Brain local PH monitoring with an ISFET catheter

Summary form only given. This paper presents a novel catheter for brain pH monitoring. The catheter consists of a tiny silicone rubber tube and includes several ion sensitive field effect transistors. Similar catheters without the sensors are regularly introduced during neurosurgery through a hole in the skull, and are placed subdurally or inside the cerebral ventricles. With the addition of the sensors, the catheter provides brain local information on pH at the cerebro-spinal fluid without modifying the therapeutic process in use today. The main objective is the diagnosis of secondary brain local ischemia. It is expected that the information provided by the catheter will help to save life and extend the life expectancy of patients undergoing neurosurgery. Preliminary clinical tests are presented.