Critical Care — MCQs

Critical Care Indian Medical PG Practice Questions and MCQs

Question 91: Which of these is least effective as first-line treatment for dangerous hyperkalemia?

A. Calcium chloride injection
B. Beta-2 agonist (Salbutamol)
C. Intravenous sodium bicarbonate (Correct Answer)
D. Dialysis (Hemodialysis)

Explanation: ***Intravenous sodium bicarbonate*** - While it can drive potassium into cells, its effect is often **delayed and unreliable** in acute, dangerous hyperkalemia, especially without concurrent acidosis. - Its efficacy is most pronounced when hyperkalemia is associated with **metabolic acidosis**, which is not always the primary driving factor of dangerous hyperkalemia. *Calcium chloride injection* - This is a **first-line treatment** for dangerous hyperkalemia, as it **stabilizes the cardiac membrane** by antagonizing the direct effects of potassium on myocardial excitability [1]. - It does not lower serum potassium levels but **protects the heart** from life-threatening arrhythmias, buying time for other therapies to reduce potassium [1]. *Beta-2 agonist (Salbutamol)* - **Beta-2 agonists** like salbutamol are effective in shifting potassium **intracellularly**, thereby lowering serum potassium levels. - This effect is mediated by stimulating the **Na+/K+-ATPase pump** on cell membranes. *Dialysis (Hemodialysis)* - **Hemodialysis** is the **most effective and rapid** method for removing excess potassium from the body, especially in cases of severe or refractory hyperkalemia. - It provides definitive treatment by directly **filtering potassium** from the blood, and is often considered when other measures fail or in patients with kidney failure.

Question 92: Refractory Septic shock is defined as?

A. Shock requiring mechanical ventilation and inotropic support
B. Shock with lactate levels >4 mmol/L despite treatment
C. Shock that does not respond to initial fluid bolus within 1 hour
D. Shock persisting despite adequate fluid resuscitation and vasopressor support (Correct Answer)

Explanation: ***Shock persisting despite adequate fluid resuscitation and vasopressor support*** - This is the **standard definition** of refractory septic shock according to current **Surviving Sepsis Campaign Guidelines** and critical care literature. - It specifically refers to the failure of **both fluid resuscitation and vasopressor therapy** to restore adequate mean arterial pressure and tissue perfusion. *Shock that does not respond to initial fluid bolus within 1 hour* - This describes **early non-response** to fluid therapy, which is concerning but not the complete definition of refractory shock. - Refractory shock requires failure of **comprehensive standard therapy** (fluids AND vasopressors), not just initial fluid bolus failure. *Shock requiring mechanical ventilation and inotropic support* - This describes a patient in **severe septic shock** with multi-organ support but does not define its **refractory nature**. - The need for these interventions indicates **organ dysfunction** and severity, not necessarily refractoriness to standard resuscitation efforts. *Shock with lactate levels >4 mmol/L despite treatment* - **Elevated lactate** indicates tissue hypoperfusion and ongoing shock, but it is a **severity marker**, not the definition of refractoriness. - High lactate levels can occur even in shock that is **responsive to standard therapy** and doesn't specifically indicate failure of resuscitation efforts.

Question 93: Main cause of shock is?

A. Hypoperfusion of tissue (Correct Answer)
B. Hypotension
C. Hypoxia
D. Dehydration

Explanation: ***Hypoperfusion of tissue*** - **Shock** is fundamentally a state of inadequate cellular energy production due to insufficient delivery of oxygen and nutrients to tissues [1], [2]. - This **tissue hypoperfusion** leads to cellular dysfunction, organ damage, and ultimately, death if not corrected [2]. *Hypotension* - **Hypotension** (low blood pressure) is a common *sign* or *symptom* of shock, but it is not the underlying cause [2]. - While significant hypotension often leads to hypoperfusion, normotensive shock can occur if tissue demands are extremely high or if microcirculation is severely impaired [2]. *Hypoxia* - **Hypoxia** refers to a deficiency in the amount of oxygen reaching the tissues. While hypoxia is a *consequence* of poor tissue perfusion in shock, it is not the main *cause* [2]. - Tissue hypoperfusion results in inadequate oxygen delivery, leading to cellular hypoxia, but the primary deficit is the overall blood flow [2]. *Dehydration* - **Dehydration** is a *cause* of **hypovolemic shock**, which is one *type* of shock [1]. - It leads to reduced intravascular volume, which can cause decreased cardiac output and subsequent tissue hypoperfusion, but it is not the main cause of shock in general.

Question 94: Which of the following is the triad of complications of massive blood transfusion?

A. Hypocalcemia, hypothermia, coagulopathy
B. Hyperkalemia, metabolic acidosis, and cardiac arrhythmias
C. Alkalosis, hyperthermia, coagulopathy
D. Acidosis, hypothermia, coagulopathy (Correct Answer)

Explanation: ***Acidosis, hypothermia, coagulopathy*** - **Massive blood transfusion** can lead to **metabolic acidosis** due to the citrate in stored blood, which is metabolized to bicarbonate and consumed. - Stored blood is cold, which can cause patient **hypothermia**, while **coagulopathy** arises from dilution of clotting factors and platelets [1]. *Hypocalcemia, hypothermia, coagulopathy* - While **hypocalcemia** can occur due to **citrate toxicity** binding calcium, it is not considered one of the primary components of the classic triad. - The classic triad focuses on the most immediate and profound threats: acidosis, hypothermia, and coagulopathy. *Hyperkalemia, metabolic acidosis, and cardiac arrhythmias* - **Hyperkalemia** can occur due to the release of potassium from lysed red blood cells in stored blood, especially with older units. - However, **cardiac arrhythmias** are a *consequence* of these electrolyte imbalances and not a primary component of the classic triad itself. *Alkalosis, hyperthermia, coagulopathy* - **Alkalosis** is not typically a direct complication; **acidosis** is more common due to the metabolic burden of citrate and hypoperfusion. - **Hypothermia** is a more prominent issue than hyperthermia, as transfused blood is stored cold.

Question 95: Burns present as all the following EXCEPT

A. Acute kidney injury
B. Shock
C. Sepsis
D. Air embolism (Correct Answer)

Explanation: ***Air embolism*** - **Air embolism** is a rare and severe complication, typically associated with central venous catheter insertion, lung trauma, or surgical procedures, not direct burn injuries [2]. - While burns can cause respiratory complications (e.g., **inhalation injury**), they do not directly cause **air embolism** [1]. *Acute kidney injury* - **Acute kidney injury (AKI)** can occur in severe burn patients due to several factors, including hypovolemic shock, rhabdomyolysis from muscle damage, and the formation of heme pigments [2]. - Decreased renal perfusion and the release of myoglobin/hemoglobin can lead to **acute tubular necrosis (ATN)**. *Shock* - **Hypovolemic shock** is a prominent and immediate concern in severe burn patients due to massive fluid loss from damaged capillaries and increased capillary permeability [3]. - This fluid shift, known as **burn shock**, results from third-spacing of fluids, leading to reduced intravascular volume. *Sepsis* - **Sepsis** is a major cause of morbidity and mortality in burn patients, especially after the initial resuscitative phase [1]. - The damaged **skin barrier**, along with immunosuppression caused by burns, makes patients highly susceptible to bacterial and fungal infections [1].

Question 96: All of the following can cause Pulseless Electrical Activity (PEA) except

A. Massive pulmonary embolism
B. Tension pneumothorax
C. Pulseless VT (Correct Answer)
D. Cardiac tamponade

Explanation: Detailed Analysis: ***Pulseless VT*** - **Pulseless VT** is a cardiac arrest rhythm where an electrocardiogram shows ventricular tachycardia, but no pulse is detectable [1]. This is itself a type of cardiac arrest, not a *cause* of PEA [1], [2]. - While it's a life-threatening arrhythmia, PEA refers to organized electrical activity (other than VT) without a palpable pulse. *Massive pulmonary embolism* - A **massive pulmonary embolism** can lead to sudden right ventricular failure and obstruction of pulmonary blood flow, causing profound hypotension and PEA. - The heart has electrical activity but cannot generate a pulse due to the severe mechanical obstruction. *Tension pneumothorax* - A **tension pneumothorax** causes significant intrathoracic pressure, which impedes venous return to the heart and compresses the great vessels and heart. - This leads to a drastic reduction in cardiac output, resulting in PEA despite ongoing electrical activity. *Cardiac tamponade* - **Cardiac tamponade** involves accumulation of fluid in the pericardial sac, compressing the heart and preventing adequate ventricular filling [3]. - The inability of the ventricles to fill sufficiently leads to a severe drop in cardiac output and subsequent PEA.

Question 97: Hypothermia is used in all except:

A. Hyperthermia
B. Arrhythmia (Correct Answer)
C. Neonatal asphyxia
D. Cardiac surgery

Explanation: ***Arrhythmia*** - While sometimes used in specific cardiac procedures or to protect organs during cardioplegia, **therapeutic hypothermia** is not a primary treatment for general cardiac arrhythmias due to its potential to exacerbate certain rhythm disturbances. - **Hypothermia** can paradoxically induce **arrhythmias** itself, particularly bradycardia and ventricular fibrillation, making it unsuitable for general arrhythmia management [1]. *Hyperthermia* - **Therapeutic hypothermia** is used to reduce high body temperatures in conditions like **malignant hyperthermia** and **heatstroke** to prevent organ damage [2]. - By actively cooling the body, hypothermia counteracts the harmful effects of sustained, extreme elevations in body temperature. *Neonatal asphyxia* - **Therapeutic hypothermia** is a standard treatment for **neonatal hypoxic-ischemic encephalopathy** (HIE) to reduce brain injury. - Cooling the infant's body temperature helps to slow down damaging metabolic processes after oxygen deprivation. *Cardiac surgery* - **Hypothermia** is commonly employed during **cardiac surgery** to protect organs, especially the brain and heart, from ischemia during periods of reduced blood flow. - **Moderate to deep hypothermia** can significantly reduce metabolic demands, extending the safe duration of cardiopulmonary bypass and aortic cross-clamping [3].

Question 98: What is the first-line fluid to be administered in a patient presenting with acute hemorrhagic shock?

A. PRBC
B. Crystalloid (Correct Answer)
C. Colloid
D. Whole blood

Explanation: ***Crystalloid*** - Initial fluid resuscitation in **hemorrhagic shock** prioritizes **crystalloids** (e.g., normal saline or lactated Ringer's) to restore intravascular volume rapidly and maintain perfusion. - This approach is based on their immediate availability, cost-effectiveness, and ability to expand the extracellular fluid compartment. *PRBC* - While **packed red blood cells (PRBCs)** are crucial for replacing oxygen-carrying capacity in significant hemorrhage, they are typically administered *after* or *concurrently* with initial crystalloid resuscitation once the need for blood products is established. - Administering PRBCs as the *first-line* fluid might delay volume expansion and could be less effective for initial circulatory support. *Colloid* - **Colloid solutions** (e.g., albumin, dextran) remain controversial in initial hemorrhagic shock resuscitation due to concerns about their cost, potential side effects, and lack of clear superiority over crystalloids in improving patient outcomes. - They are also not as readily available as crystalloids in all emergency settings. *Whole blood* - **Whole blood** is the ideal resuscitation fluid as it contains all components of blood but is generally not readily available for initial emergency resuscitation in most civilian settings. - Its use is often limited to specific trauma centers or military combat scenarios due to logistical challenges.

Question 99: According to current CPR guidelines, the immediate first action when encountering an unresponsive patient should be:

A. Intracardiac atropine
B. Hysterectomy
C. Airway maintenance (Correct Answer)
D. IV adrenaline

Explanation: ***Airway maintenance*** - **Airway maintenance** is the immediate priority in an unresponsive patient to ensure adequate oxygenation and ventilation [1]. - Establishing an open airway (e.g., head tilt-chin lift or jaw thrust) is crucial before assessing breathing or circulation [1]. *Intracardiac atropine* - **Intracardiac atropine** is not a recommended intervention in modern CPR guidelines and carries significant risks with no proven benefit. - Atropine is typically used intravenously for symptomatic **bradycardia**, not as a first-line agent for unresponsive patients in cardiac arrest. *Hysterectomy* - **Hysterectomy** is a surgical procedure to remove the uterus and is completely irrelevant to the immediate management of an unresponsive patient. - This option is medically absurd and demonstrates a clear misunderstanding of emergency medical care. *IV adrenaline* - **Intravenous (IV) adrenaline** is a crucial drug in cardiac arrest, but it is typically administered *after* establishing an airway, initiating chest compressions, and assessing the cardiac rhythm. - It is not the *immediate first action* upon encountering an unresponsive patient, as securing the airway precedes drug administration [1].

Question 100: Ramesh met an accident with a car and has been in deep coma for the last 15 days. The most suitable route for the administration of protein and calories is by :

A. Central venous hyperalimentation
B. Nasogastric tube feeding
C. Jejunostomy tube feeding (Correct Answer)
D. Gastrostomy tube feeding

Explanation: ***Jejunostomy tube feeding*** - For patients in a **deep coma** who need long-term nutritional support, **enteral feeding** is preferred over parenteral if the gut is functional [1]. - A **jejunostomy tube** is suitable when there is a risk of **gastric reflux** and aspiration, which is common in comatose patients, as feeding directly into the jejunum bypasses the stomach. *Central venous hyperalimentation* - This is **parenteral nutrition**, which is generally reserved for patients where the **gastrointestinal tract is not functional** or cannot safely be used [1]. - It carries higher risks of **infection**, **metabolic complications**, and is more expensive than enteral feeding. *Nasogastric tube feeding* - While a common route for short-term enteral feeding, **nasogastric tubes** have a higher risk of **aspiration pneumonia** in patients with an impaired gag reflex or altered consciousness, like those in a deep coma. - Long-term use can also lead to **nasal irritation**, **sinusitis**, or **esophageal erosion**. *Gastrostomy tube feeding* - A **gastrostomy tube** delivers feed directly into the stomach, which can still pose a significant risk of **gastroesophageal reflux** and subsequent **aspiration** in a comatose patient [1]. - This route is typically considered when the patient has intact gastric emptying and a low risk of aspiration [1].

Practice by Chapter

Shock Syndromes and Management

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Acute Respiratory Distress Syndrome

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Mechanical Ventilation Principles

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Hemodynamic Monitoring

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Nutrition in Critical Illness

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Sedation and Analgesia in ICU

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Multi-organ Dysfunction Syndrome

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Acid-Base and Electrolyte Disturbances

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Toxicologic Emergencies

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Neurological Emergencies in ICU

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Renal Replacement Therapy

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End-of-Life Care in ICU

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