Out-of-hospital endotracheal intubation and outcome after traumatic brain injury

Study objective

Previous studies disagree about the effect of out-of-hospital endotracheal intubation on traumatic brain injury. This study compares the effects of out-of-hospital endotracheal intubation versus emergency department (ED) endotracheal intubation on mortality and neurologic and functional outcome after severe traumatic brain injury.

Methods

From the 2000 to 2002 Pennsylvania Trauma Outcome Study (a registry of all patients treated at trauma centers in the Commonwealth of Pennsylvania), adult patients with head/neck Abbreviated Injury Scale score of 3 or greater and undergoing out-of-hospital endotracheal intubation or ED endotracheal intubation were included. Transferred patients were excluded. The primary outcome was death (on hospital discharge). The secondary outcomes were neurologic (good versus poor, inferred from discharge to home versus long-term care facility) and functional outcome (determined from a Functional Impairment Score). The key exposure was endotracheal intubation (out-of-hospital endotracheal intubation versus ED endotracheal intubation). Using multivariate logistic regression, odds estimates for out-of-hospital endotracheal intubation were adjusted using age, sex, head/neck Abbreviated Injury Scale score, Injury Severity Score, mechanism of injury (penetrating versus blunt), admission systolic blood pressure, mode of transport (ground only versus helicopter or helicopter + ground), and the use of out-of-hospital neuromuscular blocking agents. A propensity score adjustment accounted for the potential effects of preexisting conditions, inhospital complications, and social factors (drug and alcohol use, race, and insurance coverage).

Results

There were 4,098 patients with head/neck Abbreviated Injury Scale score of 3 or greater who received either out-of-hospital endotracheal intubation (n=1,797, 43.9%) or ED endotracheal intubation (n=2,301, 56.1%). Adjusted odds of death were higher for out-of-hospital endotracheal intubation than ED endotracheal intubation (odds ratio [OR] 3.99; 95% confidence interval [CI] 3.21 to 4.93). Out-of-hospital endotracheal intubation was associated with an increased adjusted odds of poor neurologic outcome (OR 1.61; 95% CI 1.15 to 2.26), moderate or severe functional impairment (Functional Impairment Score 6 to 15; OR 1.92; 95% CI 1.40 to 2.64), and severe functional impairment (Functional Impairment Score 11 to 15; OR 1.80; 95% CI 1.29 to 2.52).

Conclusion

Out-of-hospital endotracheal intubation was associated with adverse outcomes after severe traumatic brain injury. The implications for current clinical care remain undefined.

Introduction

Hypoxia is believed to be deleterious after traumatic brain injury.1., 2., 3. Current guidelines for acute traumatic brain injury therapy call for aggressive measures to prevent hypoxia, including the use of endotracheal intubation.4., 5., 6.

Although endotracheal intubation is readily accomplished in the inhospital setting, multiple factors may complicate the performance of this complex procedure in the out-of-hospital setting, especially in traumatic brain injury patients.7., 8., 9. Recent efforts have introduced controversial advanced airway management techniques to the setting for this patient subset, including the use of neuromuscular blockade–assisted endotracheal intubation.¹⁰ However, results from previous studies have generated conflicting data about the potential benefit of out-of-hospital endotracheal intubation in the therapy of traumatic brain injury, with some studies suggesting positive effects and others demonstrating adverse associations.11., 12., 13., 14.

The purpose of this study was to compare the effects of out-of-hospital endotracheal intubation versus emergency department (ED) endotracheal intubation on mortality and neurologic and functional outcome after traumatic brain injury.