Minimizing Fasting Times — MCQs

10 questions

What is the most appropriate insulin regimen for achieving tight control of blood sugar levels in a 20-year-old male with type 1 diabetes mellitus?

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 1-year-old child weighing 6 kg is suffering from acute gastroenteritis with signs of sunken eyes and skin pinch returning to normal very rapidly. What will be your management?

Ramesh met an accident with a car and has been in deep coma for the last 15 days. The most suitable route for the administration of protein and calories is by :

Which electrolyte imbalance should be corrected before surgery in a patient with hypertrophic pyloric stenosis?

All of the following are true about the action of ADH, except:

In the immediate postoperative period, body potassium is

All of the following drugs increase the risk of postoperative nausea and vomiting after squint surgery in children except?

The following are used for treatment of postoperative nausea and vomiting following squint surgery in children except:-

Q10

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

Minimizing Fasting Times Indian Medical PG Practice Questions and MCQs

Question 1: What is the most appropriate insulin regimen for achieving tight control of blood sugar levels in a 20-year-old male with type 1 diabetes mellitus?

A. Morning injections of insulin detemir with insulin aspart at mealtimes. (Correct Answer)
B. Morning injection of NPH insulin and evening injection of regular insulin.
C. Morning injections of insulin lispro with evening injections of insulin glulisine.
D. Evening injections of mixed regular insulin and insulin glargine for basal control.

Explanation: **Morning injections of insulin detemir with insulin aspart at mealtimes.** - This regimen involves a **long-acting basal insulin (insulin detemir)** to provide continuous background insulin coverage and a **rapid-acting insulin (insulin aspart)** to cover carbohydrate intake at meals, allowing for **tight glycemic control** and flexibility [1]. - This approach closely mimics the body's natural insulin secretion patterns, which is critical for managing **Type 1 Diabetes Mellitus** effectively in a young, active individual [1]. *Morning injection of NPH insulin and evening injection of regular insulin.* - **NPH insulin** is an intermediate-acting insulin with a less predictable peak and duration compared to long-acting analogs, making **tight control** more challenging due to increased risk of hypoglycemia and hyperglycemia. - Using **regular insulin** for the evening, without specific mealtime dosing, is less flexible and precise for managing postprandial glucose excursions compared to rapid-acting insulins. *Morning injections of insulin lispro with evening injections of insulin glulisine.* - Both **insulin lispro** and **insulin glulisine** are rapid-acting insulins designed to be taken with meals; using them as basal insulin without a separate long-acting component would lead to **poor basal control** and a high risk of hypoglycemia. - This regimen lacks a proper **basal insulin** component, which is essential for maintaining fasting glucose levels and preventing hyperglycemia between meals. *Evening injections of mixed regular insulin and insulin glargine for basal control.* - **Regular insulin** is a short-acting insulin and not suitable for basal control; its inclusion in a mixed dose for basal control would lead to significant fluctuations and difficulties in achieving stable glucose levels. - While **insulin glargine** is a good basal insulin, mixing it with regular insulin is generally not recommended as it can alter the **pharmacokinetic profile** of both insulins and complicate dosing [1].

Question 2: 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 3: A 1-year-old child weighing 6 kg is suffering from acute gastroenteritis with signs of sunken eyes and skin pinch returning to normal very rapidly. What will be your management?

A. RL infusion 120 ml in the first hour followed by 360 ml in the next 5 hours
B. RL infusion 180 ml in the first hour followed by 480 ml in the next 5 hours
C. RL infusion 240 ml in the first hour followed by 360 ml in the next 5 hours
D. RL infusion 180 ml in the first hour followed by 270 ml in the next 5 hours (Correct Answer)

Explanation: ***RL infusion 180 ml in the first hour followed by 270 ml in the next 5 hours*** - The child shows signs of **some dehydration** (sunken eyes, skin pinch returning very rapidly). According to **WHO Plan B**, some dehydration requires **75 ml/kg over 6 hours** for rehydration. - For a 6 kg child: **75 × 6 = 450 ml total** - **Distribution:** 30 ml/kg in first hour (180 ml) + 45 ml/kg over next 5 hours (270 ml) - This option provides exactly **450 ml (180 + 270)**, perfectly matching WHO guidelines for some dehydration *RL infusion 120 ml in the first hour followed by 360 ml in the next 5 hours* - First hour: 120 ml = only **20 ml/kg**, which is **below the recommended 30 ml/kg** initial bolus for some dehydration - Total volume: **480 ml** exceeds the required **450 ml** for a 6 kg child - Incorrect fluid distribution pattern for WHO Plan B *RL infusion 180 ml in the first hour followed by 480 ml in the next 5 hours* - First hour volume is correct at **30 ml/kg (180 ml)** - However, next 5 hours: **480 ml = 80 ml/kg**, far exceeding the recommended **45 ml/kg** - Total: **660 ml** significantly exceeds **450 ml**, risking **fluid overload** in a small child *RL infusion 240 ml in the first hour followed by 360 ml in the next 5 hours* - Initial rate: **240 ml = 40 ml/kg** is appropriate for **severe dehydration (WHO Plan C)**, not some dehydration - This child shows **some dehydration** signs, not severe (no lethargy, unconsciousness, or very slow skin pinch) - Total: **600 ml** exceeds the **450 ml** requirement, indicating overtreatment for this clinical scenario

Question 4: Ramesh met an accident with a car and has been in deep coma for the last 15 days. The most suitable route for the administration of protein and calories is by :

A. Central venous hyperalimentation
B. Nasogastric tube feeding
C. Jejunostomy tube feeding (Correct Answer)
D. Gastrostomy tube feeding

Explanation: ***Jejunostomy tube feeding*** - For patients in a **deep coma** who need long-term nutritional support, **enteral feeding** is preferred over parenteral if the gut is functional [1]. - A **jejunostomy tube** is suitable when there is a risk of **gastric reflux** and aspiration, which is common in comatose patients, as feeding directly into the jejunum bypasses the stomach. *Central venous hyperalimentation* - This is **parenteral nutrition**, which is generally reserved for patients where the **gastrointestinal tract is not functional** or cannot safely be used [1]. - It carries higher risks of **infection**, **metabolic complications**, and is more expensive than enteral feeding. *Nasogastric tube feeding* - While a common route for short-term enteral feeding, **nasogastric tubes** have a higher risk of **aspiration pneumonia** in patients with an impaired gag reflex or altered consciousness, like those in a deep coma. - Long-term use can also lead to **nasal irritation**, **sinusitis**, or **esophageal erosion**. *Gastrostomy tube feeding* - A **gastrostomy tube** delivers feed directly into the stomach, which can still pose a significant risk of **gastroesophageal reflux** and subsequent **aspiration** in a comatose patient [1]. - This route is typically considered when the patient has intact gastric emptying and a low risk of aspiration [1].

Question 5: Which electrolyte imbalance should be corrected before surgery in a patient with hypertrophic pyloric stenosis?

A. Potassium
B. Bicarbonate (HCO3)
C. Chloride (Correct Answer)
D. Sodium

Explanation: ***Chloride*** - Patients with **pyloric stenosis** lose gastric acid (HCl) due to repeated vomiting, leading to **hypochloremic metabolic alkalosis**. - Correcting **hypochloremia** is crucial for resolving the metabolic alkalosis and ensuring safe anesthesia and surgery. *Potassium* - While **hypokalemia** can occur secondary to the metabolic alkalosis and fluid shifts, it is not the primary electrolyte imbalance requiring immediate correction before surgery. - Correcting **chloride** levels often facilitates the renal reabsorption of potassium, helping to resolve hypokalemia indirectly. *Bicarbonate (HCO3)* - Elevated **bicarbonate** is a feature of the metabolic alkalosis in pyloric stenosis, but directly correcting it with bicarbonate administration is generally contraindicated. - The goal is to correct the underlying cause (**chloride deficit**), which will allow the kidneys to excrete excess bicarbonate. *Sodium* - **Hyponatremia** can occur in cases of severe dehydration or if excessive free water is administered, but it is not the primary or most critical electrolyte imbalance directly caused by pyloric stenosis itself. - The focus is often on fluid resuscitation and correcting the **chloride deficit** to stabilize the patient.

Question 6: All of the following are true about the action of ADH, except:

A. Acts on collecting ducts and increases water permeability
B. Secreted by neurosecretion from posterior pituitary
C. Post-operative increase in secretion
D. Increased secretion when plasma osmolality is low (Correct Answer)

Explanation: ***Increased secretion when plasma osmolality is low*** - **Antidiuretic hormone (ADH)** secretion is *inhibited* when plasma osmolality is low. - ADH is secreted to conserve water and *increase* plasma osmolality when it is too high, or plasma volume is too low. - Normal osmolality range is 280-290 mOsm/kg; ADH secretion increases above this threshold. *Acts on collecting ducts and increases water permeability* - This statement is true; ADH binds to **V2 receptors** on the principal cells of the collecting ducts. - This binding leads to the insertion of **aquaporin-2 channels** into the apical membrane, increasing water reabsorption. *Secreted by neurosecretion from posterior pituitary* - This statement is true; ADH is synthesized in the **hypothalamus** (supraoptic and paraventricular nuclei) and transported down nerve axons. - It is then stored in and released from the **posterior pituitary gland**, a process known as neurosecretion. *Post-operative increase in secretion* - This statement is true; surgical stress, pain, and common postoperative medications (e.g., narcotics) can stimulate ADH release. - This can lead to **hyponatremia** and fluid retention in the postoperative period due to excessive free water reabsorption.

Question 7: In the immediate postoperative period, body potassium is

A. Retained in body
B. Exchanged with magnesium
C. Exchanged with calcium
D. Excreted excessively (Correct Answer)

Explanation: ***Excreted excessively*** - In the immediate postoperative period, the body often experiences **stress-induced hormonal changes**, such as increased cortisol and aldosterone, and activation of the **renin-angiotensin-aldosterone system**. - These hormonal changes can lead to increased renal potassium excretion and **catabolism** of muscle tissue, releasing intracellular potassium which is then excreted. *Retained in body* - **Potassium retention** is typically seen in conditions like **renal failure** or in states of **hypoaldosteronism**, which are not characteristic of the immediate postoperative period. - The stress response and potential for **acidosis** generally shift potassium out of cells, leading to increased excretion rather than retention. *Exchanged with magnesium* - While potassium and magnesium are both important intracellular cations and their levels can influence each other, a direct "exchange" in the immediate postoperative period is not the primary mechanism of potassium handling. - **Hypomagnesemia** can impair potassium reabsorption leading to **hypokalemia**, but this is a secondary effect, not a direct exchange causing excessive excretion. *Exchanged with calcium* - There is no primary physiological mechanism for direct "exchange" of potassium with calcium in the context of general body fluid and electrolyte regulation in the immediate postoperative period. - **Calcium and potassium** have different regulatory pathways and serve distinct roles, though imbalances in one can indirectly affect the other's transport or cellular function.

Question 8: All of the following drugs increase the risk of postoperative nausea and vomiting after squint surgery in children except?

A. Halothane
B. Propofol (Correct Answer)
C. Nitrous Oxide
D. Opioids

Explanation: ***Propofol*** - Propofol is known to have **antiemetic properties** and is often used to reduce the incidence of postoperative nausea and vomiting (PONV). - Its mechanism involves modulating **GABA-A receptors** and potentially other pathways that suppress emetic responses. *Halothane* - **Inhalational anesthetics** like halothane are a significant risk factor for PONV, particularly in children and following surgeries like squint repair. - They tend to increase PONV by directly stimulating the **chemoreceptor trigger zone** and altering gut motility. *Opioids* - Opioids, commonly used for postoperative pain control, are a well-known cause of **nausea and vomiting**. - They activate **opioid receptors** in the chemoreceptor trigger zone and the gastrointestinal tract, leading to emesis and delayed gastric emptying. *Nitrous Oxide* - The use of **nitrous oxide** as part of a general anesthetic regimen has been consistently associated with an increased risk of PONV. - It is believed to contribute to PONV by increasing the risk of **bowel distension** and stimulating neurotransmitter release involved in emesis.

Question 9: The following are used for treatment of postoperative nausea and vomiting following squint surgery in children except:-

A. Ondansetron
B. Propofol
C. Dexamethasone
D. Ketamine (Correct Answer)

Explanation: ***Ketamine*** - **Ketamine** is an anesthetic and analgesic agent that is known to **increase the incidence of postoperative nausea and vomiting (PONV)**, particularly at higher doses, making it unsuitable for preventing PONV. - Its mechanism of action can stimulate the **chemoreceptor trigger zone** and **vestibular system**, contributing to emetogenic effects. *Ondansetron* - **Ondansetron** is a **serotonin 5-HT3 receptor antagonist** and is a first-line drug for the prevention and treatment of PONV in both adults and children. - It effectively blocks serotonin in the gastrointestinal tract and the **medulla oblongata**, reducing nausea and vomiting. *Propofol* - **Propofol** is an intravenous anesthetic that has **antiemetic properties**, making it useful for reducing PONV when used as part of the anesthetic regimen or as a sub-hypnotic bolus. - Its antiemetic effect is thought to be mediated through **dopamine receptor blockade** and action on the **GABAergic system**. *Dexamethasone* - **Dexamethasone** is a **corticosteroid** with significant antiemetic properties, commonly used as an adjunct for PONV prevention. - It is believed to act by inhibiting **prostaglandin synthesis** and reducing inflammation, thereby modulating pathways involved in nausea and vomiting.

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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