Respiratory and Airway Management Practice Questions

Q: Which of the following is NOT an indication for endotracheal intubation?

Pneumothorax. ### Explanation The primary goal of endotracheal intubation is to secure the airway, protect the lungs from aspiration, and facilitate mechanical ventilation. **Why Pneumothorax is the Correct Answer:** Pneumothorax is a clinical condition characterized by air in the pleural space, leading to lung collapse. The definitive management for a pneumothorax is **intercostal drainage (chest tube insertion)**, not intubation. In fact, initiating positive pressure ventilation (via intubation) in a patient with an untreated pneumothorax can rapidly convert it into a life-threatening **tension pneumothorax**, as the positive pressure forces more air into the pleural space with no way to escape. **Analysis of Incorrect Options:** * **A. Maintenance of a patent airway:** This is a primary indication, especially in patients with a low GCS (<8), upper airway obstruction (e.g., angioedema, trauma), or loss of protective airway reflexes. * **B. To provide positive pressure ventilation:** Intubation is required when a patient cannot ventilate or oxygenate adequately on their own, such as in respiratory failure, ARDS, or during general anesthesia with muscle relaxants. * **C. Pulmonary toilet:** Intubation allows for deep tracheal suctioning in patients who cannot clear secretions effectively (e.g., neuromuscular weakness or thick, copious secretions), preventing atelectasis and pneumonia. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for confirming ETT placement:** Capnography (EtCO2). * **Most common complication of intubation:** Sore throat; however, the most serious immediate complication is **unrecognized esophageal intubation**. * **Cormack-Lehane Classification:** Used to grade the view obtained during direct laryngoscopy. * **Indication for "Rapid Sequence Induction" (RSI):** Full stomach, pregnancy, or acute intestinal obstruction to prevent aspiration.

Q: Which of the following characterizes Mallampati class 3?

Both hard palate and soft palate visible. The **Mallampati Classification** is a clinical tool used to predict the ease of endotracheal intubation by assessing the relationship between the size of the tongue and the oral cavity. It is performed with the patient sitting upright, head in a neutral position, mouth wide open, and tongue protruded without phonation. ### **Explanation of Options** * **Correct Answer (B):** In **Class 3**, the clinician can visualize the **hard palate and the soft palate**. The base of the uvula may occasionally be seen, but the pillars and the majority of the uvula are obscured by the tongue. This indicates a potentially difficult airway. * **Option A:** This describes **Class 4**, where only the hard palate is visible. This is a strong predictor of a difficult airway. * **Option C:** This describes **Class 1**, where the soft palate, fauces, entire uvula, and anterior/posterior tonsillar pillars are all clearly visible. This usually indicates an easy intubation. ### **The Mallampati Scale Summary** * **Class 1:** Soft palate, fauces, uvula, pillars visible. * **Class 2:** Soft palate, fauces, portion of uvula visible. * **Class 3:** Soft palate and hard palate visible. * **Class 4:** Only hard palate visible. ### **High-Yield Clinical Pearls for NEET-PG** * **Samsoon and Young Modification:** The original Mallampati classification had 3 classes; the 4th class was added later by Samsoon and Young. * **Predictive Value:** Classes 3 and 4 are clinically significant predictors of **difficult laryngoscopy** (Cormack-Lehane Grade 3 or 4). * **Gold Standard:** While Mallampati is a common screening tool, the "gold standard" for assessing the glottic view is the **Cormack-Lehane classification**, performed during direct laryngoscopy. * **Mnemonic:** Remember **PUSH** (Pillars, Uvula, Soft palate, Hard palate) to recall what is visible in descending order from Class 1 to 4.

Q: The Sellick maneuver is used to prevent which of the following?

Aspiration of gastric content. **Explanation:** The **Sellick maneuver**, also known as **cricoid pressure**, is a technique used during Rapid Sequence Induction (RSI) to prevent the passive regurgitation and subsequent **aspiration of gastric contents** into the lungs. **Why Option C is correct:** The maneuver involves applying firm downward pressure on the **cricoid cartilage** (the only complete cartilaginous ring in the larynx). This pressure compresses the flexible esophagus against the body of the sixth cervical vertebra (C6), effectively occluding the esophageal lumen and preventing stomach contents from reaching the pharynx during the period between loss of consciousness and successful tracheal intubation. **Why the other options are incorrect:** * **A. Alveolar collapse:** This is prevented by PEEP (Positive End-Expiratory Pressure) or recruitment maneuvers, not by external laryngeal pressure. * **B. Hypertension:** Laryngoscopy and intubation typically cause a sympathetic surge leading to hypertension. The Sellick maneuver does not prevent this; in fact, if applied poorly, it can make intubation more difficult, potentially worsening the hypertensive response. * **C. Bradycardia:** Bradycardia is a common side effect of the maneuver, especially in children, due to stimulation of the vagus nerve (vasovagal response). It is not a preventive measure for it. **High-Yield Clinical Pearls for NEET-PG:** * **Force required:** Approximately **10 Newtons (1kg)** when awake and **30 Newtons (3kg)** once the patient is unconscious. * **Contraindications:** Active vomiting (risk of esophageal rupture/Boerhaave syndrome), unstable cervical spine fractures, and laryngeal trauma. * **BURP Maneuver vs. Sellick:** Do not confuse Sellick with the **BURP maneuver** (Backward, Upward, Rightward Pressure), which is used to improve the *view* of the glottis during laryngoscopy, not to prevent aspiration.

Q: An infant with respiratory distress was intubated. What is the fastest and most accurate method to confirm endotracheal tube placement?

Capnography. **Explanation:** **1. Why Capnography is Correct:** Capnography (End-tidal CO2 monitoring) is the **Gold Standard** for confirming endotracheal tube (ETT) placement. It provides a real-time, objective measurement of exhaled carbon dioxide. The presence of a persistent CO2 waveform (at least 5-6 breaths) confirms that the tube is in the trachea and not the esophagus, as the stomach does not produce CO2. It is the fastest method because it provides immediate visual feedback upon the first few breaths. **2. Why Other Options are Incorrect:** * **Clinical Assessment (Auscultation):** While essential, it is subjective and can be misleading. Breath sounds can be transmitted from the stomach or the contralateral lung, and in infants, the chest wall is thin, making localization difficult. * **Chest Radiography:** While it is the best method to determine the **depth** of the tube (position relative to the carina), it is too slow for initial confirmation and cannot be used in emergency settings to rule out esophageal intubation immediately. * **Airway Pressure Measurement:** This monitors lung compliance and resistance but does not differentiate between tracheal and esophageal placement. **3. NEET-PG High-Yield Pearls:** * **Gold Standard for ETT placement:** Capnography. * **Gold Standard for ETT depth/position:** Chest X-ray. * **False Positives in Capnography:** Can occur if the patient recently consumed carbonated beverages (transient CO2 in the stomach). * **False Negatives in Capnography:** May occur during **Cardiac Arrest** or severe pulmonary embolism, where CO2 is not being delivered to the lungs due to lack of pulmonary blood flow. * **Colorimetric CO2 detectors:** Use pH-sensitive paper (turns from purple to yellow) and are useful in pre-hospital settings.

Q: Which is the anesthetic agent of choice in a case of status asthmaticus?

Ketamine. **Explanation:** **Ketamine** is the induction agent of choice in status asthmaticus due to its potent **bronchodilatory properties**. It works through two primary mechanisms: 1. **Sympathomimetic effect:** It increases the release of endogenous catecholamines, which stimulate $\beta_2$ receptors, leading to smooth muscle relaxation. 2. **Direct action:** It exerts a direct relaxant effect on the bronchial smooth muscles and inhibits vagal pathways. This makes it ideal for patients with reactive airway disease where intubation is necessary. **Analysis of Incorrect Options:** * **Thiopentone:** It is generally avoided in asthmatics because it can cause **histamine release**, which may trigger or worsen bronchospasm. It also does not suppress airway reflexes as effectively as other agents. * **Ether:** While Ether is a potent bronchodilator, it is an **irritant to the respiratory mucosa**, leading to increased secretions and a high incidence of laryngospasm during induction. It is also flammable and largely obsolete in modern practice. * **Nitrous Oxide:** It is a relatively inert gas with no significant bronchodilatory or bronchoconstrictive properties. It is not used as a primary induction agent for managing status asthmaticus. **High-Yield Clinical Pearls for NEET-PG:** * **Inhalational Agent of Choice:** **Sevoflurane** is preferred for mask induction in asthmatics as it is non-pungent and a potent bronchodilator (Halothane is also a bronchodilator but sensitizes the myocardium to catecholamines). * **Muscle Relaxant to Avoid:** **Atracurium** and **Mivacurium** should be avoided due to histamine release. **Vecuronium** or **Rocuronium** are preferred. * **Pre-medication:** Glycopyrrolate is often used to reduce secretions and provide mild bronchodilation via its anticholinergic effect.

Q: What is the maximum fraction of inspired oxygen (FiO2) that can be delivered via a nasal oxygen catheter?

0.44. **Explanation:** The fraction of inspired oxygen (FiO2) delivered via a **nasal cannula (or catheter)** is determined by the flow rate and the patient’s inspiratory flow. In a normal adult, the baseline FiO2 of room air is 0.21 (21%). For every **1 liter per minute (L/min)** of supplemental oxygen added, the FiO2 increases by approximately **4% (0.04)**. The maximum effective flow rate for a nasal cannula is **6 L/min**. Beyond this, the nasal mucosa becomes irritated/dried, and the anatomical reservoir (nasopharynx) is saturated, leading to a plateau in FiO2. * **Calculation:** $21\% + (6\text{ L/min} \times 4\%) = 21\% + 24\% = 45\%$. * In clinical practice and standard textbooks, this maximum value is rounded to **0.44 (44%)**. **Analysis of Options:** * **A (1.0):** Achievable only with a closed circuit (ventilator), a tight-fitting non-rebreather mask (NRBM) with high flow, or high-flow nasal cannula (HFNC) systems. * **B (0.6):** This is the typical maximum for a **simple face mask** (at 6–10 L/min). * **C (0.2):** This represents room air (0.21) without any supplemental oxygen. **High-Yield Clinical Pearls for NEET-PG:** * **Flow Rates:** Nasal cannula flow is typically 1–6 L/min. If >4 L/min is used, humidification is required to prevent epistaxis and mucosal crusting. * **Variable Performance:** The nasal cannula is a **low-flow/variable performance device**; the actual FiO2 varies if the patient’s minute ventilation or inspiratory flow rate changes. * **Dead Space:** Nasal catheters/cannulae do not increase dead space, unlike certain masks. * **Simple Face Mask:** Minimum flow must be **5 L/min** to flush out exhaled $CO_2$ from the mask and prevent rebreathing.

Question 1

Which of the following is NOT an indication for endotracheal intubation?

Accepted Answer

Pneumothorax

Answer

Maintenance of a patent airway

Answer

To provide positive pressure ventilation

Answer

Pulmonary toilet

Question 2

What is the proper technique for endotracheal intubation?

Accepted Answer

Flexion of the neck and extension of the atlantooccipital joint

Answer

Flexion of neck

Answer

Extension of the neck

Answer

Extension of the neck and flexion of the atlantooccipital joint

Question 3

Which of the following inhalational anesthetic agents demonstrates the most potent bronchodilating effect?

Accepted Answer

Halothane

Answer

Isoflurane

Answer

Sevoflurane

Answer

Desflurane

Question 4

Which of the following statements about the infant airway compared to the adult airway is FALSE?

Accepted Answer

All of the above are true statements about the infant airway

Answer

The relatively large size of the tongue

Answer

The epiglottis is omega shaped

Answer

The larynx is funnel shaped

Question 5

Which of the following characterizes Mallampati class 3?

Accepted Answer

Both hard palate and soft palate visible

Answer

Only hard palate visible

Answer

Hard palate, soft palate, uvula and faucial pillars visible

Answer

None of the above

Question 6

During laryngoscopy and intubation procedure, all of these are true, except:

Accepted Answer

After insertion of the laryngoscope, it is levered on the upper incisors to pull up the tongue and visualize the vocal cords.

Answer

A slight pressure may be applied at the cricoid cartilage.

Answer

The laryngoscope is held in the right hand and introduced from the right side of the patient.

Answer

The neck is flexed with extension at the atlanto-occipital joint.

Question 7

The Sellick maneuver is used to prevent which of the following?

Accepted Answer

Aspiration of gastric content

Answer

Alveolar collapse

Answer

Hypertension

Answer

Bradycardia

Question 8

An infant with respiratory distress was intubated. What is the fastest and most accurate method to confirm endotracheal tube placement?

Accepted Answer

Capnography

Answer

Clinical assessment by auscultation

Answer

Chest radiography

Answer

Airway pressure measurement

Question 9

Which is the anesthetic agent of choice in a case of status asthmaticus?

Accepted Answer

Ketamine

Answer

Thiopentone

Answer

Ether

Answer

Nitrous Oxide

Question 10

What is the maximum fraction of inspired oxygen (FiO2) that can be delivered via a nasal oxygen catheter?

Accepted Answer

0.44

Answer

1.0

Answer

0.6

Answer

0.2

Respiratory and Airway Management — MCQs

Respiratory and Airway Management — MCQs

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