[A manually operated portable cardiopulmonary bypass circuit for emergency and its hydrokinetics]

We developed a manually operated portable cardiopulmonary bypass circuit for emergency. The priming volume of the circuit is about 300 ml, including the self-inflating reservoir-pump of 120 ml in capacity. The self-inflating reservoir-pump with two one-way valves can drain venous blood via the femoral vein without a water head, and return the blood into the femoral artery through a membrane lung. Bypass flow under various conditions was measured with an electromagnetic flowmeter. Pressure resistance of the artificial lung was also measured. When a DLP 21 Fr size catheter was used as a venous drainage catheter and DLP 17 Fr size for arterial infusion, bypass flow was 0.8-1.2l.min-1 without a water head for venous drainage, or 1.4-1.7l.min-1 with a 60 cm water head, respectively. One investigator could repeat squeezing the reservoir-pump for two hours under each condition. The bypass flow rates of the circuit depend upon the height of the water head and the internal diameters of the venous drainage catheter. The diameter of the arterial catheter affects the squeezing pressure, but it is overcome by manual force and has no influence on the flow rate. The lung had no significant resistance either to blood flow or insufflation gases.