Impact of systemic inflammatory response syndrome and surgical Apgar score on post-operative acute kidney injury

Abstract

Background: Surgical Apgar Score (SAS) is relatively weakly associated with post-operative outcomes in emergency surgery, compared with elective surgery. A combination of systemic inflammatory response syndrome (SIRS) and SAS may be useful for prediction of poor outcomes after emergency surgery.

Methods: A retrospective study was conducted in patients who underwent emergency abdominal or cerebral surgery from January 2005 to December 2010. AKI was diagnosed using Acute Kidney Injury Network criteria for 2 days after surgery. Pre-operative SIRS was defined as SIRS score ≥ 2. Patients were divided into those with SAS ≥ 5 and < 5. Independent risk factors for post-operative AKI were identified. Ability to predict post-operative AKI was determined using receiver operating characteristic (ROC) curve analysis.

Results: Of 742 patients, 175 (24%) had post-operative AKI. Pre-operative SIRS (OR 1.9, 95% CI: 1.2-2.9, P < 0.01) and SAS < 5 (OR 2.6, 95% CI: 1.7-4.1, P < 0.01) were independent risk factors for post-operative AKI. Patients without SIRS and SAS < 5 had an increased risk of post-operative AKI (odds ratio (OR) 3.6, 95% confidence interval (CI) 1.9-6.7, P < 0.01) and those with SIRS and SAS < 5 had increased risks of post-operative AKI (OR 5.9, 95% CI: 3.7-9.3, P < 0.01) and hospital mortality (OR 3.5, 95% CI: 1.9-6.3, P < 0.01). In ROC analysis, the c-statistic using both SIRS and SAS < 5 was 0.81 (95% CI: 0.77-0.84, P < 0.01) and higher than without use of these factors (P < 0.01).

Conclusion: Pre-operative SIRS and SAS are independently associated with post-operative AKI. Simultaneous use of pre-operative SIRS and SAS may improve prediction of poor post-operative outcomes.