LAUSR

Hypotension is a known risk factor for poor neurologic outcomes after traumatic brain injury. Current guidelines suggest that higher systolic blood pressure (SBP) thresholds likely confer a mortality benefit. However, there is no consensus on the ideal perfusion pressure amongst different age groups (i.e. recommended SBP ≥100 mm Hg for patients aged 50-69 y, ≥110 mm Hg for all other adults). We hypothesize that admission SBP ≥110 mm Hg will be associated with improved outcomes regardless of age group. A retrospective database review of the 2010-2016 Trauma Quality Improvement Program (TQIP) database was performed for adults (≥18 years) with isolated moderate to severe TBIs (head abbreviated Injury Scale [AIS] ≥3, all other AIS <3). Sub-analyses were performed after dividing patients by SBP and age; comparison groups were matched with propensity score matching. Primary outcomes were early (6 h, 12 h and 1 d) and overall in-hospital mortality. Overall, 154,725 patients met the inclusion criteria (mean age 62.8 ± 19.8 years, 89,431 [57.8%] males, ISS 13.9 ± 6.8). Multivariate logistic regression showed that the risk of in-hospital mortality decreased with increasing SBP, plateauing at 110 mm Hg. Among patients of all ages, SBP ≥110 mm Hg was associated with improved mortality (SBP 110-129 vs. 90-109 mm Hg: 12 h 0.4% vs. 0.8%, p=0.001; 1 d 0.8% vs. 1.4%, p=0.004; overall 3.2% vs. 4.9%, p<0.001). Among patients aged 50-69 years, SBP ≥110 mm Hg was associated with improved mortality (SBP 110-119 vs. 100-109 mm Hg: 12 h 0.3% vs. 0.9%, p=0.018; 1 d 0.5% vs. 1.5%, p=0.007; overall 2.7% vs. 4.3%, p=0.015). In conclusion, SBP ≥110 mm Hg is associated with lower in-hospital mortality in adult patients with isolated TBIs, including patients aged 50-69 years. SBP <110 mm Hg should be used to define hypotension in adult patients of all ages.