A low trauma cardiotomy suction system for use in open-heart surgery

Cardiopulmonary bypass (CPB) has become a safe and effective technique to maintain life support during open-heart operation. However, the cardiotomy suction catheter currently used in surgery is traumatic to the formed element of the blood. This is mainly attributed to high shear forces at the suction catheter inlet created by the simultaneous aspiration of blood and air. We have developed a suction control device completely to eliminate air aspiration. A technique to detect the blood level has been investigated based on the discrimination of different optical properties between blood and air. A special catheter with an optical sensor and coated with biocompatible membrane has been developed. This technique has been successfully used to control the rotation speed and switch on and off of the pump. The in vitro tests show that the newly designed suction system has greatly reduced the damage to blood cells and makes the blood flow less turbulent