Haemolysis during cardiopulmonary bypass: an in vivo comparison of standard roller pumps, nonocclusive roller pumps and centrifugal pumps

Abstract

Cardiopulmonary bypass (CPB) involves the use of either an occlusive roller pump or centrifugal pump. Damage to blood elements, including haemolysis, may arise from occlusion when using a roller pump; the appropriate degree of occlusion has not yet been determined scientifically. Centrifugal and nonocclusive roller pumps are reputed to reduce haemolysis. The objective of this study was to compare haemolysis caused by a standard roller pump with a dynamically set nonocclusive roller pump and with a centrifugal pump. We prospectively randomized 60 patients undergoing routine coronary artery surgery into three groups: standard roller pump (STD, n = 20), dynamically set roller pump (DYN, n = 20), or centrifugal pump (CEN, n = 20). The level of plasma free haemoglobin (FHb) was measured preoperatively, and the rate of formation of FHb (in mg/dl/min) was determined at the end of the ischaemic phase and at the end of CPB. Cardiotomy suction blood was isolated for the ischaemic phase and returned before the end of CPB. It was found that there were no differences between the groups in demographic or operative variables. The rate of formation of FHb at the end of the ischaemic phase was similar for all groups (STD 0.108 +/- 0.10, DYN 0.117 +/- 0.08, CEN 0.129 +/- 0.07). At the end of CPB, after return of the cardiotomy suction blood, there was a significant (< 0.001) increase in the rate of formation of FHb in all groups. The increase was similar for each of the groups (STD 0.424 +/- 0.17, DYN 0.481 +/- 0.20, CEN 0.471 +/- 0.18). We conclude that the rates of haemolysis are similar for each of the pump types, and no benefit is conferred by the use of either a dynamically set roller pump or a centrifugal pump compared with the standard roller pump. The return of the cardiotomy suction blood to the circulation is the principal source of plasma free haemoglobin.

Clinical evaluation of the Admiral 1.35m2 hollow-fibre membrane oxygenator

“…2 In agreement with both Pierangeli 9 and Hansbro 2 groups, we saw a small, but statistically insignificant, increase in the levels of circulating FHb, even though both other groups used significantly larger oxygenators. This suggests that design changes implemented to reduce the oxygenator surface area do not increase haemolysis during CPB.…”

“…The new ideal for a membrane oxygenator is to have a reduced contact surface area whilst still providing the same oxygenation and heat transference efficiency as larger oxygenators. The low surface area of the Admiral 1.35m 2 oxygenator combines a reduced membrane surface area with a low prime volume of 190ml. The accompanying hard-shell reservoir allows the separation of suction blood from the circulating volume.…”

Análise do perfil hidrodinâmico em diferentes modelos de bombas de rolete utilizadas em circulação extracorpórea

“…Various studies have shown the considerable effect of occlusion on hemolysis rates using both occlusive and nonocclusive settings [1,5]; however, comparisons between roller pumps and centrifugal pumps have shown conflicting results with respect to hemolysis [2,6]. The use of roller pumps to aspirate blood from the surgical field plays a role in hemolysis, a finding that has been observed clinically [6][7][8] [4,9].…”

“…The use of roller pumps to aspirate blood from the surgical field plays a role in hemolysis, a finding that has been observed clinically [6][7][8] [4,9]. Investigators do not always report details on the different characteristics of roller pump raceways.…”

Visualização de refluxo em aspirador de sangue e reservatório de cardiotomia usados em circulação extracorpórea

“…Comparisons between roller pumps in standard calibration, with non-occlusive adjustment, and centrifugal pumps were performed and no differences on the level of free hemoglobin in the plasma were found (HLp) [8].…”