The correlation of fluid balance changes during cardiopulmonary bypass to mortality in pediatric and congenital heart surgery patients

Edema acquired during the perioperative period has long been associated with increased mortality. Edema acquired during cardiopulmonary bypass (CPB) may contribute to this mortality. The intent of this retrospective study was to test the premise that edema in the form of a positive fluid balance change (FBC) acquired during CPB correlated to mortality. If so, FBC from the beginning of CPB (baseline; FBC = 0) to the end of CPB may need to be monitored, measured, and controlled on CPB with the same ardor as blood pressure and pH. This retrospective analysis reviewed the FBC of 1540 pediatric and congenital heart surgery patients at the end of CPB. Additions and subtractions of fluid to the combined patient/CPB circuit were routinely quantified during CPB procedures and during periods of modified ultrafiltration (MUF). The primary outcome assessed was mortality during hospitalization. The overall mortality of the 1540 patients was 5.65% from all causes. Eighty percent (n = 1226, mortality = 4.65%) of the patients had a zero or negative FBC immediately after CPB/MUF. Twenty percent (n = 314, mortality = 9.55%) had a positive FBC. Positive FBC patients tended to be in higher risk categories, weighed more, and had longer pump times (p < .05) with an adjusted odds ratio for mortality of 1.73 (1.01-2.96, 95% confidence interval). There is a correlation between edema acquired during CPB and increased mortality in pediatric and congenital heart surgery patients. The potential exists for the perfusionist to optimize the fluid balance changes while on CPB to reduce mortality rates.