Pediatric cardiac surgery with cardiopulmonary bypass (CPB) is associated with systemic inflammation. This trial aimed to determine whether continuous high-exchange ultrafiltration during CPB has a clinical immunomodulatory effect.

This single-center, double-blind trial enrolled pediatric patients weighing <15 kg undergoing cardiac surgery who were randomly allocated to continuous high-exchange subzero-balance ultrafiltration (H-SBUF; 60 mL/kg per hour effluent extraction) or continuous low-exchange subzero-balance ultrafiltration (L-SBUF; 6 mL/kg per hour effluent extraction) administered during CPB. The primary outcome was peak postoperative vasoactive-ventilation-renal (VVR) score. Secondary outcomes included acute kidney injury, low cardiac output syndrome, health care utilization, and inflammatory mediator fold change throughout CPB (NCT04920643).

A total of 104 patients were randomly allocated to H-SBUF (n = 52) or L-SBUF (n = 52). The primary outcome was similar between groups as the peak VVR score was 26.9 (2.1-77.9) in the H-SBUF group and 27.8 (0.8-76.7) in the L-SBUF group (P = .67). There were no operative deaths and no significant differences in acute kidney injury, low cardiac output syndrome, ventilation time, inotropic agent use time, intensive care unit stay, or hospital length of stay (P > .05). The H-SBUF group had a higher fold change for interleukin-1α, P-selectin, and vascular cell adhesion molecule 1 (P < .05), whereas 36 other mediators were not significantly different between groups (P > .05).

In pediatric patients undergoing cardiac surgery with CPB, continuous high-exchange SBUF did not reduce peak VVR score compared with low-exchange SBUF. Furthermore, there were no differences in secondary clinical outcomes, and the immunologic profile was largely similar between groups.