Objective: To investigate the incidence of hypotension associated with the use of midazolam for prehospital rapid-sequence intubation (RSI).
Methods: A retrospective review was performed using charts from the two aeromedical agencies servicing the authors' region. The RSI protocols used by crews from the northern (north) and the southern (south) parts of the region were identical, with the exception of midazolam dosing. The north crews used 0.1 mg/kg for all patients, while the south crews used 0.1 mg/kg up to a maximum of 5 mg. All patients receiving midazolam for prehospital RSI were pooled, with multiple linear regression used to investigate the relationship between midazolam dose and both hypotension and a decrease in systolic blood pressure (SBP) following RSI. Patients weighing >50 kg and patients with traumatic brain injury (TBI) were evaluated separately to determine differences between north and south with regard to midazolam dosing and incidence of hypotension. Multivariate logistical regression was used to test for these differences and for potential confounders such as age, initial SBP, and Glasgow Coma Scale score (GCS).
Results: A total of 219 patients were identified from the north (n = 75) and the south (n = 144). Multiple linear regression revealed a statistically significant relationship between midazolam dose and both hypotension and an SBP decrease following RSI. There was no difference between north and south with regard to age, sex, incidence of TBI, initial SBP, or GCS. In patients >50 kg, those from the north received higher doses of midazolam and had a higher incidence of hypotension than those from the south. This relationship was also present in 184 patients with TBI.
Conclusion: The use of midazolam with prehospital RSI is associated with a dose-related incidence of hypotension.