Respiratory and Airway Management Practice Questions

Q: What complication is NOT seen with controlled ventilation?

Cardiac tamponade. **Explanation:** Controlled ventilation involves the application of **Positive Pressure Ventilation (PPV)**, which significantly alters intrathoracic dynamics. **Why Cardiac Tamponade is the correct answer:** Cardiac tamponade is a clinical syndrome caused by the accumulation of fluid, pus, or blood in the pericardial space, leading to external compression of the heart. It is a **structural/mechanical pathology** of the pericardium and is not caused by the physiological effects of a ventilator. While PPV can mimic some hemodynamic signs of tamponade (like decreased venous return), it does not cause the condition itself. **Analysis of Incorrect Options:** * **Barotrauma:** High airway pressures during controlled ventilation can rupture alveoli, leading to pneumothorax, pneumomediastinum, or subcutaneous emphysema. * **Alkalosis:** Excessive minute ventilation (hyperventilation) during controlled breathing leads to the "blowing off" of $CO_2$. This results in **Respiratory Alkalosis**, which can shift the oxyhemoglobin dissociation curve to the left. * **Pulmonary Embolism:** While not a direct mechanical result of the breath itself, prolonged controlled ventilation (often associated with immobilization and sedation in ICU settings) significantly increases the risk of **Deep Vein Thrombosis (DVT)** and subsequent pulmonary embolism due to venous stasis. **High-Yield Clinical Pearls for NEET-PG:** * **Hemodynamic Effect:** PPV increases intrathoracic pressure, which decreases venous return (preload), leading to a potential **drop in Cardiac Output**. * **Reverse Pulsus Paradoxus:** In mechanically ventilated patients, systolic blood pressure *rises* during inspiration (the opposite of spontaneous breathing). * **VAP:** Ventilator-Associated Pneumonia is a critical infectious complication to remember for exams.

Q: Identify the pictured airway device.

Nasopharyngeal airway. ***Nasopharyngeal airway*** - Features a **soft, flexible tube** with a **beveled distal tip** and **proximal flange with safety pin** to prevent migration into the nostril. - Designed for **nasal insertion** to maintain airway patency, particularly useful in patients with **intact gag reflex** or **oral trauma**. *Oropharyngeal airway* - Has a **rigid, curved plastic design** that follows the **natural curve of the tongue** and lacks the flexible tube structure. - Inserted through the **mouth** and requires **absence of gag reflex**, making it unsuitable for conscious patients. *Proseal airway* - A **supraglottic airway device** with an **inflatable cuff** and **gastric drainage tube** for advanced airway management. - Much **larger and more complex** than simple airway adjuncts, designed for **mechanical ventilation** under anesthesia. *Flexometallic LMA* - Features a **wire-reinforced flexible shaft** with an **inflatable laryngeal mask** at the distal end. - Designed for **supraglottic ventilation** during procedures requiring **head and neck positioning** where standard LMAs might kink.

Q: In a young patient with extensive soft tissue and muscle injury, which muscle relaxant used for endotracheal intubation might lead to cardiac arrest?

Suxamethonium. **Explanation:** The correct answer is **Suxamethonium (Succinylcholine)**. **Why Suxamethonium is the correct answer:** Suxamethonium is a depolarizing neuromuscular blocker that acts by mimicking acetylcholine at the nicotinic receptors. In patients with **extensive soft tissue injury, major burns, or denervation injuries**, there is an "upregulation" of extrajunctional acetylcholine receptors. When Suxamethonium is administered, these receptors open, causing a massive efflux of potassium from the muscle cells into the extracellular fluid. This **acute hyperkalemia** can lead to severe cardiac arrhythmias and sudden **cardiac arrest**. This risk typically peaks 24–48 hours after the injury and can persist for months. **Why other options are incorrect:** * **Atracurium:** A non-depolarizing muscle relaxant (NDMR) that does not cause potassium release. It is metabolized by Hofmann elimination and is safe in renal/hepatic failure. * **Vecuronium:** An intermediate-acting NDMR with a stable cardiovascular profile; it does not cause hyperkalemia. * **Pancuronium:** A long-acting NDMR. While it may cause tachycardia (vagolytic effect), it does not trigger hyperkalemia or cardiac arrest in trauma patients. **High-Yield Clinical Pearls for NEET-PG:** * **Normal K+ rise:** In a healthy individual, Suxamethonium raises serum potassium by approximately **0.5 mEq/L**. * **Contraindications:** Avoid Suxamethonium in burns (>24 hours old), crush injuries, spinal cord injuries (paraplegia/quadriplegia), and muscular dystrophies. * **Drug of Choice for RSI:** Despite this risk, Suxamethonium remains the gold standard for Rapid Sequence Induction (RSI) due to its rapid onset and short duration, provided no contraindications exist.

Q: The ventilation chart shown depicts:

Synchronised intermittent mandatory breath. ***Synchronised intermittent mandatory breath*** - Shows **alternating large mandatory breaths** synchronized to patient effort with **smaller spontaneous breaths** in between, characteristic of SIMV mode. - Used during **ventilator weaning** to gradually reduce ventilatory support while maintaining backup mandatory breaths. *Continuous mandatory breaths* - Would show **all uniform large breaths** delivered at regular intervals without patient-initiated smaller breaths. - Represents **controlled mechanical ventilation (CMV)** where the ventilator provides all respiratory support. *Continuous spontaneous ventilation* - Would display **only small, patient-initiated breaths** without any large mandatory ventilator-delivered breaths. - Patient maintains **complete control** over breathing pattern and tidal volumes. *Continuous positive airway pressure* - Shows **continuous baseline pressure** with only **spontaneous patient efforts** and no mandatory breaths. - Maintains **constant positive pressure** throughout the respiratory cycle to prevent alveolar collapse.

Q: During a preoperative assessment of the airway, only the hard palate is visible when the patient phonates. What is the grade according to the modified Mallampati test?

Grade IV. ### Explanation The **Modified Mallampati Classification** is a clinical tool used to predict the ease of endotracheal intubation by assessing the visibility of oropharyngeal structures. The classification is performed with the patient sitting upright, mouth wide open, and tongue protruded (without phonating, though the question specifies phonation which is common in clinical practice). **Why Grade IV is Correct:** In **Grade IV**, only the **hard palate** is visible. The soft palate, faucial pillars, and uvula are completely obscured by the base of the tongue. This indicates a potentially difficult airway (Cormack-Lehane Grade 3 or 4 during laryngoscopy). **Analysis of Incorrect Options:** * **Grade I:** Full visibility of the **soft palate, fauces, entire uvula, and anterior/posterior tonsillar pillars**. This suggests an easy intubation. * **Grade II:** Visibility of the **soft palate, fauces, and the upper portion of the uvula**. The pillars are often obscured. * **Grade III:** Visibility of the **soft palate and the base of the uvula only**. The pillars and the tip of the uvula are not seen. **High-Yield Clinical Pearls for NEET-PG:** * **Samsoon and Young** provided the "Modified" Mallampati classification by adding Grade IV. * **Predictors of Difficult Airway:** Mallampati Grade III/IV, Thyromental distance <6 cm (3 fingers), Sternomental distance <12.5 cm, and limited mouth opening (<3 cm). * **LEMON Criteria:** Used in Emergency Medicine for airway assessment (Look, Evaluate 3-3-2, Mallampati, Obstruction, Neck mobility). * **Gold Standard:** While Mallampati is a good screening tool, the **Cormack-Lehane classification** (done during direct laryngoscopy) is the definitive method for grading the view of the glottis.

Q: Generally accepted indications for mechanical ventilatory support include which of the following?

Respiratory rate greater than 35 breaths/min. ### Explanation Mechanical ventilation is indicated when a patient’s spontaneous respiratory effort is insufficient to maintain adequate oxygenation, ventilation, or airway protection. The decision is based on clinical assessment and specific physiological thresholds. **1. Why Option D is Correct:** A **respiratory rate (RR) > 35 breaths/min** is a classic indication for mechanical ventilation. Such high rates significantly increase the work of breathing, leading to respiratory muscle fatigue, increased dead space ventilation, and eventual CO2 retention. It signifies impending respiratory failure. **2. Why the Other Options are Incorrect:** * **Option A:** The units and values are incorrect. A PaO2 of 50 **mmHg** (with pH 350–450 mmHg** while breathing 100% O2. A difference of 150 kPa (approx. 1125 mmHg) is physiologically impossible as it exceeds the pressure of 100% oxygen at sea level. * **Option C:** A **Vital Capacity (VC) 0.6**. * **PaO2/FiO2 Ratio:** A ratio **< 200** (suggestive of ARDS) often necessitates ventilatory support. * **Clinical Priority:** Always treat the patient, not the monitor. Tachypnea and the use of accessory muscles often precede blood gas abnormalities.

Q: What is the method to establish a safer airway in a patient with neck trauma and cricoid fracture, with a possibility of a difficult airway?

Emergency tracheostomy. ### Explanation The management of a traumatic airway requires a balance between speed and the prevention of further injury. In this scenario, the presence of a **cricoid fracture** is the critical deciding factor. **Why Emergency Tracheostomy is the Correct Choice:** In the setting of laryngeal or tracheal trauma (specifically a cricoid fracture), the airway is structurally unstable. An **Emergency Tracheostomy** is the definitive and safest method because it secures the airway **below** the level of the injury. This avoids further disruption of the fractured laryngeal framework and bypasses potential obstructions caused by edema or hematoma at the glottic level. **Why Other Options are Incorrect:** * **Orotracheal Intubation:** This is generally contraindicated or used with extreme caution in suspected laryngeal fractures. Blind or forceful passage of an Endotracheal Tube (ETT) can lead to a "complete" transection of a partially injured trachea, create a false passage, or cause total airway collapse. * **Cricothyroidotomy:** This is typically the first-line emergency surgical airway. However, it is **absolutely contraindicated** in patients with laryngeal trauma or cricoid fractures. Performing a procedure directly through the site of injury (the cricothyroid membrane) can exacerbate the fracture, worsen subglottic stenosis, and fail to provide a secure airway if the injury is distal to the site. **High-Yield Clinical Pearls for NEET-PG:** 1. **Cricoid Fracture = Tracheostomy:** Always look for signs of laryngeal trauma (hoarseness, subcutaneous emphysema, palpable fracture). If present, avoid cricothyroidotomy. 2. **Cricothyroidotomy Contraindications:** Age < 10-12 years (due to risk of subglottic stenosis) and laryngeal/cricoid trauma. 3. **Awake Fiberoptic Intubation:** This is the gold standard for *anticipated* difficult airways, but in *acute trauma* with structural instability, a surgical airway is often prioritized.

Q: A 6-year-old patient, admitted for a dog bite on the face, developed anaphylaxis to a test dose of Augmentin, presenting with stridor requiring immediate intubation. As the sole physician available, and with a No. 3 curved blade laryngoscope ready, what is the appropriate internal diameter of the endotracheal tube to request?

5.5mm. **Explanation:** The selection of an endotracheal tube (ETT) size in pediatric patients is primarily based on age-related anatomical development. For children over 2 years of age, the standard formula used to calculate the internal diameter (ID) of an **uncuffed** ETT is: **Formula: (Age / 4) + 4** Applying this to the 6-year-old patient: $(6 / 4) + 4 = 1.5 + 4 = \mathbf{5.5\text{ mm}}$. **Analysis of Options:** * **5.5 mm (Correct):** This is the standard size for an uncuffed tube in a 6-year-old. In cases of upper airway edema (like anaphylaxis/stridor), clinicians might occasionally consider a 0.5 mm smaller tube to minimize trauma, but 5.5 mm remains the calculated baseline. * **3.5 mm (Incorrect):** This size is typically used for full-term neonates or infants up to 6 months. * **4.5 mm (Incorrect):** This is the calculated size for a 2-year-old child. * **6.5 mm (Incorrect):** This size is more appropriate for an older child (approx. 10 years) or a small adult female. **High-Yield Clinical Pearls for NEET-PG:** 1. **Cuffed vs. Uncuffed:** If using a **cuffed** ETT, the formula is **(Age / 4) + 3.5**. Cuffed tubes are increasingly preferred in modern practice to prevent leaks and reduce the risk of aspiration. 2. **Depth of Insertion:** A quick bedside formula for the length of ETT insertion (at the lip) is **(Age / 2) + 12** or simply **ID × 3**. 3. **Laryngoscope Blades:** For a 6-year-old, a **Macintosh (curved) size 2** is usually standard; however, the question mentions a No. 3, which is often used for older children/adults but may be used depending on the child's size. 4. **Narrowest Part of Airway:** In children, the **cricoid cartilage** is traditionally considered the narrowest point (funnel-shaped airway), unlike the glottis in adults.

Question 1

What complication is NOT seen with controlled ventilation?

Accepted Answer

Cardiac tamponade

Answer

Barotrauma

Answer

Alkalosis

Answer

Pulmonary embolism

Question 2

Which of the following is NOT a step in rapid sequence intubation?

Accepted Answer

Bag and mask ventilation is used for positive pressure ventilation.

Answer

Intravenous thiopental and intravenous succinylcholine are used for induction and paralysis.

Answer

Sellick’s maneuver is used to prevent aspiration.

Answer

Pre-oxygenation is mandatory.

Question 3

Identify the pictured airway device.

Accepted Answer

Nasopharyngeal airway

Answer

Oropharyngeal airway

Answer

Proseal airway

Answer

Flexometallic LMA

Question 4

In a young patient with extensive soft tissue and muscle injury, which muscle relaxant used for endotracheal intubation might lead to cardiac arrest?

Accepted Answer

Suxamethonium

Answer

Atracurium

Answer

Vecuronium

Answer

Pancuronium

Question 5

The ventilation chart shown depicts:

Accepted Answer

Synchronised intermittent mandatory breath

Answer

Continuous mandatory breaths

Answer

Continuous spontaneous ventilation

Answer

Continuous positive airway pressure

Question 6

During a preoperative assessment of the airway, only the hard palate is visible when the patient phonates. What is the grade according to the modified Mallampati test?

Accepted Answer

Grade IV

Answer

Grade I

Answer

Grade II

Answer

Grade III

Question 7

Generally accepted indications for mechanical ventilatory support include which of the following?

Accepted Answer

Respiratory rate greater than 35 breaths/min

Answer

PaO2 of less than 70 kPa and PaCO2 of greater than 50 kPa while breathing room air

Answer

Alveolar-arterial oxygen tension difference of 150 kPa while breathing 100% O2

Answer

Vital capacity of 40-60 mL/kg

Question 8

What are the pulmonary changes in the lateral position in an anesthetized patient?

Accepted Answer

Dependent lung is relatively under-ventilated and over-perfused.

Answer

Dependent lung is relatively over-ventilated and over-perfused.

Answer

Dependent lung is relatively over-ventilated and under-perfused.

Answer

Dependent lung is relatively under-ventilated and under-perfused.

Question 9

What is the method to establish a safer airway in a patient with neck trauma and cricoid fracture, with a possibility of a difficult airway?

Accepted Answer

Emergency tracheostomy

Answer

Orotracheal intubation

Answer

Cricothyroidotomy

Answer

None of the above

Question 10

A 6-year-old patient, admitted for a dog bite on the face, developed anaphylaxis to a test dose of Augmentin, presenting with stridor requiring immediate intubation. As the sole physician available, and with a No. 3 curved blade laryngoscope ready, what is the appropriate internal diameter of the endotracheal tube to request?

Accepted Answer

5.5mm

Answer

3.5mm

Answer

4.5mm

Answer

6.5mm

Respiratory and Airway Management — MCQs

Respiratory and Airway Management — MCQs

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