Critical Care Medicine Practice Questions

Q: Hyperbaric oxygen therapy is not indicated in which of the following conditions?

Vasovagal syncope. **Explanation:** Hyperbaric Oxygen Therapy (HBOT) involves breathing 100% oxygen at atmospheric pressures greater than 1 ATA (usually 2–3 ATA). This increases the amount of dissolved oxygen in the plasma (Henry’s Law), facilitating tissue oxygenation even in the absence of hemoglobin-bound oxygen. **Why Vasovagal Syncope is the Correct Answer:** Vasovagal syncope is a transient loss of consciousness caused by a sudden drop in heart rate and blood pressure due to an exaggerated parasympathetic response. It is a self-limiting condition managed by placing the patient in the Trendelenburg position and ensuring adequate hydration. There is no role for hyperbaric oxygen as the underlying pathology is hemodynamic, not a lack of oxygen availability or tissue toxicity. **Analysis of Incorrect Options:** * **Carbon Monoxide (CO) Poisoning:** HBOT is the treatment of choice. It reduces the half-life of carboxyhemoglobin (from 300 mins at room air to ~20 mins at 3 ATA) and helps prevent delayed neurological sequelae. * **Gas Gangrene (Clostridial Myonecrosis):** *Clostridium perfringens* is an obligate anaerobe. HBOT inhibits bacterial toxin production and is directly bactericidal, halting the spread of infection. * **Compartment Syndrome:** HBOT causes hyperoxic vasoconstriction (reducing edema) while simultaneously increasing the oxygen tension in compromised tissues, helping to bridge the period until surgical decompression or recovery. **NEET-PG High-Yield Pearls:** * **Absolute Contraindication:** Untreated Tension Pneumothorax (due to risk of rapid expansion). * **Common Side Effect:** Middle ear barotrauma (most common) and reversible myopia. * **Other Indications:** Decompression sickness (Bends), Air embolism, Refractory osteomyelitis, and Non-healing diabetic foot ulcers.

Q: Which maneuver is generally not performed early before chest compressions in basic life support outside the hospital?

Electrical cardioversion. **Explanation:** The correct answer is **Electrical cardioversion**. In the context of Basic Life Support (BLS) for out-of-hospital cardiac arrest (OHCA), the priority follows the **C-A-B** (Compressions, Airway, Breathing) sequence. **Why Electrical Cardioversion is the correct answer:** Electrical cardioversion is a synchronized shock used to treat hemodynamically unstable tachyarrhythmias (like AFib or SVT) where a pulse is still present. In a BLS scenario involving a collapsed, pulseless victim, the immediate goal is high-quality chest compressions and, if available, **defibrillation** (unsynchronized shock). Cardioversion is an advanced intervention performed by healthcare professionals using a manual monitor, not a "basic" maneuver performed before or during early CPR. **Analysis of incorrect options:** * **Call for help (A):** This is the first step in the BLS algorithm. Activating the Emergency Medical Service (EMS) ensures advanced life support is on the way. * **Obtain airway (B) & Ventilation (D):** While the current AHA guidelines emphasize "Compressions First" (C-A-B), opening the airway and providing rescue breaths remain integral components of BLS that follow immediately after the first cycle of 30 compressions. **NEET-PG High-Yield Pearls:** * **Sequence:** The current sequence is **C-A-B**. The only exception is the newborn, where the sequence remains **A-B-C**. * **Compression Depth:** At least 2 inches (5 cm) but no more than 2.4 inches (6 cm) in adults. * **Compression Rate:** 100–120 compressions per minute. * **Defibrillation vs. Cardioversion:** Defibrillation is for pulseless rhythms (VF/Pulseless VT); Cardioversion is for symptomatic tachyarrhythmias with a pulse. * **AED:** If an Automated External Defibrillator (AED) is available, it should be used as soon as possible, but it provides *defibrillation*, not cardioversion.

Q: A young patient sustains cardiac arrest in the medical ward. Immediate defibrillation is advised when the ECG shows:

Ventricular Tachycardia. In cardiac arrest management, the primary goal is to identify whether the rhythm is **shockable** or **non-shockable**. **Why Ventricular Tachycardia is Correct:** Defibrillation is the treatment of choice for **Pulseless Ventricular Tachycardia (pVT)** and **Ventricular Fibrillation (VF)**. These are "shockable" rhythms characterized by disorganized or rapid electrical activity that prevents effective myocardial contraction. Defibrillation delivers a high-energy electrical current to depolarize a critical mass of the myocardium simultaneously, allowing the heart's natural pacemaker (SA node) to resume a coordinated rhythm. **Why the Other Options are Incorrect:** * **Asystole:** This is a "flatline" representing a total lack of electrical activity. Defibrillation is ineffective because there is no electrical activity to reset. Management focuses on high-quality CPR and Epinephrine. * **Electromechanical Dissociation (PEA):** Also known as Pulseless Electrical Activity, the ECG shows a rhythm that should produce a pulse, but the heart is not mechanically contracting. Like asystole, it is a non-shockable rhythm. * **Persistent Bradyarrhythmia:** Slow rhythms are treated with drugs (Atropine) or cardiac pacing, not defibrillation. **High-Yield Clinical Pearls for NEET-PG:** * **Shockable Rhythms:** VF and Pulseless VT. * **Non-Shockable Rhythms:** Asystole and PEA. * **Energy Levels:** For a Biphasic defibrillator, the standard initial dose is **120–200 J**. For Monophasic, it is **360 J**. * **The "Golden Rule":** Minimize interruptions in chest compressions. Even during defibrillator charging, CPR should continue. * **Reversible Causes (5Hs & 5Ts):** Always look for Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, Hypothermia; and Tension pneumothorax, Tamponade, Toxins, Thrombosis (pulmonary/coronary).

Q: Positive End Expiratory Pressure (PEEP) is useful in which of the following conditions?

All of the above. **Explanation:** Positive End-Expiratory Pressure (PEEP) is a pressure applied at the end of expiration to prevent the alveolar pressure from falling to zero. The primary physiological goal of PEEP is to **increase Functional Residual Capacity (FRC)** and prevent alveolar collapse (atelectasis), thereby improving ventilation-perfusion (V/Q) matching and oxygenation. **Why "All of the above" is correct:** * **ARDS (Option B):** This is the classic indication for PEEP. In ARDS, inflammatory exudates cause widespread alveolar collapse and shunting. PEEP "recruits" these collapsed alveoli, increasing the surface area for gas exchange and allowing for a reduction in the fraction of inspired oxygen (FiO2) to prevent oxygen toxicity. * **Pulmonary Edema (Option C):** PEEP increases intrathoracic pressure, which reduces venous return (preload) and afterload, helping a failing heart. It also shifts fluid from the alveoli back into the interstitial space, clearing the gas exchange surface. * **Pneumonia (Option A):** In severe pneumonia, localized alveolar collapse and inflammatory debris lead to hypoxemia. PEEP helps maintain patency of the airways surrounding the consolidated areas, improving oxygenation. **Clinical Pearls for NEET-PG:** * **Physiological Effects:** PEEP improves lung compliance but can decrease cardiac output due to reduced venous return. * **Complications:** High levels of PEEP can lead to **barotrauma** (pneumothorax) and increased intracranial pressure (ICP). * **Contraindication:** Absolute contraindication is an untreated tension pneumothorax. * **Auto-PEEP:** Also known as intrinsic PEEP, seen in obstructive diseases like COPD/Asthma where air trapping occurs.

Q: A patient on mechanical ventilation shows alarms for increased peak and plateau pressures during inspiration. What does this indicate?

Obstruction of the tracheal tube. To understand this question, one must distinguish between **Peak Inspiratory Pressure (PIP)** and **Plateau Pressure (Pplat)**. * **PIP** represents the total pressure required to overcome both airway resistance and alveolar elastic recoil. * **Pplat** (measured during an inspiratory hold) reflects only the pressure required to distend the alveoli, representing **lung compliance**. ### Why Option B is Correct When **both PIP and Pplat increase**, it indicates a decrease in the compliance (distensibility) of the respiratory system. This means the lungs or chest wall have become "stiffer," requiring more pressure to hold the same volume of air. Common causes include: * Parenchymal issues: ARDS, Pulmonary edema, Pneumonia. * Pleural/Chest wall issues: Tension pneumothorax, Pleural effusion, Kyphoscoliosis. * Extrinsic factors: Abdominal compartment syndrome. ### Why Other Options are Incorrect * **A & C (Obstruction/Bronchospasm):** These are **resistance** problems. In these cases, PIP increases significantly, but Pplat remains unchanged (or increases only minimally). A high PIP-Pplat gradient (>5 cmH2O) is the hallmark of airway obstruction or bronchospasm. * **D (Increased Compliance):** This would result in a **decrease** in both PIP and Pplat (e.g., in emphysema). ### High-Yield Clinical Pearls for NEET-PG 1. **The Formula:** $Compliance = \frac{Tidal Volume}{Pplat - PEEP}$. 2. **The Rule of Thumb:** * ↑PIP + Normal Pplat = **Airway Resistance** (Kinked tube, secretions, bronchospasm). * ↑PIP + ↑Pplat = **Decreased Compliance** (ARDS, Pneumothorax, Atelectasis). 3. **Tension Pneumothorax:** This is a life-threatening cause of a sudden rise in both PIP and Pplat; always auscultate the chest if these pressures spike.

Q: Which of the following is/are included in the treatment of ventricular fibrillation and subsequent cardiac arrest?

Epinephrine. **Explanation:** In the management of **Ventricular Fibrillation (VF)** and pulseless cardiac arrest, the primary goal is to restore spontaneous circulation (ROSC) through high-quality CPR and early defibrillation. When these initial measures fail, pharmacological intervention is required. **Why Epinephrine is Correct:** Epinephrine is the cornerstone vasopressor in Advanced Cardiovascular Life Support (ACLS). Its primary benefit during cardiac arrest is its **alpha-adrenergic effect**, which causes systemic vasoconstriction. This increases coronary and cerebral perfusion pressure, significantly improving the chances of ROSC. In the VF/pVT algorithm, it is administered as a 1 mg dose every 3–5 minutes after the second shock. **Why Other Options are Incorrect:** * **Atropine (A):** Previously used for PEA/Asystole, it was removed from the ACLS cardiac arrest algorithm in 2010. It is now indicated only for symptomatic bradycardia. * **External Pacing (B):** Pacing is ineffective in VF because the myocardium is in a state of chaotic electrical activity; it cannot "capture" a fibrillating heart. It is indicated for symptomatic bradycardia with a pulse. * **Antiarrhythmic Agents (D):** While Amiodarone or Lidocaine are used in "refractory" VF (after the 3rd shock), the question asks for the standard treatment of arrest. Epinephrine remains the primary drug used in all arrest rhythms, whereas antiarrhythmics are secondary. **High-Yield Pearls for NEET-PG:** 1. **Shockable Rhythms:** VF and Pulseless Ventricular Tachycardia (pVT). 2. **Non-Shockable Rhythms:** Asystole and PEA (Epinephrine is given as soon as possible here). 3. **Defibrillation Energy:** 200J for Biphasic; 360J for Monophasic. 4. **Amiodarone Dose:** 300 mg bolus (1st dose), followed by 150 mg (2nd dose) if VF persists.

Q: What is the recommended ratio of chest compressions to rescue breaths for a lone rescuer performing CPR on a patient of any age?

30:2. **Explanation:** The correct answer is **30:2**. According to the American Heart Association (AHA) and International Liaison Committee on Resuscitation (ILCOR) guidelines, a compression-to-ventilation ratio of **30:2** is recommended for **lone rescuers** across all age groups (adults, children, and infants, excluding neonates). This ratio optimizes coronary perfusion pressure by minimizing interruptions in chest compressions while providing adequate oxygenation. **Analysis of Options:** * **Option A (30:2):** Correct. This is the universal ratio for single-rescuer CPR to ensure high-quality compressions and reduce the "no-flow" time. * **Option B (15:2):** This ratio is used for **two-rescuer CPR in children and infants** (to account for their higher respiratory requirements) but is not used for lone rescuers or adults. * **Option C (3:1):** This is the specific ratio used in **Neonatal Resuscitation** (90 compressions and 30 breaths per minute) because respiratory failure is the primary cause of neonatal arrest. * **Option D (30:1):** This is not a standard recommended ratio in any current basic or advanced life support guidelines. **Clinical Pearls for NEET-PG:** * **Compression Depth:** 2–2.4 inches (5–6 cm) in adults; at least 1/3rd the AP diameter of the chest in pediatrics. * **Compression Rate:** 100–120 compressions per minute. * **Hand Placement:** Lower half of the sternum. * **Advanced Airway:** Once an endotracheal tube or supraglottic airway is in place, compressions are continuous (100–120/min) with asynchronous breaths every 6 seconds (10 breaths/min). * **Chest Recoil:** Allow complete chest recoil to ensure adequate venous return and cardiac filling.

Question 1

Hyperbaric oxygen therapy is not indicated in which of the following conditions?

Accepted Answer

Vasovagal syncope

Answer

Carbon monoxide poisoning

Answer

Gas gangrene

Answer

Compartment syndrome

Question 2

Which maneuver is generally not performed early before chest compressions in basic life support outside the hospital?

Accepted Answer

Electrical cardioversion

Answer

Call for help.

Answer

Obtain airway.

Answer

Ventilation

Question 3

A young patient sustains cardiac arrest in the medical ward. Immediate defibrillation is advised when the ECG shows:

Accepted Answer

Ventricular Tachycardia

Answer

Asystole

Answer

Electromechanical dissociation

Answer

Persistent Bradyarrhythmia

Question 4

A 43-year-old trauma patient develops acute respiratory distress syndrome (ARDS) and has difficulty oxygenating despite increased concentrations of inspired O2. After the positive end-expiratory pressure (PEEP) is increased, the patient's oxygenation improves. What is the mechanism by which this occurs?

Accepted Answer

Increasing functional residual capacity

Answer

Decreasing dead-space ventilation

Answer

Decreasing the minute ventilation requirement

Answer

Increasing tidal volume

Question 5

What is the correct sequence of Cardiopulmonary Resuscitation (CPR)?

Accepted Answer

Basic CPR, Defibrillation, Advanced Cardiovascular Life Support (ACLS)

Answer

Basic CPR, Advanced Cardiovascular Life Support (ACLS), Defibrillation

Answer

Advanced Cardiovascular Life Support (ACLS), Basic CPR, Defibrillation

Answer

Defibrillation, Advanced Cardiovascular Life Support (ACLS), Basic CPR

Question 6

Positive End Expiratory Pressure (PEEP) is useful in which of the following conditions?

Accepted Answer

All of the above

Answer

Pneumonia

Answer

Acute Respiratory Distress Syndrome (ARDS)

Answer

Pulmonary edema

Question 7

Which of the following treatments would be least effective for asystole?

Accepted Answer

Intravenous calcium gluconate, 10 ml of 10% solution

Answer

External pacemaker

Answer

Intravenous epinephrine, 10 ml of 1:10,000 solution

Answer

Intravenous atropine, 0.5 mg

Question 8

A patient on mechanical ventilation shows alarms for increased peak and plateau pressures during inspiration. What does this indicate?

Accepted Answer

Obstruction of the tracheal tube

Answer

Decreased distensibility of the lungs and chest wall

Answer

Acute bronchospasm

Answer

Increased compliance of the lungs

Question 9

Which of the following is/are included in the treatment of ventricular fibrillation and subsequent cardiac arrest?

Accepted Answer

Epinephrine

Answer

Atropine

Answer

External pacing

Answer

Antiarrhythmic agents

Question 10

What is the recommended ratio of chest compressions to rescue breaths for a lone rescuer performing CPR on a patient of any age?

Accepted Answer

30:2

Answer

15:2

Answer

3:1

Answer

30:1

Critical Care Medicine — MCQs

Critical Care Medicine — MCQs

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