The incidence and outcomes of acute kidney injury amongst patients admitted to a level I trauma unit

Purpose

This study aimed to identify the incidence and outcomes of patients with trauma related acute kidney injury (AKI), as defined by RIFLE criteria, at a single level I trauma centre and trauma ICU.

Methods

We performed a retrospective observational study of 666 patients admitted to a trauma ICU from a level I trauma unit from March 2008 to March 2011. We conducted multivariable logistic regression to identify independent predictors for AKI and mortality.

Results

The overall incidence of AKI was 15% (n = 102). Median injury severity score (ISS) was 25 (inter quartile range IQR] 16–34) and mean age was 39 (SD 16.3) in the AKI group. Thirteen patients (13%) were referred with rhabdomyolysis associated renal Failure. Overall mortality in the AKI group was 57% (n = 58) but was significantly lower in the rhabdomyolysis Failure group (23% versus 64%; p = 0.012). AKI was independently associated with older age, base excess (BE) < −12 (odd ratio OR] 22.9, 95% confidence interval CI] 1.89–276.16), IV contrast administration (OR 2.7 95% CI 1.39–5.11) and blunt trauma (OR 2.2 95% CI 1.04–4.71). AKI was an independent predictor of mortality (OR 8.5, 95% CI 4.51–15.95). Thirty-nine (38%) patients required renal replacement therapy.

Conclusions

AKI in critically ill trauma patients is an independent risk factor for mortality and is independently associated with increasing age and low BE. Renal replacement therapy utilisation is high in this group and represents a significant health care cost burden.