Evaluation of Renal Function After Major Renal Injury: Correlation With the American Association for the Surgery of Trauma Injury Scale

Abstract

In this study we evaluated the effect of major kidney injury on renal function. A retrospective cross-sectional analysis was conducted of all patients who sustained renal trauma between 1977 and 2008 at San Francisco General Hospital, and underwent post-injury dimercapto-succinic acid renal scan (67). Decrease in renal function was defined as the absolute percentage difference between the affected and unaffected kidney on dimercapto-succinic acid scan. Univariate (Spearman rank correlation) and multivariate (linear regression) analyses of the American Association for the Surgery of Trauma renal injury grade, patient age, mechanism of injury (blunt vs penetrating), side of injury, treatment used (nonoperative vs surgery), shock, gender, presence of gross hematuria, serum creatinine on hospital admission, postoperative complications and associated injuries were performed. Of the 67 renal injuries 23 (34%) were managed nonoperatively. There were 43 (64%) injuries due to penetrating trauma and 24 (36%) due to blunt injury. Mean decrease in renal function for grade III, IV and V injuries was 15%, 30% and 65%, respectively. Univariate analysis demonstrated a significant association between decrease in renal function and injury grade (rho 0.43, p <0.005). There was no difference in the decrease in kidney function between parenchymal and vascular causes for grade IV and V injuries. Although the right kidney demonstrated a greater decrease in function (rho 0.26, p = 0.033) on univariate analysis, multivariate analysis showed that only American Association for the Surgery of Trauma injury grade correlated with decreased function (correlation coefficient 14.3, 95% CI 4.7-24.8, p <0.005). Decrease in kidney function is directly correlated with American Association for the Surgery of Trauma renal injury grade.