CONTINUOUS ONLINE OPTICAL ABSORBENCY RECORDING OF BLOOD-VOLUME CHANGES DURING HEMODIALYSIS

Conventional techniques that measure blood volume changes during hemod ialysis are invasive, hard to reproduce, and provide only intermittent evaluations. To overcome these drawbacks, we have developed an optoel ectronic instrument that estimates intradialytic blood volume percenta ge changes by the optical absorbance of blood. This device is based on the absorption of light transmitted through blood, which is directly related to the hemoglobin concentration. A personal computer interface d to the device provides a continuous on-line graphic display of the h emoglobin levels and the percentage changes in blood volume. The nonin vasive measurement of dialysis blood volume changes by an optical meth od may be helpful in detecting the appearance of severe hypovolemia th at can be dangerous in critically ill patients.