Prehospital tracheal intubation in severely injured patients: a Danish observational study

Introduction

The value of advanced prehospital life support for patients with severe trauma—for example, endotracheal intubation by ambulance staff—is unclear. Only one randomised controlled trial was found among 2034 papers in a Cochrane review, concluding that advanced trauma life support by ambulance crews should be initiated only as part of rigorously conducted trials.1 A critical review also failed to show benefit and reported success rates for endotracheal intubation from 57% to 92%.2 The review questioned whether prehospital staff could master the required skills. These reviews focus on paramedic based systems.

The helicopter emergency medical services in London is staffed by doctors; the service studied 486 trauma patients intubated without anaesthesia at the scene.3 One patient (0.2%) survived—after thoracotomy at the scene. The service debated the practice of paramedics doing endotracheal intubation without anaesthesia because this is possible only in profoundly unconscious trauma patients with a poor prognosis.

In Denmark, ambulance crews do not intubate, and emergency medicine is not a separate specialty. Anaesthetists work in emergency care in and out of hospitals.

We describe the number of severely injured patients having endotracheal intubation with and without anaesthetic drugs (hypnotics, analgesics, and muscle relaxants) out of hospital and assess their chances of survival.

Participants, methods, and results

In Aarhus (population 330 000), one mobile emergency care unit, staffed with an anaesthetist, runs in addition to ambulances and is dispatched in the most severe cases. From the databases of the mobile unit and the trauma centre, we identified severely injured patients who were intubated out of hospital (table). We defined a severely injured patient as having an injury severity score greater than 15.

Between 1998 and 2000, the trauma team was activated in a total of 741 cases, and 220 patients were severely injured. The mobile unit brought 172 of these to hospital, and prehospital intubation was done in 43% (74/172) of severely injured patients. Of these, 84% (62/74) received anaesthetics. Fifty eight per cent (36/62) of patients who were given anaesthetics and 8% (1/12) of patients who were not survived at least six months (P = 0.003, Fisher's exact test).

Comment

Prehospital intubation was done in 43% of severely injured patients, mostly with anaesthesia; only 12 intubations were done without anaesthesia during three years, and although survival was considerably lower in this group, it was not negligible. The helicopter emergency medical service in London found prehospital intubation without drugs was hopeless,3 but we found that 8% of patients survived. The number was small, with the lower limit of the confidence interval of 0.2% just equal to the mean survival reported by the helicopter service.

Anaesthesia and intubation can be complicated by head and facial injuries, cervical fractures, risk of oesophageal intubation, aspiration, circulatory deterioration, and increased intracerebral pressure. The environment out of hospital is different from in hospital and support and resources are limited. We question whether anaesthesia and intubation of trauma patients can be mastered and routine be maintained by ambulance personnel.