Thiopentone in Pediatric Anesthesia
Recommended Dosing by Age
For anesthesia induction in pediatric patients, thiopentone dosing must be stratified by age: neonates (0-14 days) require 3.4 mg/kg IV, infants (1-6 months) require 6.3 mg/kg IV, and older children require 6.5-7.1 mg/kg IV for unpremedicated patients. 1, 2
Age-Specific Dosing Algorithm
Neonates (0-14 days): 3.4 mg/kg IV as a single bolus provides satisfactory induction in 50% of patients (ED50), with significantly lower requirements than older infants 1
Infants (1-6 months): 6.3 mg/kg IV required for ED50, representing nearly double the neonatal dose 1
Children (3-14 years, unpremedicated): 6.5-7.1 mg/kg IV for routine induction 2
Children with premedication: Doses can be reduced substantially:
Preparation and Administration
Standard concentration: Prepare as 2.5% solution (25 mg/mL) 4
Pediatric dilution: Can be diluted to 1% solution (10 mg/mL) for more precise dosing in smaller children 4
Administration technique: Give as single IV bolus through rapidly running peripheral line, assess response at 30-60 seconds 1, 5
Special Populations Requiring Dose Adjustment
Children with extensive burn injury (>15% body surface area) who are more than 1 year post-recovery require dramatically increased doses: ED50 for loss of lid reflex is 4.78 mg/kg and for mask acceptance is 6.74 mg/kg, significantly higher than non-burned children 5
Critical Safety Considerations
Respiratory effects: Apnea occurs in approximately 50% of children receiving thiopentone, requiring readiness to provide respiratory support 2
Cardiovascular monitoring: Mean arterial pressure decreases by approximately 10% with standard dosing 6
Movement during induction: Spontaneous movement and hypertonus occur in approximately 20% of children, which is expected and not indicative of inadequate dosing 2
Have additional doses immediately available should intubation prove difficult 4
Clinical Context and Alternatives
Thiopentone has been largely supplanted by propofol in modern pediatric anesthesia practice due to propofol's superior suppression of airway reflexes, easier preparation, and greater clinician familiarity 4. However, when thiopentone is used:
Propofol (2.5-2.9 mg/kg) provides comparable induction with better hemodynamic stability during intubation and significantly faster recovery (awakening occurs earlier after cessation of anesthesia) 2, 6
Etomidate (0.2-0.3 mg/kg) may be preferred for hemodynamically unstable patients 7
For ICP protection during intubation, thiopentone is mentioned as a neuroprotective agent that reduces ICP, with lidocaine (1-2 mg/kg) considered an optional adjunct 8
Common Pitfalls to Avoid
Underdosing unpremedicated children: The ED90 for unpremedicated children is 10.5 mg/kg, substantially higher than commonly appreciated 3
Failing to account for burn injury: Children recovered from major burns may require 50-100% higher doses even years after injury 5
Not preparing for respiratory depression: With 50% apnea rate, bag-mask ventilation equipment and oxygen must be immediately available 2
Inadequate preparation: Fresh solutions must be prepared immediately before use; alkaline solutions will precipitate thiopentone 4