Respiratory and Airway Management — MCQs

Respiratory and Airway Management Indian Medical PG Practice Questions and MCQs

Question 221: Which of the following is NOT a benefit of a laryngeal mask airway?

A. Easy and fast insertion
B. Less hemodynamic imbalance
C. Tolerates a lesser plane of anesthesia
D. Prevents aspiration (Correct Answer)

Explanation: The **Laryngeal Mask Airway (LMA)** is a supraglottic airway device (SAD) that sits above the glottis. Understanding its limitations is crucial for NEET-PG. ### **Why "Prevents Aspiration" is the Correct Answer** The primary disadvantage of a standard LMA is that it **does not provide a definitive seal** for the trachea. Unlike an endotracheal tube (ETT), which has a cuff inflated below the vocal cords to physically block gastric contents from entering the lungs, the LMA cuff sits in the hypopharynx. It cannot protect the airway against pulmonary aspiration of gastric contents. Therefore, it is contraindicated in patients with a "full stomach," hiatal hernia, or morbid obesity. ### **Analysis of Incorrect Options** * **A. Easy and fast insertion:** LMAs are designed for "blind" insertion without the need for a laryngoscope. They have a high first-attempt success rate, even for non-anesthesiologists, making them ideal for "cannot intubate, cannot ventilate" scenarios. * **B. Less hemodynamic imbalance:** Laryngoscopy and intubation cause significant sympathetic stimulation (tachycardia and hypertension). LMA insertion is much less invasive and results in minimal hemodynamic fluctuations. * **C. Tolerates a lesser plane of anesthesia:** Because the LMA does not stimulate the sensitive tracheal mucosa (unlike an ETT), patients can tolerate the device at lighter planes of anesthesia without coughing or laryngospasm. ### **High-Yield Clinical Pearls for NEET-PG** * **Gold Standard for Aspiration Protection:** Endotracheal Intubation (Cuffed). * **LMA ProSeal:** A second-generation LMA that features a gastric drain tube to vent stomach contents, offering *better* (but still not absolute) protection compared to the Classic LMA. * **Maximum Inflation Pressure:** The intracuff pressure of an LMA should not exceed **60 cm H₂O** to avoid mucosal nerve injury. * **Size Selection:** Size 3 (30-50kg), Size 4 (50-70kg), Size 5 (70-100kg).

Question 222: Respiratory obstruction in comatose patients is usually due to which of the following?

A. Presence of airway
B. Presence of Ryle's tube
C. Tracheostomy
D. Falling back of tongue (Correct Answer)

Explanation: **Explanation:** The most common cause of upper airway obstruction in an unconscious or comatose patient is the **falling back of the tongue**. In a state of coma or deep anesthesia, there is a significant loss of muscle tone in the **genioglossus muscle** (the primary muscle responsible for protruding the tongue). When this muscle relaxes, gravity causes the base of the tongue to fall backward against the posterior pharyngeal wall, effectively occluding the airway. **Analysis of Options:** * **A. Presence of airway:** An artificial airway (like an oropharyngeal or nasopharyngeal airway) is actually used to **relieve** obstruction by keeping the tongue away from the posterior pharyngeal wall. * **B. Presence of Ryle’s tube:** While a nasogastric tube occupies space in the esophagus and nasopharynx, it does not typically cause respiratory obstruction. Its primary risks are aspiration or esophageal trauma. * **C. Tracheostomy:** This is a surgical procedure performed to **bypass** an upper airway obstruction. It provides a definitive patent airway and is not a cause of obstruction itself. **Clinical Pearls for NEET-PG:** * **The "Safety Muscle":** The genioglossus is known as the safety muscle of the tongue. * **First-line Management:** The initial maneuvers to relieve this obstruction are the **Head Tilt-Chin Lift** (stretches the anterior neck muscles) or the **Jaw Thrust** (displaces the mandible forward, pulling the genioglossus with it). * **Trauma Alert:** In suspected cervical spine injury, the **Jaw Thrust** is the maneuver of choice as it avoids neck extension. * **Triple Airway Maneuver:** Consists of Head tilt, Jaw thrust, and Mouth opening.

Question 223: What is the major disadvantage of pressure control ventilation (PCV)?

A. Variable alveolar volume when lung compliance decreases (Correct Answer)
B. Patient discomfort
C. Barotrauma
D. Controlled peak alveolar pressure

Explanation: **Explanation:** In **Pressure Control Ventilation (PCV)**, the ventilator delivers a breath until a preset inspiratory pressure is reached and maintains that pressure for a set inspiratory time. **Why Option A is correct:** The primary disadvantage of PCV is that **Tidal Volume ($V_T$) is not guaranteed**. Since the pressure is fixed, the volume of air delivered depends entirely on the patient's lung mechanics. According to the formula $V = \text{Compliance} \times \text{Pressure}$, if **lung compliance decreases** (e.g., ARDS, pulmonary edema) or **airway resistance increases** (e.g., bronchospasm), the resulting tidal volume and alveolar ventilation will drop significantly. This can lead to acute hypoventilation and hypercarbia. **Analysis of Incorrect Options:** * **B. Patient discomfort:** PCV is generally considered *more* comfortable than Volume Control Ventilation (VCV) because it uses a decelerating flow pattern that matches the patient's natural inspiratory demand. * **C. Barotrauma:** PCV actually **reduces** the risk of barotrauma because it strictly limits the peak inspiratory pressure (PIP), preventing the high pressure spikes often seen in VCV. * **D. Controlled peak alveolar pressure:** This is an **advantage**, not a disadvantage. By capping the pressure, PCV protects the lungs from overdistension. **High-Yield Clinical Pearls for NEET-PG:** * **VCV vs. PCV:** In VCV, **Volume is constant** but Pressure is variable. In PCV, **Pressure is constant** but Volume is variable. * **Flow Pattern:** PCV uses a **decelerating flow** (square pressure waveform), which improves gas distribution and oxygenation compared to the constant flow of VCV. * **Best Use:** PCV is often preferred in patients with low compliance (ARDS) or where high airway pressures must be avoided (e.g., pediatrics, emphysema).

Question 224: Endotracheal intubation is not useful for which of the following conditions?

A. Pneumothorax (Correct Answer)
B. Pulmonary toilet
C. Airway obstruction
D. Decreased level of consciousness

Explanation: **Explanation:** **1. Why Pneumothorax is the Correct Answer:** Endotracheal intubation is a procedure used to secure the airway and facilitate mechanical ventilation. In a **Pneumothorax**, the primary pathology is the presence of air in the pleural space, leading to lung collapse. Intubation does not treat this; in fact, initiating positive pressure ventilation (PPV) via an endotracheal tube can worsen a simple pneumothorax or convert it into a life-threatening **Tension Pneumothorax**. The definitive treatment for pneumothorax is a needle decompression or chest tube (intercostal drain) insertion, not intubation. **2. Analysis of Incorrect Options:** * **Pulmonary Toilet:** Intubation allows for direct access to the lower respiratory tract for frequent suctioning of secretions in patients with a poor cough reflex or excessive mucus production. * **Airway Obstruction:** Intubation bypasses upper airway obstructions (e.g., epiglottitis, laryngeal edema, or foreign bodies) to ensure a patent conduit for oxygenation. * **Decreased Level of Consciousness:** Patients with a GCS ≤ 8 lose their protective airway reflexes (gag and cough). Intubation is mandatory to prevent aspiration of gastric contents and to manage hypoventilation. **Clinical Pearls for NEET-PG:** * **The "GCS 8, Intubate" Rule:** A classic indication for securing the airway in trauma or neurological insult. * **Tension Pneumothorax Warning:** If a patient’s hemodynamics deteriorate immediately after intubation and PPV, always suspect a tension pneumothorax. * **Indications for Intubation (The 3 Ps):** **P**atency (obstruction), **P**rotection (aspiration risk), and **P**ump failure (respiratory failure/ventilation).

Question 225: Cardiopulmonary resuscitation in adults with cardiac arrest should be:

A. A 30:2 compression-to-ventilation ratio. (Correct Answer)
B. A 15:2 compression-to-ventilation ratio.
C. Continuous chest compressions without ventilation.
D. Vocal stimulation with chest compressions.

Explanation: **Explanation:** The correct answer is **A. A 30:2 compression-to-ventilation ratio.** According to the **AHA (American Heart Association) and ERC (European Resuscitation Council) guidelines**, the standard of care for Basic Life Support (BLS) in adults is a compression-to-ventilation ratio of **30:2**. This ratio is designed to maximize coronary perfusion pressure by minimizing interruptions in chest compressions while providing adequate oxygenation. **Analysis of Options:** * **Option B (15:2):** This ratio is used for **infants and children** when there are **two rescuers** present. In single-rescuer pediatric CPR, the ratio remains 30:2. * **Option C (Continuous compressions):** While "Hands-Only CPR" is encouraged for untrained bystanders, the formal medical protocol for healthcare providers in cardiac arrest (before an advanced airway is placed) requires synchronized ventilations. Once an advanced airway (ET tube/LMA) is in place, compressions become continuous at 100–120/min with 1 breath every 6 seconds. * **Option D (Vocal stimulation):** This is part of the initial assessment (checking for responsiveness) but is not a component of the resuscitation process itself. **High-Yield Clinical Pearls for NEET-PG:** * **Compression Depth:** 2–2.4 inches (5–6 cm) in adults. * **Compression Rate:** 100–120 per minute. * **Recoil:** Allow complete chest recoil after each compression to ensure cardiac filling. * **Advanced Airway:** Once an advanced airway is secured, do **not** cycle 30:2; provide continuous compressions and 10 breaths/min. * **Sequence:** Remember the **C-A-B** sequence (Compressions, Airway, Breathing).

Question 226: To prevent pulmonary aspiration of gastric content in high-risk patients, which of the following is practiced during intubation?

A. Rapid sequence induction (Correct Answer)
B. BURP maneuver
C. Pharmacological therapy
D. All of the above

Explanation: To prevent pulmonary aspiration of gastric contents (Mendelson’s syndrome) in high-risk patients (e.g., full stomach, intestinal obstruction, pregnancy), **Rapid Sequence Induction (RSI)** is the gold standard technique. ### **1. Why Rapid Sequence Induction (RSI) is Correct** RSI is designed to minimize the time between the loss of protective airway reflexes and the placement of a cuffed endotracheal tube. The core components include: * **Pre-oxygenation** (to provide a safety buffer of apnea time). * **Administration of a fixed dose of induction agent** followed immediately by a fast-acting neuromuscular blocker (e.g., Succinylcholine or Rocuronium). * **Avoidance of positive pressure ventilation** (bag-mask ventilation) before intubation to prevent gastric insufflation, which increases the risk of regurgitation. * **Application of Cricoid Pressure (Sellick’s Maneuver)** to manually occlude the esophagus. ### **2. Why Other Options are Incorrect** * **BURP Maneuver (Backward, Upward, Rightward Pressure):** This is used to improve the **visualization of the glottis** during laryngoscopy. It is not designed to prevent aspiration; in fact, it is distinct from cricoid pressure. * **Pharmacological Therapy:** While drugs like H2 blockers (Ranitidine), proton pump inhibitors (Pantoprazole), or prokinetics (Metoclopramide) are used as *pre-medication* to reduce gastric volume and acidity, they are not "practiced during intubation" to physically prevent aspiration. * **All of the Above:** Incorrect because BURP is for visualization, not aspiration prophylaxis. ### **3. Clinical Pearls for NEET-PG** * **Sellick’s Maneuver:** Uses 30 Newtons (approx. 3kg) of pressure on the cricoid cartilage. * **Mendelson’s Syndrome:** Aspiration pneumonitis defined by gastric pH <2.5 and volume >0.4 ml/kg (25 ml). * **Drug of Choice for RSI:** Succinylcholine remains the classic choice due to its rapid onset (30–60s) and short duration. Rocuronium (1.2 mg/kg) is the alternative.

Question 227: High-quality CPR includes all of the following except?

A. Chest compressions at 200 per minute (Correct Answer)
B. Depth of 2 inches or more
C. Complete chest recoil after each compression
D. Avoidance of excessive ventilation

Explanation: 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 228: What does VAT stand for in the context of mechanical ventilation?

A. Ventilator associated trauma
B. Ventilator associated treatment
C. Ventilator associated tracheobronchitis (Correct Answer)
D. None of the above

Explanation: **Explanation:** **Ventilator-associated tracheobronchitis (VAT)** is a clinical condition characterized by inflammation of the tracheobronchial tree in patients who have been intubated and mechanically ventilated for at least 48 hours. It is considered an intermediate stage between colonization of the lower respiratory tract and **Ventilator-associated Pneumonia (VAP)**. **Why Option C is correct:** VAT is defined by the presence of fever (with no other source), increased or purulent tracheal secretions, and a positive tracheal aspirate culture ($>10^5$ CFU/mL). Crucially, unlike VAP, VAT presents **without** new or progressive infiltrates on a chest X-ray. Recognizing VAT is vital because, if left untreated, it frequently progresses to VAP, leading to prolonged weaning and increased ICU stay. **Why other options are incorrect:** * **Option A:** While mechanical ventilation can cause trauma (Barotrauma, Volutrauma, or Atelectrauma), the standard medical acronym for this is **VALI** (Ventilator-associated Lung Injury) or **VILI** (Ventilator-induced Lung Injury), not VAT. * **Option B:** "Ventilator associated treatment" is not a recognized clinical entity or standard terminology in critical care. **High-Yield Clinical Pearls for NEET-PG:** * **The "X-ray Rule":** The primary diagnostic differentiator between VAT and VAP is the **absence of new pulmonary infiltrates** in VAT. * **Common Pathogens:** Similar to VAP, the most common organisms are *Pseudomonas aeruginosa*, *Staphylococcus aureus* (MRSA), and *Acinetobacter* species. * **Prevention:** The "Ventilator Bundle" (Head of bed elevation 30-45°, daily sedation holidays, subglottic secretion drainage, and oral hygiene with chlorhexidine) helps prevent both VAT and VAP.

Question 229: A 40-year-old man presents to the emergency department one hour after a motor vehicle accident with severe maxillofacial trauma. His pulse rate is 120/min, BP is 100/70 mm Hg, and SpO2 is 80% on oxygen. What is the immediate management?

A. Nasotracheal intubation
B. Orotracheal intubation (Correct Answer)
C. Intravenous fluid resuscitation
D. Tracheostomy

Explanation: **Explanation:** The primary objective in trauma management follows the **ABC (Airway, Breathing, Circulation)** protocol. This patient presents with severe maxillofacial trauma and respiratory distress (SpO2 80%), indicating an immediate need for a definitive airway. **1. Why Orotracheal Intubation is correct:** In the emergency setting, **Orotracheal intubation** is the preferred method for establishing a definitive airway. Despite the maxillofacial trauma, it is faster and more reliable than surgical options. It allows for direct visualization (often with the aid of a video laryngoscope or manual in-line stabilization if a cervical spine injury is suspected) and immediate ventilation to correct hypoxia. **2. Why other options are incorrect:** * **Nasotracheal intubation:** This is **contraindicated** in severe maxillofacial or suspected basilar skull fractures (e.g., Le Fort II/III) due to the risk of accidental intracranial tube placement through a fractured cribriform plate. * **Intravenous fluid resuscitation:** While the patient is tachycardic and potentially hypotensive (Circulation), the immediate life-threat is the airway and hypoxia (SpO2 80%). Airway management always takes precedence over fluid resuscitation in the ABC sequence. * **Tracheostomy:** This is a time-consuming surgical procedure and is not the first-line "immediate" management. If orotracheal intubation fails, a **Cricothyroidotomy** is the preferred emergency surgical airway, not a tracheostomy. **Clinical Pearls for NEET-PG:** * **Definitive Airway:** Defined as a cuffed tube in the trachea (Orotracheal, Nasotracheal, or Surgical). * **Golden Rule:** In trauma, always assume a cervical spine injury; perform intubation with **Manual In-Line Stabilization (MILS)**. * **Hard Signs for Airway Intervention:** Apnea, GCS ≤ 8, severe maxillofacial fractures, or impending airway obstruction (stridor/hematoma).

Question 230: Which of the following features is NOT present in a Proseal LMA (PLMA), a variant of the Laryngeal Mask Airway?

A. Gastric drain tube port
B. Posterior cuff
C. Wire reinforced airway
D. Tracheal cuff (Correct Answer)

Explanation: The **Proseal LMA (PLMA)** is a second-generation supraglottic airway device (SAD) designed to provide a better seal and improved safety compared to the classic LMA. ### **Explanation of the Correct Answer** **D. Tracheal cuff:** This is the correct answer because the Proseal LMA is a **supraglottic** device. By definition, it sits above the glottis (vocal cords) and does not enter the trachea. Therefore, it does not possess a tracheal cuff. Tracheal cuffs are characteristic features of Endotracheal Tubes (ETTs) or Tracheostomy tubes, which provide a subglottic seal. ### **Analysis of Incorrect Options** * **A. Gastric drain tube port:** This is a hallmark feature of the PLMA. It allows for the passage of a gastric tube to decompress the stomach and separates the alimentary and respiratory tracts, reducing the risk of aspiration. * **B. Posterior cuff:** Unlike the classic LMA, the PLMA has an additional cuff on the posterior aspect of the mask. This increases the seal pressure (up to 30 cm H₂O), allowing for more effective positive pressure ventilation. * **C. Wire reinforced airway:** The breathing tube of the PLMA is wire-reinforced (flexible) to prevent kinking and to accommodate the presence of the parallel gastric drain tube. ### **High-Yield Clinical Pearls for NEET-PG** * **Seal Pressure:** PLMA provides a higher oropharyngeal leak pressure (approx. 30 cm H₂O) compared to the Classic LMA (approx. 20 cm H₂O). * **Bite Block:** The PLMA features a built-in silicone bite block to prevent airway occlusion if the patient bites down. * **Maximum Size of Gastric Tube:** For a Size 4 PLMA, a 14 Fr or 16 Fr Ryle’s tube is typically used. * **Comparison:** While the **LMA Fastrach** is designed for intubation, the **PLMA** is designed for controlled ventilation and gastric drainage.

Practice by Chapter

Respiratory Physiology

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Airway Anatomy

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Preoxygenation Techniques

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Mask Ventilation

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Supraglottic Airway Devices

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Direct Laryngoscopy

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Video Laryngoscopy

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Fiberoptic Intubation

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Surgical Airway Management

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One-Lung Ventilation Techniques

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Ventilation Strategies During Anesthesia

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Extubation Criteria and Techniques

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