Respiratory and Airway Management — MCQs

Respiratory and Airway Management Indian Medical PG Practice Questions and MCQs

Question 51: The openings of the tube of a bronchoscope are known as:

A. Holes
B. Apertures
C. Vents (Correct Answer)
D. Any of the above

Explanation: ### Explanation The correct answer is **Vents (Option C)**. In anesthesiology and pulmonology, a **rigid bronchoscope** is a hollow metal tube used for airway management, foreign body removal, and massive hemoptysis. The distal end of the bronchoscope tube features specific side-holes known as **Murphy eyes** or, more technically, **Vents**. **Why "Vents" is the correct term:** The primary function of these openings is to allow for **collateral ventilation**. When the tip of the bronchoscope is positioned deep within a mainstem bronchus (e.g., the right main bronchus), the vents ensure that the contralateral lung (the left lung) can still be ventilated via the side-holes, preventing complete collapse of the non-instrumented lung and maintaining oxygenation. **Analysis of Incorrect Options:** * **Holes (Option A):** While anatomically descriptive, "holes" is a generic term and not the formal medical nomenclature used in airway equipment design. * **Apertures (Option B):** In medical physics and optics (like the lens of a fiberoptic bronchoscope), "aperture" refers to an opening that limits light. It is not the standard term for the ventilation ports on the tube's shaft. * **Any of the above (Option D):** Incorrect because "Vents" is the specific technical term used in clinical practice and standard textbooks (e.g., Miller’s Anesthesia). **High-Yield Clinical Pearls for NEET-PG:** * **Rigid vs. Flexible:** Rigid bronchoscopy is the gold standard for **foreign body removal** in children and managing **massive hemoptysis**. * **Ventilation:** During rigid bronchoscopy, ventilation is typically achieved via **Sanders jet ventilation** or a side-arm attachment to the anesthesia circuit. * **Size:** The size of a rigid bronchoscope is defined by its **internal diameter (ID)**, unlike endotracheal tubes which are often categorized by both ID and OD.

Question 52: In basic life support, how is oxygen typically delivered?

A. Through a mask (Correct Answer)
B. Through an endotracheal tube
C. By rebreathing expired air
D. By blowing air over a tube

Explanation: ### Explanation **1. Why Option A is Correct:** In **Basic Life Support (BLS)**, the primary goal is to maintain oxygenation and circulation using minimal equipment before advanced help arrives. Oxygen delivery in BLS is typically achieved via a **pocket mask** or a **Bag-Valve-Mask (BVM)** device. These interfaces allow the rescuer to provide rescue breaths (at a concentration of 21% room air or higher if supplemental oxygen is attached) while creating an effective seal over the patient's nose and mouth. **2. Why Other Options are Incorrect:** * **Option B (Endotracheal Tube):** This is a component of **Advanced Cardiac Life Support (ACLS)**, not BLS. Intubation requires specialized training and equipment (laryngoscope) to secure a definitive airway. * **Option C (Rebreathing expired air):** While mouth-to-mouth resuscitation uses expired air (which contains ~16-17% oxygen), "rebreathing" implies a closed circuit where the patient breathes their own exhaled CO₂, which is ineffective and dangerous in a cardiac arrest scenario. * **Option D (Blowing air over a tube):** This is not a recognized clinical technique for ventilation. Effective ventilation requires positive pressure to be delivered *into* the lungs, not merely "over" an orifice. **3. NEET-PG High-Yield Pearls:** * **Compression-Ventilation Ratio:** For adults in BLS, the ratio is **30:2** (for both 1 and 2 rescuers). For children/infants, it is 30:2 (1 rescuer) and **15:2** (2 rescuers). * **The "E-C Clamp" Technique:** This is the standard hand position used to hold a mask during BVM ventilation to ensure an airtight seal. * **Gold Standard for Airway:** While BLS uses a mask, the **Endotracheal Tube** remains the gold standard for protecting the airway from aspiration in ACLS. * **First Step in BLS:** Always ensure **Scene Safety** before checking for responsiveness and activating the emergency response system.

Question 53: Which of the following conditions is NOT an indication for securing the airway?

A. Difficult intubation
B. Cardiopulmonary resuscitation
C. A child undergoing elective eye surgery
D. A patient with a large tumor in the oral cavity (Correct Answer)

Explanation: ### Explanation The goal of "securing the airway" is to ensure patency and protect the lungs from aspiration. This question focuses on the clinical judgment required to decide when to intubate versus when to avoid it due to potential complications. **Why Option D is the Correct Answer:** In a patient with a **large tumor in the oral cavity**, the primary concern is a **"can't intubate, can't ventilate" (CICV)** scenario. Attempting to secure the airway via conventional endotracheal intubation can lead to tumor trauma, bleeding, or complete airway obstruction due to the mass. In such cases, the airway is often managed via **awake fiberoptic intubation** or a **surgical airway (tracheostomy/cricothyroidotomy)** under local anesthesia, rather than standard induction and intubation. Therefore, it is considered a contraindication for routine "securing" methods until a specialized plan is in place. **Analysis of Incorrect Options:** * **B. Cardiopulmonary Resuscitation (CPR):** This is a definitive indication. Securing the airway prevents gastric insufflation during chest compressions and ensures adequate oxygenation and ventilation. * **C. Elective Eye Surgery in a Child:** Children undergoing ocular surgery require a secure airway (usually an ETT or LMA) to prevent the **oculocardiac reflex** and to ensure the airway is shared safely with the surgeon without movement. * **A. Difficult Intubation:** While it sounds counterintuitive, a *known* or *predicted* difficult airway is the most critical reason to plan for and eventually secure the airway using specialized techniques (like a video laryngoscope or bougie) to prevent hypoxia. **High-Yield Clinical Pearls for NEET-PG:** * **Indications for Intubation:** Glasgow Coma Scale (GCS) ≤ 8, respiratory failure (Type I or II), and loss of airway protective reflexes. * **LEMON Criteria:** Used to predict a difficult airway (Look, Evaluate 3-3-2, Mallampati, Obstruction, Neck mobility). * **Management of Upper Airway Tumors:** Always maintain spontaneous respiration; avoid neuromuscular blockers until the airway is secured.

Question 54: Which is the most useful supraglottic airway device in abdominal surgery?

A. FAST-trach LMA
B. PROSEAL LMA (Correct Answer)
C. SLIPA
D. Cobra-PLA LMA

Explanation: The **ProSeal LMA (PLMA)** is considered the gold standard supraglottic airway device (SAD) for abdominal surgeries due to its unique design features that address the specific challenges of such procedures (increased intra-abdominal pressure and the need for controlled ventilation). ### Why ProSeal LMA is the Correct Choice: 1. **Gastric Drainage Port:** It features a dedicated second tube (drain tube) that allows for the passage of a gastric tube to decompress the stomach and provides a channel for regurgitated fluid to escape, reducing the risk of aspiration. 2. **High Seal Pressure:** It has a posterior cuff that provides a better seal (up to 30 cm H₂O) compared to the Classic LMA. This allows for **Positive Pressure Ventilation (PPV)**, which is often required in abdominal surgeries to overcome decreased lung compliance. 3. **Bite Block:** It includes an integrated bite block to prevent airway occlusion. ### Why Other Options are Incorrect: * **A. FAST-trach LMA (ILMA):** Specifically designed as a conduit for **intubation** in difficult airway scenarios. It is rigid and not intended for maintenance during routine abdominal surgery. * **C. SLIPA (Streamlined Liner of the Pharynx Airway):** A cuffless, single-use SAD. While it has a chamber to trap regurgitated fluid, it does not offer the high-pressure seal or gastric drainage efficiency of the ProSeal. * **D. Cobra-PLA:** A disposable SAD with a wide "head" to lift the epiglottis. It lacks a gastric drainage channel, making it less safe for abdominal procedures. ### High-Yield Pearls for NEET-PG: * **LMA Supreme:** Often described as the "disposable version" of the ProSeal; it also features a gastric port and is frequently used in similar clinical settings. * **Maximum Seal Pressure:** Classic LMA (~20 cm H₂O) < ProSeal LMA (~30 cm H₂O). * **Contraindication:** SADs are generally avoided in patients with a "full stomach" or morbid obesity, though ProSeal is the safest among them if an SAD must be used.

Question 55: What is the recommended distance of the endotracheal tube tip from the carina?

A. 5 cm above the xiphisternum
B. 4 cm above the carina (Correct Answer)
C. 1 cm above the carina
D. At the carina

Explanation: In clinical anesthesiology, the ideal placement of an endotracheal tube (ETT) ensures adequate ventilation of both lungs while minimizing the risk of accidental endobronchial intubation or vocal cord injury. ### **Explanation of the Correct Answer** The recommended distance for the ETT tip is **3 to 5 cm above the carina** (with **4 cm** being the standard textbook answer for an adult in a neutral neck position). * **The Concept:** The carina is the bifurcation point of the trachea. Placing the tip 4 cm above this point provides a "safety buffer." During neck flexion, the ETT moves toward the carina (caudad), and during neck extension, it moves away from the carina (cephalad). A 4 cm gap prevents the tube from entering the right mainstem bronchus during head movement or surgical positioning. ### **Analysis of Incorrect Options** * **Option A (5 cm above xiphisternum):** The xiphisternum is an external anatomical landmark for the stomach/diaphragm, not the airway. It has no clinical relevance to ETT tip positioning. * **Option C (1 cm above the carina):** This is too close. Even minor neck flexion or downward displacement of the diaphragm (e.g., during laparoscopy) could push the tube into the right mainstem bronchus, leading to one-lung ventilation and hypoxia. * **Option D (At the carina):** This is dangerous. It guarantees carinal irritation (causing coughing/bronchospasm) and carries a near-certain risk of endobronchial intubation. ### **High-Yield NEET-PG Pearls** * **Confirmation:** The "Gold Standard" for confirming ETT position is **Capnography** (ETCO2). * **The "21/23 Rule":** In adults, the average depth of insertion at the teeth is **21 cm for females** and **23 cm for males**. * **Chest X-ray:** On a radiograph, the ETT tip should ideally lie at the level of the **T2-T4 vertebrae** or the mid-trachea. * **Pediatric Formula:** For children >2 years, depth (cm) = **(Age/2) + 12**.

Question 56: Perioperative respiratory failure is best described as which of the following types?

A. Type I respiratory failure
B. Type II respiratory failure
C. Type III respiratory failure (Correct Answer)
D. Type IV respiratory failure

Explanation: **Explanation:** Respiratory failure is classified into four distinct types based on the underlying pathophysiology. **Type III respiratory failure** is specifically defined as **perioperative respiratory failure**. **Why Option C is correct:** Type III respiratory failure occurs primarily in the postoperative period. It is characterized by **atelectasis** resulting from a decrease in Functional Residual Capacity (FRC). Factors contributing to this include upper abdominal incisions, anesthesia-induced changes in diaphragm motion, obesity, and pain, which lead to shallow breathing and collapse of small airways. This is the most common form of respiratory failure encountered by anesthesiologists in the recovery room. **Why the other options are incorrect:** * **Type I (Hypoxemic):** Characterized by $PaO_2 < 60$ mmHg with normal or low $PaCO_2$. It is caused by V/Q mismatch or shunting (e.g., pulmonary edema, pneumonia). * **Type II (Hypercapnic/Ventilatory):** Characterized by $PaCO_2 > 45$ mmHg. It results from pump failure (e.g., COPD, neuromuscular disorders, or drug overdose). * **Type IV (Shock):** Occurs in patients who are intubated and ventilated during the stabilization of hypovolemic, cardiogenic, or septic shock to reduce the oxygen demand of the respiratory muscles. **High-Yield Clinical Pearls for NEET-PG:** * **Management of Type III:** The mainstay of treatment is lung expansion maneuvers, including **incentive spirometry**, chest physiotherapy, and **PEEP** (Positive End-Expiratory Pressure) to reopen collapsed alveoli. * **Positioning:** Placing the patient in a semi-recumbent (upright) position helps increase FRC and is a key preventive measure. * **Type III vs. Type I:** While Type III involves hypoxemia (like Type I), it is distinguished by its specific perioperative context and the mechanism of atelectasis.

Question 57: A drug is to be delivered by a nebuliser. What is the optimal droplet size for humidification?

A. < 5 micrometers (Correct Answer)
B. 10-15 micrometers
C. 15-20 micrometers
D. > 20 micrometers

Explanation: ### Explanation The effectiveness of aerosol therapy depends primarily on the **particle size**, which determines the site of deposition in the respiratory tract. This concept is known as **selective deposition**. **1. Why < 5 micrometers is correct:** For a drug to be effective during nebulization, it must reach the lower respiratory tract (bronchioles and alveoli). Particles sized **1–5 micrometers** are optimal because they are small enough to remain suspended in the air stream until they reach the narrow peripheral airways, where they deposit via **sedimentation**. Particles smaller than 1 micrometer are often exhaled back out, while those between 1-5 micrometers provide the best balance for therapeutic humidification and drug delivery. **2. Why the other options are incorrect:** * **B (10–15 μm):** Particles of this size are too large to bypass the upper airway. They are typically trapped in the **mouth and oropharynx** due to inertial impaction. * **C & D (> 15 μm):** These large droplets deposit almost exclusively in the **upper respiratory tract (nose and nasopharynx)**. While useful for treating upper airway conditions (like croup or epiglottitis), they are ineffective for systemic absorption or lower airway humidification. **Clinical Pearls for NEET-PG:** * **Inertial Impaction:** Occurs with large particles (> 5 μm) in the upper airway where airflow is fast and turbulent. * **Gravitational Sedimentation:** The primary mechanism for 1–5 μm particles in the smaller airways. * **Diffusion (Brownian motion):** The mechanism for very small particles (< 1 μm) in the alveoli. * **Ideal Breathing Pattern:** Slow, deep breaths with a breath-hold (5–10 seconds) maximize the deposition of 1–5 μm particles by allowing more time for sedimentation.

Question 58: All of the following are absolute indications for intubation except?

A. Depressed level of consciousness
B. Bleeding into the airway
C. Falling O2 saturation
D. Maxillofacial fractures (Correct Answer)

Explanation: **Explanation:** In airway management, it is crucial to distinguish between **absolute indications** for intubation (where the airway is lost or immediately threatened) and **relative indications** (where intubation is likely but depends on clinical severity). **Why Maxillofacial Fractures is the Correct Answer:** Maxillofacial fractures are considered a **relative indication**. While severe trauma can lead to airway obstruction due to edema or hemorrhage, many patients with stable facial fractures can maintain their own airway. Intubation is only mandatory if the fracture causes secondary issues like massive bleeding, loss of protective reflexes, or mechanical obstruction. **Analysis of Incorrect Options:** * **Depressed Level of Consciousness (GCS ≤ 8):** This is an absolute indication. A patient with a low GCS cannot protect their airway, leading to a high risk of aspiration and tongue-fall obstruction. * **Bleeding into the Airway:** This is an absolute indication. Active hemorrhage poses an immediate risk of aspiration and can rapidly obscure the view for intubation; thus, early definitive airway control is mandatory. * **Falling O2 Saturation:** Persistent hypoxemia despite supplemental oxygen (respiratory failure) is an absolute indication. It signifies that the patient’s compensatory mechanisms have failed. **Clinical Pearls for NEET-PG:** * **The "GCS 8" Rule:** "GCS of 8, we intubate" is a classic mnemonic for airway protection. * **Difficult Airway:** Maxillofacial trauma is often a predictor of a *difficult* airway (LEMON criteria), but the trauma itself is not an automatic indication for intubation. * **Other Absolute Indications:** Apnea, impending airway obstruction (e.g., inhalation burns/stridor), and severe shock.

Question 59: What is the maximum fraction of inspired oxygen (FiO2) that can be delivered using a simple face mask (Hudson mask)?

A. 0.6 (Correct Answer)
B. 0.4
C. 0.8
D. 1.0

Explanation: **Explanation:** The **Simple Face Mask (Hudson mask)** is a low-flow oxygen delivery device. It delivers an FiO2 ranging from **0.4 to 0.6 (40% to 60%)** at flow rates of **5 to 10 L/min**. The FiO2 is determined by the oxygen flow rate, the mask's reservoir volume, and the patient’s inspiratory flow rate. It cannot deliver 100% oxygen because the mask has open side ports (exhalation ports) that allow room air to entrain and dilute the oxygen during inspiration. **Analysis of Options:** * **Option A (0.6) - Correct:** This is the maximum achievable FiO2. At a flow rate of 8–10 L/min, the mask reservoir is filled sufficiently to provide 60% oxygen. * **Option B (0.4):** This is the *minimum* FiO2 typically delivered by a simple mask. Flow rates below 5 L/min should be avoided as they lead to CO2 rebreathing. * **Option C (0.8) & D (1.0):** These levels cannot be reached with a simple mask. To achieve an FiO2 > 0.6 (up to 0.9 or 1.0), a **Non-Rebreather Mask (NRBM)** with a reservoir bag and one-way valves is required. **High-Yield Clinical Pearls for NEET-PG:** 1. **Flow Rate Caution:** Never use a simple mask at <5 L/min; the flow must be high enough to flush out exhaled CO2 from the mask's dead space. 2. **Nasal Cannula:** Delivers FiO2 of 0.24–0.44 (approx. 4% increase per liter of O2). 3. **Venturi Mask:** The device of choice for precise FiO2 delivery (e.g., in COPD patients) using the Bernoulli principle. 4. **NRBM:** The highest FiO2 (up to 90-100%) among non-invasive low-flow devices.

Question 60: In cases of medical emergencies, what is an invasive technique used to manage airway obstruction?

A. Chest thrust
B. Abdominal thrust
C. Mouth to mouth resuscitation
D. Laryngoscopy (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Laryngoscopy** **Medical Concept:** In the context of managing an airway obstruction, **Laryngoscopy** is considered an invasive diagnostic and therapeutic procedure. It involves the use of a laryngoscope to visualize the glottis and vocal cords. In an emergency, it is the critical first step for **Endotracheal Intubation**, which bypasses the obstruction to secure a definitive airway. It can also be used to identify and remove foreign bodies using Magill forceps. While "invasive" often refers to surgical techniques (like cricothyrotomy), in the hierarchy of basic vs. advanced life support, laryngoscopy is the primary invasive maneuver used to instrument the airway. **Analysis of Incorrect Options:** * **A. Chest Thrust:** This is a **non-invasive** manual maneuver used in the Heimlich maneuver variant for pregnant or obese patients to increase intrathoracic pressure and expel a foreign body. * **B. Abdominal Thrust:** Also known as the Heimlich maneuver, this is a **non-invasive** technique that uses subdiaphragmatic pressure to create an artificial cough. * **C. Mouth-to-Mouth Resuscitation:** This is a **non-invasive** method of rescue breathing used in Basic Life Support (BLS) to provide oxygenation; it does not bypass or mechanically clear an obstruction. **NEET-PG High-Yield Pearls:** * **Gold Standard for Airway:** Endotracheal intubation (facilitated by laryngoscopy) is the gold standard for securing a definitive airway. * **Surgical Airway:** If laryngoscopy fails ("Cannot Intubate, Cannot Oxygenate"), the next invasive step is a **Cricothyrotomy**. * **Sniffing Position:** Optimal position for laryngoscopy involves flexion of the neck and extension of the head (aligning oral, pharyngeal, and laryngeal axes). * **Difficult Airway Predictor:** The **Mallampati Classification** is the most common bedside tool used to predict difficult laryngoscopy.

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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