BASE DEFICIT IN THE ELDERLY - A MARKER OF SEVERE INJURY AND DEATH

Background: Base deficit has been used as a marker of significant inju ry and to predict resource utilization and mortality. The significance of base deficit in trauma patients 55 years and older has not been sp ecifically evaluated. The purpose of this study was to determine the u tility of base deficit in assessing older trauma patients versus a you nger cohort. Methods: Data were obtained from the trauma registry on t rauma patients admitted to a Level I trauma center. Arterial blood gas es were obtained within 1 hour of arrival, by protocol, in 2,631 patie nts, and of these, 274 patients were 55 years or older. Data are prese nted as means +/- SEM, Statistical analysis was done by paired t test, analysis of variance, and chi(2) analysis. Significance was attribute d to ap value < 0.05, Results: Patients older than 55 years were signi ficantly more likely to have sustained blunt trauma (86 vs. 69%; p < 0 .001), Despite similar Injury Severity Scores and base deficit values, older patients had markedly greater mortality and intensive care unit lengths of stay. A base deficit of less than or equal to -6 had posit ive predictive values for Injury Severity Scores greater than or equal to 16 for 76% of patients younger than 55 years and 78% of patients 5 5 years and older. The negative predictive value of a normal base defi cit for Injury Severity Scores less than or equal to 16 was 60% for th e younger cohort and only 40% for patients 55 years and older (p < 0.0 01; chi(2)). Conclusions: A base deficit of less than or equal to -6 i s a marker of severe injury and significant mortality in all trauma pa tients, but it is particularly ominous in patients 55 years and older. Patients older than 55 years may have significant injuries and mortal ity risk without manifesting a base deficit out of the normal range.