engleski

Quasi-Periodic Electroencephalogram during Continuous Infusion of Thiopental

Continuous infusion of thiopental is used for the treatment of status epilepticus. It is also used for induction of general anesthesia. The specific well-known biphasic changes of electroencephalogram during infusion of thiopental have been described by visual analysis of signal. Mathematical analysis of the electroencephalogram can detect quasi-periodic and chaotic oscillations. These patterns of elecroencephalogram can predict seizures in epileptic patient. They can also indicate an epileptoform activity during induction of anesthesia.The occurrence of quasi-periodic electroencephalogram during induction of general anesthesia with continuous infusion of thiopental has not been reported. The aim of this study was to investigate the occurrence of quasi-periodic electroencephalogram in non-epileptic patients during induction of general anesthesia with continuous infusion of thiopental. Twenty-five ASA I (American Society of Anesthesiologists perioperative risk classification) patients operates on for herniated lumbar disk received continuous infusion of thiopental (5 g/h) for induction of general anesthesia. After the appearance of the "burst-suppression" electroencephalogram the infusion was stopped. Four channels were used for electroencephalogram recording: Cz-T6, Cz-T5, Cz-C4, Cz-C3, Fz ground. The sampling rate was 200 Hz. The storage and analysis of the electroencephalogram were made3 by in-home made software. The mathematical analysis included autocorrelation function, spectral analysis, phase space construction with lage in time, correlation dimension, maximal Lyapunov exponent and reccurence plot. Epoch of 2560 point were analysed. Quasi-periodic electroencephalogram was observed in five of 25 patients. The authors conclude that during the general anesthesia with continuous infusion of thiopental quasi-periodic electroencephalogram could be detected.

eeg; nelinear dinamiks; anesthesia

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