Time of hypotension and discharge outcome in children with severe traumatic brain injury

We performed a retrospective study at a level I pediatric trauma center of patients admitted between 1998 and 2005 to determine the time after severe pediatric traumatic brain injury (TBI) that hypotension (systolic blood pressure SBP] of <5th percentile) is most strongly associated with poor outcome. One hundred forty-six patients of <18 years of age with TBI, head Abbreviated Injury Score (AIS) of >or=3, and PICU admission Glasgow Coma Scale (GCS) score of <9 formed the analytic sample. Available SBP readings through the first 72 h after severe TBI were collected. SBP of <5th percentile was defined as hypotension. Discharge Glasgow Outcome Scale (GOS) score of <4 defined poor outcome. Of 146, 59 (40%) patients had discharge GOS of <4 and 12% died. The adjusted risk of poor outcome associated with hypotension stabilized by 8 h (adjusted risk ratio RR] 1.7; 95% confidence interval CI] 1.1-2.6) after injury. The risk of poor outcome peaked with hypotension occurring within the first 6 h after injury (RR 2.0, 95% CI 1.3-3.3). Poor discharge GOS was predicted by hypotension occurring during the first 6 h after injury. SBP data beyond the first 6 h did not improve our ability to predict poor discharge GOS. The first 6 h after severe pediatric TBI may represent a critical time period for either predicting or improving outcome.