A 4-week-old infant requires rapid sequence intubation. Compared with adults, the intravenous dose of succinylcholine required in this infant is:
- A Higher, about 2 mg/kg, due to a larger volume of distribution ✓
- B The same as adults, about 1 mg/kg
- C Lower, about 0.5 mg/kg, due to enhanced plasma cholinesterase activity
- D Higher, about 3 mg/kg, due to receptor insensitivity
Correct answer: A. Higher, about 2 mg/kg, due to a larger volume of distribution
Explanation
Infants need approximately 2 mg/kg intravenous succinylcholine versus 1 mg/kg in adults, chiefly because of their larger volume of distribution per kilogram, not altered enzyme or receptor function. Plasma cholinesterase levels are actually reduced in neonates. Because young children are prone to profound bradycardia with succinylcholine, atropine pretreatment is routine in paediatric practice.
Reference: Miller's Anesthesia, 9th ed.
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Written and medically reviewed by the StethoPrep medical team.