Pediatric Anesthesia — MCQs

Pediatric Anesthesia Indian Medical PG Practice Questions and MCQs

Question 41: In infant (full term) diameter (mm) length (cm) of ETT used are –

A. 3.5,12 (Correct Answer)
B. 7,12
C. 3.5,16
D. 7, 10

Explanation: ***3.5, 12*** - For a full-term infant requiring endotracheal intubation, the recommended internal diameter (ID) of the endotracheal tube (ETT) is typically **3.5 mm**. - The appropriate insertion length of the ETT at the lip for a full-term infant is approximately **12 cm**. *7, 12* - An ETT with an internal diameter of **7 mm** is generally used for older children or adults, not for full-term infants. - While **12 cm** might be the correct insertion length, the ETT diameter is incorrect for an infant. *3.5, 16* - While **3.5 mm** is the appropriate ETT internal diameter for a full-term infant, an insertion length of **16 cm** is too long and would likely lead to right mainstem bronchus intubation. - This length is typically seen in older children or adults. *7, 10* - Both the internal diameter of **7 mm** and the insertion length of **10 cm** are incorrect for a full-term infant. - An ETT of 7 mm is too large, and an insertion length of 10 cm is generally too short, risking accidental extubation.

Question 42: Spontaneous breathing circuit used in children is -

A. Mapleson C or water's to & fro canister
B. Bain's circuit
C. Jackson Rees modification of Ayre's T piece (Correct Answer)
D. Mapleson A or Magill's circuit

Explanation: ***Jackson Rees modification of Ayre's T piece*** - This circuit is particularly well-suited for **children** due to its low resistance and suitability for both spontaneous and controlled ventilation. - The **Ayre's T-piece** itself provides minimal mechanical dead space, and the Jackson Rees modification adds a reservoir bag, which improves control over ventilation and reduces gas waste. *Mapleson C or water's to & fro canister* - The **Mapleson C circuit** is inefficient for spontaneous breathing due to its high rebreathing potential and lack of a dedicated reservoir bag to mitigate CO2 accumulation. - The **Water's to & fro canister** utilizes a soda lime canister for CO2 absorption, which can be cumbersome and less effective for dynamic spontaneous breathing in children. *Bain's circuit* - The **Bain's circuit** (a modification of the Mapleson D) is primarily used for controlled ventilation and is less efficient for spontaneous breathing in children due to its high fresh gas flow requirements to prevent CO2 rebreathing. - Its design makes it more prone to heat and humidity loss, which can be detrimental in pediatric patients. *Mapleson A or Magill's circuit* - The **Mapleson A circuit** (Magill's circuit) is considered the most efficient for spontaneous breathing in adults, but its design leads to significant rebreathing of expired gases in children due to their higher respiratory rates and lower tidal volumes. - The fresh gas flow required to prevent rebreathing in children using this circuit would be excessively high, leading to increased gas consumption and potential hypothermia.

Question 43: Inhalational agent of choice for induction in children is

A. Halothane
B. Sevoflurane (Correct Answer)
C. Desflurane
D. Isoflurane

Explanation: ***Sevoflurane*** - **Sevoflurane** is the inhalational agent of choice for children due to its **low pungency**, rapid onset, and pleasant odor. - This makes it well-tolerated and suitable for mask induction without causing irritation or breath-holding. *Halothane* - **Halothane** was previously used but is now largely replaced due to its association with **hepatotoxicity** (halothane hepatitis) and cardiac arrhythmias. - While it has a sweet odor, its safety profile is inferior to newer agents. *Desflurane* - **Desflurane** has a very **pungent odor** and is highly irritating to the airway, making it unsuitable for mask induction, especially in children. - It often causes coughing, breath-holding, and laryngospasm during induction if given via a mask. *Isoflurane* - **Isoflurane** also has a **pungent odor** and can cause airway irritation, leading to coughing and breath-holding, making it less ideal for mask inductions in children. - Its slower onset and irritating properties make it less preferred for pediatric induction compared to sevoflurane.

Question 44: The ideal muscle relaxant used for a neonate undergoing porto-enterostomy for biliary atresia is:

A. Vecuronium
B. Pancuronium
C. Atracurium (Correct Answer)
D. Rocuronium

Explanation: ***Atracurium*** - **Atracurium** undergoes **Hofmann elimination** and **ester hydrolysis**, making its elimination independent of renal or hepatic function. This characteristic is particularly beneficial in neonates, especially those with conditions like biliary atresia where hepatic function may be compromised. - Its **predictable duration of action** and minimal cardiovascular effects make it a safe choice for neonates with potentially unstable physiological systems. *Vecuronium* - **Vecuronium** is primarily metabolized by the **liver** and excreted through the bile and kidneys. - In neonates, especially those with **biliary atresia**, its clearance may be prolonged due to immature or compromised liver function, leading to a prolonged duration of action and potential accumulation. *Pancuronium* - **Pancuronium** is predominantly eliminated by the **kidneys** and, to a lesser extent, by hepatic metabolism. - Neonates have **immature renal function**, which can significantly prolong the elimination half-life of Pancuronium, making its use less predictable and increasing the risk of prolonged paralysis. *Rocuronium* - **Rocuronium** is primarily eliminated by the **liver** and partially cleared by the kidneys. - In neonates, its elimination can be **prolonged due to immature hepatic function**, leading to a longer duration of block and potential for accumulation, especially in cases of compromised liver function.

Question 45: In a one year old child intubation is done using -

A. Curved blade with cuffed tube
B. Straight blade with uncuffed tube (Correct Answer)
C. Curved blade with uncuffed tube
D. Straight blade with cuffed tube

Explanation: ***Straight blade with uncuffed tube*** - A **straight blade (Miller blade)** is generally preferred in infants due to the more anterior and cephalad position of the larynx and the larger, floppier epiglottis, which it can directly lift. - An **uncuffed tube** is used in children under 8 years of age due to the natural narrowing of the subglottic region, which provides a functional seal and minimizes the risk of tracheal injury. *Curved blade with cuffed tube* - A **curved blade (Macintosh blade)** is typically used in older children and adults, as it indirectly lifts the epiglottis by engaging the vallecula. - A **cuffed tube** is generally avoided in children under 8 years due to the risk of tracheal stenosis and pressure necrosis, as the cricoid cartilage is the narrowest point of the pediatric airway. *Curved blade with uncuffed tube* - A **curved blade** is usually less effective in providing adequate visualization of the glottis in infants compared to a straight blade. - While an **uncuffed tube** is appropriate for a one-year-old, the choice of the curved blade is less optimal for this age group. *Straight blade with cuffed tube* - A **straight blade** is the preferred choice for intubation in an infant. - However, a **cuffed tube** is inappropriate for a one-year-old due to the risk of airway damage and subglottic stenosis.

Question 46: The recommended size of endotracheal tube for a 1-year-old child is:

A. 2.5
B. 5
C. 3
D. 4 (Correct Answer)

Explanation: ***4*** - For children between 1 and 2 years of age, the recommended uncuffed endotracheal tube size is typically **4.0 mm** internal diameter. - A common formula to estimate endotracheal tube size for children older than 1 year is (Age in years / 4) + 4 for uncuffed tubes. For a 1-year-old, this would be (1/4) + 4 = 4.25, with 4.0 being the closest practical size. *2.5* - An endotracheal tube of **2.5 mm** is generally used for **preterm neonates** or very small infants, not for a 1-year-old child. - Using a tube this small in a 1-year-old would likely result in an inadequate airway and high airway resistance. *5* - An endotracheal tube of **5.0 mm** would be considered too large for a 1-year-old and could cause **tracheal trauma**, pressure necrosis, or difficulty with insertion. - This size is typically appropriate for older children, often in the 4-6 years old range, depending on the specific formula used. *3* - A **3.0 mm** endotracheal tube is commonly used for **term neonates** or very young infants, usually less than 6 months of age. - For a 1-year-old, a 3.0 mm tube would be too small, leading to inadequate ventilation and increased work of breathing.

Question 47: The Blade of the laryngoscope used in intubation of newborn is

A. Straight blade with uncuffed tube (Correct Answer)
B. Straight blade with Cuffed tube
C. Curved blade with uncuffed tube
D. Curved blade with cuffed tube

Explanation: ***Straight blade with uncuffed tube*** - A **straight blade** (e.g., Miller blade) is preferred in neonates because their **epiglottis is U-shaped** and relatively long, making it easier to lift directly with a straight blade. - **Uncuffed endotracheal tubes** are used in newborns and young children because their cricoid cartilage is the narrowest part of the airway, providing a natural seal and reducing the risk of **subglottic stenosis** from cuff pressure. *Straight blade with Cuffed tube* - While a **straight blade** is appropriate for neonates, a **cuffed tube** is generally avoided due to the higher risk of tracheal damage and the natural anatomical seal provided by the cricoid cartilage in this age group. - The cuff can cause **pressure ischemia** and lead to **post-extubation stridor** or subglottic stenosis in small airways. *Curved blade with uncuffed tube* - A **curved blade** (e.g., Macintosh blade) is typically used in older children and adults to indirectly lift the epiglottis by placing it in the vallecula, which is less effective in neonates due to their more anterior and U-shaped epiglottis. - Although an **uncuffed tube** is correct for neonates, the curved blade choice is generally inappropriate. *Curved blade with cuffed tube* - Both a **curved blade** and a **cuffed tube** are generally unsuitable for neonatal intubation. - The curved blade is less effective for the neonatal airway anatomy, and the cuffed tube carries a significant risk of **airway compromise** and injury in this population.

Question 48: In a 2 months old infant undergoing surgery for biliary atresia, you would avoid one of the following anaesthetic -

A. Propofol
B. Halothane (Correct Answer)
C. Thiopentone
D. Sevoflurane

Explanation: ***Halothane*** - **Halothane** is a potent hepatotoxic agent and should be avoided in patients with **biliary atresia** or other liver conditions. - Its metabolism can lead to the formation of **toxic metabolites** that can worsen pre-existing liver dysfunction. *Propofol* - **Propofol** is primarily metabolized by the liver, but its hepatic clearance is generally **high** and less dependent on liver function than some other anesthetics. - It is often used for induction and maintenance of anesthesia in patients with liver disease, with **dose adjustments** as needed. *Thiopentone* - **Thiopentone** (thiopental) is an ultra-short-acting barbiturate primarily eliminated by **hepatic metabolism**. - While it has a good safety profile for liver disease compared to halothane, careful **dose titration** is needed due to potential for prolonged effects with severe hepatic impairment. *Sevoflurane* - **Sevoflurane** is an inhalation anesthetic with minimal hepatic metabolism and a low potential for hepatotoxicity. - It is often considered a **preferred agent** in patients with liver disease due to its favorable metabolic profile.

Question 49: A 6-year-old child is scheduled for tonsillectomy. Which inhalational agent is most suitable for induction?

A. Isoflurane
B. Halothane
C. Sevoflurane (Correct Answer)
D. Desflurane

Explanation: ***Sevoflurane*** - **Sevoflurane** is preferred for inhalational induction in pediatric patients due to its **low pungency** and rapid onset/offset, making it well-tolerated and less likely to cause coughing or breath-holding. - Its **minimal airway irritancy** facilitates a smooth induction, which is particularly important in children who may be uncooperative or anxious. *Isoflurane* - **Isoflurane** is a **pungent** inhalational agent, making it unsuitable for inhalational induction, especially in children, as it can cause coughing, breath-holding, and laryngospasm. - While it has a good safety profile for maintenance, its irritant properties preclude its use for a smooth mask induction. *Halothane* - **Halothane** was previously a common pediatric anesthetic but is rarely used now due to its association with **hepatotoxicity** (halothane hepatitis) and increased risk of **cardiac arrhythmias**. - Although it has a pleasant odor, its significant side effect profile has led to its replacement by safer agents like sevoflurane. *Desflurane* - **Desflurane** is very **pungent** and highly irritating to the airway, causing coughing, breath-holding, and laryngospasm, making it unsuitable for inhalational induction, especially in pediatric patients. - It also has a **high MAC value**, requiring higher concentrations that can exacerbate airway irritation.

Question 50: Which inhalational agent is preferred for the induction of anesthesia in a child with a history of asthma?

A. Halothane
B. Sevoflurane (Correct Answer)
C. Isoflurane
D. Desflurane

Explanation: ***Sevoflurane*** - **Sevoflurane** is preferred for asthmatic children due to its **less irritating nature** to the airway and potent **bronchodilating effects**. - It has a **pleasant odor** and a **rapid onset** of action, making it suitable for pediatric inhalational induction. *Halothane* - While **halothane** is a potent bronchodilator, its use has significantly declined due to concerns about **hepatotoxicity** (halothane hepatitis). - It also has a **slower onset** and offset compared to newer agents like sevoflurane. *Isoflurane* - **Isoflurane** is a **pungent** agent that can cause **airway irritation**, leading to coughing and bronchospasm, especially in children with reactive airways like asthma. - Although it is a bronchodilator, its irritant properties make it less suitable for asthmatic patients. *Desflurane* - **Desflurane** is highly **pungent** and a significant airway irritant, frequently causing **coughing, breath-holding, laryngospasm, and bronchospasm**. - This makes it particularly unsuitable for induction in patients with asthma or other reactive airway diseases.

Practice by Chapter

Anatomical and Physiological Differences in Children

Practice Questions

Pharmacological Considerations in Pediatrics

Practice Questions

Preoperative Evaluation of Pediatric Patients

Practice Questions

Induction Techniques in Children

Practice Questions

Airway Management in Children

Practice Questions

Fluid Management in Pediatric Anesthesia

Practice Questions

Temperature Regulation in Children

Practice Questions

Regional Anesthesia in Children

Practice Questions

Anesthesia for Common Pediatric Surgeries

Practice Questions

Anesthesia for Congenital Heart Disease

Practice Questions

Emergence Delirium in Children

Practice Questions

Perioperative Pain Management in Children

Practice Questions

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