Mechanical Ventilation of Severe Traumatic Brain Injury Patients in the Prehospital Setting

Suboptimal ventilation may impact outcomes in patients with traumatic brain injury (TBI). This study compares the incidence of eucapnia between manually and mechanically ventilated patients with severe TBI during helicopter transport.

This retrospective chart review included consecutive intubated adults with severe TBI (Glasgow Coma Scale score < 9) transported by helicopter from the scene of injury to a level 1 trauma center between 2009 and 2015. The primary outcome was the first venous partial pressure of carbon dioxide obtained in the emergency department. Hypocapnia, eucapnia, and hypercapnia were defined based on the normal range for the testing instrument. The Fisher exact test was used to compare groups.

Of 1,070 trauma patients intubated and transported, 93 met the inclusion criteria with full data. The mean age was 43 years, 81 of 93 were white, and 70 of 93 were men. The mean Injury Severity Score was 29, and 26 of 93 were mechanically ventilated. Hypocapnia occurred in 4 of 93 and hypercapnia in 56 of 93. There was no difference in the rate of eucapnia in manually ventilated compared with mechanically ventilated patients (36% vs. 35%, P = 1.00).

Eucapnia at emergency department arrival occurred in 36% of patients and was unaffected by whether ventilation was manually or mechanically controlled. Few patients were hypocapnic, indicating a low incidence of hyperventilation during helicopter transport.