Predictors of Outcome for Blunt High Grade Renal Injury Treated With Conservative Intent

Purpose: Management for blunt high grade renal injury is controversial with most disagreement concerning indications for exploration. At our institution all patients are considered candidates for conservative treatment regardless of injury grade or computerized tomography appearance with clinical status the sole determinant for intervention. We define clinical factors predicting the need for emergency intervention as well the development of complications. Materials and Methods: We analyzed the records of 117 patients with high grade renal injury (III to V) secondary to blunt trauma who presented to our institution in an 8-year period. Patients were categorized by the need for emergency intervention and, in those treated conservatively, by complications. We generated logistic regression models to identify significant clinical predictors of each outcome. Results: Grade III to V injury occurred in 48 (41.1%), 42 (35.9%) and 27 patients (23%), respectively. Of the 117 patients 20 (17.1%) required emergency intervention. On multivariate analysis only grade V injury (RR 4.4, 95% CI 1.9-10.5, p = 0.001) and the need for platelet transfusion (RR 8.9, 95% CI 2.1-32.1, p <0.001) significantly predicted the need for intervention. A total of 90 patients (82.9%) who did not require emergency intervention underwent a trial of conservative treatment, of whom 9 (9.3%) experienced complications requiring procedural intervention. On multivariate analysis only patient age (RR 1.06, 95% CI 1.02-1.1, p = 0.004) and hypotension (RR 12, 95% CI 1.9-76.7, p = 0.009) were significant predictors. Conclusions: High grade injury can be successfully managed conservatively. However, grade V injury and the need for platelet transfusion predict the need for emergency intervention while older patient age and hypotension predict complications.