Critical Care Practice Questions

Q: Which of the following is NOT an evidence-based recommended therapy for the management of acute respiratory distress syndrome?

Inhaled nitric oxide. **Explanation:** The management of Acute Respiratory Distress Syndrome (ARDS) focuses on "lung-protective" strategies and improving oxygenation without causing further injury. **Why Inhaled Nitric Oxide (iNO) is the correct answer:** While iNO is a potent pulmonary vasodilator that can transiently improve oxygenation by reducing ventilation-perfusion (V/Q) mismatch [1], large clinical trials and meta-analyses have shown that it **does not improve mortality** in ARDS. Furthermore, it is associated with an increased risk of renal impairment. Therefore, it is not recommended for routine use and is considered only as a "rescue therapy" for refractory hypoxemia. **Analysis of incorrect options:** * **Low Tidal Volume (6 mL/kg PBW):** This is the cornerstone of ARDS management (ARDSNet protocol). It prevents **volutrauma** and barotrauma, significantly reducing mortality [1]. * **Minimize Left Atrial Filling Pressures:** A "conservative fluid strategy" (FACTT trial) is recommended. By maintaining lower filling pressures (CVP <4 mmHg or PAOP <8 mmHg), clinicians can reduce pulmonary edema and improve lung function without compromising organ perfusion. * **Prone Positioning:** For patients with severe ARDS (PaO2/FiO2 <150), prone positioning for at least 16 hours a day (PROSEVA trial) significantly reduces mortality by improving recruitment and V/Q matching [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Berlin Definition of ARDS:** Acute onset (<1 week), bilateral opacities on imaging, and respiratory failure not fully explained by heart failure (PaO2/FiO2 ratio <300) [1]. * **Neuromuscular Blockade (Cisatracurium):** May be used in early severe ARDS to improve patient-ventilator synchrony. * **Target SpO2:** 88–95% is generally acceptable to avoid oxygen toxicity.

Q: What are the diagnostic criteria for acute respiratory distress syndrome?

PaO2/FiO2 ratio is < 300 mmHg. The diagnostic criteria for **Acute Respiratory Distress Syndrome (ARDS)** are defined by the **Berlin Criteria (2012)** [1]. To diagnose ARDS, a patient must meet four specific requirements: 1. **Timing:** Acute onset within 1 week of a known clinical insult or new/worsening respiratory symptoms [1]. 2. **Chest Imaging:** Bilateral opacities not fully explained by effusions, collapse, or nodules [1]. 3. **Origin of Edema:** Respiratory failure not fully explained by heart failure or fluid overload (requires objective assessment like echocardiography if no risk factor is present) [1]. 4. **Oxygenation:** A **PaO2/FiO2 ratio < 300 mmHg** with a minimum PEEP of 5 cmH2O [1]. **Analysis of Options:** * **Option B (Correct):** The threshold for diagnosing ARDS starts at a PaO2/FiO2 ratio of **< 300 mmHg**. This represents the "Mild" category of the disease. * **Option A & D:** These represent the thresholds for **Moderate (< 200 mmHg)** and **Severe (< 100 mmHg)** ARDS, respectively. While they fall under the umbrella of ARDS, they are sub-classifications rather than the entry diagnostic criterion. * **Option C:** A ratio of < 400 mmHg is considered abnormal but does not meet the formal Berlin definition for ARDS. **High-Yield NEET-PG Pearls:** * **PCWP:** Under the old American-European Consensus (AECC) criteria, a Pulmonary Capillary Wedge Pressure (PCWP) < 18 mmHg was required. The Berlin criteria **removed** the mandatory PCWP measurement. * **Management:** The mainstay of treatment is **Low Tidal Volume Ventilation (6 mL/kg of predicted body weight)** to prevent volutrauma. * **Prone Positioning:** Recommended for severe ARDS (PaO2/FiO2 < 150) to improve V/Q matching.

Q: What is the commonest cause of death in ARDS?

Non-pulmonary organ failure. ### Explanation **1. Why "Non-pulmonary organ failure" is correct:** While ARDS is primarily a respiratory syndrome characterized by non-cardiogenic pulmonary edema and refractory hypoxemia, patients rarely die from the lung injury itself [1]. Modern mechanical ventilation strategies (like Lung Protective Ventilation) have significantly reduced deaths from acute respiratory failure. Instead, the systemic inflammatory response syndrome (SIRS) triggered by the underlying cause of ARDS (e.g., sepsis) leads to **Multiple Organ Dysfunction Syndrome (MODS)**. Most patients succumb to secondary complications, primarily **sepsis** and **multi-organ failure** (renal, hepatic, or cardiovascular), rather than an inability to oxygenate [1]. **2. Why the other options are incorrect:** * **Hypoxemia & Respiratory failure:** Although these are the hallmark clinical features of ARDS, they are usually manageable with advanced ventilatory support (PEEP, prone positioning, or ECMO). Death directly attributable to "hypoxic arrest" or isolated respiratory failure occurs in less than 15-20% of cases [1]. * **Hypotension:** While common in the setting of septic shock or high PEEP (which decreases venous return), hypotension is typically a component of the broader multi-organ failure spectrum rather than the primary cause of death. **3. NEET-PG High-Yield Pearls:** * **Commonest cause of ARDS:** Sepsis (specifically Gram-negative sepsis). * **Pathological hallmark:** Diffuse Alveolar Damage (DAD). * **Berlin Criteria:** Acute onset (<1 week), bilateral opacities on imaging, $PaO_2/FiO_2$ ratio <300 mmHg, and exclusion of cardiac failure (PCWP <18 mmHg) [1]. * **Gold Standard Management:** Low Tidal Volume Ventilation (6 mL/kg of predicted body weight) to prevent Volutrauma/Biotrauma [1]. * **Mortality:** Overall mortality remains high (approx. 30-40%), with age and non-pulmonary organ dysfunction being the strongest predictors of death [1].

Q: With reference to the optimal management of patients with sepsis in the intensive care unit, all of the following interventions are evidence-based except?

Intensive blood glucose monitoring and prevention of hyperglycemia improves survival in critically ill patients.. The correct answer is **C**. This question tests your knowledge of the **Surviving Sepsis Campaign** guidelines and landmark clinical trials. **Why Option C is the correct answer (The "Except" statement):** Historically, the Van den Berghe study (2001) suggested that "tight" glucose control (80–110 mg/dL) improved outcomes. However, the landmark **NICE-SUGAR Trial** later proved that intensive glucose control actually increased mortality due to a higher incidence of life-threatening **hypoglycemia**. Current guidelines recommend a more moderate target (typically **140–180 mg/dL**) rather than intensive prevention of hyperglycemia. **Analysis of other options:** * **Option A:** The **ARDSNet trial** established that low tidal volume ventilation (6 mL/kg of predicted body weight) reduces barotrauma and mortality in patients with sepsis-induced ARDS. * **Option B:** Rivers’ **Early Goal-Directed Therapy (EGDT)** protocol emphasized monitoring CVP (target 8–12 mmHg), Mean Arterial Pressure (≥65 mmHg), and urine output (≥0.5 mL/kg/hr) to optimize tissue perfusion. * **Option D:** **Drotrecogin alpha** (Recombinant Activated Protein C) was initially indicated only for high-risk patients (APACHE II score ≥25). *Note: It has since been withdrawn from the market globally after the PROWESS-SHOCK trial showed no benefit, but it remains a common historical "fact" in older question banks.* **High-Yield Clinical Pearls for NEET-PG:** 1. **NICE-SUGAR Trial:** Target blood glucose in ICU is <180 mg/dL; avoid <110 mg/dL. 2. **Sepsis Bundle:** Initial fluid resuscitation should be **30 mL/kg** of crystalloids within the first 3 hours. 3. **Vasopressor of Choice:** Norepinephrine is the first-line agent for septic shock. 4. **Lactate:** Serial lactate measurement is a key marker of tissue hypoxia and response to therapy.

Q: Which of the following is true about anaphylactic shock?

Raised pulse rate. **Explanation:** Anaphylactic shock is a type of **distributive shock** caused by a severe Type I hypersensitivity reaction. The release of inflammatory mediators (like histamine) leads to massive systemic vasodilation and increased capillary permeability [1]. **1. Why "Raised pulse rate" is correct:** In anaphylaxis, the sudden drop in systemic vascular resistance (SVR) leads to profound hypotension. To maintain tissue perfusion and cardiac output, the body initiates a **compensatory baroreceptor reflex**, resulting in **tachycardia** (raised pulse rate). This is a hallmark of most forms of shock, including distributive shock. **2. Why the other options are incorrect:** * **Peripheral vasoconstriction:** Anaphylaxis causes massive **vasodilation** (not constriction) due to the effect of histamine on H1 and H2 receptors [1]. This leads to the characteristic "warm shock" early on. * **Raised blood pressure:** By definition, shock involves **hypotension** (low blood pressure) due to decreased SVR and relative hypovolemia from fluid leaking into the extravascular space [1]. * **Raised cardiac output:** While the heart rate increases, the **total cardiac output (CO) typically decreases** in anaphylactic shock. This is due to "venous pooling" and plasma leakage, which reduces venous return (preload) to the heart. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Adrenaline (Epinephrine) 1:1000 concentration, **0.5 mg IM** (Intramuscular) in the anterolateral thigh [2]. * **Hemodynamic Profile:** Low SVR (Systemic Vascular Resistance), Low PCWP (Pulmonary Capillary Wedge Pressure), and Low CO (Cardiac Output). * **Biphasic Reaction:** Symptoms can recur 1–72 hours after initial resolution; hence, patients should be monitored for at least 4–6 hours [2]. * **Kounis Syndrome:** Anaphylaxis-induced acute coronary syndrome (vasospastic angina).

Q: Which of the following differentiates Systemic Inflammatory Response Syndrome (SIRS) from sepsis?

Absence of definitive evidence of infection. **Explanation:** The fundamental difference between **Systemic Inflammatory Response Syndrome (SIRS)** and **Sepsis** lies in the etiology. SIRS is a clinical syndrome representing a generalized state of inflammation that can be triggered by both infectious (e.g., pneumonia) and non-infectious insults [1]. **Sepsis** is defined specifically as **SIRS caused by a documented or suspected infection.** Therefore, the absence of definitive evidence of infection is what characterizes SIRS in isolation. **Analysis of Options:** * **Option C (Correct):** As per the classic criteria, SIRS becomes Sepsis only when an infectious source is identified [1]. * **Options A, B, and D (Incorrect):** These are all constituent **criteria for SIRS**. To diagnose SIRS, at least two of the following must be present: 1. Temperature >38°C (100.4°F) or 90 beats/min. 3. Respiratory rate >20 breaths/min or PaCO2 12,000/mm³, 10% bands. Since these parameters are present in *both* SIRS and Sepsis, they cannot be used to differentiate between the two. **High-Yield Clinical Pearls for NEET-PG:** * **Sepsis-3 Definitions:** Modern guidelines (Sepsis-3) have shifted away from SIRS, defining Sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection, measured by a **SOFA score ≥ 2**. * **qSOFA (Quick SOFA):** A bedside tool to identify patients at risk (Altered mental status, Systolic BP ≤100 mmHg, Respiratory rate ≥22/min). * **Septic Shock:** Sepsis plus persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg AND serum lactate >2 mmol/L despite adequate fluid resuscitation.

Q: Which type of shock is characterized by high cardiac output and low peripheral resistance?

Septic shock. **Explanation:** The correct answer is **Septic Shock**. **1. Why Septic Shock is correct:** Septic shock is the classic example of **Distributive Shock**. The underlying pathophysiology involves a systemic inflammatory response to infection, leading to the release of inflammatory mediators (like Nitric Oxide). This causes massive **peripheral vasodilation**, which significantly decreases **Systemic Vascular Resistance (SVR)** [2]. To compensate for the drop in blood pressure and meet metabolic demands, the heart increases its rate and stroke volume, resulting in a **high Cardiac Output (CO)** [1]. This is often referred to as "Warm Shock" because the skin remains warm and flushed due to vasodilation [2]. **2. Why the other options are incorrect:** * **Hypovolemic Shock:** Caused by loss of blood or fluid volume. This leads to low CO (due to low preload) and a compensatory **increase in SVR** (vasoconstriction) to maintain BP. * **Cardiogenic Shock:** Caused by primary pump failure (e.g., MI) [3]. It is characterized by **low CO** and a compensatory **increase in SVR**. * **Anaphylactic Shock:** While also a type of distributive shock with low SVR [3], the question specifically targets the classic hemodynamic profile of high CO/low SVR most commonly associated with early (hyperdynamic) sepsis in clinical exams. **3. NEET-PG High-Yield Pearls:** * **Hemodynamic Rule:** In almost all shocks, SVR is high (compensatory), **EXCEPT** in Distributive shocks (Sepsis, Anaphylaxis, Neurogenic), where SVR is low [4]. * **PCWP (Pulmonary Capillary Wedge Pressure):** It is **high** in Cardiogenic shock (fluid backs up) but **low** in Hypovolemic and Septic shock. * **Mixed Venous Oxygen Saturation ($SvO_2$):** It is typically **increased** in Septic shock (due to high flow and impaired tissue extraction) but **decreased** in Cardiogenic and Hypovolemic shock.

Q: In ARDS management, what is the usual tidal volume setting for mechanical ventilation?

5-7 ml/kg. **Explanation:** The cornerstone of managing **Acute Respiratory Distress Syndrome (ARDS)** is **Lung Protective Ventilation (LPV)**. In ARDS, the lungs are heterogeneously affected, with significant areas of consolidation and collapse, leaving only a small portion of functional, aerated lung—a concept known as the **"Baby Lung."** **1. Why 5-7 ml/kg is correct:** Standard tidal volumes (10-12 ml/kg) can cause **Volutrauma** (overdistension) and **Biotrauma** (inflammatory release) in the remaining functional lung units. The ARDSNet protocol recommends a low tidal volume strategy, typically starting at **6 ml/kg of Predicted Body Weight (PBW)**, with a range of **5-8 ml/kg** (most closely represented by option B). This reduces mortality by preventing ventilator-associated lung injury (VALI). **2. Why other options are incorrect:** * **A (2-3 ml/kg):** This is excessively low and would lead to severe hypercapnia and significant atelectasis, making it impossible to maintain adequate minute ventilation. * **C (5-10 ml/kg):** While it starts correctly, the upper limit (10 ml/kg) is too high for ARDS and risks barotrauma. * **D (12-14 ml/kg):** These are traditional high tidal volumes used decades ago, now known to increase mortality in ARDS patients. **High-Yield Clinical Pearls for NEET-PG:** * **PBW vs. Actual Weight:** Tidal volume is always calculated based on **Predicted Body Weight** (based on height and sex), not actual weight, because lung size does not increase with obesity. * **Plateau Pressure ($P_{plat}$):** The goal is to keep $P_{plat}$ **< 30 cm $H_2O$**. * **Permissive Hypercapnia:** To maintain low tidal volumes, clinicians may allow $PaCO_2$ to rise and pH to drop (up to 7.20), provided the patient tolerates it. * **Driving Pressure:** Calculated as ($P_{plat} - PEEP$); keeping this **< 15 cm $H_2O$** is a strong predictor of survival.

Question 1

Which of the following is NOT an evidence-based recommended therapy for the management of acute respiratory distress syndrome?

Accepted Answer

Inhaled nitric oxide

Answer

Low tidal volume mechanical ventilation

Answer

Minimize left atrial filling pressures

Answer

Prone positioning

Question 2

What are the diagnostic criteria for acute respiratory distress syndrome?

Accepted Answer

PaO2/FiO2 ratio is < 300 mmHg

Answer

PaO2/FiO2 ratio is < 200 mmHg

Answer

PaO2/FiO2 ratio is < 400 mmHg

Answer

PaO2/FiO2 ratio is < 100 mmHg

Question 3

What is the commonest cause of death in ARDS?

Accepted Answer

Non-pulmonary organ failure

Answer

Hypoxemia

Answer

Hypotension

Answer

Respiratory failure

Question 4

With reference to the optimal management of patients with sepsis in the intensive care unit, all of the following interventions are evidence-based except?

Accepted Answer

Intensive blood glucose monitoring and prevention of hyperglycemia improves survival in critically ill patients.

Answer

Low tidal volume during assisted ventilation prevents acute lung injury.

Answer

For outcome of goal-oriented management of sepsis patients, monitoring of central venous pressure, hourly urine output and blood pressure is adequate.

Answer

The use of drotrecogin alpha is restricted to severely ill patients with APACHE score 25.

Question 5

Which of the following is true about anaphylactic shock?

Accepted Answer

Raised pulse rate

Answer

Peripheral vasoconstriction

Answer

Raised blood pressure

Answer

Raised cardiac output

Question 6

A patient in the ICU has normal pulmonary artery pressure, low systemic peripheral resistance, low cardiac index, and arterial PO2 of 93 mmHg. What are the diagnostic possibilities?

Accepted Answer

Cardiac tamponade

Answer

Cardiogenic shock

Answer

Septic shock

Answer

Acute tubular necrosis

Question 7

Which of the following differentiates Systemic Inflammatory Response Syndrome (SIRS) from sepsis?

Accepted Answer

Absence of definitive evidence of infection

Answer

Heart rate > 90 beats per minute

Answer

Temperature > 38 degrees Celsius

Answer

White blood cell count > 12,000 cells/mm³

Question 8

Which type of shock is characterized by high cardiac output and low peripheral resistance?

Accepted Answer

Septic shock

Answer

Hypovolemic shock

Answer

Cardiogenic shock

Answer

Anaphylactic Shock

Question 9

In ARDS management, what is the usual tidal volume setting for mechanical ventilation?

Accepted Answer

5-7 ml/kg

Answer

2-3 ml/kg

Answer

5-10 ml/kg

Answer

12-14 ml/kg

Question 10

In cardiopulmonary resuscitation, calcium can be given in all of the following conditions, EXCEPT:

Accepted Answer

Hypokalemia

Answer

Hypocalcemia

Answer

Hyperkalemia

Answer

Calcium channel blocker toxicity

Critical Care — MCQs

Critical Care — MCQs

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