Spectral analysis of the EEG during halothane anaesthesia: Input-output relations
article
1. 1. The "Halothane-brain compartment" system was investigated in dogs. The input was the inspired concentration of Halothane. The output was the intensity of EEG spectral components. The EEG was analysed by a hybrid system (analogue filters and digital integration in a small computer). For the anaesthesia only a mixture of Halothane and oxygen was used. Temperature, CO2 and pH were kept constant. 2. 2. Input-output relations were determined by recording responses to step and sinusoidal changes of concentration. The most sensitive output parameters were the intensities of the 2-6 c/sec and 14-20 c/sec components. 3. 3. The rise and decay times of the responses to positive and negative steps were in the range 120-400 sec and 100-400 sec (5 dogs), respectively. 4. 4. The sinusoidal average responses showed some distortion, particularly at low frequencies of modulation (T = 11 min), indicating the existence of non-linearities. Evidence for the phenomena of adaptation and saturation was also found. Attenuation of response amplitude and increase in phase shift were found as frequency of modulation was increased, as in a low pass filter. With the data available it was not possible to determine the order of the linear approximation to the system with sufficient accuracy. 5. 5. A dose-response linear relation within the range of Halothane in inspired air between 1.0 and 2.5% was obtained for one dog. 6. 6. It is proposed that the quantitative data obtained in this study provide a basis for constructing a reliable monitoring system of Halothane anaesthesia. © 1972.
Chemicals/CAS: halothane, 151-67-7, 66524-48-9; Halothane, 151-67-7
Chemicals/CAS: halothane, 151-67-7, 66524-48-9; Halothane, 151-67-7
Topics
TNO Identifier
227345
ISSN
00134694
Source
Electroencephalography and Clinical Neurophysiology, 33(3), pp. 311-319.
Pages
311-319
Files
To receive the publication files, please send an e-mail request to TNO Repository.