LAUSR

Purpose: To determine the efficacy of Doppler renal resistive index in the prediction of acute kidney injury after major surgery. Methods: A systematic review and meta‐analysis of cohort studies was conducted. Medline (1966–2018), Scopus (2004–2018), Clinicaltrials.gov (2008–2018) and Google Scholar (2004–2018) databases were systematically searched. Prospective studies that examined the diagnostic accuracy of renal resistive index in postoperative acute kidney injury were included. Results: The meta‐analysis was based on 10 studies, including a total number of 911 patients. Patients who developed acute kidney injury presented higher renal resistive index values preoperatively (MD: 0.02, 95% CI: [0.00–0.03]), immediately after surgery (MD: 0.07, 95% CI: [0.04–0.11]) and 24hours postoperatively (MD: 0.07, 95% CI: [0.04–0.09]). The pooled sensitivity was 81.8%, the specificity 77.6% and the area under the curve 0.866. Fagan's nomogram indicated that the post‐test probability was increased to 60.6% (positive test) and decreased to 9.5% (negative test), when the pre‐test probability was 30%. Conclusions: Renal resistive index represents a useful marker with fair performance in the prediction of postoperative acute kidney injury. Future cohorts should establish the optimal timing of measurement and evaluate the most appropriate cut‐off value that should be used in the clinical setting. HIGHLIGHTSPrediction of postoperative acute kidney injury is essential.Renal resistive index increases in patients with acute kidney injury after surgery.The predictive efficacy of renal resistive index is promising.Future studies should define the optimal cut‐off values.