Respiratory and Airway Management Practice Questions

Q: A 53-year-old woman has been intubated for several days after sustaining a right pulmonary contusion and multiple rib fractures following a motor vehicle collision. Which of the following is a reasonable indication to attempt extubation?

A rapid shallow breathing index of 80. **Explanation:** The decision to extubate a patient depends on their ability to maintain spontaneous ventilation and oxygenation. The **Rapid Shallow Breathing Index (RSBI)**, calculated as the ratio of respiratory rate (f) to tidal volume (Vt in liters), is one of the most reliable predictors of weaning success. **1. Why Option D is Correct:** An **RSBI < 105** is a strong predictor of successful weaning. An RSBI of 80 indicates that the patient is taking adequate tidal volumes without excessive tachypnea, suggesting that the respiratory muscles are not fatigued and can handle the work of breathing independently. **2. Why the Other Options are Incorrect:** * **Option A:** A **Negative Inspiratory Force (NIF)** (or MIP) should be more negative than **-20 to -30 cm H2O**. A value of -15 cm H2O indicates significant inspiratory muscle weakness, making extubation risky. * **Option B:** While a PO2 of 60 mmHg is acceptable, it is being achieved with a **PEEP of 10 cm H2O**. For extubation, a patient should generally be stable on a "minimal" PEEP of **5–8 cm H2O**. High PEEP requirements suggest the lung collapse or edema has not yet sufficiently resolved. * **Option C:** A spontaneous respiratory rate of **35 breaths per minute** indicates tachypnea and increased work of breathing. A rate ** 150–200. * Vital Capacity > 10 mL/kg. * Tidal Volume > 5 mL/kg. * **The "Gold Standard"** for assessing readiness is the **Spontaneous Breathing Trial (SBT)** for 30–120 minutes.

Q: Which of the following is true regarding endotracheal tube cuffs?

Low volume, high pressure. ### Explanation The correct answer is **A. Low volume, high pressure**. **1. Understanding the Concept** Endotracheal tube (ETT) cuffs are classified based on their compliance and the pressure they exert on the tracheal mucosa. Historically, the first ETTs were **Low Volume, High Pressure (LVHP)**. These cuffs have a small surface area of contact with the trachea. To create an effective seal against aspiration and air leaks, they must be inflated to pressures significantly exceeding the capillary perfusion pressure of the tracheal mucosa (approx. 25–30 mmHg). **2. Analysis of Options** * **Option A (Correct):** LVHP cuffs are the traditional design. While they provide a good seal, their high pressure carries a significant risk of mucosal ischemia, necrosis, and subsequent tracheal stenosis. * **Option B & D:** These are not standard classifications for ETT cuffs. * **Option C (Incorrect):** Modern practice prefers **High Volume, Low Pressure (HVLP)** cuffs. These have a larger surface area, allowing the pressure to be distributed more widely, thus maintaining a seal at pressures below the capillary perfusion threshold (ideally 20–30 cmH₂O). **3. NEET-PG High-Yield Pearls** * **Gold Standard:** Modern anesthesia uses **HVLP** cuffs to minimize tracheal trauma. * **Cuff Pressure Monitoring:** Should be maintained between **20–30 cmH₂O**. * 30 cmH₂O: Risk of tracheal ischemia and stenosis. * **Nitrous Oxide (N₂O) Effect:** N₂O can diffuse into the cuff, increasing the volume and pressure during surgery; therefore, cuff pressure should be monitored intraoperatively. * **Pediatric Note:** Traditionally, uncuffed tubes were used in children <8 years due to the narrow cricoid ring; however, cuffed tubes are now increasingly used.

Q: Which of the following is a contraindication for nasotracheal intubation?

Basal skull fractures. **Explanation:** **1. Why Basal Skull Fracture is the Correct Answer:** Basal skull fracture (BSF) is a **relative to absolute contraindication** for nasotracheal intubation. The primary concern is the potential fracture of the **cribriform plate** of the ethmoid bone. If this plate is disrupted, a blindly inserted nasotracheal tube (or nasogastric tube) can inadvertently pass through the fracture site and enter the **intracranial space**, causing direct brain parenchyma injury or introducing infection (meningitis). Clinical signs like Raccoon eyes, Battle’s sign, or CSF rhinorrhea should immediately alert the clinician to avoid the nasal route. **2. Analysis of Incorrect Options:** * **B. Neonate:** While technically challenging due to narrow nasal passages and the risk of adenoidal trauma/bleeding, neonates can undergo nasotracheal intubation, especially for long-term ventilation in the NICU to improve tube stability. * **C. Difficult Intubation:** Nasotracheal intubation is often a **rescue technique** or a planned approach for difficult airways (e.g., limited mouth opening/trismus), as it provides a better surgical field for intraoral procedures. * **D. Prolonged Intubation:** Nasal tubes are generally **better tolerated** and more stable than oral tubes for patients requiring prolonged ventilation, as they reduce the risk of accidental extubation and are more comfortable for the patient. **High-Yield Clinical Pearls for NEET-PG:** * **Other Contraindications:** Coagulopathy (risk of epistaxis), nasal polyps, and severe mid-face (Le Fort II/III) fractures. * **Complications:** The most common complication of nasal intubation is **epistaxis**. Long-term complications include **maxillary sinusitis** due to blockage of sinus drainage. * **Technique Tip:** To prevent bleeding, use a vasoconstrictor (e.g., Oxymetazoline or Xylocaine with Adrenaline) and choose the more patent nostril.

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.

Question 1

What is the theoretical optimal PEEP in ARDS?

Accepted Answer

12 - 15 mm Hg

Answer

0 - 5 mm Hg

Answer

5 - 12 mm Hg

Answer

15 - 18 mm Hg

Question 2

A 53-year-old woman has been intubated for several days after sustaining a right pulmonary contusion and multiple rib fractures following a motor vehicle collision. Which of the following is a reasonable indication to attempt extubation?

Accepted Answer

A rapid shallow breathing index of 80

Answer

Negative inspiratory force (NIF) of -15 cm H2O

Answer

PO2 of 60 mm Hg while breathing 30% inspired FiO2 with a positive end-expiratory pressure (PEEP) of 10 cm H2O

Answer

Spontaneous respiratory rate of 35 breaths per minute

Question 3

Which of the following is true regarding endotracheal tube cuffs?

Accepted Answer

Low volume, high pressure

Answer

Low volume, low pressure

Answer

High volume, high pressure

Answer

Equal volume and pressure

Question 4

Which of the following is a contraindication for nasotracheal intubation?

Accepted Answer

Basal skull fractures

Answer

Neonate

Answer

Difficult intubation

Answer

Prolonged intubation

Question 5

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 6

Nitrous oxide is contraindicated in patients with pneumothorax, pneumopericardium, or intestinal obstruction because it:

Accepted Answer

Causes the expansion of air-filled body cavities

Answer

Depresses an already compromised myocardium

Answer

Permits the use of a limited FIO2 only

Answer

Is less soluble than nitrogen

Question 7

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 8

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 9

IPPV can cause all of the following except:

Accepted Answer

Pleural effusion

Answer

Barotrauma

Answer

Pneumothorax

Answer

None of the above

Question 10

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

Respiratory and Airway Management — MCQs

Respiratory and Airway Management — MCQs

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