This retrospective study investigated the relationship between differing thresholds of Conventional Ultrafiltration (CUF) and postoperative hemoglobin (HGB) in cardiac surgery cases involving cardiopulmonary bypass.

The study utilized EPIC and STS data for patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). It included three groups: those without CUF (n = 106), low CUF (volume <20 mL/kg; n = 33), and high CUF (volume ≥20 mL/kg); n = 18). HGB levels were assessed at the following points: Pre-operative, end-bypass, first hour in the ICU, discharge, and 30 days post-procedure. Total intravenous fluid administration at 72 hours postoperatively was also evaluated.

There was no significant difference between the three groups in HGB pre-operatively, end-bypass, or during the first hour in the ICU. At discharge, the non-CUF group had significantly higher HGB levels than the high CUF group (p = 0.028), and HGB in the low CUF group was not significantly different from the high CUF (p = 0.102) group. At 30 days, HGB in the low CUF group was significantly higher than those with high CUF (p = 0.022). Additionally, HGB levels in the non-CUF group were not significantly different than those with high CUF (0.078). Surprisingly, there was no difference in total IV fluid volume administered at 72 hours post-op (p = 0.181) between any of the groups.

Low CUF is superior to no CUF, and high CUF in the preservation of hemoglobin levels – even at 30 days. Additionally, CUF of any volume was not associated with increased IV fluid resuscitation postoperatively.