Predictive factors of dialytic acute kidney injury in patients admitted to the intensive care unit after nontraumatic emergency abdominal surgery

Introduction

Although postoperative risk factors for dialytic acute kidney injury (DAKI) are well described in a wide range of clinical settings, we have few data regarding nontraumatic emergency abdominal surgery. The aim of this study was to describe these factors in this subgroup of patients.

Methods

We have conducted a retrospective cohort study in order to identify independent risk factors. We reviewed data from patients admitted to the ICU after nontraumatic emergency abdominal surgery from April 2003 to October 2006. Epidemiological data, outcome and ICU resource utilization were recorded. Statistical analysis was performed by univariate analysis (Fisher's exact test, chi-square test) followed by multivariate stepwise logistic regression.

Results

There were 168 consecutive patients (86 males). The mean age was 55 ± 19 years. The mean APACHE II score was 11 ± 8. Main reasons for ICU admission according to APACHE II classification were gastrointestinal perforation/obstruction n = 100, gastrointestinal surgery due to neoplasia n = 21, vascular surgery n = 18, gastrointestinal bleeding n = 6, hemorrhagic shock n = 5, sepsis n = 5, chronic cardiovascular disease n = 4, respiratory failure n = 3, cardiovascular n = 3, metabolic disturbance n = 2 and renal surgery due to neoplasia n = 1. The mean LOS was 5 ± 13 days. The DAKI frequency was 6.5% (n = 11). By means of univariable analysis, risk factors for DAKI were male sex, creatinine level ≥ 1.5 mg/dl at admission, APACHE II score ≥ 25, use of a pulmonary artery catheter, need for mechanical ventilation ≥ 48 hours, hemoglobin level ≤ 7 g/dl, and enteral and parenteral nutritional support. In the multivariate analysis, only APACHE II score ≥ 25 (OR 14.9; 95% CI 1.9–111.6, P = 0.008), use of enteral support (OR 20.3; 95% CI 3.5–117.7, P < 0.001) and use of pulmonary artery catheter (OR 10.7; 95% CI 1.3–88.5, P = 0.028) were independent predictors of DAKI. The overall postoperative mortality rate was 10.7%; it was 54% in patients with DAKI compared with 7.6% in patients without DAKI.

Conclusion

DAKI following nontraumatic emergency abdominal surgery has a high mortality rate, and APACHE II score ≥ 25, use of enteral nutritional support and use of pulmonary artery catheter are its postoperative predictive factors.