Effect of xenon on central nervous system electrical activity during sevoflurane anaesthesia in cats: comparison with nitrous oxide

• Published in: British journal of anaesthesia : BJA Vol. 80; no. 5; pp. 628 - 633
• Main Authors: Utsumi, J, Adachi, T, Kurata, J, Miyazaki, Y, Shibata, M, Murakawa, M, Arai, T, Mori, K
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.1998; Oxford University Press; Oxford Publishing Limited (England)
• Subjects: Anesthetics, Combined - pharmacology; Anesthetics, Inhalation - pharmacology; Anesthetics. Neuromuscular blocking agents; Animals; Biological and medical sciences; Brain - drug effects; Brain - physiology; Cats; Electroencephalography - drug effects; Evoked Potentials, Somatosensory - drug effects; Female; Male; Medical sciences; Methyl Ethers - pharmacology; Neuropharmacology; Nitrous Oxide - pharmacology; Pharmacology. Drug treatments; Reticular Formation - drug effects; Reticular Formation - physiology; Sevoflurane; Xenon - pharmacology; Volatile compound; Fissipedia; Carnivora; Central nervous system; Xenon; General anesthesia; Electroencephalography; Sevoflurane; Electrodiagnosis; Gases; Vertebrata; Mammalia; General anesthetic; Animal; Cat; Fluorine Organic compounds; Nitrogen protoxide; Somatosensory evoked potential; Comparative study; Monitoring
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/80.5.628

We have compared the effects of xenon and nitrous oxide on central nervous system (CNS) electrical activity during sevoflurane anaesthesia in cats by recording the electroencephalogram (EEG), multi-unit activity of the midbrain reticular formation (R-MUA) and somatosensory evoked potentials (SEP). Basal anaesthesia with 2% and 5% sevoflurane was used. With 2% sevoflurane, 70% xenon initially produced rhythmic slow waves which were followed by bursts of high-amplitude sharp waves interrupted by low amplitude slow waves on the EEG. Xenon induced an initial increase, followed by a decrease in R-MUA. Nitrous oxide 70% decreased the amplitude of the EEG activity which was associated with an increase in R-MUA. Xenon suppressed the amplitude of both the initial positive and negative deflections of the SEP to a greater extent than nitrous oxide. With 5% sevoflurane anaesthesia, both anaesthetics increased the frequency of spikes on the EEG and facilitated R-MUA. These findings indicate that xenon has a stimulatory action on CNS background activity and a suppressive action on CNS reactive capability which is more potent than that of nitrous oxide.