Brain viability and function analyzer: multiparametric real-time monitoring in neurosurgical patients.

We have developed the Brain Viability (BVA) and Brain Function (BFA) Analyzers for monitoring the following parameters from the human cerebral cortex cerebral blood flow: (CBF), NADH redox state, Electro corticography (ECoG), brain temperature, extracellular K+, DC potential and intracranial pressure (ICP). The BVA monitors the first 4 parameters only. The Brain viability probe (BVP) and Brain function multiprobe (BFM) were used during 11 operations and in 18 ICU patients, respectively. Preliminary results from the OR showed that 5 patients exhibited a typical increase in CBF in response to changes in end-tidal CO2 without a significant change in the NADH redox state. In 4 other patients no changes in CBF and NADH were observed. Two patients exhibited a "steeling response", i.e., a decrease in CBF and an increase in NADH. In 18 comatose patients monitored in the ICU, the ICP, CBF and ECoG were measured correctly in most patients, whereas NADH and K+ were more problematic. One patient exhibited a typical response, may be due to repeated cortical spreading depression cycles and an ischemic depolarization event. Continuous realtime multiparametric monitoring in neurosurgical patients is feasible and practical in the OR and the ICU. The information provided could be used as a diagnostic tool to guide the procedures or treatment given to the patients.