Abstract
PURPOSE: To assess the effects of conventional ultrafiltration and conventional plus zero-balanced ultrafiltration on delirium and cognition in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). METHODS: A total of 116 adults who were scheduled for cardiac surgery with CPB were randomly assigned to the conventional ultrafiltration group or the conventional plus zero-balanced ultrafiltration group. CPB was managed with standard protocols. In the conventional ultrafiltration group, ultrafiltration began during the rewarming phase and was performed until the CPB was terminated. In another group, perfusionists conducted zero-balance ultrafiltration after aortic cross-clamping and began conventional ultrafiltration during the rewarming phase. The primary outcome was the incidence of postoperative delirium (POD) within 7 days; the secondary outcome was postoperative cognitive dysfunction (POCD) at 1 and 3 months. In addition, the patients' vital signs and postoperative complications at different points during the operation were also recorded. RESULTS: During the first 7 postoperative days, POD was observed in 12 patients in the zero-balance ultrafiltration group and 27 patients in the conventional ultrafiltration group (12/53 [22.64%] vs 27/53 [50.94%]; RR 0.45, 95% CI 0.25 to 0.78; P = 0.005). At 1 month after surgery, POCD occurred in 12 patients in the zero-balance ultrafiltration group versus 18 patients in the conventional ultrafiltration group (12/53 [22.64%] vs 18/53 [33.96%]; RR = 0.67; 95% CI 0.36-1.24; P = 0.281). By 3 months postoperatively, postoperative cognitive dysfunction occurred in 4 patients in the zero-balance ultrafiltration group and 7 patients in the conventional ultrafiltration group (4/53 [7.55%] vs 7/53 [13.21%]; RR = 0.57; 95% CI 0.18-1.84; P = 0.524). CONCLUSION: In patients who underwent cardiac surgery with CPB, zero-balance ultrafiltration significantly reduced the incidence of delirium compared with conventional ultrafiltration alone within the first 7 postoperative days. In contrast, the incidence of cognitive dysfunction did not differ significantly between the two groups at 1 or 3 months postoperatively.