Respiratory and Airway Management Practice Questions

Q: Which of the following is a fixed oxygen delivery device?

Venturi mask. ### Explanation Oxygen delivery devices are classified into two categories: **Variable Performance (Low-flow)** and **Fixed Performance (High-flow)** systems. **1. Why Venturi Mask is Correct:** The **Venturi mask** is a high-flow device that works on the **Bernoulli principle** and the **Venturi effect**. It delivers a constant, precise Fraction of Inspired Oxygen ($FiO_2$) regardless of the patient’s inspiratory flow rate or respiratory pattern. Oxygen under pressure passes through a narrow orifice, creating a vacuum that draws in a specific amount of room air. Because the total flow provided by the device exceeds the patient's peak inspiratory flow, the $FiO_2$ remains "fixed." **2. Why the Other Options are Incorrect:** * **Nasal Cannula & Nasal Mask:** These are low-flow systems. The $FiO_2$ delivered (typically 24–44%) is **variable** because it depends on the patient’s tidal volume and respiratory rate. If a patient breathes deeply or quickly, they entrain more room air, thereby diluting the oxygen and lowering the $FiO_2$. * **Non-rebreather Mask (NRM):** Although it can deliver high concentrations of oxygen (up to 60–90%), it is still considered a **variable performance** device. The $FiO_2$ fluctuates based on the mask's seal and the patient's inspiratory demands. **Clinical Pearls for NEET-PG:** * **Best for COPD:** The Venturi mask is the gold standard for patients with Type II Respiratory Failure (COPD) to prevent suppressing their hypoxic respiratory drive. * **Color Coding:** Venturi valves are color-coded for specific $FiO_2$ (e.g., Blue = 24%, White = 28%, Orange = 31%, Yellow = 35%, Red = 40%, Green = 60%). * **Flow Rate Rule:** For a nasal cannula, $FiO_2$ increases by approximately **4% for every 1 L/min** increase in oxygen flow.

Q: Which of the following ventilation modes reduces work of breathing by overcoming the resistance created by ventilator tubing?

Pressure support mode. **Explanation:** **Pressure Support Ventilation (PSV)** is a spontaneous mode of ventilation where the ventilator provides a preset level of positive pressure once the patient triggers a breath. The primary physiological goal of PSV is to **overcome the resistive work of breathing (WOB)** imposed by the endotracheal tube, the breathing circuit, and the demand valves. Because the patient determines the respiratory rate, inspiratory flow, and inspiratory time, it is highly comfortable and is the mainstay for weaning patients from mechanical ventilation. **Analysis of Incorrect Options:** * **Controlled Mandatory Ventilation (CMV):** The ventilator delivers a set tidal volume or pressure at a fixed rate regardless of patient effort. The machine does all the work; it does not "assist" the patient in overcoming tubing resistance during spontaneous efforts. * **Assist Control (AC) Mode:** Every breath (whether patient-triggered or machine-timed) receives the full preset tidal volume or pressure. While it supports the patient, it is not specifically designed to titrate against circuit resistance; rather, it provides full ventilatory support. * **Synchronized Intermittent Mandatory Ventilation (SIMV):** This mode delivers a set number of mandatory breaths while allowing spontaneous breaths in between. Without added pressure support, those spontaneous breaths must overcome the circuit resistance entirely on their own, actually *increasing* the work of breathing compared to PSV. **Clinical Pearls for NEET-PG:** * **Trigger:** PSV is always **patient-triggered** (usually by flow or pressure). * **Cycling:** PSV is **flow-cycled** (inspiration ends when the inspiratory flow drops to a certain percentage of the peak flow, usually 25%). * **High-Yield Fact:** PSV is the preferred mode for the **Spontaneous Breathing Trial (SBT)** during the weaning process to assess if a patient can maintain adequate ventilation post-extubation.

Q: Which of the following conditions are contraindications for both oral and nasal intubation?

Acute tracheo-laryngo-bronchitis. **Explanation:** The correct answer is **Acute tracheo-laryngo-bronchitis (Croup)**. In patients with acute tracheo-laryngo-bronchitis, the airway is severely inflamed, edematous, and highly irritable. Attempting either oral or nasal intubation can trigger catastrophic **laryngospasm** or worsen the subglottic edema, leading to complete airway obstruction. In such cases, the preferred management is conservative (oxygen, racemic epinephrine, steroids); if the airway must be secured, it is often done via tracheostomy or in a highly controlled surgical setting to avoid trauma to the friable mucosa. **Analysis of Incorrect Options:** * **Laryngeal edema:** While it makes intubation difficult, it is not an absolute contraindication for both routes. If the edema is supraglottic, a skilled clinician may still perform oral intubation, though a surgical airway may be required if the glottis is obscured. * **CSF Rhinorrhea:** This is a classic contraindication for **nasal** intubation (due to the risk of meningitis or intracranial tube placement via a fractured cribriform plate), but **oral** intubation remains the safe and preferred route. * **Comatose patient:** Coma is an **indication** for intubation (to protect the airway from aspiration), not a contraindication. **High-Yield Clinical Pearls for NEET-PG:** * **Absolute Contraindication for Nasal Intubation:** Base of skull fractures (CSF rhinorrhea/raccoon eyes), coagulopathy, and nasal polyps. * **Epiglottitis vs. Croup:** In Epiglottitis (cherry-red epiglottis), intubation is usually performed in the OR under GA; in Croup (steeple sign), intubation is avoided unless respiratory failure is imminent. * **Gold Standard for Airway:** Endotracheal intubation is the gold standard for protecting the airway against aspiration.

Q: A Macintosh curved blade laryngoscope is a type of:

Direct laryngoscope. **Explanation:** The **Macintosh blade** is the most widely used **direct laryngoscope** in clinical practice. The fundamental principle of direct laryngoscopy is to create a **straight line of sight** from the clinician's eye to the patient's glottis by physically displacing the tongue and soft tissues. * **Why Option B is correct:** The Macintosh blade is a curved blade designed to be inserted into the **vallecula** (the space between the base of the tongue and the epiglottis). When the handle is lifted, it puts tension on the hyoepiglottic ligament, which indirectly elevates the epiglottis to reveal the vocal cords for direct visualization. * **Why Option A & D are incorrect:** **Indirect laryngoscopy** (including **Video laryngoscopes** like the McGrath or Glidescope) uses mirrors, prisms, or fiberoptic/digital cameras to "see around the corner." These do not require a straight line of sight and allow the clinician to view the glottis on a screen or via an eyepiece. * **Why Option C is incorrect:** A **Bronchoscope** is a flexible or rigid fiberoptic instrument used primarily for visualizing the tracheobronchial tree, not for routine laryngoscopy. **High-Yield Clinical Pearls for NEET-PG:** * **Miller Blade:** A straight blade that is passed *over* the epiglottis to lift it directly. It is preferred in infants/pediatrics due to their long, floppy, omega-shaped epiglottis. * **McCoy Blade:** A modified Macintosh blade with a **hinged tip** operated by a lever on the handle, useful in "difficult" airways to lift the epiglottis further. * **Positioning:** The "Sniffing position" (flexion of the lower cervical spine and extension of the atlanto-occipital joint) is essential to align the oral, pharyngeal, and laryngeal axes for direct laryngoscopy.

Q: Which of the following is contraindicated during this procedure?

Neck flexion at atlanto-occipital joint. ***Neck flexion at atlanto-occipital joint*** - **Atlanto-occipital flexion** is contraindicated during direct laryngoscopy as it worsens visualization of the vocal cords and glottis. - The correct position requires **atlanto-occipital extension** combined with **cervical flexion** (sniffing position) to align the oral, pharyngeal, and laryngeal axes. *Introduction of blade towards the right side of oropharynx* - This is the **correct technique** for laryngoscope insertion to avoid trauma to teeth and soft tissues. - The blade is inserted from the **right corner of the mouth** and then advanced towards the **midline** to reach the vallecula. *Head elevation* - **Head elevation** (ramping) is beneficial and recommended, especially in obese patients to improve laryngoscopic view. - It helps achieve optimal **sniffing position**. *Preoxygenation with 100% oxygen* - **Preoxygenation** is a standard and essential step before laryngoscopy to maximize oxygen reserves. - It provides a **safety margin** of 3-5 minutes during apnea and prevents **hypoxemia** during intubation attempts.

Q: What is a contraindication for nasotracheal intubation?

Anterior cranial fossa fracture. ### Explanation **1. Why Anterior Cranial Fossa (ACF) Fracture is the Correct Answer:** Nasotracheal intubation is strictly contraindicated in patients with suspected or confirmed **Anterior Cranial Fossa fractures** (often clinically indicated by CSF rhinorrhea, Raccoon eyes, or Battle’s sign). The anatomical basis is the potential disruption of the **cribriform plate of the ethmoid bone**. If the cribriform plate is fractured, a blindly inserted nasogastric or nasotracheal tube can inadvertently pass through the fracture site and enter the **intracranial space**, causing direct brain parenchyma injury or introducing infection (meningitis). **2. Analysis of Incorrect Options:** * **B & C (Middle and Posterior Cranial Fossa Fractures):** While these are serious injuries, they do not involve the cribriform plate. The risk of intracranial tube entry is specific to the ACF. However, in clinical practice, any basilar skull fracture generally warrants extreme caution or avoidance of the nasal route. * **D (GCS < 8):** A GCS score of less than 8 is an **indication** for intubation (to protect the airway), not a contraindication. While orotracheal intubation is usually the preferred rapid method, a low GCS does not specifically prohibit the nasal route if otherwise indicated. **3. High-Yield Clinical Pearls for NEET-PG:** * **Absolute Contraindications for Nasal Intubation:** ACF fracture, mid-face fractures (Le Fort II and III), coagulopathy/bleeding disorders, and severe nasal obstruction (e.g., polyps). * **Preferred Route:** Orotracheal intubation is the "Gold Standard" for emergency airway management. * **Tube Size:** A nasotracheal tube is typically **0.5–1.0 mm smaller** in internal diameter than an orotracheal tube for the same patient. * **Vasoconstriction:** Always use a topical vasoconstrictor (e.g., Oxymetazoline or Xylometazoline) to prevent epistaxis, the most common complication of nasal intubation.

Q: What is the Bailey maneuver in patients at high risk of laryngospasm?

The deflated LMA is placed behind the in situ ETT. The ETT is removed, and the LMA is inflated.. The **Bailey Maneuver** (also known as the "LMA-exchange technique") is a specialized extubation strategy designed to ensure a smooth transition from deep to awake anesthesia, primarily to prevent airway reflexes like coughing, bucking, or laryngospasm. ### **Explanation of the Correct Answer (C)** The technique involves placing a **deflated LMA behind the existing endotracheal tube (ETT)** while the patient is still in a deep plane of anesthesia. Once the LMA is positioned, the ETT is removed, and the LMA is immediately inflated. This allows the LMA to "take over" the airway. The patient can then emerge and wake up with the LMA in situ, which is much better tolerated than an ETT, significantly reducing the risk of laryngospasm and sympathetic stimulation. ### **Analysis of Incorrect Options** * **Option A:** Suggests inserting the LMA *after* removing the ETT. This creates a period of "unprotected airway" where the patient might laryngospasm before the LMA is placed. * **Option B:** Describes a general concept of using different devices but lacks the specific "exchange" sequence that defines the Bailey maneuver. ### **NEET-PG High-Yield Pearls** * **Indications:** Ideal for patients where straining must be avoided (e.g., intraocular surgery, neurosurgery, hernia repairs, or patients with reactive airway disease/asthma). * **Key Advantage:** It provides a "bridge" to extubation, maintaining a patent airway while avoiding the intense stimulation of a tracheal tube during emergence. * **Prerequisite:** The patient must have a "low risk of aspiration" (Fasting/NPO status must be confirmed) since an LMA does not protect against gastric reflux as effectively as an ETT.

Q: What is the best indicator of successful endotracheal tube extubation?

Negative inspiratory pressure. **Explanation:** The decision to extubate a patient requires a comprehensive assessment of their ability to maintain a patent airway and sustain adequate spontaneous ventilation. Among the options provided, **Negative Inspiratory Pressure (NIP)**, also known as Maximal Inspiratory Pressure (MIP), is the most reliable objective indicator of respiratory muscle strength. **1. Why Negative Inspiratory Pressure (NIP) is correct:** NIP measures the maximum pressure generated by the patient against an occluded airway. It specifically reflects the strength of the diaphragm and intercostal muscles. A value **more negative than -20 to -30 cm H₂O** indicates that the patient has sufficient muscle power to cough, clear secretions, and maintain ventilation independently, making it a gold-standard predictor for successful extubation. **2. Why other options are incorrect:** * **Minute Volume (MV):** While an MV of <10 L/min is generally required, it can be misleading. A patient can achieve a normal MV through a high respiratory rate and low tidal volume (rapid shallow breathing), which leads to early fatigue and extubation failure. * **Respiratory Rate (RR):** A rate <30-35 breaths/min is a prerequisite, but it does not account for the quality of gas exchange or the strength of the respiratory muscles. * **Tin Box Index:** This is a distractor and not a standard clinical parameter used in anesthesia or intensive care for weaning or extubation. **Clinical Pearls for NEET-PG:** * **Rapid Shallow Breathing Index (RSBI):** Calculated as RR/Tidal Volume (L). An **RSBI 10-15 mL/kg** for successful extubation. * **The "Gold Standard" Clinical Test:** The patient’s ability to follow simple commands (e.g., "squeeze my hand" or "lift your head for 5 seconds") is a crucial subjective indicator of neurological recovery from anesthesia.

Question 1

Which of the following is NOT true about endotracheal intubation?

Accepted Answer

Increased esophageal peristalsis

Answer

Hypertension and tachycardia

Answer

Raised intraocular pressure

Answer

Raised intracranial pressure

Question 2

Which of the following is a fixed oxygen delivery device?

Accepted Answer

Venturi mask

Answer

Nasal cannula

Answer

Nasal mask

Answer

Non-rebreather mask

Question 3

Which of the following ventilation modes reduces work of breathing by overcoming the resistance created by ventilator tubing?

Accepted Answer

Pressure support mode

Answer

Controlled mandatory ventilation

Answer

Synchronized intermittent mandatory breath

Answer

Assist control mode

Question 4

Which of the following conditions are contraindications for both oral and nasal intubation?

Accepted Answer

Acute tracheo-laryngo-bronchitis

Answer

Laryngeal edema

Answer

Cerebrospinal fluid (CSF) rhinorrhea

Answer

Comatose patient

Question 5

A Macintosh curved blade laryngoscope is a type of:

Accepted Answer

Direct laryngoscope

Answer

Indirect laryngoscope

Answer

Bronchoscope

Answer

Video laryngoscope

Question 6

Which of the following is contraindicated during this procedure?

Accepted Answer

Neck flexion at atlanto-occipital joint

Answer

Introduction of blade towards the right side of oropharynx

Answer

Head elevation

Answer

Preoxygenation with 100% oxygen

Question 7

What is a contraindication for nasotracheal intubation?

Accepted Answer

Anterior cranial fossa fracture

Answer

Middle cranial fossa fracture

Answer

Posterior cranial fossa fracture

Answer

GCS < 8

Question 8

What is the best method for airway maintenance in a patient experiencing cardiopulmonary arrest?

Accepted Answer

Orotracheal intubation

Answer

Bag-valve-mask ventilation

Answer

Nasotracheal intubation

Answer

Guedel airway

Question 9

What is the Bailey maneuver in patients at high risk of laryngospasm?

Accepted Answer

The deflated LMA is placed behind the in situ ETT. The ETT is removed, and the LMA is inflated.

Answer

Laryngeal mask airway (LMA) is inserted just before reversal of anesthesia after removing the endotracheal tube (ETT).

Answer

During intubation and extubation, LMA is used, and during the intraoperative period, ETT is used.

Answer

None of the above.

Question 10

What is the best indicator of successful endotracheal tube extubation?

Accepted Answer

Negative inspiratory pressure

Answer

Tin box index

Answer

Minute volume

Answer

Respiratory rate

Respiratory and Airway Management — MCQs

Respiratory and Airway Management — MCQs

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