NPO Guidelines — MCQs
Mendelsons syndrome is:
In the management of prolonged intussusception with signs of shock, which of the following interventions is least appropriate?
A 4-month-old child can be given clear fluid until how many hours prior to surgery?
The following are true of Mendelson's syndrome –
Patient with BMI 40 presents for emergency surgery. All are correct about airway management EXCEPT:
Child with aspiration risk needs emergency surgery. Best induction sequence is:
Which of the following actions should be avoided during the delivery of an Rh-negative mother?
A diabetic patient's fasting blood glucose level is found to be $160 \mathrm{mg} / \mathrm{dL}$. What will you advise the patient regarding non-pharmacological management?
Nil per oral orders for an 8-year-old child posted for elective nasal polyp surgery at 8 AM include all of the following EXCEPT:
A 50 year old male is posted for elective laparoscopic cholecystectomy. No history of comorbidities. His surgery is scheduled at 2 PM on the day of surgery. Which of the following is against the ASA guidelines for preoperative fasting
NPO Guidelines Indian Medical PG Practice Questions and MCQs
Question 1: Mendelsons syndrome is:
- A. Allergic reaction to inhalational anesthetics
- B. Aspiration of gastric contents (Correct Answer)
- C. Aspiration of nasal secretions
- D. Complications from improper intubation
Explanation: ***Aspiration of gastric contents*** - Mendelson's syndrome refers to a chemical pneumonitis resulting from the **aspiration of acidic gastric contents** into the respiratory tract. - This typically occurs during **anesthesia**, sedation, or altered consciousness when airway reflexes are blunted. *Allergic reaction to inhalational anesthetics* - Allergic reactions to anesthetics are distinct from Mendelson's syndrome and involve an **immunological response**, not direct chemical burn. - Symptoms would include rash, bronchospasm, and hypotension, rather than pneumonitis from aspiration. *Aspiration of nasal secretions* - While aspiration of nasal secretions can occur, it's generally less irritating and does not typically lead to the severe inflammatory lung injury characteristic of Mendelson's syndrome, which is specifically due to **acidic gastric contents**. - Nasal secretions are usually **less acidic** and contain different microbial flora. *Complications from improper intubation* - Improper intubation can lead to complications such as **esophageal intubation**, trauma to the airway, or vocal cord damage. - These are **mechanical injuries** or misplacements and are distinct from aspiration pneumonitis caused by gastric contents.
Question 2: In the management of prolonged intussusception with signs of shock, which of the following interventions is least appropriate?
- A. Nasogastric tube
- B. Barium enema (Correct Answer)
- C. IV fluid
- D. Give O2
Explanation: ***Barium enema*** - A barium enema is used for the diagnosis and *non-operative reduction* of intussusception in hemodynamically stable children. - In a patient with **prolonged intussusception** and **signs of shock**, there is an increased risk of **bowel ischemia** or **perforation**, making a barium enema potentially dangerous and inappropriate. *IV fluid* - **Intravenous fluids** are crucial to correct **hypovolemia** and **electrolyte imbalances** resulting from poor oral intake, vomiting, and third-spacing associated with intussusception and shock. - They are vital for stabilizing the patient's **hemodynamics** prior to any definitive intervention. *Give O2* - Administering **oxygen** helps address **tissue hypoxia** that can occur in patients in shock due to poor perfusion. - It supports aerobic metabolism and may reduce the burden on the cardiovascular system. *Nasogastric tube* - A **nasogastric tube** is inserted to **decompress the stomach** and *prevent aspiration* in patients with intestinal obstruction and vomiting. - It also helps reduce further abdominal distension, making the patient more comfortable and potentially improving ventilation.
Question 3: A 4-month-old child can be given clear fluid until how many hours prior to surgery?
- A. 2 hrs (Correct Answer)
- B. 4 hrs
- C. 3 hrs
- D. 1 hr
Explanation: ***2 hrs*** - Current guidelines from the **American Society of Anesthesiologists (ASA)** recommend a minimum fasting period of **2 hours for clear liquids** in infants and children. - This recommendation balances the risk of **pulmonary aspiration** with the benefit of preventing dehydration and patient discomfort. *4 hrs* - A 4-hour fasting period for clear fluids is longer than typically required for infants and children and may lead to unnecessary dehydration without additional safety benefits. - This duration is more commonly associated with non-human milk formula or solid food. *3 hrs* - While closer to the recommended time, 3 hours for clear fluids in an infant is still slightly longer than the current standard. - It does not offer a significant advantage over the 2-hour guideline and may still contribute to prolonged fasting. *1 hr* - A 1-hour fasting period for clear fluids in an infant is generally considered too short and carries an increased risk of **pulmonary aspiration** during induction of anesthesia. - Insufficient time for gastric emptying could lead to complications if regurgitation occurs.
Question 4: The following are true of Mendelson's syndrome –
- A. Steroids have been shown to improve outcome
- B. Critical volume of aspirate is 50 mls
- C. Critical pH of gastric aspirate is 1.5
- D. Onset of symptoms generally occurs within 30 minutes (Correct Answer)
Explanation: ***Onset of symptoms generally occurs within 30 minutes*** - Mendelson's syndrome refers to **chemical pneumonitis** resulting from pulmonary aspiration of sterile gastric contents. - Symptoms like **bronchospasm**, **dyspnea**, and **tachycardia** typically manifest rapidly, often within minutes to 30 minutes post-aspiration. *Steroids have been shown to improve outcome* - **Corticosteroids** are generally **not recommended** for the treatment of Mendelson's syndrome or chemical pneumonitis caused by gastric aspiration. - Their use can potentially increase the risk of **secondary bacterial pneumonia** due to immunosuppression, without significant clinical benefit in improving lung injury. *Critical volume of aspirate is 50 mls* - The critical volume of aspirate associated with Mendelson's syndrome is generally considered to be **25 mL** or **0.3 mL/kg** of gastric contents. - Aspiration of volumes greater than this threshold significantly increases the risk of developing **severe pneumonitis**. *Critical pH of gastric aspirate is 1.5* - The critical pH of gastric aspirate associated with Mendelson's syndrome is generally considered to be **less than 2.5**. - A pH below this value indicates highly acidic gastric contents, which cause **severe chemical burns** to the tracheobronchial tree and lung parenchyma.
Question 5: Patient with BMI 40 presents for emergency surgery. All are correct about airway management EXCEPT:
- A. Extended ramping
- B. Avoid cricoid pressure (Correct Answer)
- C. Rapid sequence induction
- D. Avoid preoxygenation
Explanation: ***Avoid cricoid pressure*** - While **cricoid pressure** (Sellick's maneuver) is used to prevent **aspiration** by compressing the esophagus, its effectiveness in **obese patients** is highly debated and often hindered by excess neck tissue. - In obese patients, cricoid pressure can actually worsen the view during laryngoscopy, making intubation more difficult and potentially causing airway trauma. *Extended ramping* - **Ramping** the patient, where the head and shoulders are elevated, is crucial in **obese patients** to align the **oral, pharyngeal, and laryngeal axes**. - This position improves the view during laryngoscopy and facilitates successful intubation by effectively displacing excess tissue. *Rapid sequence induction* - **Rapid sequence induction (RSI)** is often indicated in **obese patients** undergoing emergency surgery due to their increased risk of **gastric reflux** and **pulmonary aspiration**. - RSI involves administering a sedative and a paralytic agent in rapid succession, followed immediately by intubation, to minimize the time the airway is unprotected. *Avoid preoxygenation* - **Preoxygenation** is essential in **obese patients** to maximize their **oxygen reserves** before intubation. - Obese patients have reduced **functional residual capacity (FRC)** and increased **oxygen consumption**, making them desaturate rapidly during apnea, so preoxygenation significantly prolongs safe apnea time.
Question 6: 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 7: Which of the following actions should be avoided during the delivery of an Rh-negative mother?
- A. Gently perform manual removal of placenta if necessary (Correct Answer)
- B. Withhold ergometrine until after anterior shoulder delivery
- C. Administer IV fluids
- D. Apply fundal pressure during second stage of labor
Explanation: ***Gently perform manual removal of placenta if necessary*** - **Manual removal of the placenta** can significantly increase the risk of **fetomaternal hemorrhage**, which is particularly dangerous in an **Rh-negative mother**. Large amounts of fetal blood entering the maternal circulation can lead to significant alloimmunization, making subsequent pregnancies high-risk. - This procedure should be **avoided if possible** due to the heightened risk of sensitizing the mother to Rh antigens; if it is absolutely necessary, a **higher dose of Rh immunoglobulin** may be required. *Withhold ergometrine until after anterior shoulder delivery* - **Ergometrine** is a uterotonic agent used to prevent **postpartum hemorrhage**. Withholding it until after the birth of the anterior shoulder is a **standard practice** to prevent uterine tetany before the baby is fully delivered. - This action does not pose a specific risk to an **Rh-negative mother** related to Rh sensitization; it is a general obstetric safety measure to ensure safe delivery and should **not be avoided**. *Apply fundal pressure during second stage of labor* - **Fundal pressure** (applying pressure to the top of the uterus to expedite delivery) is a **controversial practice** that is generally discouraged due to potential maternal and fetal complications. - While it may theoretically carry a small risk of **fetomaternal hemorrhage**, it is not specifically contraindicated in Rh-negative mothers more than in others. The main concerns are **uterine rupture**, **maternal injury**, and **fetal trauma**. If appropriate precautions with **Rh immunoglobulin** are taken, Rh status alone is not a reason to avoid this practice (though it should generally be avoided for other safety reasons). *Administer IV fluids* - **Intravenous fluids** are commonly administered during labor and delivery to maintain **hydration**, support **blood pressure**, and provide a route for medications. This is a **routine and safe practice**. - Administering IV fluids has no direct impact on **Rh sensitization** and is not contraindicated in an **Rh-negative mother**.
Question 8: A diabetic patient's fasting blood glucose level is found to be $160 \mathrm{mg} / \mathrm{dL}$. What will you advise the patient regarding non-pharmacological management?
- A. At least 25-35 g of dietary fibre
- B. <30 % of the calories should come from fat (Correct Answer)
- C. Dietary cholesterol <300 mg per day
- D. <2.3 g sodium intake every day
Explanation: ***<30 % of the calories should come from fat*** - Reducing dietary fat intake to less than 30% of total calories is a crucial non-pharmacological strategy for diabetic patients to manage blood glucose levels and prevent cardiovascular complications [1]. - Excess dietary fat, especially saturated and trans fats, can contribute to insulin resistance and weight gain, both of which negatively impact glycemic control [1]. *At least 25-35 g of dietary fibre* - While adequate dietary fiber (typically 25-30g for adults, sometimes up to 35g for men) is beneficial for managing blood glucose, it is generally recommended as a baseline for healthy eating and not the primary or most impactful intervention to address a fasting glucose of 160 mg/dL [1]. - Fiber helps slow glucose absorption and can improve insulin sensitivity, but a specific "at least 25-35g" statement without further context on total caloric intake or other macronutrient distribution might not be the most targeted advice for this specific glucose level [1]. *Dietary cholesterol <300 mg per day* - Limiting dietary cholesterol to less than 300 mg per day is a general recommendation for cardiovascular health, which is particularly important for diabetic patients due to their increased risk of atherosclerosis [2]. - However, for directly addressing a fasting blood glucose of 160 mg/dL, focusing on overall fat intake and carbohydrate quality would have a more immediate impact on glucose control than dietary cholesterol alone. *<2.3 g sodium intake every day* - Restricting sodium intake to less than 2.3 g per day is recommended for managing hypertension and reducing cardiovascular risk, which is often comorbid with diabetes [2]. - While important for overall health in diabetic patients, this recommendation does not directly target blood glucose control and would not be the primary non-pharmacological advice for a fasting glucose of 160 mg/dL.
Question 9: Nil per oral orders for an 8-year-old child posted for elective nasal polyp surgery at 8 AM include all of the following EXCEPT:
- A. Apple juice can be taken at 10 PM previous night
- B. Milk can be taken at 7 AM in morning (Correct Answer)
- C. Can take sips of water up to 6 AM in morning
- D. Rice can be consumed at 11 PM previous night
Explanation: **Milk can be taken at 7 AM in morning** - For an 8-year-old undergoing elective surgery at 8 AM, **milk is considered a solid or heavy fluid** and should be stopped at least **6 hours pre-operatively**. - Taking milk at 7 AM, just one hour before surgery, significantly increases the risk of **pulmonary aspiration** during anesthesia. *Apple juice can be taken at 10 PM previous night* - **Clear liquids**, such as apple juice, can generally be consumed up to **2 hours before surgery** in children. - Taking apple juice at 10 PM the night before for an 8 AM surgery falls well within the safe fasting window for clear liquids. *Can take sips of water up to 6 AM in morning* - **Sips of water** are considered a clear liquid and can be consumed up to **2 hours before surgery** in children. - Allowing water until 6 AM for an 8 AM surgery is appropriate and helps prevent dehydration without increasing aspiration risk. *Rice can be consumed at 11 PM previous night* - **Solid foods**, like rice, require a longer fasting period, typically at least **6-8 hours before surgery**. - Consuming rice at 11 PM the night before, for an 8 AM surgery, allows for sufficient gastric emptying and is generally safe.
Question 10: A 50 year old male is posted for elective laparoscopic cholecystectomy. No history of comorbidities. His surgery is scheduled at 2 PM on the day of surgery. Which of the following is against the ASA guidelines for preoperative fasting
- A. Water at 12:00 PM
- B. Black coffee at 5:30 AM
- C. Pancakes at 10:00 AM (Correct Answer)
- D. A non-clear liquid (e.g., orange juice) at 7:30 AM
Explanation: **Pancakes at 10:00 AM** - According to ASA guidelines, the fasting period for solid food is typically **6-8 hours** before surgery. Eating pancakes, which are solid food, at 10:00 AM for a 2:00 PM surgery (4-hour interval) violates this guideline. - This short fasting period for solids increases the risk of **pulmonary aspiration** during induction of anesthesia. *Water at 12:00 PM* - Water is considered a clear liquid, and ASA guidelines typically allow clear liquids until **2 hours** before surgery. Drinking water at 12:00 PM for a 2:00 PM surgery is within these guidelines. - Rapid gastric emptying of clear liquids minimizes the risk of aspiration. *Black coffee at 5:30 AM* - Black coffee is considered a clear liquid, and it is consumed well within the **2-hour** fasting window for clear liquids before a 2:00 PM surgery. - The absence of milk or cream ensures it is treated as a clear liquid, which empties quickly from the stomach. *A non-clear liquid (e.g., orange juice) at 7:30 AM* - Non-clear liquids, such as orange juice, are treated similarly to light meals and generally require a fasting period of **6 hours** before surgery. Drinking orange juice at 7:30 AM for a 2:00 PM surgery (6.5-hour interval) is compliant with these guidelines. - The protein and pulp in non-clear liquids delay gastric emptying compared to clear liquids.
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