Trajectories of early secondary insults after traumatic brain injury: a new approach to evaluate impact on outcome

Introduction: Secondary insults (SI) occur frequently after traumatic brain injury (TBI). Their presence is associated with a worse outcome. We examined the early trajectories of hypotension (SBP<90mmHg), hypoxia (SpO2<90%) and pupillary abnormalities from the prehospital settings to the Emergency Department (ED), and their relationship with 6-months outcome. Methods: In this retrospective, observational study we included all TBI patients admitted to our Neuro Intensive Care Unit (NICU) from January 1997 to December 2016. We defined the trajectories of SI: – "sustained" if present on the scene of accident and at hospital admission, – "resolved" if present on the scene but resolved in ED, – "new event" if absent on the scene and present in ED, – "none" if no insults were recorded. We investigated the association of SI trajectories with 6-months dichotomized outcome (Glasgow Outcome Scale (GOS); favorable=4-5; unfavorable=1-3). Results: 967 patients were enrolled in the final analysis. Hypoxia and hypotension were related with unfavourable outcome when sustained (70.6% and 78.8%) and resolved (59.3% and 58.8%) while pupillary abnormalities were associated with unfavourable outcome when sustained and new events (65% and 66.7%). Results are summarized in the two figures below. Conclusions: Trajectories could better define the dynamic and the burden of SI and their impact on outcome of TBI patients. Early treatments can influence evolution of SI and improve outcome.