Respiratory and Airway Management Practice Questions

Q: What is the appropriate size of a Laryngeal Mask Airway (LMA) for a 25kg child?

2.5. ### Explanation The selection of a **Laryngeal Mask Airway (LMA)** size is primarily based on the patient's **ideal body weight**. For a child weighing 25 kg, the correct size is **2.5**. #### Why Size 2.5 is Correct: The standard sizing guidelines for LMAs are categorized by weight ranges. Size 2.5 is specifically designed for children weighing between **20 kg and 30 kg**. Selecting the correct size ensures an effective perilaryngeal seal, minimizing gastric insufflation and ensuring adequate ventilation. #### Analysis of Incorrect Options: * **Size 1:** Used for neonates and infants weighing **up to 5 kg**. * **Size 1.5:** Used for infants weighing **5–10 kg**. * **Size 4:** Used for average-sized adults weighing **50–70 kg**. #### High-Yield Clinical Pearls for NEET-PG: * **LMA Sizing Table (Must-Know):** * **Size 1:** < 5 kg * **Size 1.5:** 5–10 kg * **Size 2:** 10–20 kg * **Size 2.5:** 20–30 kg * **Size 3:** 30–50 kg (Small adults) * **Size 4:** 50–70 kg (Normal adults) * **Size 5:** 70–100 kg (Large adults) * **Maximum Cuff Inflation:** For a Size 2.5 LMA, the maximum air volume for the cuff is **14 ml**. * **Placement:** The tip of the LMA rests against the **upper esophageal sphincter** (cricopharyngeus muscle). * **Contraindication:** LMA is a "supraglottic" device and does not protect against aspiration; therefore, it is contraindicated in patients with a "full stomach" or hiatus hernia.

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

Tracheal cuff. 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.

Q: Among the following, in which condition MMP grade IV can be seen?

Large tongue. **Explanation:** The **Mallampati Classification (MMP)** 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. **Why "Large Tongue" is correct:** MMP grading is specifically based on the **visibility of oropharyngeal structures** (soft palate, fauces, uvula, and pillars) when the patient opens their mouth. In **Macroglossia (Large tongue)**, the base of the tongue is disproportionately large relative to the oral cavity, completely obscuring the soft palate and uvula. This corresponds to **MMP Grade IV**, where only the hard palate is visible. **Analysis of Incorrect Options:** * **B. Postburn contracture neck:** This primarily affects **atlanto-occipital extension** and neck mobility. While it indicates a difficult airway, it is assessed via the thyromental distance or neck range of motion, not the Mallampati score. * **C. Fracture mandible:** This usually results in a "receding chin" or instability. While it may complicate intubation, it does not inherently change the anatomical visibility of the oropharynx required for MMP grading. * **D. TM joint ankylosis:** This condition limits **mouth opening** (inter-incisor distance). If the patient cannot open their mouth, a Mallampati score cannot be accurately assessed, as the test requires a wide-open mouth without phonation. **High-Yield Clinical Pearls for NEET-PG:** * **Modified Mallampati Classification (Samsoon & Young):** * **Class I:** Soft palate, fauces, uvula, pillars visible. * **Class II:** Soft palate, fauces, portion of uvula visible. * **Class III:** Soft palate and base of uvula visible. * **Class IV:** Only hard palate visible. * **MMP Class III and IV** are strong predictors of a **difficult airway**. * **Rule of Thumb:** MMP assesses the "capacity of the oral cavity to house the tongue."

Q: IPPV can cause all of the following except:

Pleural effusion. **Explanation:** Intermittent Positive Pressure Ventilation (IPPV) involves the mechanical delivery of gas into the lungs under positive pressure. While life-saving, it significantly alters intrathoracic dynamics. **Why Pleural Effusion is the Correct Answer:** Pleural effusion is an accumulation of fluid in the pleural space, typically caused by inflammation, malignancy, or heart failure. IPPV does **not** cause pleural effusion. In fact, the positive pressure exerted by IPPV increases intrathoracic pressure, which can actually decrease the formation of pulmonary edema and pleural transudates by increasing interstitial hydrostatic pressure and improving lymphatic drainage in some clinical contexts. **Why the other options are incorrect:** * **Barotrauma (Option A):** This is a well-known complication of IPPV. High peak inspiratory pressures (PIP) can lead to alveolar rupture, allowing air to escape into the interstitium. * **Pneumothorax (Option C):** This is the clinical manifestation of severe barotrauma. When air from ruptured alveoli tracks into the pleural space, it results in a pneumothorax, which can rapidly progress to a life-threatening **tension pneumothorax** due to the continuous positive pressure. **High-Yield Clinical Pearls for NEET-PG:** 1. **Hemodynamic Effects:** IPPV increases intrathoracic pressure, which **decreases venous return (preload)** to the right heart, potentially leading to hypotension. 2. **V/Q Mismatch:** IPPV often redirects blood flow to poorly ventilated areas (Zone 3 to Zone 1/2), potentially increasing physiological dead space. 3. **Protective Lung Ventilation:** To prevent barotrauma and volutrauma, modern practice favors "Lung Protective Ventilation" using low tidal volumes (6 mL/kg of PBW) and limiting plateau pressures to <30 cm H₂O.

Q: All are true regarding endotracheal intubation except?

Saturation falls to not more than 90% after 2 minutes. **Explanation** In the context of endotracheal intubation, the goal is to confirm correct placement and ensure patient safety. Option **A** is the correct answer because it is a **false statement**. In an apneic patient (even after pre-oxygenation), oxygen saturation ($SpO_2$) does not remain above 90% for a fixed duration of 2 minutes for everyone. The rate of desaturation depends on the patient's Functional Residual Capacity (FRC) and metabolic rate. For example, in obese patients, children, or pregnant women, $SpO_2$ can fall below 90% in less than 1 minute. **Analysis of other options:** * **Option B (Presence of $CO_2$ in expired air):** This is the **Gold Standard** for confirming tracheal intubation. Detection of $CO_2$ via capnography for at least 5–6 breaths confirms the tube is in the airway and not the esophagus. * **Option C (Inserted under direct vision):** During conventional laryngoscopy, the primary goal is to visualize the vocal cords (glottis) and pass the tube through them to ensure tracheal placement. * **Option D (Bilateral chest movement):** This is a clinical sign of successful intubation. Observing symmetrical chest rise and auscultating bilateral breath sounds helps rule out esophageal intubation and endobronchial (one-sided) intubation. **Clinical Pearls for NEET-PG:** * **Gold Standard Confirmation:** Capnography (ETCO2). * **Most reliable clinical sign:** Visualizing the tube passing through the vocal cords. * **Pre-oxygenation:** Aim is to replace nitrogen in the FRC with oxygen ("Denitrogenation"), providing a safety buffer of apnea time. * **First sign of esophageal intubation:** Absence of $CO_2$ waveforms on capnography and gurgling sounds over the epigastrium.

Question 1

What is the appropriate size of a Laryngeal Mask Airway (LMA) for a 25kg child?

Accepted Answer

2.5

Answer

1

Answer

1.5

Answer

4

Question 2

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

Accepted Answer

Rapid sequence induction

Answer

BURP maneuver

Answer

Pharmacological therapy

Answer

All of the above

Question 3

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

Accepted Answer

Tracheal cuff

Answer

Gastric drain tube port

Answer

Posterior cuff

Answer

Wire reinforced airway

Question 4

A patient presents to the emergency room following a road traffic accident and exhibits cyanosis. Which of the following statements regarding cyanosis in this patient is true?

Accepted Answer

Cyanosis is a late sign of hypoxia.

Answer

Cyanosis is an early sign of hypoxia.

Answer

Absence of cyanosis indicates an adequate airway.

Answer

Absence of cyanosis indicates adequate tissue perfusion.

Question 5

Among the following, in which condition MMP grade IV can be seen?

Accepted Answer

Large tongue

Answer

Postburn contracture neck

Answer

Fracture mandible

Answer

TM joint ankylosis

Question 6

Absence of which of the following protective reflexes is suggestive of airway obstruction?

Accepted Answer

Coughing

Answer

Sneezing

Answer

Gag reflex

Answer

None of the above

Question 7

IPPV can cause all of the following except:

Accepted Answer

Pleural effusion

Answer

Barotrauma

Answer

Pneumothorax

Answer

None of the above

Question 8

Laryngeal mask airway is indicated in:

Accepted Answer

Difficult airway

Answer

To prevent aspiration of stomach contents

Answer

Short surgical procedure

Answer

Where endotracheal intubation is contraindicated

Question 9

All are true regarding endotracheal intubation except?

Accepted Answer

Saturation falls to not more than 90% after 2 minutes

Answer

Presence of CO2 in expired air

Answer

Endotracheal tube is inserted under direct vision of the glottis

Answer

Bilateral chest movement is observed

Question 10

When wheezing occurs intraoperatively, which of the following measures is NOT appropriate?

Accepted Answer

Intratracheal administration of mucolytic agents

Answer

Use of a volatile anesthetic agent (e.g., halothane)

Answer

Rechecking breath sounds bilaterally

Answer

Intravenous hydrocortisone

Respiratory and Airway Management — MCQs

Respiratory and Airway Management — MCQs

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