Abstract
A method for detecting thrombus formation on the artificial surfaces of the indwelling catheters was developed and its clinical feasibility was confirmed experimentally in the dogs.
The proposed method is based on the principle that the change in thermal conductivity of the blood due to thrombus formation can be detected thermometrically. A commercial peripheral blood flowmeter probe comprising of two sets of thermocouples, one for heating and another for detecting local temperature, was placed in the lumen of a catheter, which then was implanted in the vena cava of a dog. As the thrombus forms on the surface of implanted catheter, the heat transfer resistance of the thrombus layer increases and the temperature inside the catheter increases. The change of temperature was correlated to the thickness of the thrombus layer.
Antithrombogenicity of the indwelling catheters currently used as well as those of new materials and the effectiveness of anticoagulant (cytidine diphosphate choline) were tested by the above method. A continuous and long-term observation of thrombus formation in vivo up to serveral weeks was made possible by our method without sacrificing animals.
