Airway Ultrasound — MCQs
What is the name of this technique for palpation of thyroid where a thumb is placed on the lateral side of trachea and patient is swallowing?
Which of the following cartilages has signet ring shape?
In acoustic neuroma, which cranial nerve is involved earliest?
Endotracheal tube in the esophagus is best assessed by:
A child presents with respiratory distress. A vascular ring is suspected. Investigation of choice is -
In correct positioning the tip of the instrument shown in the image should lie at:
Modified Mallampati grading is used in assessment of -
A construction worker met with an accident when a cement block fell on his face. He sustained severe maxillofacial and laryngeal injury. He was not able to open his mouth and is having jaw fracture with obstruction in nasopharynx and oropharynx. To stabilize his airway, the following procedure was done on him. Which option describes the procedure done on him?
During ultrasound-guided internal jugular vein cannulation, you observe the vein collapsing with minimal probe pressure while the artery remains patent. The vein appears enlarged and the artery-to-vein ratio is 1:3. A spontaneously breathing patient shows respiratory variation. Evaluate the most appropriate interpretation and management strategy.
A 55-year-old patient with previous lumbar spine surgery requires epidural catheter placement for postoperative analgesia. Pre-procedure ultrasound shows loss of normal posterior complex and irregular acoustic shadowing at L3-L4 and L4-L5 levels. The L2-L3 level shows preserved anatomy with a depth of 6 cm to the epidural space. Which technical modification would provide the best success rate?
Airway Ultrasound Indian Medical PG Practice Questions and MCQs
Question 1: What is the name of this technique for palpation of thyroid where a thumb is placed on the lateral side of trachea and patient is swallowing?
- A. Pizzilo method
- B. Lahey's method
- C. Crile method (Correct Answer)
- D. Kocher's test
Explanation: Crile method - The Crile method for thyroid palpation involves placing a thumb on one side of the trachea and gently pushing the thyroid lobe to the opposite side to better assess it during swallowing. - This technique helps to stabilize the gland and makes it easier to feel for nodules or enlargement. Pizzilo method - There is no widely recognized or standardized thyroid palpation technique called the Pizzilo method in medical literature. - This term is therefore incorrect in the context of thyroid examination. Lahey's method - Lahey's method for thyroid examination involves standing behind the patient and palpating the thyroid gland as the patient swallows, using both hands [1]. - It differs from the Crile method by typically using both hands from behind the patient, rather than focusing on a single thumb on the lateral side of the trachea [1]. Kocher's test - Kocher's test is primarily used to assess for exophthalmos in patients with Graves' disease, by observing the involuntary retraction of the upper eyelid when gazing downwards. - It is not a technique for the palpation of the thyroid gland itself.
Question 2: Which of the following cartilages has signet ring shape?
- A. Cricoid (Correct Answer)
- B. Cuneiform
- C. Thyroid
- D. Arytenoid
Explanation: ***Cricoid*** - The **cricoid cartilage** is the only complete ring of cartilage in the airway, forming the base of the larynx. - Its unique shape, with a narrow anterior arch and a broad posterior lamina, resembles a **signet ring**. *Cuneiform* - **Cuneiform cartilages** are small, rod-shaped cartilages found within the aryepiglottic folds. - They provide support to the folds but do not have a signet ring shape. *Thyroid* - The **thyroid cartilage** is the largest laryngeal cartilage and is shield-shaped, commonly known as the Adam's apple. - It is an incomplete ring posteriorly and does not have a signet ring appearance. *Arytenoid* - **Arytenoid cartilages** are paired pyramidal cartilages that articulate with the cricoid cartilage. - They are crucial for vocal cord movement but are not ring-shaped.
Question 3: In acoustic neuroma, which cranial nerve is involved earliest?
- A. CN V
- B. CN VII
- C. CN VIII (Correct Answer)
- D. CN X
Explanation: ***CN VIII*** - An **acoustic neuroma** (also known as a **vestibular schwannoma**) originates from the **Schwann cells** of the **vestibulocochlear nerve (CN VIII)**. - Due to its origin, symptoms related to **hearing loss**, **tinnitus**, and **balance issues** (all functions of CN VIII) are typically the earliest to manifest [1]. *CN V* - The **trigeminal nerve (CN V)** is responsible for **facial sensation** and **mastication**. - Compression of CN V usually occurs in later stages of acoustic neuroma growth, leading to **facial numbness** or **pain**. *CN VII* - The **facial nerve (CN VII)** controls **facial expressions** and taste sensation in the anterior two-thirds of the tongue. - **Facial weakness** or **paralysis** due to CN VII involvement typically occurs after significant tumor growth, as the nerve runs adjacent to the acoustic neuroma [1]. *CN X* - The **vagus nerve (CN X)** is involved in diverse functions including **swallowing**, **speech**, and **autonomic regulation** of organs like the heart and digestive tract. - **Vagal nerve** symptoms such as **dysphagia** or **hoarseness** are extremely rare in acoustic neuromas and would indicate a very extensive tumor likely compressing structures much more distant from the primary site.
Question 4: Endotracheal tube in the esophagus is best assessed by:
- A. Direct laryngoscopy
- B. Auscultation
- C. CO2 Exhalation (Correct Answer)
- D. Chest wall movement
Explanation: ***CO2 Exhalation*** - Measuring **CO2 exhalation** (capnography) is the most reliable method to confirm endotracheal tube placement, as CO2 is present in the trachea but not in the esophagus. - A persistent **waveform on the capnograph** indicates proper tracheal intubation. *Direct laryngoscopy* - While helpful for initial visualization during intubation, **direct laryngoscopy** cannot confirm continuous tracheal placement after the tube is advanced. - It only confirms the tube passing through the vocal cords, not its final position in the trachea versus esophagus. *Auscultation* - **Auscultation** can be misleading because stomach sounds can be transmitted to the chest, and breath sounds can be heard in the epigastrium even with esophageal intubation. - It relies on subjective interpretation and is less definitive than capnography. *Chest wall movement* - Observing **chest wall movement** is not a definitive sign, as the chest can still rise with esophageal intubation due to air entering the stomach. - This method is unreliable and can be mistaken for proper ventilation, leading to dangerous delays in correcting tube misplacement.
Question 5: A child presents with respiratory distress. A vascular ring is suspected. Investigation of choice is -
- A. Angiography
- B. MRI (Correct Answer)
- C. CT
- D. PET
Explanation: ***MRI/MRA*** - **Magnetic Resonance Imaging (MRI) with MR Angiography** provides excellent visualization of the **aortic arch** and its branches without ionizing radiation, making it ideal for pediatric patients with suspected **vascular rings**. - MRI clearly delineates **vascular anatomy, tracheal and esophageal compression**, confirming the diagnosis and guiding surgical planning. - Particularly preferred when **radiation-free imaging** is prioritized in children. *CT Angiography* - **CT Angiography (CTA) with 3D reconstruction** provides excellent vascular imaging and is widely used for vascular ring diagnosis in many centers. - **Advantage**: Faster acquisition time, less need for sedation, excellent anatomical detail with 3D reconstruction. - **Disadvantage**: Involves **ionizing radiation** exposure, which is a concern in pediatric patients when equally diagnostic radiation-free alternatives exist. - Both MRI and CTA are considered appropriate first-line investigations; choice depends on institutional expertise and clinical context. *Conventional Angiography* - **Catheter angiography** is invasive, involves radiation, and has been largely replaced by non-invasive cross-sectional imaging (MRI/CT). - May be reserved for cases requiring intervention or when non-invasive imaging is inconclusive. *PET* - **Positron Emission Tomography (PET)** detects metabolic activity and is used for cancer or inflammation, not for **anatomical vascular anomalies**. - Not indicated for vascular ring diagnosis.
Question 6: In correct positioning the tip of the instrument shown in the image should lie at:
- A. Thyroid cartilage
- B. Above esophagus
- C. Vocal cords
- D. Epiglottis (Correct Answer)
Explanation: ***Epiglottis*** - The image shows a **Laryngeal Mask Airway (LMA)**, which is designed to sit in the hypopharynx, with its tip resting at the **epiglottis**. - This positioning allows the LMA to create a seal around the laryngeal inlet, facilitating effective ventilation without entering the trachea. *Vocal cords* - The LMA is designed to provide a seal *above* the vocal cords, ensuring ventilation of the trachea without direct intubation of the vocal cords themselves. - Positioning the tip *at* the vocal cords would hinder proper airway sealing and could cause trauma. *Thyroid cartilage* - The thyroid cartilage is an anterior neck structure and is not the anatomical landmark for the tip of a properly placed LMA. - The LMA sits deeper in the pharynx, above the glottic opening, making the epiglottis the relevant landmark. *Above esophagus* - While the LMA sits **above the esophageal inlet**, diverting air primarily into the trachea, its *tip* specifically rests at the epiglottis, covering the laryngeal opening. - Stating "above the esophagus" is too general; the precise anatomical placement for the tip is at the epiglottis.
Question 7: Modified Mallampati grading is used in assessment of -
- A. Difficulty of intubation (Correct Answer)
- B. Obstruction of the airway
- C. Aspiration-related death
- D. Endotracheal intubation procedure
Explanation: ***Difficulty of intubation*** - The **Modified Mallampati score** assesses the visibility of pharyngeal structures, which directly correlates with the ease or difficulty of performing **direct laryngoscopy** and **endotracheal intubation**. - A higher Mallampati class (e.g., III or IV) indicates less visibility of the soft palate, uvula, and pillars, suggesting a more difficult airway and increased likelihood of a challenging intubation. *Obstruction of the airway* - While a high Mallampati score might indirectly indicate potential for **airway obstruction** during anesthesia due to anatomical features, its primary purpose is not to diagnose or quantify existing airway obstruction. - Airway obstruction is more directly assessed by monitoring breathing sounds, respiratory effort, and oxygen saturation. *Aspiration-related death* - The **Mallampati score** helps predict the difficulty of securing the airway but does not directly assess the risk of **aspiration**. - Aspiration risk is evaluated based on factors like gastric contents, gag reflex, and patient positioning. *Endotracheal intubation procedure* - The **Modified Mallampati score** helps in **planning the intubation procedure** by identifying potential difficulties but is not a measure of the intubation procedure itself. - It is a **pre-procedure assessment tool** to gauge airway anatomy, not a description or evaluation of the steps involved in endotracheal intubation.
Question 8: A construction worker met with an accident when a cement block fell on his face. He sustained severe maxillofacial and laryngeal injury. He was not able to open his mouth and is having jaw fracture with obstruction in nasopharynx and oropharynx. To stabilize his airway, the following procedure was done on him. Which option describes the procedure done on him?
- A. Cricothyroidotomy
- B. Subcutaneous tracheostomy
- C. Tracheostomy (Correct Answer)
- D. Submental insertion of ET
Explanation: ***Tracheostomy*** - A tracheostomy creates a surgical opening in the **trachea** to establish a direct airway, bypassing the upper airway. This is crucial when the **nasopharynx and oropharynx are obstructed** due to severe maxillofacial and laryngeal injuries, as described in the case. - The procedure allows for ventilation and prevents aspiration, making it the most suitable long-term solution for definitive airway management in patients with extensive facial and jaw trauma preventing oral or nasal intubation. *Cricothyroidotomy* - This procedure involves making an incision through the **cricothyroid membrane** into the trachea. It is typically a **rapid, emergency airway** procedure. - While it provides an immediate airway, it is generally considered a temporary measure due to potential complications like **subglottic stenosis** with prolonged use, and not ideal for the described severe, multifocal obstruction requiring a more stable, long-term solution. *Subcutaneous tracheostomy* - This term is **not a recognized medical procedure** for establishing an airway. - Tracheostomies are performed with direct access to the trachea, not subcutaneously. *Submental insertion of ET* - This technique involves passing an endotracheal tube through a submental incision into the oropharynx, bypassing the mouth in cases of **maxillofacial trauma** and securing the airway. - However, the question describes **obstruction in both the nasopharynx and oropharynx**, and also a laryngeal injury, which would likely preclude the passage of an endotracheal tube even via a submental approach, making a direct tracheal access (tracheostomy) a more appropriate and definitive solution.
Question 9: During ultrasound-guided internal jugular vein cannulation, you observe the vein collapsing with minimal probe pressure while the artery remains patent. The vein appears enlarged and the artery-to-vein ratio is 1:3. A spontaneously breathing patient shows respiratory variation. Evaluate the most appropriate interpretation and management strategy.
- A. This indicates hypovolemia; fluid resuscitation should be considered before central line insertion (Correct Answer)
- B. This is normal anatomy; proceed with cannulation using standard technique
- C. This suggests venous thrombosis; consider alternative site
- D. This indicates increased central venous pressure; use ultrasound compression technique
Explanation: ***This indicates hypovolemia; fluid resuscitation should be considered before central line insertion*** - Significant **respiratory variation** and ease of **venous collapse** with minimal probe pressure are classic ultrasound indicators of a **low intravascular volume state**. - Managing the **hypovolemia** first improves the safety of the procedure by increasing the target vessel size, thereby reducing the risk of **accidental arterial puncture**. *This is normal anatomy; proceed with cannulation using standard technique* - While the **internal jugular vein** is normally larger than the artery, excessive **compressibility** and collapse indicate an abnormal physiological state that complicates cannulation. - Proceeding without addressing the **underfilled vein** increases the technical difficulty and the likelihood of a **transfixion injury** where the needle passes through both walls. *This suggests venous thrombosis; consider alternative site* - **Venous thrombosis** would manifest as a **non-compressible** vein, often containing visible **distal echoes** or intraluminal clots. - In this scenario, the vein is noted to be **highly compressible**, which is the physiological opposite of what is seen in **deep vein thrombosis (DVT)**. *This indicates increased central venous pressure; use ultrasound compression technique* - High **central venous pressure (CVP)** would result in a **distended, non-collapsible** vein that does not vary significantly with the respiratory cycle. - An **artery-to-vein ratio** where the vein is excessively small or collapses easily specifically contradicts the diagnosis of **fluid overload** or **right heart failure**.
Question 10: A 55-year-old patient with previous lumbar spine surgery requires epidural catheter placement for postoperative analgesia. Pre-procedure ultrasound shows loss of normal posterior complex and irregular acoustic shadowing at L3-L4 and L4-L5 levels. The L2-L3 level shows preserved anatomy with a depth of 6 cm to the epidural space. Which technical modification would provide the best success rate?
- A. Use paramedian approach at L3-L4 with fluoroscopy guidance
- B. Attempt midline approach at L2-L3 with ultrasound pre-scanning for trajectory (Correct Answer)
- C. Perform caudal epidural with threading of catheter to lumbar level
- D. Use loss of resistance to saline at L4-L5 with multiple attempts
Explanation: ***Attempt midline approach at L2-L3 with ultrasound pre-scanning for trajectory*** - Identifying a level with **preserved anatomy** (L2-L3) via ultrasound is the most reliable predictor of success in patients with prior **spinal surgery**. - **Pre-scanning** allows for precise measurement of **epidural depth** and determination of the optimal needle trajectory, bypassing levels with surgical scarring. *Use paramedian approach at L3-L4 with fluoroscopy guidance* - The L3-L4 level shows **irregular acoustic shadowing** and loss of normal complexes, indicating surgical distortion that makes access difficult despite a paramedian approach. - While **fluoroscopy** provides real-time imaging, it involves **radiation exposure** and is less desirable than utilizing a healthy adjacent level (L2-L3). *Perform caudal epidural with threading of catheter to lumbar level* - Threading a **caudal catheter** to the mid-lumbar levels is technically challenging and frequently results in **malpositioning** or inadequate analgesia. - This approach is generally reserved for patients where all **lumbar access** points are completely obliterated by extensive fusion or hardware. *Use loss of resistance to saline at L4-L5 with multiple attempts* - Multiple attempts at L4-L5, which shows **anatomical distortion**, significantly increase the risk of **dural puncture** and technical failure. - Relying solely on **loss of resistance** without respecting ultrasound signs of **posterior complex loss** is poor clinical practice in
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