Systolic blood pressure criteria in the National Trauma Triage Protocol for geriatric trauma: 110 is the new 90.

BACKGROUND: Undertriage is a concern in geriatric patients. The National Trauma Triage Protocol (NTTP) recognized that systolic blood pressure (SBP) less than 110 mm Hg may represent shock in those older than 65 years. The objective was to evaluate the impact of substituting an SBP of less than 110 mm Hg for the current SBP of less than 90 mm Hg criterion within the NTTP on triage performance and mortality.

METHODS: Subjects undergoing scene transport in the National Trauma Data Bank (2010-2012) were included. The outcome of trauma center need was defined as Injury Severity Score (ISS) greater than 15, intensive care unit admission, urgent operation, or emergency department death. Geriatric (age > 65 years) and adult (age, 16-65 years) cohorts were compared. Triage characteristics and area under the curve (AUC) were compared between SBP of less than 110 mm Hg and SBP of less than 90 mm Hg. Hierarchical logistic regression was used to determine whether geriatric patients newly triaged positive under this change (SBP, 90-109 mm Hg) have a risk of mortality similar to those triaged positive with SBP of less than 90 mm Hg.

RESULTS: There were 1,555,944 subjects included. SBP of less than 110 mm Hg had higher sensitivity but lower specificity in geriatric (13% vs. 5%, 93% vs. 99%) and adult (23% vs. 10%, 90% vs. 98%) cohorts. AUC was higher for SBP of less than 110 mm Hg individually in both geriatric and adult (p < 0.01) cohorts. Within the NTTP, the AUC was similar for SBP of less than 110 mm Hg and SBP of less than 90 mm Hg in geriatric subjects but was higher for SBP of less than 90 mm Hg in adult subjects (p < 0.01). Substituting SBP of less than 110 mm Hg resulted in an undertriage reduction of 4.4% with overtriage increase of 4.3% in the geriatric cohort. Geriatric subjects with SBP of 90 mm Hg to 109 mm Hg had an odds of mortality similar to those of geriatric patients with SBP of less than 90 mm Hg (adjusted odds ratio, 1.03; 95% confidence interval, 0.88-1.20; p = 0.71).

CONCLUSION: SBP of less than 110 mm Hg increases sensitivity. SBP of less than 110 mm Hg has discrimination as good as that of SBP of less than 90 mm Hg, with superior improvements in undertriage relative to overtriage in geriatric patients. Geriatric patients newly triaged to be positive under this change have a risk of mortality similar to those under the current SBP criterion. This change in SBP criteria may be merited in geriatric patients, warranting further study to consider elevation to a Step 1 criterion in the NTTP.

LEVEL OF EVIDENCE: Diagnostic study, level IV.