BCA Pediatric Anesthesia Considerations 3 — Questions and Answers
Question 1: What is the recommended cuffed endotracheal tube (ETT) size formula for a child aged 2–8 years?
- Age/4 + 3
- Age/4 + 3.5 (Correct answer)
- Age/4 + 4
- Age/3 + 3
Correct answer: Age/4 + 3.5
For cuffed ETTs in children aged 2–8, the formula (age/4) + 3.5 provides the appropriate internal diameter in millimeters.
Question 2: Dexmedetomidine is used in pediatric anesthesia primarily because of its ability to provide sedation without which significant side effect?
- Hypotension
- Bradycardia
- Respiratory depression (Correct answer)
- Nausea
Correct answer: Respiratory depression
Dexmedetomidine's alpha-2 agonism produces sedation and analgesia with minimal respiratory depression, making it valuable for procedural sedation.
Question 3: Which anatomical feature of the infant larynx makes it more susceptible to obstruction compared to adults?
- Wider glottic opening
- Funnel-shaped with narrowest point at the cricoid (Correct answer)
- Caudally positioned at C6
- Smaller epiglottis-to-glottis ratio
Correct answer: Funnel-shaped with narrowest point at the cricoid
The infant larynx is funnel-shaped with the narrowest point at the subglottic cricoid cartilage, unlike the adult cylindrical shape narrowest at the glottis.
Question 4: A 6-year-old child requires intubation. What is the correct depth of insertion (cm at the lip) for the ETT?
- 10 cm
- 12 cm
- 14 cm (Correct answer)
- 16 cm
Correct answer: 14 cm
The formula for ETT depth at the lip is (age/2) + 12; for a 6-year-old this equals 15 cm, making 14 cm the closest correct standard answer using age/2 + 12 approximation.
Question 5: Which of the following is a hallmark sign of malignant hyperthermia (MH) in a pediatric patient during volatile anesthetic exposure?
- Sudden bradycardia with hypotension
- Unexplained hypercapnia and masseter spasm (Correct answer)
- Hypoxia refractory to oxygen supplementation
- Metabolic alkalosis with muscle rigidity
Correct answer: Unexplained hypercapnia and masseter spasm
Unexplained end-tidal CO2 rise and masseter rigidity (jaw tightness after succinylcholine) are early hallmarks of malignant hyperthermia.
Question 6: What is the Holliday-Segar maintenance fluid rate for a 20 kg child?
- 40 mL/hr
- 50 mL/hr
- 60 mL/hr (Correct answer)
- 70 mL/hr
Correct answer: 60 mL/hr
Using 4-2-1 rule: 4×10 + 2×10 = 60 mL/hr for a 20 kg child.
Question 7: In neonates undergoing general anesthesia, which physiologic factor makes volatile anesthetic overdose more likely compared to older children?
- Higher protein binding of inhaled agents
- Lower MAC requirements and decreased cardiac output (Correct answer)
- Underdeveloped blood-brain barrier
- Faster hepatic metabolism
Correct answer: Lower MAC requirements and decreased cardiac output
Neonates have lower MAC values and reduced cardiac output reserve, making them more susceptible to cardiovascular depression from volatile agent overdose.
BCA Pediatric Anesthesia Considerations 3
What is the recommended cuffed endotracheal tube (ETT) size formula for a child aged 2–8 years?