The Head Injury Retrieval Trial (HIRT): a single-centre randomised controlled trial of physician prehospital management of severe blunt head injury compared with management by paramedics only

Abstract

Background: Advanced prehospital interventions for severe brain injury remains controversial. No previous randomised trial has been conducted to evaluate additional physician intervention compared with paramedic only care.

Methods: Participants in this prospective, randomised controlled trial were adult patients with blunt trauma with either a scene GCS score <9 (original definition), or GCS<13 and an Abbreviated Injury Scale score for the head region ≥3 (modified definition). Patients were randomised to either standard ground paramedic treatment or standard treatment plus a physician arriving by helicopter. Patients were evaluated by 30-day mortality and 6-month Glasgow Outcome Scale (GOS) scores. Due to high non-compliance rates, both intention-to-treat and as-treated analyses were preplanned.

Results: 375 patients met the original definition, of which 197 was allocated to physician care. Differences in the 6-month GOS scores were not significant on intention-to-treat analysis (OR 1.11, 95% CI 0.74 to 1.66, p=0.62) nor was the 30-day mortality (OR 0.91, 95% CI 0.60 to 1.38, p=0.66). As-treated analysis showed a 16% reduction in 30-day mortality in those receiving additional physician care; 60/195 (29%) versus 81/180 (45%), p<0.01, Number needed to treat =6. 338 patients met the modified definition, of which 182 were allocated to physician care. The 6-month GOS scores were not significantly different on intention-to-treat analysis (OR 1.14, 95% CI 0.73 to 1.75, p=0.56) nor was the 30-day mortality (OR 1.05, 95% CI 0.66 to 1.66, p=0.84). As-treated analyses were also not significantly different.

Conclusions: This trial suggests a potential mortality reduction in patients with blunt trauma with GCS<9 receiving additional physician care (original definition only). Confirmatory studies which also address non-compliance issues are needed.

Trial registration number: NCT00112398.

Keywords: Trauma, head; comparitive system research; emergency ambulance systems, effectiveness; prehospital care, doctors in PHC; prehospital care, helicopter retrieval.

Figure 1

Randomisation, enrolment and outcome data for the original criteria subgroup. Between 14 May 2005 and 14 March 2011, the study randomised 3124 incidents yielding 3696 identifiable patients. Of these, 375 patients met the original criteria for severe head injury.

Figure 2

Randomisation, enrolment and outcome data for the modified criteria subgroup. Between 14 May 2005 and 14 March 2011, the study randomised 3124 incidents yielding 3696 identifiable patients. Of these, 338 patients met the modified criteria for severe head injury.

Figure 3

Main intention-to-treat results by treatment allocated and mechanisms subgroups. OR>1 indicates higher risk in the physician treated group.

Figure 4

Sensitivity analyses for the primary outcome and mortality. OR>1 indicates higher risk in the physician treated group. Three missing 6-month outcomes in the Original Head Injury Criteria group (one compliant patient and two non-compliant patients).