Novel heat exchanger in extracorporeal circuit: technical and biological feasibility

To evaluate a novel anticoagulation strategy in an extracorporeal circuit, we introduce a device that induces local hypothermia as blood flows through the circuit. Using a pig model, we assess its technical feasibility, biocompatibility, and safety.16 pigs were randomly assigned to either the ‘cooled’ or ‘control’ group and underwent midline laparotomy to establish extracorporeal circulation (blood flow 500 ml/min) via the caudal vena cava for up to four hours. During the experiment, blood samples were collected at four time points at the baseline and at the 15th, 60th, and 240th minute of the experiment. In the ‘cooled’ group, blood was cooled to 20°C and rewarmed to 37°C, while in the control group, blood was maintained at 37°C. A total of 6 ‘cooled’ and 4 ‘control’ pigs survived the experiment. Our findings confirm the technical feasibility of the proposed device, which effectively maintained the required temperature differentials and kept the pressure differentials in the circuit within 150 mmHg. No issues with circuit patency were observed. Additionally, no adverse effects were detected on renal, liver, cardiac, or erythrocyte function. On the contrary, our data suggests that local hypothermia in the extracorporeal circuit reduces blood coagulation and may mitigate surgery induced inflammation or stress.