Respiratory and Airway Management Practice Questions

Q: Which of the following general anesthetic techniques is most appropriate for anesthesia in oral surgery?

Nasoendotracheal tube with throat pack. **Explanation:** The primary challenge in oral surgery is the **sharing of the airway** between the surgeon and the anesthesiologist. The correct answer is **Nasoendotracheal tube with throat pack** for the following reasons: 1. **Airway Protection & Access:** Nasotracheal intubation removes the breathing tube from the oral cavity, providing the surgeon with an unobstructed field. 2. **Prevention of Aspiration:** Oral surgeries involve blood, secretions, and bone debris. A **throat pack** (moistened gauze placed in the oropharynx) acts as a physical barrier, preventing these materials from entering the trachea or esophagus, thereby reducing the risk of aspiration and postoperative nausea/vomiting (PONV). 3. **Controlled Ventilation:** Endotracheal intubation ensures a definitive airway, allowing for positive pressure ventilation and precise delivery of volatile anesthetics. **Analysis of Incorrect Options:** * **Open drop method:** An obsolete technique (e.g., Schimmelbusch mask) that provides no airway protection and leads to significant environmental pollution. * **Nasopharyngeal airway:** While it maintains patency, it does not protect the lungs from aspiration of blood or surgical debris. * **Intravenous anesthesia with $N_2O/O_2$:** Without a cuffed tube, the airway remains unprotected. $N_2O$ is an inhalational agent, not intravenous; this option is pharmacologically inconsistent. **High-Yield Clinical Pearls for NEET-PG:** * **Throat Pack Safety:** Always document the insertion and removal of the throat pack. A "forgotten" pack is a classic cause of postoperative airway obstruction. * **Contraindication:** Nasal intubation is contraindicated in patients with suspected **basal skull fractures** (risk of intracranial entry) or severe coagulopathy. * **Magill Forceps:** These are specifically used to guide the nasotracheal tube into the laryngeal inlet under direct vision.

Q: Which of the following is considered a definitive airway?

Nasotracheal airway. ### **Explanation** A **definitive airway** is defined as a tube placed in the **trachea** with the **cuff inflated below the vocal cords**, connected to a form of oxygen-enriched ventilation, and secured in place with tape or a commercial device. **Why Nasotracheal Airway is Correct:** A nasotracheal tube is a type of **endotracheal tube (ETT)**. Because it passes through the larynx and into the trachea, and features an inflatable cuff that provides a reliable seal against aspiration while ensuring positive pressure ventilation, it meets all criteria for a definitive airway. **Analysis of Incorrect Options:** * **Orotracheal Airway (Guedel Airway):** This is a **simple airway adjunct**. It merely prevents the tongue from obstructing the posterior pharynx in an unconscious patient. It does not enter the trachea or protect against aspiration. * **Nasopharyngeal Airway (Nasal Trumpet):** Similar to the oropharyngeal airway, this is an **adjunct** used to bypass upper airway obstruction. It terminates in the pharynx, not the trachea. * **Laryngeal Mask Airway (LMA):** This is a **Supraglottic Airway Device (SAD)**. While it provides an effective channel for ventilation, it sits above the vocal cords. It does not provide a definitive seal against gastric aspiration and is therefore not considered a definitive airway. ### **High-Yield Clinical Pearls for NEET-PG:** 1. **Three types of definitive airways:** * Orotracheal tube (most common). * Nasotracheal tube. * Surgical airway (Cricothyroidotomy or Tracheostomy). 2. **Gold Standard for Confirmation:** The most reliable clinical method to confirm definitive airway placement is **Continuous Waveform Capnography (EtCO2)**. 3. **Indication:** A definitive airway is mandatory if the patient has a **GCS ≤ 8** ("8, terminate/intubate"), impending airway obstruction, or severe respiratory failure.

Q: What is the purpose of the bevel on the proximal tip of an endotracheal tube?

To facilitate passage through the vocal cords. ### Explanation The **bevel** is the slanted opening at the distal (patient) end of an endotracheal tube (ETT). Its primary purpose is to **facilitate passage through the vocal cords** by providing a tapered point that improves visibility and allows the tube to glide more easily through the glottic opening. **1. Why Option A is Correct:** The bevel is typically left-facing. This design allows the clinician to maintain a better line of sight of the vocal cords during laryngoscopy. The slanted tip acts as a wedge, making it easier to navigate the narrowest part of the upper airway (the rima glottidis) without causing significant trauma. **2. Why Other Options are Incorrect:** * **Option B:** While preventing occlusion is a critical safety feature, this is specifically the function of the **Murphy Eye** (a side hole located opposite the bevel). If the bevel tip rests against the tracheal wall, the Murphy Eye provides an alternate pathway for gas flow. * **Option C:** High-pressure ventilation is a function of the tube’s internal diameter and the seal created by the **cuff**, not the shape of the tip. * **Option D:** Since B and C are incorrect, "All of the above" is invalid. **High-Yield Clinical Pearls for NEET-PG:** * **Murphy Eye:** Its presence distinguishes a "Murphy Tube" from a "Magill Tube" (which lacks the eye). * **Bevel Orientation:** Standard ETTs have a **left-facing bevel**. This is designed to optimize the view when using a Macintosh laryngoscope (which displaces the tongue to the left). * **Tube Material:** Most modern ETTs are made of **Polyvinyl Chloride (PVC)**, which is disposable and thermosoftening. * **Vocal Cord Marker:** A black line proximal to the cuff helps the clinician ensure the tube is placed at the correct depth (usually 21 cm for females and 23 cm for males at the corner of the mouth).

Q: Which intravenous anaesthetic can be used for upper airway manipulation in the absence of neuromuscular blockers?

Propofol. **Explanation:** The correct answer is **Propofol**. **Why Propofol is correct:** Propofol is the drug of choice for upper airway manipulations (like Laryngeal Mask Airway insertion or bronchoscopy) when neuromuscular blockers are not used. This is because Propofol significantly **depresses the upper airway reflexes** (pharyngeal and laryngeal reflexes) to a greater extent than other induction agents. This profound suppression allows for easier instrumentation of the airway without causing gagging, coughing, or laryngospasm. **Why other options are incorrect:** * **Thiopentone:** It does not suppress airway reflexes effectively. In fact, it may lead to "light" anesthesia where airway manipulation can trigger severe **laryngospasm**. * **Etomidate:** It maintains hemodynamic stability but has a minimal effect on suppressing airway reflexes. It is also associated with myoclonus, which can interfere with airway management. * **Ketamine:** It is known for **preserving upper airway reflexes** and increasing secretions (sialorrhea). Attempting airway manipulation under ketamine alone often triggers protective reflexes, making it unsuitable for this purpose. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of choice for LMA insertion:** Propofol. * **Drug of choice for Day Care Surgery:** Propofol (due to rapid recovery and anti-emetic properties). * **Antiemetic effect:** Propofol has intrinsic anti-emetic properties (at doses of 10–20 mg). * **Pain on injection:** A common side effect of Propofol and Etomidate; can be reduced by using larger veins or pre-treatment with Lidocaine. * **Contraindication:** Avoid Propofol in patients with egg or soy allergy (due to the lipid emulsion vehicle).

Q: A very high Positive End-Expiratory Pressure (PEEP) results in which of the following?

Hypotension. **Explanation:** The correct answer is **Hypotension**. **Mechanism of Action:** Positive End-Expiratory Pressure (PEEP) maintains airway pressure above atmospheric pressure at the end of expiration. While beneficial for recruitment of alveoli and improving oxygenation, high levels of PEEP significantly impact hemodynamics through **heart-lung interactions**: 1. **Increased Intrathoracic Pressure:** High PEEP increases the pressure within the chest cavity. 2. **Decreased Venous Return:** This pressure compresses the superior and inferior vena cava, reducing the preload (venous return) to the right atrium. 3. **Reduced Cardiac Output:** A decrease in preload leads to a decrease in stroke volume and overall cardiac output, manifesting clinically as **hypotension**. 4. **Right Ventricular Afterload:** High PEEP can also increase pulmonary vascular resistance, further straining the right heart. **Analysis of Incorrect Options:** * **A. Hypertension:** PEEP typically decreases blood pressure; it does not cause hypertension. * **B & D. Hypothermia/Hyperthermia:** PEEP is a mechanical ventilation setting and does not directly influence the body’s thermoregulatory center or core temperature. **Clinical Pearls for NEET-PG:** * **Zone 3 to Zone 1:** High PEEP can convert West Zone 3 (well-perfused) areas of the lung into Zone 1 (dead space), increasing the V/Q mismatch. * **Barotrauma:** Excessive PEEP increases the risk of alveolar rupture, leading to pneumothorax or subcutaneous emphysema. * **Auto-PEEP:** Also known as "intrinsic PEEP," this occurs in COPD/Asthma patients when there is insufficient expiratory time, leading to air trapping and similar hemodynamic instability. * **Standard PEEP:** Physiological PEEP is usually **5 cm H₂O**, used to prevent micro-atelectasis in intubated patients.

Question 1

Which of the following general anesthetic techniques is most appropriate for anesthesia in oral surgery?

Accepted Answer

Nasoendotracheal tube with throat pack

Answer

Open drop method

Answer

Anesthesia with nasopharyngeal airway

Answer

Intravenous anesthesia with nitrous oxide and oxygen

Question 2

A 42-year-old patient presents to the emergency department with difficulty in breathing, 7 months after discharge from the burns unit. On examination, O2 saturation was decreasing to 80%, respiratory rate was 20/min, and blood pressure was 110/74 mmHg. Local examination of the neck revealed post-burn contracture with restricted neck extension. What is the ideal method of intubation in this case?

Accepted Answer

Fiber optic intubation

Answer

Laryngeal mask airway

Answer

Nasal intubation after intravenous induction

Answer

Tracheostomy

Question 3

The Mallampati test is used for assessing which of the following?

Accepted Answer

The size of the tongue relative to the oral cavity, indicating potential airway difficulty.

Answer

The range of motion of the cervical spine.

Answer

The degree of neck flexion and extension.

Answer

The appropriate size of an endotracheal tube.

Question 4

Which of the following always indicates obstruction to the airway?

Accepted Answer

Strenuous breathing

Answer

Slow pounding pulse

Answer

Increase in pulse rate

Answer

Decrease in blood pressure

Question 5

What is a laser tube?

Accepted Answer

A tube made up of PVC wrapped in two layers, one metallic and another non-reflective layer.

Answer

A tube made up of red rubber.

Answer

A metallic tube to prevent any airway fire.

Answer

A tube made up of laser-resistant material.

Question 6

Intubation-induced laryngeal spasm cannot be prevented by which of the following?

Accepted Answer

Promethazine

Answer

Local anesthesia spray

Answer

Fentanyl

Answer

Diltiazem

Question 7

Which of the following is considered a definitive airway?

Accepted Answer

Nasotracheal airway

Answer

Orotracheal airway

Answer

Nasopharyngeal airway

Answer

Laryngeal mask airway (LMA)

Question 8

What is the purpose of the bevel on the proximal tip of an endotracheal tube?

Accepted Answer

To facilitate passage through the vocal cords

Answer

To prevent occlusion of the tube tip by the tracheal wall

Answer

To enable high-pressure ventilation

Answer

All of the above

Question 9

Which intravenous anaesthetic can be used for upper airway manipulation in the absence of neuromuscular blockers?

Accepted Answer

Propofol

Answer

Thiopentone

Answer

Etomidate

Answer

Ketamine

Question 10

A very high Positive End-Expiratory Pressure (PEEP) results in which of the following?

Accepted Answer

Hypotension

Answer

Hypertension

Answer

Hypothermia

Answer

Hyperthermia

Respiratory and Airway Management — MCQs

Respiratory and Airway Management — MCQs

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