Difficult Airway in Obstetrics — MCQs
Which of the following lung volumes remains unchanged during pregnancy?
Which of the following is an effective sign of successful neonatal resuscitation?
Child with aspiration risk needs emergency surgery. Best induction sequence is:
A pregnant lady with persistent variable decelerations with cervical dilatation of 6 cm is planned for emergency LSCS. Which of the following is NOT done in management while preparing patient for surgery
All are cardiovascular system changes in pregnancy except.
Anaesthesia of choice for manual removal of the placenta is?
All are features of difficult airway except which of the following?
Difficult intubation is anticipated in all except the following conditions.
Modified Mallampati grading is used in assessment of -
During rapid sequence intubation in a child after taking brief history and clinical examination next step is:
Difficult Airway in Obstetrics Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following lung volumes remains unchanged during pregnancy?
- A. Total Lung Capacity (Correct Answer)
- B. Tidal Volume
- C. Functional Residual Capacity
- D. Inspiratory Capacity
Explanation: ***Total Lung Capacity*** - The **total lung capacity (TLC)** represents the total volume of air the lungs can hold after a maximum inspiration and remains largely **unchanged** during pregnancy due to opposing physiological shifts. - While other lung volumes are affected by mechanical compression from the gravid uterus and hormonal changes, the **increase in inspiratory capacity** often balances the **decrease in functional residual capacity**, leading to a relatively stable TLC. *Functional Residual Capacity* - **Functional Residual Capacity (FRC)**, the volume of air remaining in the lungs after a normal expiration, **decreases significantly** during pregnancy due to the upward displacement of the diaphragm by the enlarging uterus. - This **reduction in FRC** makes pregnant individuals more susceptible to hypoxemia during periods of apnea or hypoventilation. *Inspiratory Capacity* - **Inspiratory Capacity (IC)**, the maximum volume of air that can be inhaled from the end-expiratory position, typically **increases during pregnancy**. - This increase is primarily due to a **higher tidal volume** and an enhanced ability to expand the chest wall. *Tidal Volume* - **Tidal Volume (TV)**, the amount of air inhaled or exhaled during normal breathing, **increases progressively** throughout pregnancy. - This increase is driven by **progesterone-mediated stimulation** of the respiratory center, leading to increased minute ventilation despite a relatively constant respiratory rate.
Question 2: Which of the following is an effective sign of successful neonatal resuscitation?
- A. Change in skin color
- B. Presence of air entry
- C. Increased heart rate (Correct Answer)
- D. None of the options
Explanation: ***Increased heart rate*** - A definitive increase in **heart rate** (typically above 100 bpm) is the most critical and rapid indicator of effective neonatal resuscitation, signifying improved oxygenation and cardiac output. - The goal of neonatal resuscitation is to establish effective ventilation, which subsequently leads to an improved heart rate. *Change in skin color* - **Skin color** changes, while reassuring, are often a delayed and less reliable indicator of immediate resuscitation success compared to heart rate. - Peripheral cyanosis can persist even with adequate central oxygenation, making it a subjective and less sensitive marker. *Presence of air entry* - While **air entry** into the lungs is essential for effective ventilation, merely hearing breath sounds does not guarantee sufficient oxygen exchange or circulatory improvement. - Air entry can be present even with ineffective ventilation (e.g., inadequate tidal volume or airway obstruction), and it doesn't directly measure the systemic response. *None of the options* - This option is incorrect because **increased heart rate** is indeed a primary and immediate sign of successful neonatal resuscitation.
Question 3: Child with aspiration risk needs emergency surgery. Best induction sequence is:
- A. Preoxygenation-ketamine-succinylcholine
- B. Sevoflurane-propofol-succinylcholine
- C. Midazolam-propofol-rocuronium
- D. Preoxygenation-propofol-succinylcholine (Correct Answer)
Explanation: ***Preoxygenation-propofol-succinylcholine*** - This sequence describes a **rapid sequence intubation (RSI)**, which is the preferred method for patients at high risk of aspiration, including children needing emergency surgery with an unknown fasting status. - **Preoxygenation** provides an oxygen reserve during the apneic period, **propofol** offers rapid induction with good hemodynamic stability, and **succinylcholine** provides fast-onset, short-acting neuromuscular blockade, crucial for preventing aspiration. *Preoxygenation-ketamine-succinylcholine* - While preoxygenation and succinylcholine are appropriate for RSI, **ketamine** may not be the optimal choice for a child with aspiration risk due to its potential to increase secretions and maintain laryngeal reflexes, which could complicate intubation. - Ketamine can also cause **emergence delirium** in some children, making it less favorable for a smooth anesthetic course compared to propofol. *Sevoflurane-propofol-succinylcholine* - **Sevoflurane** is an inhaled anesthetic often used for mask induction in children due to its non-pungent odor and rapid onset. However, it is generally **not suitable for RSI** in patients with aspiration risk as it has a slower induction time compared to intravenous agents and can cause coughing or laryngospasm. - Using both sevoflurane and propofol for induction in an RSI scenario is redundant and prolongs the induction phase, increasing aspiration risk. *Midazolam-propofol-rocuronium* - **Midazolam** is a benzodiazepine used for anxiolysis and sedation but has a **slower onset** and longer duration of action compared to propofol for rapid induction. - **Rocuronium** is a non-depolarizing neuromuscular blocker with a slower onset of action than succinylcholine, making it less ideal for RSI where immediate paralysis for intubation is critical to prevent aspiration.
Question 4: A pregnant lady with persistent variable decelerations with cervical dilatation of 6 cm is planned for emergency LSCS. Which of the following is NOT done in management while preparing patient for surgery
- A. O2 inhalation
- B. I.V. fluid
- C. Foley catheterization
- D. Supine position (Correct Answer)
Explanation: ***Supine position*** - Maintaining a **supine position** in a pregnant woman can lead to **aortocaval compression**, reducing **venous return** and **cardiac output**, which compromises uterine blood flow and fetal oxygenation. - To prevent this, the patient should be placed in a **left lateral tilt** (wedge under the right hip) to displace the uterus off the great vessels. *O2 inhalation* - Administering **oxygen via face mask** increases the mother's partial pressure of oxygen (PaO2), which can improve **fetal oxygenation** and potentially alleviate fetal distress. - This is a standard and safe intervention to maximize oxygen delivery to the fetus, especially in cases of **fetal compromise** indicated by variable decelerations. *I.V. fluid* - Administering **intravenous fluids** helps maintain maternal hydration and **circulatory volume**, crucial for adequate uterine perfusion. - This can improve **placental blood flow**, potentially reducing the frequency or severity of variable decelerations by increasing amniotic fluid volume and relieving **cord compression**. *Foleys catheterisation* - **Foley catheterization** is essential before a Cesarean section to **decompress the bladder**, preventing injury during surgery and improving surgical exposure. - A full bladder can obstruct the surgical field and increases the risk of accidental incision, therefore, it is a routine pre-operative step.
Question 5: All are cardiovascular system changes in pregnancy except.
- A. Increase in blood volume
- B. Increase in heart rate
- C. Increase in peripheral resistance (Correct Answer)
- D. Increase in cardiac output
Explanation: ***Increase in peripheral resistance*** - During normal pregnancy, **peripheral vascular resistance actually decreases** due to the effects of hormones like progesterone and the presence of the low-resistance uteroplacental circulation. - This decrease in resistance helps accommodate the increased blood volume and cardiac output. *Increase in cardiac output* - **Cardiac output increases significantly** during pregnancy (by 30-50%) to meet the metabolic demands of the growing fetus and maternal tissues. - This is primarily achieved through an increase in both stroke volume and heart rate. *Increase in blood volume* - **Blood volume increases substantially** (by 30-50%) during pregnancy, with plasma volume increasing more than red blood cell mass. - This expansion supports the increased cardiac output and placental perfusion. *Increase in heart rate* - **Heart rate increases** during pregnancy, typically by 10-20 beats per minute, contributing to the overall increase in cardiac output. - This physiological adaptation helps maintain adequate circulation.
Question 6: Anaesthesia of choice for manual removal of the placenta is?
- A. General Anesthesia (GA)
- B. Spinal Anesthesia (Correct Answer)
- C. Epidural Anesthesia
- D. Paracervical Block
Explanation: ***Spinal Anesthesia*** - Provides **rapid onset** and dense sensory and motor block, which is ideal for a quick procedure like manual placental removal. - The **uterine atony** associated with spinal anesthesia, while a concern, is less pronounced or easier to manage than the deep relaxation often seen with general anesthesia, especially with inhaled anesthetics. *General Anesthesia (GA)* - Can lead to significant **uterine relaxation** (atony), increasing the risk of postpartum hemorrhage, especially with volatile anesthetics. - While it provides excellent pain control, the associated risks of airway management, aspiration, and deeper uterine relaxation make it less desirable as a primary choice. *Epidural Anesthesia* - Provides good analgesia but has a **slower onset** of full surgical anesthesia compared to spinal, which may be critical in an urgent situation. - While it can be titrated to achieve surgical depth, it might not provide the rapid, dense motor block required for comfortable and efficient manual removal. *Paracervical Block* - Primarily provides analgesia to the **cervix and lower uterine segment**, but offers insufficient pain relief for the fundal manipulation and full uterine exploration required during manual placental removal. - This block does not adequately anesthetize the entire uterus or provide the necessary muscle relaxation for a comfortable and safe procedure.
Question 7: 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 8: Difficult intubation is anticipated in all except the following conditions.
- A. Increase in posterior depth of mandible
- B. Increased alveolar- mental distance
- C. Temporomandibular joint fibrosis
- D. Receding incisors (Correct Answer)
Explanation: ***Receding incisors*** - **Receding incisors** do not typically obstruct the laryngoscope blade or alter the alignment of the oral, pharyngeal, and laryngeal axes, making intubation easier rather than difficult. - A receding or absent maxilla can actually improve the line of sight to the **glottis**, reducing the likelihood of a difficult intubation. *Increase in posterior depth of mandible* - An **increased posterior depth of the mandible** (a large jaw) can make intubation more challenging by increasing the distance from the incisors to the larynx, making it harder to visualize the glottis. - This anatomical feature can limit the space for manipulating the **laryngoscope blade** and positioning the airway. *Increased alveolar- mental distance* - An **increased alveolar-mental distance** refers to a longer distance from the alveolar ridge to the mental protuberance, which indicates a longer mandible. - A longer mandible can push the laryngeal axis posteriorly, making it difficult to align the oral, pharyngeal, and laryngeal axes for direct **laryngoscopy**. *Temporomandibular joint fibrosis* - **Temporomandibular joint fibrosis** restricts mouth opening, a crucial factor for successful intubation. - Limited mouth opening significantly impedes the insertion and manipulation of the **laryngoscope blade**, making glottis visualization difficult or impossible.
Question 9: 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 10: During rapid sequence intubation in a child after taking brief history and clinical examination next step is:
- A. Administer oxygen (Correct Answer)
- B. Analgesic injection with Fentanyl
- C. Preanaesthetic medication with atropine and lignocaine
- D. IV anesthetic Diazepam/Ketamine
Explanation: ***Administer oxygen*** - Pre-oxygenation with 100% oxygen is critical before **rapid sequence intubation (RSI)** to maximize **oxygen reserves** and extend the safe apnea time. - This step helps prevent **hypoxemia** during the intubation procedure, especially in children who have lower functional residual capacity. *Analgesic injection with Fentanyl* - While fentanyl is often used in RSI for its **analgesic** and **sedative properties**, it typically follows pre-oxygenation and is administered as part of the **induction phase**, often concurrently with a paralytic. - Administering fentanyl alone without prior oxygenation or other induction agents would not be the immediate next step in a structured RSI protocol. *Preanaesthetic medication with atropine and lignocaine* - **Atropine** may be used in children to prevent **bradycardia** during intubation, particularly in infants, but it's not the immediate next step after initial assessment; pre-oxygenation is more critical. - **Lidocaine** can be used to blunt the sympathetic response to intubation or to suppress cough, but it's not universally required and comes after pre-oxygenation and other induction medications. *IV anesthetic Diazepam/Ketamine* - **Diazepam** and **ketamine** are **induction agents** that cause sedation and loss of consciousness, but they are administered after pre-oxygenation and often just before the paralytic agent. - Administering an induction agent without adequate pre-oxygenation would increase the risk of **hypoxemia** during the subsequent apnea.
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