Haemodynamic response to pre-hospital emergency anaesthesia in trauma patients within an urban helicopter emergency medical service

Purpose Pre-hospital emergency anaesthesia is routinely used in the care of severely injured patients by pre-hospital critical care services. Anaesthesia, intubation, and positive pressure ventilation may lead to haemodynamic instability. The aim of this study was to identify the frequency of new-onset haemodynamic instability after induction in trauma patients with a standardised drug regime. Methods A retrospective database analysis was undertaken of all adult patients treated by a physician-led urban pre-hospital care service over a 6-year period. The primary outcome measure was the frequency of new haemodynamic instability following pre-hospital emergency anaesthesia. The association of patient characteristics and drug regimes with new haemodynamic instability was also analysed. Results A total of 1624 patients were included. New haemodynamic instability occurred in 231 patients (17.4%). Patients where a full-dose regime was administered were less likely to experience new haemodynamic instability than those who received a modified dose regime (9.7% vs 24.8%, p < 0.001). The use of modified drug regimes became more common over the study period (p < 0.001) but there was no change in the rates of pre-existing (p = 0.22), peri-/post-anaesthetic (p = 0.36), or new haemodynamic instability (p = 0.32). Conclusion New haemodynamic instability within the first 30 min following pre-hospital emergency anaesthesia in trauma patients is common despite reduction of sedative drug doses to minimise their haemodynamic impact. It is important to identify non-drug factors that may improve cardiovascular stability in this group to optimise the care received by these patients.