EEG Changes During Induction of Propofol Anesthesia

PropoStatus is a prospective observational study investigating the EEG changes seen in neurologically healthy patients during induction of general anesthesia with propofol. EEG changes are investigated in different levels of anesthesia from awake state to deep anesthesia in which burst suppression pattern (BSP) is seen in the EEG. Furthermore, the relation of EEG changes and clinically evaluated depth of anesthesia is studied.

The study population is comprised of neurologically healthy individuals who come to the hospital for elective surgery requiring general anesthesia. The patients will not receive any pre-medication. They will give a written consent to participate to the study. During induction of anesthesia, the vital signs will be monitored using the standard protocol of the operating room. EEG will be recorded using a wireless measurement device. The EEG is observed during the recording from a laptop or tablet computer. The anesthesia is induced using propofol with a fixed infusion rate of 30 mg/kg/h. The patient is asked to squeeze the anesthetist's hand repeatedly every 10 s. The moment at which the patients does not respond to the command anymore is considered as the loss of consciousness. The infusion is continued until BSP is observed in the EEG. The infusion is then continued for 3 min after which the recording of EEG is stopped. The administration of anesthesia is then continued as required by the operation.

The EEG recording will be carried out using two different devices. The first dataset, including 20 patients, will be collected using Bittium BrainStatus EEG electrode and device. The second dataset, including 30 patients, will be collected using Nihon Kohden CerebAir device.

Inclusion criteria

• ASA 1-2 (no neurological or cardiovascular diseases)

Exclusion criteria

• BMI > 30