FMGE 2025 - Anesthesiology Practice Questions

Q: The waveform shown in the image represents which of the following physiological parameters?

End-tidal carbon dioxide. ***End-tidal carbon dioxide*** - The image displays a **capnogram**, which is a graphical representation of the concentration or partial pressure of **carbon dioxide (CO2)** in respiratory gases over time. The y-axis is clearly labeled **CO2 (mmHg)**. - The characteristic rectangular waveform represents the respiratory cycle: the plateau indicates the exhalation of **alveolar gas**, and the peak at the end of the plateau is the **end-tidal CO2 (ETCO2)**, which normally ranges from 35-45 mmHg. *Arterial oxygen saturation* - Arterial oxygen saturation (SpO2) is measured by **pulse oximetry** and is reported as a **percentage**, not in mmHg. - The waveform associated with pulse oximetry is a **plethysmograph**, which reflects changes in blood volume in the tissue with each heartbeat, not respiratory gas exchange. *Functional residual capacity* - **Functional residual capacity (FRC)** is a static lung **volume** (measured in liters or milliliters), representing the amount of air remaining in the lungs after a normal exhalation. - It is not a dynamically changing parameter measured with each breath and cannot be represented by this type of real-time waveform. *Tidal volume* - **Tidal volume** is the **volume** of air inhaled or exhaled during a single breath, measured in milliliters or liters. - A graph of tidal volume over time (spirometry) would show a sinusoidal wave representing the volume change, which looks distinctly different from the capnogram shown.

Q: What is the primary function of the inflatable cuff of the endotracheal tube shown in the image?

Prevention of air leakage and aspiration. ***Prevention of air leakage and aspiration*** - When inflated, the cuff creates a seal against the wall of the **trachea**. This prevents air delivered during **positive pressure ventilation** from escaping around the tube, ensuring adequate tidal volume delivery to the lungs. - The seal also protects the airway by preventing oropharyngeal and gastric secretions from entering the lungs, thus reducing the risk of **aspiration pneumonia**. *Facilitation of vocal cord visualization* - Vocal cord visualization is achieved using a **laryngoscope** during the intubation procedure *before* the cuff is inflated. - The endotracheal tube cuff is positioned *below* the vocal cords; its inflation would not aid in their visualization. *Monitoring airway pressure* - Airway pressure (e.g., peak inspiratory pressure) is monitored through the **ventilator circuit**, not the cuff. The pressure within the cuff is monitored separately via the **pilot balloon** using a manometer. - While maintaining appropriate **cuff pressure** (typically 20-30 cm H2O) is vital to prevent tracheal injury, the cuff's primary function is sealing, not monitoring overall airway pressure. *Suctioning of lower respiratory tract secretions* - Suctioning is performed by passing a sterile **suction catheter** through the lumen of the endotracheal tube to clear secretions from the lower airways. - The cuff itself has no suctioning capability, although some specialized tubes have a separate **subglottic suction port** located above the cuff to remove pooled secretions.

Q: During general anesthesia, which nerve is commonly monitored using a nerve stimulator to assess neuromuscular blockade?

Ulnar nerve. ***Ulnar nerve*** - The **ulnar nerve** is the most common site for monitoring neuromuscular blockade because it is superficially located at the wrist, making it easily accessible for stimulation with surface electrodes. - Stimulation of the ulnar nerve causes contraction of the **adductor pollicis** muscle, leading to thumb adduction, which is a reliable and easily observable response to assess the degree of muscle relaxation. *Radial nerve* - The **radial nerve** is located deeper at the wrist compared to the ulnar nerve, making it more difficult to stimulate effectively with surface electrodes. - While it can be stimulated to produce wrist and finger extension, the response is generally less consistent and harder to quantify than the thumb adduction seen with ulnar nerve stimulation. *Median nerve* - Stimulation of the **median nerve** causes contraction of the thenar muscles, resulting in thumb opposition, which can be a more complex and sometimes painful response. - The median nerve lies between the tendons of the flexor carpi radialis and palmaris longus, making precise electrode placement more challenging and potentially leading to direct muscle stimulation. *Tibial nerve* - The **tibial nerve** can be stimulated behind the medial malleolus to elicit plantar flexion of the great toe (via the **flexor hallucis brevis** muscle). - However, the foot is often less accessible than the hand during surgery due to patient positioning and surgical draping, making the ulnar nerve a more practical choice.

Q: A patient under anesthesia is found to be in a “cannot intubate, cannot ventilate” (CICV) scenario. What is the next best step in management?

Perform a cricothyroidotomy. ***Perform a cricothyroidotomy*** - In a “cannot intubate, cannot ventilate” (**CICV**) scenario, immediate establishment of a surgical airway is life-saving to prevent **hypoxic brain injury** and death. - A **cricothyroidotomy** is the fastest and most definitive emergency procedure to secure the airway by making an incision through the **cricothyroid membrane** into the trachea, bypassing any upper airway obstruction. *Insert nasopharyngeal airway* - A nasopharyngeal airway is a basic airway adjunct designed to relieve soft tissue obstruction at the level of the pharynx. It does not provide a definitive airway for ventilation. - In a **CICV** situation, basic maneuvers and adjuncts like this have already been attempted and failed; it is an inadequate intervention for this life-threatening emergency. *Insert a laryngeal mask airway* - A laryngeal mask airway (**LMA**) is a supraglottic airway device. A **CICV** scenario is declared only after attempts to secure the airway with both an endotracheal tube and a supraglottic device have failed. - Wasting further time attempting to insert an LMA is inappropriate when ventilation is not possible and a surgical airway is urgently needed. *Perform a tracheostomy* - A **tracheostomy** is a formal, time-consuming surgical procedure that is more complex and has a higher complication rate in an emergency setting compared to a cricothyroidotomy. - While it is a definitive airway, it is not the procedure of choice for a time-critical airway emergency. A cricothyroidotomy is the standard emergent surgical airway.

Q: A patient undergoing surgery develops sudden deranged vitals following a failed attempt at subclavian vein catheterization. On examination, the trachea is shifted to one side and breath sounds are absent on the opposite side. What is the most likely diagnosis?

Tension pneumothorax. ***Correct: Tension pneumothorax*** - **Classic complication of subclavian vein catheterization** - inadvertent puncture of the pleura causes air accumulation in the pleural space - **Pathognomonic clinical features** present in this case: - **Tracheal deviation away from the affected side** (toward the opposite side where breath sounds are absent) - **Absent breath sounds on the affected side** due to complete lung collapse - **Hemodynamic instability** ("deranged vitals") from mediastinal shift compressing the great vessels and heart - **Medical emergency** requiring immediate needle decompression followed by chest tube insertion - The **tension** component occurs when air enters pleural space during inspiration but cannot escape during expiration (one-way valve effect), causing progressive pressure buildup *Incorrect: Aspiration pneumonitis* - Would present with bilateral crackles, hypoxia, and potential bronchospasm - Does **not cause tracheal deviation** or unilateral absent breath sounds - Typically occurs during induction or emergence from anesthesia, not during vascular access procedures *Incorrect: Pulmonary embolism* - Presents with sudden dyspnea, hypoxia, tachycardia, and possible hypotension - Does **not cause tracheal deviation** or unilateral absent breath sounds - Breath sounds remain present bilaterally (though may have localized crackles) - Not directly related to subclavian catheterization attempts *Incorrect: Bronchospasm* - Presents with **bilateral wheezing** and increased airway pressures - Does **not cause tracheal deviation** or unilateral findings - Breath sounds present bilaterally (though may be diminished with severe bronchospasm) - Would not explain the immediate temporal relationship with failed subclavian line attempt

Question 1

The waveform shown in the image represents which of the following physiological parameters?

Accepted Answer

End-tidal carbon dioxide

Answer

Tidal volume

Answer

Arterial oxygen saturation

Answer

Functional residual capacity

Question 2

What is the primary function of the inflatable cuff of the endotracheal tube shown in the image?

Accepted Answer

Prevention of air leakage and aspiration

Answer

Suctioning of lower respiratory tract secretions

Answer

Facilitation of vocal cord visualization

Answer

Monitoring airway pressure

Question 3

A patient is scheduled for laparoscopic surgery under general anesthesia in a day care setting. Which of the following factors makes him unsuitable for day care surgery?

Accepted Answer

No attendant is available at home to care for the patient postoperatively

Answer

The patient has had general anesthesia in the past without complications

Answer

The surgical procedure is expected to last slightly over 1 hour

Answer

Home is 45 minutes away from the hospital

Question 4

During general anesthesia, which nerve is commonly monitored using a nerve stimulator to assess neuromuscular blockade?

Accepted Answer

Ulnar nerve

Answer

Tibial nerve

Answer

Median nerve

Answer

Radial nerve

Question 5

A patient under anesthesia is found to be in a “cannot intubate, cannot ventilate” (CICV) scenario. What is the next best step in management?

Accepted Answer

Perform a cricothyroidotomy

Answer

Insert a laryngeal mask airway

Answer

Insert nasopharyngeal airway

Answer

Perform a tracheostomy

Question 6

A patient undergoing surgery develops sudden deranged vitals following a failed attempt at subclavian vein catheterization. On examination, the trachea is shifted to one side and breath sounds are absent on the opposite side. What is the most likely diagnosis?

Accepted Answer

Tension pneumothorax

Answer

Aspiration pneumonitis

Answer

Pulmonary embolism

Answer

Bronchospasm

FMGE 2025 — Anesthesiology