Physician-based emergency medical service deployment characteristics in severe traumatic brain injury: a Dutch multicenter study

Prehospital guidelines advise advanced life support in all patients with severe traumatic brain injury (TBI). In the Netherlands, it is recommended that prehospital advanced life support is particularly provided by a physician-based helicopter emergency medical service (P-HEMS) in addition to paramedic care (EMS). Previous studies have however shown that a substantial part of severe TBI patients is exclusively treated by an EMS team. In order to better understand this phenomenon, we evaluated P-HEMS deployment characteristics in severe TBI in a multicenter setting. The database included patient demographics, prehospital and injury severity parameters and determinants of EMS or EMS/P-HEMS dispatch in 334 patients with severe TBI admitted to level 1 trauma centres in the Netherlands. P-HEMS was deployed in 62% of patients with severe TBI. Patients treated by the P-HEMS had a higher injury severity score (29 (20-38)) vs. (25 (16-30); P <0.001), more frequently required blood product transfusions (41% vs. 29%; P=0.03) and recurrently suffered from TBI with extracranial injuries (33% vs. 6%; P <0.001) than patients solely treated by an EMS. The prehospital endotracheal intubation rate was higher in the P-HEMS group in isolated TBI (93% vs. 19%; P <0.001) or TBI with extracranial injuries (96% vs. 43%; P <0.001) compared to the EMS group. In the EMS group, more patients were secondary referred to a level 1 trauma centre (32% vs. 4%; P <0.001 vs. P-HEMS). Despite higher injury severity levels in P-HEMS patients, 6-month mortality rates were similar among groups, irrespective of the presence of extracranial injuries in addition to TBI. Deployment of P-HEMS estimated 52% and 72% (P <0.001) in urban and rural regions, respectively, with comparable endotracheal intubation rates among regions. This study shows that a physician-based HEMS was more frequently deployed in patients with severe TBI in the presence of extracranial injuries, and in rural trauma regions. Treatment of severe TBI patients by a paramedic EMS only was associated with a higher incidence of secondary referrals to a level I trauma centre. Our data support adjustment of local prehospital guidelines for patients with severe TBI to the geographical context