Hematocrite and Vascular Access Blood Flow Monitoring

Abstract

It is known that an increase or decrease of fluid in the blood may cause a defect in some of the body function. Hematocrite is and indicator of the fluid. The measurement of access blood flow rate helps nursing staff in the dialysis unit to adjust the speed of the peristaltic pump and recirculation ratio which helps to predict the incidence of thrombosis and stenosis at this access.

This project aims to design and implement a system for measuring the Hematocrite (HCT) percentage in the blood using the optical method. The idea is to use two LEDs with different wavelengths, one transmits visible beam and the other transmits infrared beam. Then, the system calculates the value of light transmittance for each wavelength. Comparing the light transmittance between the wavelengths, it is possible to obtain an estimate of the HCT percentage. This can be used to calculate the blood plasma volume. Further, the system is capable of measuring vascular access blood flow rate and recirculation ratio in patient access. This is achieved by using a technology and based on the temperature difference between the blood in the artery and the blood in the vein.