Effects of combined conventional ultrafiltration and a simplified modified ultrafiltration in adult cardiac surgery

Abstract

Today’s practice of cardiac surgery encounters an increasing number of older and/or sicker patients, who are expected to have higher morbidity and mortality. Ultrafiltration during cardiac surgery is one of the strategies to prevent major vital organ dysfunction associated with cardiopulmonary bypass (CPB) and therefore might reduce the morbidity and mortality in these patients. This study aims to evaluate the effects of combined conventional ultrafiltration (CUF) and a simplified modified ultrafiltration (S-MUF) on clinical outcome in sick adult patients undergoing cardiac surgery. In this prospective, randomized controlled study fifty adult patients with > 3 Euro SCORE who underwent open heart surgery were enrolled. In this study group (n=25), both CUF and S-MUF was performed, using a simplified circuit. The control group of patients (n=25) were treated identically to the study group except no ultrafiltration was performed. Effects of ultrafiltration on hemodynamics, hematocrit, pulmonary function, postoperative blood loss and homologous blood and blood component usage were recorded. During the immediate S-MUF period there was a significant increase in MAP (mean arterial pressure) and haematocrit (54.3 ± 11.6 to 74.3 ± 9.1 mmHg; p < 0.001) and (28.6 ± 5.4% to 36.6 ± 4%; p < 0.001 respectively) in the study group, where as no such phenomenon was observed in the control group. This fact remains true for both the groups during the post operative period. In contrary to the control group, the oxygenation parameters were improved significantly (p < 0.05), immediately after S-MUF and remained at a higher level (p < 0.05) during the postoperative period in the study. The total postoperative blood loss was significantly less in the study group than the control group (402 ± 249 ml vs 603 ± 377 ml, p < 0.05) and (1.8 ± 1.3 U/patient vs 3.1 ± 1.1 U/patient, p < 0.001 respectively). The total duration of mechanical ventilation, ICU stay, inotropic/vasodilator support and hospital stay were similar in both the groups. The use of combined CUF and S-MUF can effectively concentrate the blood, transiently improve pulmonary function and decrease postoperative blood loss as well as postoperative requirement of allogenic blood transfusion in sick adult patients. It did not have any major impact on clinical outcome.