Comparison of Accuracy of Different Methods for Detection of Postoperative Renal Impairment in Colorectal Surgery with Restrictive Fluid Strategy

Objective: Perioperative fluid restriction in major abdominal surgeries carries a potential risk of organ dysfunction such as acute kidney injury. Profound fluid restriction should be applied cautiously. The aim of this study is to compare the accuracy of (serum creatnine, urine output and KDIGO compared to NGAL for detection of postoperative AKI after colorectal surgery.Methods: Restrictive fluid strategy was applied to all patients with 5 mL/kg/h of lactated ringer (LR) and was administered intraoperatively starting from the induction of general anesthesia till the end of surgery and patient extubation. Data collected included incidence of AKI with three screening tools in addition to intra and postoperative complications.Results: None of the above tested AKI based criteria has satisfactory both sensitivity and specificity. The sensitivity of urine output for detection of AKI was 72.7 [39.0-94.0] while its specificity was 79.8 [69.9-87.6], for creatinine above 0.3 mg/dl; the sensitivity was 63.6 [30.8-89.1] and specificity was 98.9 [93.9-99.9], and for KDIGO the sensitivity was 81.8 % [95% CI 48.2-97.7] and specificity was 74.2% [95% CI 63.8-82.9].Conclusion: Despite use CVP for detection of hypovolemia, there is still high incidence of AKI. Creatinine based criteria, urine based criteria or combination of both are inaccurate when volume restriction is applied.