Respiratory and Airway Management — MCQs

Respiratory and Airway Management Indian Medical PG Practice Questions and MCQs

Question 261: Plan C of anesthetic airway management involves which of the following?

A. Standard laryngoscopy and intubation
B. Intubation catheter guided intubation
C. Insertion of laryngeal mask airway and fiberoptic bronchoscopy (Correct Answer)
D. Cancel the surgery or perform tracheostomy

Explanation: This question is based on the **Difficult Airway Society (DAS) Guidelines**, which provide a structured sequential approach to managing an unanticipated difficult intubation in an adult. ### **Explanation of the Correct Answer** **Plan C** is the "Final attempt at ventilation." When Plan A (Initial tracheal intubation) and Plan B (Secondary intubation attempts using a Supraglottic Airway Device - SAD) have failed, the priority shifts from intubation to **oxygenation and ventilation**. * **Option C** involves the insertion of a **Laryngeal Mask Airway (LMA)** to maintain oxygenation. Once ventilation is established via the LMA, a **Fiberoptic Bronchoscope (FOB)** can be used to facilitate intubation through the device, or the patient can be woken up. ### **Analysis of Incorrect Options** * **Option A (Plan A):** This is the initial step involving standard laryngoscopy and tracheal intubation. It allows for up to 3+1 attempts (the 4th by a senior colleague). * **Option B:** This is a technique that may be used during Plan A or B but does not define a specific "Plan" stage in the DAS algorithm. * **Option D (Plan D):** This is the "Rescue" phase for a **"Cannot Intubate, Cannot Oxygenate" (CICO)** scenario. If Plan C fails to maintain oxygenation, the final step is emergency front-of-neck access (e.g., Scalpel Cricothyroidotomy), not elective tracheostomy. ### **High-Yield Clinical Pearls for NEET-PG** * **Plan A:** Initial tracheal intubation (Limit attempts to avoid airway trauma). * **Plan B:** Secondary intubation attempts (SADs are the mainstay). * **Plan C:** Maintenance of oxygenation and ventilation (Wake the patient up if possible). * **Plan D:** Emergency Front of Neck Access (e.g., **Scalpel-Bougie-Tube** technique). * **Gold Standard for Difficult Airway:** Awake Fiberoptic Intubation (AFOI). * **Pre-oxygenation:** The most critical step to increase the "duration of apnea without desaturation."

Question 262: All of the following are examples of definite airways, except?

A. Nasotracheal tube
B. Orotracheal tube
C. Laryngeal Mask airway (Correct Answer)
D. Cricothyroidotomy

Explanation: ### Explanation The concept of a **"Definitive Airway"** is a high-yield topic in emergency medicine and anesthesiology. By definition, a definitive airway requires a tube present in the **trachea** with the **cuff inflated below the vocal cords**, connected to an oxygen-enriched ventilation source, and secured in place. **Why Laryngeal Mask Airway (LMA) is the correct answer:** The LMA is a **supraglottic airway device**. It sits in the hypopharynx and masks the glottic opening but does not enter the trachea. Because it does not provide a physical barrier within the trachea, it does not reliably protect against pulmonary aspiration of gastric contents. Therefore, it is considered an "intermediate" or "temporary" airway, not a definitive one. **Analysis of Incorrect Options:** * **Orotracheal Tube (B) & Nasotracheal Tube (A):** These are the gold standards for definitive airways. The tube passes through the vocal cords into the trachea, and the inflated cuff provides a seal that protects the lungs from aspiration and allows for positive pressure ventilation. * **Cricothyroidotomy (D):** This is a **surgical definitive airway**. Whether performed via needle or surgical incision, the tube is placed directly into the trachea through the cricothyroid membrane, meeting the criteria for a definitive airway. **Clinical Pearls for NEET-PG:** * **Indications for a Definitive Airway:** Apnea, inability to maintain a patent airway by other means, protection from aspiration (blood/vomitus), or significant head injury (GCS ≤ 8). * **The "GCS 8, Intubate" Rule:** A classic mnemonic for when a definitive airway is mandatory. * **Surgical Airway:** If "cannot intubate, cannot ventilate" occurs, a surgical definitive airway (Cricothyroidotomy) is the final step in the difficult airway algorithm. * **Tracheostomy** is also a definitive airway, usually reserved for long-term management rather than acute resuscitation.

Question 263: Which of the following maneuvers is NOT performed during laryngoscopy and endotracheal intubation?

A. Flexion of the neck
B. Extension of the head at the atlanto-occipital joint
C. The laryngoscope is lifted upwards, levering over the upper incisors (Correct Answer)
D. In a straight blade laryngoscope, the epiglottis is lifted by the tip

Explanation: **Explanation:** The goal of direct laryngoscopy is to create a straight line of sight from the operator's eye to the glottic opening. This is achieved through the **"Sniffing Position"** and proper instrument technique. **Why Option C is the correct answer (The Incorrect Maneuver):** The laryngoscope should be lifted **upward and forward** (at a 45-degree angle away from the patient) to displace the soft tissues of the tongue and submandibular space. One must **never lever the blade over the upper incisors**, as this uses the teeth as a fulcrum. This maneuver is a technical error that frequently leads to dental trauma (chipped or dislodged teeth) and provides a poorer view of the larynx by narrowing the visual field. **Analysis of Other Options:** * **Option A (Flexion of the neck):** This is a component of the sniffing position. Flexing the neck at the lower cervical spine (C6-C7) helps align the laryngeal and pharyngeal axes. * **Option B (Extension of the head):** Extension at the atlanto-occipital joint aligns the oral axis with the other two axes, completing the sniffing position for optimal visualization. * **Option D (Straight blade/Miller):** Unlike the curved Macintosh blade (which sits in the vallecula), a straight blade is designed to pass posterior to the epiglottis and **lift it directly** to expose the vocal cords. **High-Yield Clinical Pearls for NEET-PG:** * **Sniffing Position:** "Flexion of the neck, Extension of the head." * **3-3-2 Rule:** Used for predicting a difficult airway (Mouth opening >3 fingers; Hyoid-mental distance >3 fingers; Hyoid-thyroid distance >2 fingers). * **BURP Maneuver:** (Backward, Upward, Rightward Pressure) on the thyroid cartilage is used to improve the laryngoscopic view. * **Cormack-Lehane Classification:** Used to grade the view obtained during laryngoscopy (Grade I is full view of glottis; Grade IV is no epiglottis or glottis seen).

Question 264: Difficulty in laryngoscopy and intubation is seen in all except:

A. Cervical joint immobility
B. Modified Mallampati class 2 (Correct Answer)
C. Upper lip bite test negative
D. Interincisor gap of <3cm

Explanation: **Explanation:** The goal of airway assessment is to predict a "difficult airway." Difficulty in laryngoscopy and intubation occurs when there is limited access to the oral cavity or restricted alignment of the oral, pharyngeal, and laryngeal axes. **Why Modified Mallampati Class 2 is the correct answer:** The Modified Mallampati Classification (MPC) assesses the visibility of structures in the oropharynx. * **Class 1 & 2** are generally considered predictors of an **easy intubation**. In Class 2, the soft palate, fauces, and uvula are visible. * **Class 3 & 4** (where only the base of the uvula or only the hard palate is visible) are strong predictors of a **difficult intubation**. Therefore, Class 2 does not typically indicate difficulty. **Analysis of Incorrect Options:** * **Cervical joint immobility:** Extension at the atlanto-occipital joint is crucial for the "sniffing position." Immobility (seen in ankylosing spondylitis or trauma) prevents the alignment of airway axes, making laryngoscopy extremely difficult. * **Upper lip bite test (ULBT) negative:** This is a slight distractor in the phrasing. A **positive** ULBT (Class 3: cannot bite the upper lip at all) predicts difficulty. However, in many clinical contexts, a "negative" result in the context of a "difficult airway" question refers to the inability to perform the maneuver (Class 3), which correlates with a poor laryngoscopic view. * **Interincisor gap <3 cm:** A normal gap is >4 cm (approx. 3 fingers). A gap of <3 cm restricts the space available to insert the laryngoscope blade and visualize the glottis, signifying a difficult airway. **High-Yield Clinical Pearls for NEET-PG:** * **LEMON Criteria:** Used for predicting difficult intubation (**L**ook externally, **E**valuate 3-3-2 rule, **M**allampati, **O**bstruction, **N**eck mobility). * **3-3-2 Rule:** Normal findings are Interincisor distance >3 fingers; Hyoid-mental distance >3 fingers; Hyoid-thyroid distance >2 fingers. * **Thyromental Distance:** A distance **<6 cm** (or <3 fingerbreadths) suggests a difficult intubation.

Question 265: All statements are true about modified rapid sequence induction except?

A. Rocuronium is used as a neuromuscular blocker.
B. Any IV induction agent can be used.
C. Positive pressure ventilation with bag and mask is not performed.
D. Preoxygenation is not mandatory. (Correct Answer)

Explanation: **Explanation:** The goal of **Rapid Sequence Induction (RSI)** is to secure the airway as quickly as possible to prevent the aspiration of gastric contents in "full stomach" patients. The **Modified RSI** differs from Classic RSI by allowing gentle mask ventilation and prioritizing hemodynamic stability. **1. Why Option D is the Correct Answer (The "Except" statement):** Preoxygenation is **absolutely mandatory** in both Classic and Modified RSI. Since the patient is not ventilated (or ventilated minimally) during the period of apnea between induction and intubation, preoxygenation (3 minutes of tidal breathing or 8 vital capacity breaths with 100% $O_2$) creates a functional residual capacity (FRC) reservoir. This provides a "safety margin" of time before desaturation occurs. **2. Analysis of Incorrect Options:** * **Option A:** In Modified RSI, **Rocuronium** (1.2 mg/kg) is a preferred alternative to Succinylcholine, especially when the latter is contraindicated (e.g., hyperkalemia, burns). It provides excellent intubating conditions within 60 seconds. * **Option B:** While Thiopental was the classic choice, **any IV induction agent** (Propofol, Etomidate, or Ketamine) can be used based on the patient’s hemodynamic status. * **Option C:** In **Classic RSI**, bag-mask ventilation (BMV) is strictly avoided to prevent gastric insufflation. However, in **Modified RSI**, gentle positive pressure ventilation (keeping airway pressure <20 cm $H_2O$) is often performed to maintain oxygenation, especially in patients with low physiological reserve. **Clinical Pearls for NEET-PG:** * **The "Gold Standard" for RSI:** Traditionally Succinylcholine due to rapid onset and short duration. * **Cricoid Pressure (Sellick’s Maneuver):** Its routine use is now controversial and often omitted in modified techniques if it hinders the view of the glottis. * **Indication for Modified RSI:** Used when the risk of rapid desaturation outweighs the risk of aspiration (e.g., obese patients, pediatrics, or severe lung disease).

Question 266: What is the preferred method of intubation for patients undergoing oral surgeries with bilateral temporomandibular joint (TMJ) ankylosis?

A. North pole RAE tube (Correct Answer)
B. South pole RAE tube
C. Tracheostomy
D. Cricothyrotomy

Explanation: **Explanation:** In patients with **bilateral temporomandibular joint (TMJ) ankylosis**, the primary anesthetic challenge is a "cannot ventilate, cannot intubate" scenario due to restricted mouth opening. For oral surgeries, the surgeon requires an unobstructed surgical field. **Why North Pole RAE is correct:** The **RAE (Ring-Adair-Elwyn) tube** is a pre-formed, angled endotracheal tube designed to prevent kinking and improve surgical access. The **North Pole RAE tube** is specifically designed for **nasotracheal intubation**. It features a pre-formed bend that directs the tube upward (towards the patient's head/north) after exiting the nostril. This allows the breathing circuit to be positioned away from the mouth, providing the surgeon with an unobstructed view and access to the oral cavity and TMJ. **Why other options are incorrect:** * **South Pole RAE tube:** These are designed for **orotracheal intubation**. The bend directs the tube downward (towards the feet/south) over the chin. In TMJ ankylosis, the mouth cannot open sufficiently for oral intubation, and the tube would obstruct the surgical site. * **Tracheostomy/Cricothyrotomy:** These are invasive surgical airways. While they may be used in emergencies or for long-term ventilation, they are not the "preferred" initial method for elective oral surgery if a fiberoptic-guided nasal intubation is feasible. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for TMJ Ankylosis:** Awake Fiberoptic Intubation (AFOI) via the nasal route is the safest approach. * **RAE Mnemonic:** **N**orth = **N**asal (for oral/dental surgery); **S**outh = **O**ral (for ENT/ophthalmic/cranial surgery). * **Magill Forceps:** Often used during nasal intubation to guide the tube into the glottis, though caution is needed in limited mouth opening.

Question 267: Which general anesthetic is most likely to cause bronchodilation?

A. Thiopentone
B. Ketamine (Correct Answer)
C. Propofol
D. Fentanyl

Explanation: **Explanation:** **Ketamine** is the correct answer because it is a potent bronchodilator. Its mechanism involves a direct relaxant effect on bronchial smooth muscle and an indirect effect via the inhibition of catecholamine reuptake, which increases circulating adrenaline. This makes Ketamine the **induction agent of choice for patients with reactive airway diseases**, such as bronchial asthma or COPD. **Analysis of Incorrect Options:** * **Thiopentone (Option A):** It is known to cause respiratory depression and can trigger **histamine release**. This may lead to bronchospasm, making it contraindicated in asthmatic patients. * **Propofol (Option C):** While Propofol does produce some bronchodilation (by inhibiting vagal tone and calcium signaling), it is less potent than Ketamine in this regard. It is generally safe for asthmatics but is not the "most likely" to be tested for its bronchodilatory properties compared to Ketamine. * **Fentanyl (Option D):** As an opioid, Fentanyl can cause respiratory depression. High doses or rapid administration can lead to **"Chest Wall Rigidity"** (Wooden Chest Syndrome), which severely impairs ventilation. **High-Yield Clinical Pearls for NEET-PG:** * **Ketamine** is also the induction agent of choice for **hypovolemic shock** due to its sympathomimetic effects (increases HR and BP). * **Avoid Ketamine** in patients with hypertension, ischemic heart disease, or increased intracranial/intraocular pressure. * Among volatile (inhalational) anesthetics, **Sevoflurane** is the most potent bronchodilator and is preferred for gas induction in asthmatics. * **Halothane** also causes bronchodilation but sensitizes the myocardium to catecholamines, increasing the risk of arrhythmias.

Question 268: During an anesthetic procedure, what is the primary purpose of compressing the cricoid cartilage?

A. To prevent spinal headache
B. To help in preventing regurgitation (Correct Answer)
C. To aid in intubation
D. To relieve reflex bronchospasm

Explanation: **Explanation:** The compression of the cricoid cartilage is known as **Sellick’s Maneuver**. It is a key component of Rapid Sequence Induction (RSI), used primarily in patients with a "full stomach" who are at high risk of aspiration. **1. Why Option B is Correct:** The cricoid cartilage is the only complete cartilaginous ring in the larynx. Applying firm downward pressure (approx. 30 Newtons) compresses the esophagus against the body of the fifth or sixth cervical vertebra. This mechanical occlusion prevents the passive regurgitation of gastric contents into the pharynx, thereby reducing the risk of pulmonary aspiration. **2. Why Other Options are Incorrect:** * **Option A:** Spinal headaches (Post-Dural Puncture Headaches) are complications of neuraxial anesthesia, managed with bed rest, hydration, or an epidural blood patch, not airway maneuvers. * **Option C:** While **BURP** (Backwards, Upwards, Rightwards Pressure) on the *thyroid* cartilage is used to improve the glottic view during intubation, the primary goal of *cricoid* pressure is aspiration prophylaxis, not visualization. * **Option D:** Bronchospasm is a reactive airway issue treated with bronchodilators or deepening the plane of anesthesia; physical compression of the airway would likely worsen the situation. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Cricoid pressure should be applied while the patient is awake (before induction) and maintained until the ETT cuff is inflated and position is confirmed. * **Contraindications:** Active vomiting (may cause esophageal rupture), unstable cervical spine fractures, and laryngeal trauma. * **Pressure:** 10N when awake, increasing to 30N once consciousness is lost.

Question 269: Which of the following devices is most effective in preventing aspiration?

A. Laryngeal Mask Airway (LMA)
B. Oropharyngeal airway
C. Nasopharyngeal airway
D. Proseal Laryngeal Mask Airway (LMA) (Correct Answer)

Explanation: **Explanation:** The **Proseal Laryngeal Mask Airway (PLMA)** is the correct answer because it is a second-generation supraglottic airway device specifically designed to improve safety compared to the classic LMA. Its primary advantage is the inclusion of a **drain tube** (gastric channel) that allows for the passage of a gastric tube to decompress the stomach and provides a bypass for regurgitated fluid, significantly reducing the risk of aspiration. Additionally, it features a larger, deeper cuff that provides a better posterior seal and allows for higher positive pressure ventilation (up to 30 cm H₂O). **Analysis of Incorrect Options:** * **Laryngeal Mask Airway (Classic LMA):** While it maintains a patent airway, it does not protect against aspiration. It sits above the glottis and lacks a gastric drain, meaning regurgitated contents can easily enter the trachea. * **Oropharyngeal Airway (OPA):** This is a simple adjunct used to prevent the tongue from obstructing the posterior pharynx in unconscious patients. It provides no protection for the lower airway against gastric contents. * **Nasopharyngeal Airway (NPA):** Similar to the OPA, this is a conduit to maintain upper airway patency. It does not seal the glottis or isolate the esophagus, offering no protection against aspiration. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** The **Endotracheal Tube (ETT)** remains the absolute gold standard for preventing aspiration; however, among the *listed* supraglottic/adjunct devices, the Proseal LMA is superior. * **Second-Generation SADs:** Devices like the Proseal LMA, Supreme LMA, and I-gel are characterized by their ability to allow gastric drainage. * **Indication:** PLMA is often preferred in controlled ventilation cases where a higher seal pressure is required compared to a classic LMA.

Question 270: All are true about armoured endotracheal tubes except?

A. These are tubes with a metal wire coil embedded in the wall of the tube shaft.
B. It has a radiopaque line like a normal ETT. (Correct Answer)
C. It is bend resistant.
D. It has a slightly thicker outer wall as compared to a normal ETT.

Explanation: **Explanation:** Armoured endotracheal tubes (also known as **reinforced** or **anode tubes**) are specialized airways designed for specific clinical scenarios where tube patency is at risk due to positioning. **1. Why Option B is the Correct Answer (The False Statement):** Unlike standard PVC endotracheal tubes, which require a **radiopaque line** (Blue Line) for X-ray visualization, armoured tubes do not need one. The **stainless steel or nylon wire coil** embedded throughout the shaft is inherently radio-dense. Therefore, the entire length of the tube is visible on a chest X-ray, making a separate radiopaque line redundant. **2. Analysis of Other Options:** * **Option A:** This is the defining feature. The wire coil provides structural integrity while maintaining flexibility. * **Option C:** The primary clinical advantage is that they are **kink-resistant**. They are ideal for surgeries involving extreme head/neck flexion (e.g., posterior fossa surgery) or where the surgeon may lean on the tube (e.g., ENT/Maxillofacial surgery). * **Option D:** To accommodate the embedded wire coil within the silicone or PVC matrix, the outer wall is slightly thicker than a standard ETT of the same internal diameter. **High-Yield Clinical Pearls for NEET-PG:** * **The "Floppy" Nature:** While kink-resistant, these tubes are very flexible and usually require a **stylet** for intubation. * **The Danger of Biting:** If a patient bites an armoured tube, the wire coil can deform permanently, **occluding the lumen**. Unlike standard ETTs, it will not "spring back." A bite block is mandatory. * **MRI Safety:** Most modern armoured tubes use non-ferromagnetic materials, but older versions with stainless steel coils are a contraindication for MRI. * **No Shortening:** You cannot cut an armoured tube to shorten it, as this would expose the wire coil.

Practice by Chapter

Respiratory Physiology

Practice Questions

Airway Anatomy

Practice Questions

Preoxygenation Techniques

Practice Questions

Mask Ventilation

Practice Questions

Supraglottic Airway Devices

Practice Questions

Direct Laryngoscopy

Practice Questions

Video Laryngoscopy

Practice Questions

Fiberoptic Intubation

Practice Questions

Surgical Airway Management

Practice Questions

One-Lung Ventilation Techniques

Practice Questions

Ventilation Strategies During Anesthesia

Practice Questions

Extubation Criteria and Techniques

Practice Questions

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