Blood warming, pump heating and haemolysis in low-flow extracorporeal life support; An in vitro study using freshly donated human blood

Low-flow extracorporeal life support can be used for cardiopulmonary support of paediatric and neonatal patients and is also emerging as a therapy for patients suffering from exacerbation of chronic obstructive pulmonary disease. However, pump heating and haemolysis have proven to negatively affect the system and outcome. This in vitro study aimed at gaining insight into blood warming, pump heating and haemolysis related to the performance of a new low-flow centrifugal pump. Pump performance in the 400-1,500 ml/min flow range was modulated using small-sized dual-lumen catheters and freshly donated human blood. Measurements included plasma free haemoglobin, blood temperature, pump speed, pump pressure, blood flow and thermographic imaging. Blood warming (T_max=0.5°C) had no relationship with pump performance or haemolysis (R²_max=0.05). Pump performance-related parameters revealed no relevant relationships with haemolysis (R²_max=0.36). Thermography showed no relevant heat zones in the pump (T_max=36°C). Concerning blood warming, pump heating and haemolysis, we deem the centrifugal pump applicable for low-flow extracorporeal circulation.