Rectal ketamine during paediatric burn wound dressing procedures: a randomised dose-finding study.

Background: Worldwide, ketamine is used during paediatric procedures, but no recommendations are available regarding a suitable dose for rectal administration during procedures involving high levels of pain and/or anxiety such as burn wound dressing change.

Methods: We evaluated three different single doses of rectally administered racemic ketamine mixed with a fixed dose of 0.5mg/kg of midazolam. In total, 90 children - aged 6 months to 4 years - were randomised 1:1:1 to receive 4mg/kg (K-4 group), 6mg/kg (K-6 group) or 8mg/kg (K-8 group) of racemic ketamine for a maximum of three consecutive procedures. Primary outcome measure was procedural pain evaluated by Face, Legs, Activity, Cry, Consolability (FLACC) behavioural scale. Secondary outcome included feasibility and recovery time. Patient safety was evaluated using surrogate outcomes.

Results: In total, 201 procedures in 90 children aged 19±8months were completed. The median maximum pain was FLACC 0 in all groups (p=0.141). The feasibility was better for groups K-6 (p=0.049) and K-8 (p=0.027) compared with K-4, and the mean recovery time was the longest for group K-8 (36±22min) compared with groups K-4 (25±15min; p=0.003) and K-6 (27±20min; p=0.025). Median maximum sedation measured by the University of Michigan Sedation Scale (UMSS) was higher in group K-8 compared with group K-4 (p<0.0001) and K-6 (p=0.023). One child in group K-8 had a study drug-related serious adverse event - laryngospasm/airway obstruction. No rescue analgosedative medication was administered for group K-6.

Conclusions: A rectally administered mixture of racemic ketamine (6mg/kg) and midazolam (0.5mg/kg) during paediatric burn dressing procedures with a duration of approximately 30min provides optimal conditions regarding pain relief, feasibility, recovery time and patient safety, with no need for rescue analgosedative medication.