Pre-hospital emergency anaesthesia in awake hypotensive trauma patients: beneficial or detrimental?

Abstract

The benefits of pre-hospital emergency anaesthesia (PHEA) are controversial. Patients who are hypovolaemic prior to induction of anaesthesia are at risk of severe cardiovascular instability post-induction. This study compared mortality for hypovolaemic trauma patients (without major neurological injury) undergoing PHEA with a patient cohort with similar physiology transported to hospital without PHEA. A retrospective database review was performed to identify patients who were hypotensive on scene [systolic blood pressure (SBP) < 90 mmHg], and GCS 13-15. Patient records were reviewed independently by two pre-hospital clinicians to identify the likelihood of hypovolaemia. Primary outcome measure was mortality defined as death before hospital discharge. Two hundred and thirty-six patients were included; 101 patients underwent PHEA. Fifteen PHEA patients died (14.9%) compared with six non-PHEA patients (4.4%), P = 0.01; unadjusted OR for death was 3.73 (1.30-12.21; P = 0.01). This association remained after adjustment for age, injury mechanism, heart rate and hypovolaemia (adjusted odds ratio 3.07 (1.03-9.14) P = 0.04). Fifty-eight PHEA patients (57.4%) were hypovolaemic prior to induction of anaesthesia, 14 died (24%). Of 43 PHEA patients (42.6%) not meeting hypovolaemia criteria, one died (2%); unadjusted OR for mortality was 13.12 (1.84-578.21). After adjustment for age, injury mechanism and initial heart rate, the odds ratio for mortality remained significant at 9.99 (1.69-58.98); P = 0.01. Our results suggest an association between PHEA and in-hospital mortality in awake hypotensive trauma patients, which is strengthened when hypotension is due to hypovolaemia. If patients are hypovolaemic and awake on scene it might, where possible, be appropriate to delay induction of anaesthesia until hospital arrival.