Endotracheal Intubation — MCQs
During preanaesthetic evaluation, an anaesthetist wrote a Mallampati grade 3. What does this signify?
Endotracheal tube in the esophagus is best assessed by:
In cases of severe head trauma, at what GCS is endotracheal intubation advised?
All are features of difficult airway except which of the following?
Capnography is useful for
Steps of intubation - arrange in sequence:- a. Head extension and flexion of neck b. Introduction of laryngoscope c. Inflation of cuff d. Check breath sounds with stethoscope e. fixation of the tube to prevent dislodgement
For the immediately life-threatening injuries of the chest "Flail chest", select the proper intervention (SELECT 1 INTERVENTION)
In correct positioning the tip of the instrument shown in the image should lie at:
What is the grade of laryngeal view?
What is the staging system used for the condition seen in the patient after a history of intubation, as shown in the image?
Endotracheal Intubation Indian Medical PG Practice Questions and MCQs
Question 1: During preanaesthetic evaluation, an anaesthetist wrote a Mallampati grade 3. What does this signify?
- A. Limited neck extension
- B. An enlarged epiglottis
- C. Jaw stiffness
- D. Soft palate and base of uvula visible (Correct Answer)
Explanation: **Soft palate and base of uvula visible** - A **Mallampati grade 3** classification indicates that only the **soft palate** and the **base of the uvula** are visible when the patient opens their mouth and protrudes their tongue. - This grade suggests a moderate difficulty for **endotracheal intubation** because the visualization of the glottis may be partially obstructed. *Limited neck extension* - Limited **neck extension** is assessed separately during a preanesthetic evaluation and is not directly indicated by the Mallampati score. - It is a factor that can independently contribute to a difficult airway by limiting the ability to achieve the **sniffing position** for intubation. *An enlarged epiglottis* - The **epiglottis** is not visible during a standard awake Mallampati examination, which assesses oral pharyngeal structures. - Visualization of the epiglottis typically occurs during **laryngoscopy** and an enlarged epiglottis (e.g., in epiglottitis) is a medical emergency, not a Mallampati finding. *Jaw stiffness* - **Jaw stiffness** or limited mouth opening is assessed by measuring the **interincisor distance** and is not directly part of the Mallampati classification process. - Significant jaw stiffness can independently predict a difficult airway by restricting the view during laryngoscopy, even with a favorable Mallampati score.
Question 2: 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 3: In cases of severe head trauma, at what GCS is endotracheal intubation advised?
- A. 12
- B. <=8 (Correct Answer)
- C. 10
- D. <=3
Explanation: ***<=8*** - A **Glasgow Coma Scale (GCS) score of 8 or less** indicates significantly impaired consciousness, putting the patient at high risk for **airway compromise** and **aspiration**. - **Endotracheal intubation** is advised to protect the airway, ensure adequate ventilation, and facilitate neurological assessment and management in these critically ill patients. - This is the standard **"rule of 8"** used in trauma management protocols worldwide. *12* - A GCS score of 12, while indicating some level of altered consciousness, is generally **not low enough** to mandate immediate endotracheal intubation solely based on GCS criteria. - Patients with this GCS may still be able to **maintain their airway** and have a **gag reflex** intact, though close monitoring is crucial. *10* - A GCS score of 10 suggests moderate head injury and **altered mental status**, but generally, the patient can still **protect their airway** adequately. - While careful monitoring is essential, intubation is usually not indicated unless there are **other signs of respiratory compromise** or impending deterioration. *<=3* - A GCS score of 3 is the **lowest possible score**, indicating **deep coma** and severe neurological impairment, which would certainly warrant intubation. - However, this option is **too restrictive** as it would exclude patients with **GCS 4-8 who also require intubation** for airway protection. - The correct threshold is **GCS ≤8**, not just the most severe cases.
Question 4: All are features of difficult airway except which of the following?
- A. Miller's sign
- B. Micrognathia with macroglossia
- C. TMJ ankylosis
- D. Increased thyromental distance (Correct Answer)
Explanation: ***Increased thyromental distance*** - An **increased thyromental distance** (typically > 6.5 cm) indicates more space between the thyroid cartilage and the mentum (chin), suggesting a **less acute angle for intubation** and often a **straightforward airway**. - This measurement correlates with a **better laryngeal view** during direct laryngoscopy. *Miller's sign* - **Miller's sign** refers to the presence of **subglottic stenosis** or **tracheal narrowing**, which can make intubation and ventilation extremely difficult. - This condition can lead to significant challenges in passing an endotracheal tube and securing the airway. *Micrognathia with macroglossia* - **Micrognathia** (small jaw) reduces the space for the tongue, while **macroglossia** (large tongue) further obstructs the airway. - This combination creates a **severely restricted oral and pharyngeal space**, making visualization of the larynx and intubation very challenging. *TMJ ankylosis* - **Temporomandibular joint (TMJ) ankylosis** significantly **limits mouth opening**, which is critical for successful direct laryngoscopy and intubation. - A restricted mouth opening makes it difficult to insert the laryngoscope blade and visualize the vocal cords.
Question 5: Capnography is useful for
- A. Determining Vaporizer malfunction or contamination
- B. Determining circuit hypoxia
- C. Detecting concentration of oxygen in the anesthetic circuit.
- D. Determining the appropriate placement of endotracheal (Correct Answer)
Explanation: ***Determining the appropriate placement of endotracheal*** - Capnography provides a direct and continuous measurement of **exhaled CO2**, which confirms proper **endotracheal tube (ETT) placement** in the trachea. - The presence of a square-wave capnogram with a distinct end-tidal CO2 (ETCO2) value indicates CO2 detection, confirming the ETT is in the airway and not the esophagus. *Determining Vaporizer malfunction or contamination* - **Anesthetic gas analyzers**, not capnographs, are used to detect vaporizer malfunctions or contamination by measuring the concentration of specific anesthetic agents. - While a capnograph might show changes in CO2 if ventilation is affected by an issue with the vaporizer, it does not directly diagnose the vaporizer problem itself. *Determining circuit hypoxia* - **Oxygen analyzers** in the anesthetic circuit are used to determine the concentration of oxygen, which helps detect circuit hypoxia. - Capnography monitors CO2 levels, and while changes in CO2 might indirectly result from hypoxia, it doesn't directly measure oxygen concentration or alert to hypoxia. *Detecting concentration of oxygen in the anesthetic circuit.* - **Oxygen sensors or galvanic cells**, integrated into the anesthesia machine, are specifically designed to measure the inspired oxygen concentration. - Capnography measures carbon dioxide, not oxygen, and therefore cannot directly assess the oxygen levels within the anesthetic circuit.
Question 6: Steps of intubation - arrange in sequence:- a. Head extension and flexion of neck b. Introduction of laryngoscope c. Inflation of cuff d. Check breath sounds with stethoscope e. fixation of the tube to prevent dislodgement
- A. CBAED
- B. ACBED
- C. DBCEA
- D. ABCDE (Correct Answer)
Explanation: **ABCDE** - The correct sequence for intubation starts with proper patient positioning (**A. Head extension and flexion of neck**) followed by insertion of the laryngoscope (**B. Introduction of laryngoscope**). - After visualizing the glottis and inserting the endotracheal tube, the cuff is inflated (**C. Inflation of cuff**), tube placement is confirmed by checking breath sounds (**D. Check breath sounds with stethoscope**), and finally, the tube is secured (**E. Fixation of the tube to prevent dislodgement**). *CBAED* - This sequence is incorrect because inflating the cuff (C) and introducing the laryngoscope (B) occur before head positioning (A), and checking breath sounds (E) and fixation (D) are not in the correct order after intubation. - Proper patient positioning is the critical first step to align the oral, pharyngeal, and laryngeal axes for optimal visualization. *ACBED* - This sequence incorrectly places the inflation of the cuff (C) before the introduction of the laryngoscope (B) and confirmation steps (E and D). - The cuff is inflated only after the tube is properly placed in the trachea, and confirmation of placement always precedes fixation. *DBCEA* - This sequence is incorrect as it begins with checking breath sounds (D), which is a step for confirming tube placement, not initiating the intubation process. - Head positioning (A) is also placed last, which is contrary to the vital initial steps of airway management for intubation.
Question 7: For the immediately life-threatening injuries of the chest "Flail chest", select the proper intervention (SELECT 1 INTERVENTION)
- A. Tube thoracostomy
- B. Subxiphoid window
- C. Cricothyroidotomy
- D. Endotracheal intubation (Correct Answer)
Explanation: ***Endotracheal intubation*** - **Endotracheal intubation** with **positive pressure ventilation** is the definitive intervention for flail chest to stabilize the chest wall and ensure adequate ventilation. - This prevents paradoxical chest wall movement and improves oxygenation, addressing the life-threatening impact on respiratory mechanics. *Tube thoracostomy* - **Tube thoracostomy** is primarily indicated for **pneumothorax** or **hemothorax**, which may co-exist with flail chest but is not the direct treatment for the flail segment itself. - While necessary for associated conditions, it does not stabilize the flail segment to improve ventilation. *Subxiphoid window* - A **subxiphoid window** is a diagnostic procedure performed to detect **pericardial effusion** or **cardiac tamponade**, not a primary intervention for flail chest. - It does not address the mechanical instability or respiratory compromise caused by a flail chest. *Cricothyroidotomy* - **Cricothyroidotomy** is an emergency procedure for securing an airway when **oral or nasal intubation is not possible** due to obstruction or trauma to the upper airway. - It is an airway intervention but does not specifically address the chest wall instability or paradoxical movement seen in flail chest.
Question 8: 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 9: What is the grade of laryngeal view?
- A. Grade I (Correct Answer)
- B. Grade II
- C. Grade III
- D. Grade IV
Explanation: ***Grade I*** - In a **Grade I laryngeal view**, a **full view of the glottis** (vocal cords) is achieved during laryngoscopy. - This provides optimal conditions for endotracheal intubation, as seen in the image where the entire opening to the trachea is visible. *Grade II* - A **Grade II view** means only a **partial view of the glottis** is obtained, often with only the posterior commissure visible. - The anterior portion of the vocal cords may be obstructed by the epiglottis or other structures, making intubation more challenging. *Grade III* - **Grade III** indicates that only the **epiglottis** is visible, with no part of the glottis or vocal cords being seen. - Intubation is significantly more difficult in this scenario and often requires special techniques or adjuncts. *Grade IV* - A **Grade IV view** is the most difficult, where **neither the epiglottis nor the glottis** can be visualized. - This implies that only the soft palate or base of the tongue is seen, representing a very challenging airway.
Question 10: What is the staging system used for the condition seen in the patient after a history of intubation, as shown in the image?
- A. Cormack and Lehane (Correct Answer)
- B. AJCC
- C. TNM
- D. Radkowski
Explanation: ***Cormack and Lehane*** - The **Cormack and Lehane classification** system is used to grade the view of the **larynx** during **direct laryngoscopy** for intubation. - Given the history of intubation and the image showing the laryngeal view, this system is the most appropriate for staging the visual difficulty or success of intubation. *AJCC* - The **American Joint Committee on Cancer (AJCC) staging system** is primarily used for **oncological staging**, classifying the extent of cancer. - It is not relevant for assessing the view of the larynx during intubation. *TNM* - **TNM staging** (Tumor, Node, Metastasis) is a widely used system for classifying the **progression of cancer**. - This system is specific to cancer staging and is not applicable to the assessment of airways for intubation. *Radkowski* - The **Radkowski staging system** is used to classify **pediatric subglottic stenosis**, a narrowing of the airway below the vocal cords. - While it deals with airway issues, the question focuses on the view during intubation, not the severity of subglottic stenosis, and the image does not specifically point to this condition.
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