Pharmacological Considerations in Pediatrics — MCQs
What is the correct dose of i.v. adrenaline in term infants during neonatal resuscitation?
Regarding FeNa, which of the following is true?
Newborns as compared to adults eliminate lidocaine:
Which drug is used to reverse the effects of non-depolarizing muscle relaxants?
The best inhalational agent of choice for induction of anesthesia in a six-year-old child who refuses IV access is –
Which of the following statements about the differences between neonates and adults is true?
A young male was administered regional anesthesia with 0.25% bupivacaine. The patient became unresponsive, and the pulse became unrecordable. What is the best management in this situation?
A 6 month old child is suffering from patent ductus arteriosus (PDA) with congestive cardiac failure. Ligation of ductus arteriosus was decided for surgical management. The most appropriate inhalational anaesthetic agent of choice with minimal haemodynamic alteration for induction of anaesthesia is –
Which of the following statements about Nitrous Oxide (N2O) is true?
A one-year-old child, preterm, and low birth weight with delayed milestones is posted for elective hernia repair. Which of the following statements is true?
Pharmacological Considerations in Pediatrics Indian Medical PG Practice Questions and MCQs
Question 1: What is the correct dose of i.v. adrenaline in term infants during neonatal resuscitation?
- A. 0.1-0.3 ml/kg in 1:10,000 (Correct Answer)
- B. 0.03-0.05 ml/kg in 1:1,000
- C. 0.01-0.03 ml/kg in 1:1,000
- D. 0.3-0.5 ml/kg in 1:10,000
Explanation: ***0.1-0.3 ml/kg in 1:10,000*** - The recommended intravenous adrenaline dose for neonatal resuscitation is **0.01-0.03 mg/kg** using a **1:10,000 solution (0.1 mg/mL)**. - Volume calculation: 0.01-0.03 mg/kg ÷ 0.1 mg/mL = **0.1-0.3 mL/kg**. - This is the standard dose as per **NRP (Neonatal Resuscitation Program)** and **AHA guidelines** [2]. - The 1:10,000 concentration is safer for IV/umbilical venous catheter administration in neonates. *0.01-0.03 ml/kg in 1:1,000* - This volume is far too low for a 1:1,000 solution. - Would deliver only 0.01-0.03 mg total (not per kg), resulting in a **sub-therapeutic dose**. - The 1:1,000 concentration contains 1 mg/mL, which is **10 times more concentrated** than the recommended dilution. *0.3-0.5 ml/kg in 1:10,000* - This volume would deliver 0.03-0.05 mg/kg, which **exceeds the recommended maximum** of 0.03 mg/kg. - Higher doses can cause **severe adverse effects** including hypertension, arrhythmias, decreased myocardial function, and compromised coronary perfusion. - Not recommended as the standard initial dose. *0.03-0.05 ml/kg in 1:1,000* - The 1:1,000 concentration (1 mg/mL) is **too concentrated for IV use** in neonates [1]. - This volume would deliver 0.03-0.05 mg/kg from a highly concentrated solution, increasing risk of **severe cardiovascular complications**. - The 1:1,000 solution is reserved for **endotracheal administration** (at higher volumes of 0.5-1 mL/kg), not IV route.
Question 2: Regarding FeNa, which of the following is true?
- A. Measurement of FeNa is NOT affected by use of diuretic
- B. FeNa is higher in intrinsic renal failure than pre renal failure (Correct Answer)
- C. FeNa is lower in neonates when compared to children
- D. FeNa is similar in both pre term and term neonate
Explanation: ***FeNa is higher in intrinsic renal failure than pre renal failure*** - In **intrinsic renal failure**, the kidneys lose their ability to conserve sodium effectively, leading to a **higher fractional excretion of sodium (FeNa)**, typically > 2%. - Conversely, in **prerenal failure**, the kidneys avidly reabsorb sodium to compensate for decreased renal perfusion, resulting in a **low FeNa**, usually < 1%. *Measurement of FeNa is NOT affected by use of diuretic* - The use of **diuretics** significantly impacts FeNa by directly inhibiting sodium reabsorption, thus rendering FeNa values unreliable for distinguishing between prerenal and intrinsic acute kidney injury [1]. - When a patient is on diuretics, the FeNa will be artificially elevated, regardless of the underlying cause of kidney injury [1]. *FeNa is lower in neonates when compared to children* - **Neonates** generally have a **higher FeNa** compared to older children because their immature renal tubules are less efficient at reabsorbing sodium. - As the kidneys mature during infancy and childhood, sodium reabsorption improves, leading to lower FeNa values. *FeNa is similar in both pre term and term neonate* - **Preterm neonates** typically have a **higher FeNa** than full-term neonates due to even greater renal immaturity, particularly in tubular function. - Their kidneys are less developed, resulting in a reduced capacity for sodium reabsorption compared to full-term infants.
Question 3: Newborns as compared to adults eliminate lidocaine:
- A. Variable
- B. More rapidly
- C. Equally fast
- D. More slowly (Correct Answer)
Explanation: ***More slowly*** - Newborns have **immature hepatic enzyme systems**, particularly for **CYP1A2** and **CYP3A4**, which are crucial for lidocaine metabolism. - Reduced **plasma protein binding** and a larger **volume of distribution** in newborns can also impact lidocaine clearance, leading to slower elimination. *Variable* - While there can be individual variability in drug metabolism, the general trend for lidocaine elimination in newborns is consistently slower due to physiological immaturity, not merely variable. - This option does not capture the overall physiological characteristic of drug elimination in neonates. *More rapidly* - This is incorrect because newborns have underdeveloped liver function and enzyme systems, which would hinder, not accelerate, the metabolism and elimination of drugs like lidocaine. - A more rapid elimination would suggest a highly efficient metabolic pathway, which is not the case in neonates. *Equally fast* - This is incorrect as the **pharmacokinetic profile** of drugs, including lidocaine, differs significantly between newborns and adults due to developmental differences in organ function (e.g., liver, kidneys). - The liver's metabolic capacity in newborns is not fully mature enough to eliminate lidocaine at the same rate as in adults.
Question 4: Which drug is used to reverse the effects of non-depolarizing muscle relaxants?
- A. Atropine
- B. Neostigmine (Correct Answer)
- C. Glycopyrrolate
- D. Edrophonium
Explanation: ***Neostigmine*** - **Neostigmine** is an **acetylcholinesterase inhibitor** that increases the amount of acetylcholine at the neuromuscular junction. - This increased acetylcholine can then compete with **non-depolarizing muscle relaxants** for receptors, reversing their effects. *Atropine* - **Atropine** is an **anticholinergic drug** that blocks muscarinic receptors. - It is often co-administered with neostigmine to counteract the **parasympathetic side effects** of neostigmine, such as bradycardia and increased salivation, but does not reverse muscle relaxation directly. *Glycopyrrolate* - **Glycopyrrolate** is also an **anticholinergic drug** similar to atropine, but with less central nervous system penetration. - It is co-administered with neostigmine for the same reason as atropine, to mitigate the **cholinergic side effects** of neostigmine, not to reverse muscle paralysis. *Edrophonium* - **Edrophonium** is a short-acting **acetylcholinesterase inhibitor** historically used to reverse non-depolarizing muscle relaxants. - While it can reverse muscle relaxation, it has a **shorter duration of action** compared to neostigmine and is less commonly used for this purpose in modern practice.
Question 5: The best inhalational agent of choice for induction of anesthesia in a six-year-old child who refuses IV access is –
- A. Sevoflurane (Correct Answer)
- B. Methoxyflurane
- C. Desflurane
- D. Isoflurane
Explanation: ***Sevoflurane*** - **Sevoflurane** has a **low pungency** and a **rapid onset** due to its low blood/gas solubility, making it ideal for inhalational inductions in children who are often uncooperative with IV access. - Its pleasant odor and non-irritating properties minimize coughing and breath-holding, ensuring a smooth and quick induction. *Methoxyflurane* - **Methoxyflurane** is **nephrotoxic** and has a very slow onset, making it unsuitable for rapid inhalational induction, especially in children where kidney function can be more sensitive. - Due to its significant side effects and slow induction profile, it is rarely used today for general anesthesia. *Desflurane* - **Desflurane** has a very **pungent odor** and a high incidence of airway irritation, including coughing and breath-holding, which makes it a poor choice for gas induction, particularly in children. - Although it has a rapid onset due to very low blood/gas solubility, its irritating properties outweigh this benefit for pediatric inhalational induction. *Isoflurane* - **Isoflurane** is also highly **pungent** and associated with significant airway irritation, making it uncomfortable for inhaled induction and poorly tolerated by children. - It has a slower onset compared to sevoflurane and desflurane, further diminishing its suitability for uneventful inhalational induction in pediatric patients.
Question 6: Which of the following statements about the differences between neonates and adults is true?
- A. They can tolerate large doses of certain drugs on body weight basis.
- B. Their excretory ability of the kidney is less well developed. (Correct Answer)
- C. Their gastric emptying is prolonged.
- D. Their hepatic metabolizing enzyme activity is slower.
Explanation: ***Their excretory ability of the kidney is less well developed.*** - Neonates have **immature renal function** with lower glomerular filtration rate (GFR) and tubular secretion/reabsorption capabilities compared to adults. - This reduced excretory capacity affects the **elimination of renally cleared drugs**, often requiring dose adjustments. - This is a **universally accepted true statement** about neonatal physiology. *Their gastric emptying is prolonged.* - While gastric emptying in neonates is indeed slower and more variable than in adults, the statement as written is **somewhat ambiguous** because "prolonged" could be interpreted different ways. - However, **this statement is also factually TRUE** - neonatal gastric emptying IS prolonged compared to adults. - **Note:** This creates ambiguity as both this and the correct answer are true statements. *They can tolerate large doses of certain drugs on body weight basis.* - This is **FALSE** - Neonates generally have **reduced drug tolerance** compared to adults due to immature organ systems. - They are **more susceptible to adverse drug effects** and typically require lower mg/kg doses for most medications. - This is the only clearly **incorrect** statement among the options. *Their hepatic metabolizing enzyme activity is slower.* - This is **TRUE** - The activity of many hepatic drug-metabolizing enzymes (e.g., **cytochrome P450 enzymes**, glucuronidation) is **reduced at birth**. - This slower metabolism can lead to **prolonged half-lives** and increased drug accumulation. - **Note:** This statement is also factually accurate, creating potential ambiguity. **Clinical Note:** This question has inherent ambiguity as three of the four statements are medically accurate. In exam context, the renal excretion option is selected as it represents the most fundamental and clinically significant difference affecting drug dosing in neonates.
Question 7: A young male was administered regional anesthesia with 0.25% bupivacaine. The patient became unresponsive, and the pulse became unrecordable. What is the best management in this situation?
- A. ECPR with calcium
- B. ECPR with dobutamine
- C. ECPR with 20% intralipid (Correct Answer)
- D. ECPR with sodium bicarbonate
Explanation: ***ECPR with 20% intralipid*** - The scenario describes **Local Anesthetic Systemic Toxicity (LAST)**, likely due to bupivacaine, leading to cardiovascular collapse. - **Intralipid 20%** is the first-line treatment for LAST-induced cardiovascular toxicity, as it acts as a lipid sink for the lipophilic local anesthetic. *ECPR with calcium* - While calcium may be used in certain cardiac arrest scenarios, it is **not the primary treatment for bupivacaine-induced cardiovascular collapse** and LAST. - Calcium might offer some cardiac support but does not directly neutralize the local anesthetic's toxic effects. *ECPR with dobutamine* - **Dobutamine is an inotropic agent** used to improve cardiac contractility but is not indicated as a primary rescue therapy for severe LAST. - It would not address the underlying toxicity caused by bupivacaine and could potentially worsen the situation by increasing myocardial oxygen demand without reversing toxin effects. *ECPR with sodium bicarbonate* - **Sodium bicarbonate** is used to treat metabolic acidosis and can be beneficial in certain drug overdoses to enhance excretion or stabilize cardiac membranes. - However, it is **not the primary or most effective treatment for bupivacaine-induced LAST** and cardiovascular collapse compared to lipid emulsion therapy.
Question 8: A 6 month old child is suffering from patent ductus arteriosus (PDA) with congestive cardiac failure. Ligation of ductus arteriosus was decided for surgical management. The most appropriate inhalational anaesthetic agent of choice with minimal haemodynamic alteration for induction of anaesthesia is –
- A. Sevoflurane (Correct Answer)
- B. Isoflurane
- C. Enflurane
- D. Halothane
Explanation: ***Sevoflurane*** - **Sevoflurane** is the preferred inhalational anesthetic for induction in pediatric patients, especially those with cardiovascular compromise, due to its **less pungent odor**, leading to smoother induction and minimal airway irritation. - It maintains **hemodynamic stability** better than other volatile agents at equipotent doses, making it suitable for children with congenital heart defects like PDA. *Isoflurane* - **Isoflurane** has a more **pungent odor** than sevoflurane, making it less suitable for mask induction in pediatric patients due to potential airway irritation and resistance. - While it offers good hemodynamic stability, its higher pungency can lead to coughing or laryngospasm during induction, which is undesirable in a child with cardiac compromise. *Enflurane* - **Enflurane** is now largely replaced by newer agents like sevoflurane and isoflurane due to its potential to cause **seizures** and myocardial depression, especially at higher concentrations. - It also carries a risk of inducing **nephrotoxicity** due to fluoride metabolism and is associated with more significant hemodynamic alterations compared to sevoflurane. *Halothane* - **Halothane** is associated with significant **myocardial depression**, leading to reduced cardiac output and hypotension, which is particularly detrimental in a child with congestive cardiac failure due to PDA. - It also has a risk of causing **halothane hepatitis**, a rare but severe liver toxicity, making it a less safe option compared to modern inhalational agents.
Question 9: Which of the following statements about Nitrous Oxide (N2O) is true?
- A. Least potent inhalational anesthetic (Correct Answer)
- B. Lighter than air
- C. Effective muscle relaxant
- D. Does not cause diffusion hypoxia
Explanation: **Least potent inhalational anesthetic** - Nitrous oxide has a **high Minimum Alveolar Concentration (MAC)** of approximately 104%, making it the least potent of the commonly used inhalational anesthetics. - Its high MAC means a very high concentration is required to achieve surgical anesthesia, which is why it is typically used as an adjunct to more potent agents. *Lighter than air* - The molecular weight of nitrous oxide (N2O) is 44, which is **heavier than air** (average molecular weight approximately 29 g/mol). - Its density is greater than air, meaning it would tend to sink rather than rise. *Effective muscle relaxant* - Nitrous oxide provides **minimal to no skeletal muscle relaxation** benefits. - If muscle relaxation is required, a neuromuscular blocking agent must be administered separately. *Does not cause diffusion hypoxia* - Nitrous oxide rapidly diffuses out of the blood into the alveoli during emergence, diluting the oxygen and carbon dioxide there. - This rapid diffusion can lead to **diffusion hypoxia** (also known as the "second gas effect"), necessitating the administration of 100% oxygen during recovery to prevent this complication.
Question 10: A one-year-old child, preterm, and low birth weight with delayed milestones is posted for elective hernia repair. Which of the following statements is true?
- A. Wait for complete neurological evaluation (Correct Answer)
- B. Avoidance of regional anesthesia
- C. Avoidance of combination of inhalational and muscle relaxation
- D. Inhalational agents are contraindicated in this scenario.
Explanation: ***Wait for complete neurological evaluation*** - Preterm, low birth weight, and delayed milestones suggest a heightened risk of **neurological complications** and underscore the importance of a thorough pre-operative neurological assessment. - A comprehensive evaluation can identify specific neurological deficits or vulnerabilities, informing anesthesia planning and **post-operative monitoring** to prevent exacerbation or new onset issues. *Inhalational agents are contraindicated in this scenario.* - **Inhalational agents** are not absolutely contraindicated in preterm, low-birth-weight children with delayed milestones, but their use requires careful titration due to potential for **hemodynamic instability** and increased risk of apnea. - The choice of anesthetic technique depends on the child's specific condition and the surgeon's preference, with a focus on **neuroprotective strategies** and minimizing risks. *Avoidance of regional anesthesia* - **Regional anesthesia** can be beneficial in preterm infants for hernia repair by potentially reducing the need for systemic opioids and their associated side effects, as well as lowering the incidence of **post-operative apnea**. - Its use, however, requires careful consideration of the child's coagulation status, cardiovascular stability, and the expertise of the anesthesiologist in performing blocks in this vulnerable population. *Avoidance of combination of inhalational and muscle relaxation* - The combination of **inhalational agents** and **muscle relaxants** is routinely used in pediatric anesthesia for appropriate surgical conditions and is not inherently contraindicated in this population. - Careful titration of both agents is essential to minimize their respective side effects, such as cardiovascular depression from inhalational agents and prolonged muscle weakness from neuromuscular blockers, especially in a child with baseline neurological challenges.
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