconds. * **EtCO₂ Monitoring:** A Capnography reading of **<10 mmHg** during CPR indicates poor quality compressions; a sudden rise to **35–40 mmHg** is a sign of ROSC (Return of Spontaneous Circulation). * **Defibrillation:** For shockable rhythms (VF/Pulseless VT), the first shock should be 120–200 J (Biphasic) or 360 J (Monophasic).

Question 1

A 60-year-old man is being weaned from a ventilator in the ICU. Which of the following findings suggests that weaning is likely to fail?

Accepted Answer

A vital capacity (VC) of 5 mL/kg body weight

Answer

A respiratory rate of 24 breaths/min

Answer

A PaO2 of 80 mm Hg on FiO2 of 40%

Answer

A minute ventilation of 8 L/min

Question 2

During cardiac resuscitation, which of the following complications can occur?

Accepted Answer

Disseminated intravascular coagulation

Answer

Rupture of lungs

Answer

Rupture of liver

Answer

Rupture of stomach

Question 3

Which of the following statements regarding glycemic control in ICU patients is true?

Accepted Answer

A target glucose range of 140-180 mg/dL (7.8 - 10.0 mmol/L) is recommended.

Answer

Monitoring of blood insulin levels is far better than monitoring blood glucose levels in SICU patients.

Answer

Maintenance of normoglycemia in a medical ICU is of no benefit.

Answer

Stringent glucose goals, such as 110-140 mg/dL, are required for all patients.

Question 4

Which of the following is NOT true regarding type-III respiratory failure?

Accepted Answer

There is impaired central nervous system drive to breathe.

Answer

It is also known as perioperative respiratory failure.

Answer

It occurs as a result of atelectasis.

Answer

It can be managed conservatively.

Question 5

The best chances of recovery after successful cardiopulmonary resuscitation are seen in which cardiac rhythm?

Accepted Answer

Ventricular Tachycardia

Answer

Ventricular Fibrillation

Answer

Asystole

Answer

Electromechanical dissociation

Question 6

In hyperbaric oxygenation, what is the maximum allowed pressure of O2?

Accepted Answer

3 atm

Answer

1 atm

Answer

5 atm

Answer

9 atm

Question 7

After successful resuscitation and achieving stable spontaneous circulation, what is the next appropriate step?

Accepted Answer

Assess central nervous system involvement

Answer

Measure blood glucose

Answer

Evaluate spontaneous respiratory effort

Answer

Assess volume status

Question 8

Which statement is true regarding cardiopulmonary resuscitation?

Accepted Answer

Adrenaline is given if cardioversion fails.

Answer

The most common presentation in ECG is asystole.

Answer

The compression to ventilation ratio is 5:1.

Answer

Calcium gluconate is given immediately.

Question 9

Which of the following is not widely used in cardiopulmonary resuscitation?

Accepted Answer

Calcium

Answer

Adrenaline

Answer

Atropine

Answer

Vasopressin

Question 10

High-quality CPR includes all of the following except?

Accepted Answer

Chest compressions at 200 per minute

Answer

Depth of 2 inches or more

Answer

Complete chest recoil after each compression

Answer

Avoidance of excessive ventilation

Critical Care Medicine — MCQs

Critical Care Medicine — MCQs

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