Hemolysis in extracorporeal circulation: relationship between time and procedures

Abstract

Introduction: Extracorporeal circulation (EC) is very important in cardiac surgery but causes significant damage to the blood, including hemolysis.Objective: To quantify the rate of hemolysis at different times during EC in elective coronary artery bypass grafting.Methods: We measured rates of hemolysis of 22 patients at 6 different times during myocardial revascularization during EC: T0 -before the start of EC, T1 -five minutes after of the EC initiation, T2 -30 minutes of EC, T3 -immediately before the aortic unclamping, T4 -immediately before passage of the residual volume to the patient and T5 -five minutes after the passage of the residual volume to the patient. Rates of hemolysis were calculated between the intervals of time: T0-T1; T1-T2; T2-T3; T3-T4 and T4-T5.Results: The first 5 minutes after the EC showed the highest rate of hemolysis (P = 0.0003) compared to the others calculated rates, representing 29% of the total haemolysis until T4 (Immediately before passage of the residual volume to the patient).Conclusion: There were no significant changes in the rate of hemolysis during the suction in the aortic root (P > 0.38), nor with the procedure used for the passage of the residual volume of blood in the circuit to the patient.Keywords: Extracorporeal circulation. Hemolysis. Blood. ResumoIntrodução: A circulação extracorpórea (CEC) é indispensável para a maioria das operações cardíacas, mas causa danos significantes ao sangue, dentre eles a hemólise.Objetivo: Quantificar as taxas de hemólise em diferentes tempos nas operações para revascularização do miocárdio com uso de CEC. 536Rev Bras Cir Cardiovasc 2012;27(4) Resultados: Os primeiros 5 minutos após a CEC demonstraram maior taxa de hemólise (P = 0,0003) em comparação às outras taxas calculadas, representando 29% da hemólise total até T4 (imediatamente antes da passagem do volume residual para o paciente).Conclusão: Não foram observadas variações significantes nas taxas de hemólise durante a aspiração na raiz da aorta (P > 0,38) nem com o procedimento utilizado para a passagem do volume residual de sangue no circuito para os pacientes.

Hemolysis and Inflammatory Response to Extracorporeal Circulation during On-Pump CABG: Comparison between Roller and Centrifugal Pump Systems

“…The immune system responds to trauma with varying degrees of severity by releasing molecular compounds, including those of the complement system, which stimulate release of proinflammatory cytokines such as IL-1β, IL-6 and TNF-α. Hemolysis may occur through three distinct mechanisms: natural selection in the spleen; physical or chemical imbalances (generally pathological); or exposure of cells to mechanical trauma [ 3 , 20 ] . According to Kameneva et al [ 21 ] , the intensity of hemolysis depends on the flow rate of suction, on the degree of blood viscosity, on the duration of extracorporeal perfusion, and on the storage time of the packed red blood cells used in perfusate or otherwise during the CPB procedure.…”

“…As the blood passes through the CPB circuit and comes into contact with synthetic materials, it undergoes mechanical insults, trauma, and cellular changes. The changes induced by these insults, including hemolytic and inflammatory alterations, can have major clinical implications [ 2 , 3 ] . To Vieira Junior et al.…”

“…To Vieira Junior et al. [ 3 ] , hemolysis in CPB is a result of the passage of blood through the pump rollers or the contact of blood with different surfaces at varying speeds. These authors noted that the basic requirement for developing an appropriate CPB pump would be to achieve an optimal balance between shear stress and exposure time to minimize the rate of hemolysis.…”

Is there a “safe” suction pressure in the venous line of extracorporeal circulation system?

“…However, repeated reports of hemolysis, especially in younger patients, call for caution in using these pumps in neonatology and in pediatric intensive care. [6][7][8][9][10][11] Distinct to industrial pumps, which are designed to work at a single pump speed, pumps for an extracorporeal circulation are required to cover a wide range of flow rates. Furthermore, most of these pumps, especially axial and mixed-flow impeller pumps, are high-flow low-pressure pumps.…”

“…However, repeated reports of hemolysis, especially in younger patients, call for caution in using these pumps in neonatology and in pediatric intensive care. 6 – 11 …”