[Electrophysiological features of xenon anesthesia]

One of the central problems of zenon anesthesia is evaluation of its adequacy. The bispectral index (BIS) is estimated empirically on the basis of electroencephalograms of patients treated with vapor-forming anesthetics. We investigated clinical and electrophysiological parallels of xenon monoanesthesia by using the EEG bispectral index. The study was carried out in 40 patients (ASA I-II) during venectomy under Xe anesthesia. Electrophysiological parameters were stable during maintenance and corresponded to the depth of anesthesia. Hence, monitoring of BIS and SEF-95 provides for an adequate control of anesthesia, while during induction and awakening the values of these indices are doubtful. The incorrectness of EEG BIS at these stages of Xe anesthesia is due to specific electrophysiological mechanisms of Xe, affecting mainly HMDA and H-cholinergic receptors of the CNS.