Modified ultrafiltration and postoperative course in patients undergoing repair of tetralogy of fallot.

Background: Expected benefits of modified ultrafiltration (MUF) include increased hematocrit, reduction of total body water and inflammatory mediators, improved left ventricular systolic function, and improved systolic blood pressure and cardiac index (CI) following cardiopulmonary bypass (CPB). This prospective randomized trial tested this hypothesis.

Methods: Seventy-nine patients undergoing intracardiac repair of tetralogy of fallot were randomized to conventional ultrafiltration (CUF) + MUF (n = 39) or only CUF group (n = 40). The primary outcome was a change in hematocrit. Secondary outcomes were changes in peak airway pressures, ventilatory support, blood transfusions, time to peripheral rewarming, mean arterial pressure, central venous pressure, inotrope score (IS), and CI. Serum inflammatory markers were measured.

Results: Baseline hematocrit was 50.6 ± 10.02 in the only CUF group whereas it was 43.9 ± 5.55 in the CUF + MUF group (p = .36). Following MUF, the CUF + MUF group had higher hematocrit (44.7 ± 0.50 g/dl) compared to the only CUF group (37.2 ± 0.49 g/dl), p ≤ .001 after adjusting for baseline hematocrit. Central venous pressure (mmHg) immediately following sternal closure was 9.27 ± 3.12 mmHg in the CUF + MUF group and 10.52 ± 2.2 mmHg in the only CUF group (p = .04). In the intensive care unit (ICU), they were 11.52 ± 2.20 mmHg in the only CUF group and 10.84 ± 2.78 mmHg in the CUF + MUF group (p = .02). Time to peripheral rewarming was 6.30 ± 3.91 h in the CUF + MUF group and 13.67 ± 3.91 h in the only CUF group (p = .06). Peak airway pressures in ICU were 17 ± 2 mmHg versus 20.55 ± 2.97 mmHg in CUF + MUF group & only CUF group, respectively, p < .001). Duration of mechanical ventilation was 6.3 ± 2.7 h in CUF + MUF group compared to 14.7 ± 3.5 h in the only CUF group (p = .002). IS was 11.52 ± 2.20 in the only CUF group compared to 10.84 ± 2.78 in CUF + MUFs group. Eight of 39 (20.5%) patients in the CUF + MUF group had IS > 10 compared to 22 of 40 (55%) patients in the only CUF group (p = .02). Serum Troponin-T and interleukin-6 levels were lower in the CUF + MUF group; TNF-α and CPK-MB were similar. ICU and hospital stay were similar.

Conclusion: Patients undergoing a combination of CUF and MUF had higher postoperative hematocrit, decreased duration of mechanical ventilation, lower need for inotropes and lower interleukin-6 and Troponin-T levels. This group had better postoperative outcomes. This study was registered with the Clinical trials registry of India (CTRI/2017/11/010512) before commencement.