Background: Postoperative acute kidney injury (AKI) is associated with increased morbidity and mortality both in the short- and longterm, even when increases in creatinine level are small. Information on the incidence of AKI after non-cardiac surgery is scarce.
Goal of study: The aim of this study was to evaluate the incidence and risk factors for postoperative AKI after major non-cardiac surgery.
Methods: A prospective cohort study was performed in 2 tertiary hospitals during 7 randomized weeks over 6 months in 2011-12. Eligible subjects were patients undergoing intermediate-high surgery-specific risk of non-cardiac (elective or urgent) surgery, under general or regional anaesthesia. AKI was defined and stratified according to the AKI Network classification when diagnostic criteria is met: serum creatinine rises by ≥ 26μmol/L within 48 hours or serum creatinine rises ≥ 1.5 fold from the reference value. Preoperative and intraoperative risk factors for AKI were analysed. SPSS 19.0 statistical package was used to compile descriptive statistics and compare qualitative variables with a χ2 test and quantitative variables with a t test. Bivariable and multivariable analyses were performed. Relative risks and their 95 % confidence intervals were calculated.
Results: Data were based on a sample of 198 patients. AKI was developed in 18 (9.1 %) patients: 14 (7.1%) stage I, 3 (1.5%) stage II, and 1( 0.5%) stage III. Risk factors for AKI were: history of peripheral vascular disease 4.4 (1.7-11.4) and chronic kidney disease 3.0 (1.1-8.2); preoperative corticoids 5.1 (2.1-12.2), and, postoperative antibiotics 2.5 (1.1-6.2). Multivariable analysis showed -peripheral vascular disease (4.5; 1.1 -18.7) and corticoids (5.8; 1.8-21.3) were statistically significant. AKI was associated with postoperative hypotension 5.0 (1.9-12.9), tachycardia 6.7 (1.2-37), decreased urine output 2.2 (1.6-3.2), postoperative infection 3.8 (1.5-9.5), SIRS 7.5 (1.8-31), and longer ICU and hospital stay (25.4 vs 14.8 hours and 9.3 vs 14 days, respectively).
Conclusion: A history of peripheral vascular disease and preoperative corticoid use were significant risk factors for postoperative AKI. Hospital and ICU stay were higher in patients who developed AKI. Recognising early stages of renal dysfunction allows early action to prevent progression.
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