Epileptiform EEG Patterns During Induction of General Anaesthesia With Sevoflurane Compared to Those With Propofol (EEG)
General Anaesthesia, Depth of Anaesthesia, Intraoperative Awareness
About this trial
This is an interventional diagnostic trial for General Anaesthesia focused on measuring Epileptiform patterns, sevoflurane, propofol, bispectral index, state entropy, response entropy, A-line Auto Regressive Index, middle latency auditory evoked potentials
Eligibility Criteria
Inclusion Criteria:
- an American Society of Anaesthesiologists (ASA) score I-II
- written informed consent to undergo general anaesthesia
Exclusion Criteria:
- history of epilepsy, medical treatment that might interfere with the EEG (e.g., tranquilizers, antiepileptic drugs), pregnancy, drug or alcohol abuse, history of neurological disease or a neurosurgical operation that would impair EEG or BIS monitoring, history of pulmonary disease, or the presence of signs predicting difficult mask ventilation or intubation. any pre-existing epileptic EEG patterns in standard 30-minute initial EEG recordings performed in all the patients participating in the study.
Sites / Locations
- Medical University of Silesia
Arms of the Study
Arm 1
Arm 2
Arm 3
Experimental
Experimental
Experimental
sevoflurane - increasing concentrations
sevoflurane - vital capacity
propofol - intravenous induction
The patient was breathing spontaneously via the face mask and the sevoflurane concentration in the inhaled gas was doubled every 10 breaths starting from 0.3 vol. % in a sequence 0.3-0.6-1.2-2.4-4.8-8 vol. % until a minimal alveolar concentration (MAC) of 2 was obtained in the exhalation gas. Electroencephalography (EEG), bispectral index (BIS), response and state entropy (RE and SE), middle latency auditory evoked potentials (MLAEP) were monitored.
The anaesthetic circuit was prefilled with 8% sevoflurane. The patients were asked to exhale to the residual volume. Then the patients were explained to perform a vital-capacity breath with a face mask applied tightly to their faces. Then the patients were encouraged to hold their breaths as long as possible. Thereafter, the patients were asked to breathe spontaneously. Electroencephalography (EEG), bispectral index (BIS), response and state entropy (RE and SE), middle latency auditory evoked potentials (MLAEP) were monitored.
the patients were preoxygenated with 100% oxygen following which propofol was intravenously administered at a single dose of 2.5 mg/kg of body weight, after which it was infused with an infusion speed of 4 mg/kg body weight/h. Electroencephalography (EEG), bispectral index (BIS), response and state entropy (RE and SE), middle latency auditory evoked potentials (MLAEP) were monitored.