Effect of Modified Ultrafiltration on the Postoperative State after Pediatric Open Heart Surgery

Bang, Jong Kyung; Chun, Jong Rok; Kim, Kyou Tae

Abstract

Cardiopulmonary bypass (CPB) in children is associated with the accumulation of body water after cardiac operation, as a consequence of an inflammatory capillary leak. Following work by Elliott in 1991, modified ultrafiltration (MUF) was introduced after bypass as a means of hemoconcentrating patients and a potential way of removing water from the tissues. We have carried out a prospective randomized study of 20 children undergoing open heart surgery, comparing MUF with nonfiltered controls. MUF was carried out for a mean of 18.9 minutes after completion of CPB to a hematocrit of 37.1% (mean). The mean water volulme removed by the ultrafiltration was 38.4 ml/kg and the mean blood volume retransfused from the oxygenator during the ultrafiltration was 32.1 ml/kg. Fluid balance, hemodynamics, hematocrit, osmolarity and dosage of drug treatment were recorded for 4~12 hours postoperatively. The results were analyzed using Student t-test and ANOVA, comparing controls (n=10) to MUF (n=10). Blood loss (ml/kg/24hr) was 14.5 (mean) in MUF versus 13.7 in controls; blood transfused (ml/kg/24hr) 6.6 in MUF versus 15.2 in controls; plasma transfused (ml/kg/24hr) 65.7 in MUF versus 59.6 in controls. There was rise in arterial blood pressure and hematocrit during MUF. Percent rise of systolic blood pressure was 28.8% in MUF versus 18.7% in controls (p=0.366); percent rise of diastolic blood pressure was 28.8% in MUF versus 8.5% in controls (p=0.135); and percent rise of mean blood pressure was 36.2% in MUF versus 8.2% in controls (p=0.086). Percent rise of hematocrit was 40.0% in MUF versus 23.5% in controls (p=0.002). There was no significant difference in the inotropic requirement and the postoperative serum osmolarity between two groups. The number of days on the ventilator, the duration of stay in the intensive care unit, and the postoperative hospital stay were not significantly different between the two groups.