USE OF PH-ISFET SENSORS DURING EXTRACORPOREAL-CIRCULATION

This paper presents the use of an ISFET sensor during extracoporeal circulation (ECC). Initially, the ISFET time response and stability were measured. The flow rate dependency was also determined. The sensor gave a correct response in a few milliseconds which, compared with presently available sensors, is very good. Stability provided to be as good as with Ingold pH sensors (glass electrode). The sensitivity of the sensor used for the experiment was then evaluated precisely, before installation in the ECC arterial line. An Ag/AgCl reference was used. An Ingold sensor was used simultaneously in order to provide comparative measurements. ECC was then performed on a sheep for 6 h. Flow rate stabilized at approximately 31/min and blood temperature was set and regulated to 37°C. Standard laboratory blood gas measurements were performed every 15 min for the first hour and every 30 min thereafter so as to obtain a good control. The results show that standard measurement, Ingold probe and ISFET sensor values vary in the same way and experimentation is continuing. © 1990.