Inhaled methoxyflurane as a prehospital analgesic in children.

Objective: Despite widespread use of methoxyflurane as an inhaled analgesic by ambulance services in Australia there are no published data as to its use pattern, efficacy and safety in the prehospital setting. We set out to characterize methoxyflurane use in children in the prehospital setting.

Methods: An observational case series was conducted over an 8 month period. Children who received methoxyflurane while being transported to a tertiary children's hospital by ambulance were enrolled. We analysed indications for use, verbal numerical pain scores, adverse events and depth of sedation based on paramedic, patient, parent and ED staff surveys and review of ambulance care records.

Results: During the study period 105 patients were enrolled with an age range of 15 months to 17 years (median age 11 years). Methoxyflurane was mainly used for extremity injuries (82%). Paramedic pain scores dropped from a mean of 7.9 (95% confidence interval [CI] 7.5-8.3) prior to methoxyflurane use to 4.5 (95% CI 3.9-5.0) at 2-5 min and to 3.2 (95% CI 2.8-3.7) at 10 min. There were no serious adverse events (one-sided 97.5% CI 0-3%). Mild adverse events occurred in 38 patients (36.2%; 95% CI 27.0-46.1%). Five of 15 (33.3%) patients under 5 years of age were deeply sedated.

Conclusion: In the present paediatric case series methoxyflurane appears to be an efficacious analgesic with a low adverse events profile. In young children in particular it can briefly lead to deep sedation.