Controlled low central venous pressure after cardiopulmonary bypass reduces acute kidney injury following cardiac surgery: a randomized controlled trial

Background Postoperative acute kidney injury (AKI) is a serious complication of cardiac surgery. This study aimed to determine whether targeting central venous pressure (CVP) readings of ≤10 mmHg using vasoactive drugs and reversing the Trendelenburg position was associated with a lower incidence of AKI than usual care in patients undergoing cardiac surgery requiring cardiopulmonary bypass (CPB). Methods We conducted a randomized controlled trial. Patients were randomized in a 1:1 ratio to receive controlled low central venous pressure (CLCVP) or usual care. Patients in the CLCVP group received nitroglycerin and were placed in the reverse Trendelenburg position from 20 min after CPB until the end of surgery. The primary outcome was incidence of 7-day postoperative AKI defined by KDIGO criteria. Results The trial included 505 subjects in the final analysis. There were fewer patients with postoperative AKI in the CLCVP group [114 (44.9%)] compared with the control group [150 (59. 8%)] [Absolute risk reduction (ARR): −14.9%; 95% confidence interval [CI]: (−23. 5%, −6. 3%); P = 0. 001]. Eight (3.1%) participants in the CLCVP group and 14 (5.6%) participants in the control group developed AKI of Stage 2 and above [ARR: −2. 4%; 95% CI: (−6. 0, 1. 1%); P = 0. 263]. This reduction was primarily driven by a lower incidence of Stage 1 AKI, whereas the incidence of Stage 2 or higher AKI did not differ significantly between groups. Median time-weighted CVP was lower in the CLCVP group (6.7 mm Hg vs. 8.1 mm Hg, P < 0. 001). Conclusion This randomized clinical trial demonstrated that cardiac surgery patients with CLCVP exhibited lower CVP and fewer postoperative kidney injuries compared to those receiving usual care. Clinical Trial Registration https://clinicaltrials.gov/study/NCT05855954 , identifier NCT05855954.