Haemodynamic changes to a midazolam–fentanyl–rocuronium protocol for pre-hospital anaesthesia following return of spontaneous circulation after cardiac arrest

Following the return of spontaneous circulation after cardiac arrest, neurological dysfunction, airway or ventilatory compromise can impede transport to early percutaneous coronary intervention, necessitating pre-hospital or emergency department anaesthesia to facilitate this procedure. There are no published reports of the ideal induction agents in these patients. We sought to describe haemodynamic changes associated with a midazolam (0.1mg/kg) fentanyl (2mcg/kg) rocuronium (1mg/kg) regimen developed from expert opinion, and adherence to the protocol by our pre-hospital teams. We performed a retrospective review of electronic vital-signs recorded during induction of return of spontaneous circulation patients over a 30-month period. We analysed the changes in systolic blood pressure and heart rate using a repeated-measures design, and the rate of new hypotension or hypertension. Sixty four patients had four consecutive measurements for analysis (one pre-induction and three post-induction). Systolic blood pressure was significantly lower than the pre-induction value at all three post-induction measurements. Heart rate did not differ between any time-point. New episodes of hypotension (systolic pressure <90mmHg) occurred in 6% at the first measurement post-induction (95%CI 2% to 15%) and 16% at the third measurement (95%CI 8% to 27%). Three patients (5%; 95%CI 1% to 13%) had a hypertensive response. Median midazolam dose given at induction was 0.04mg/kg, only 14% of patients received 0.1mg/kg midazolam. Adherence to recommended fentanyl and rocuronium doses was high. Overall, systolic blood pressure reduced post-induction and systolic pressures