Abstract
Continuous measurement of blood pressure is one of the most urgent problems to be solved in the effort to develop precise hemodialysis treatment. A new approach has been developed, based on analysis with an electric equivalent circuit of the patient's cardio-vascular system, and is presented here. The result of this analysis revealed a simple but useful relation between blood pressures measured at the dialysis circuit and those in the brachial artery. To put this observation to clinical use, a new dialysis circuit was designed so that the inlet of the circuit has an air-trap as well as an outlet side. The inlet air-trap should be rigid enough to withstand negative pressure due to suctioning of blood by the pump. The pressures at the two air-traps were measured and the mean brachial pressure was calculated for on-line display. The results of clinical tests were acceptable and had the advantage of being non-invasive.
