Early WAKE-up Predictors After Out-of-Hospital Cardiac Arrest

Measurements will be performed on comatose participants at 0-6 hours, 20-28, 44-52 and 66-72 hours after enrolment for both pupils and include: Neurological pupil index, pupillary size, pupillary minimum diameter, pupillary constriction amplitude, pupillary constriction velocity, pupillary maximum constriction velocity, pupillary latency and pupillary dilation velocity.

Measurements will be performed on comatose participants at 0-6 hours, 20-28, 44-52 and 66-72 hours after enrolment on both middle cerebral arteries and include the following: Peak systolic velocity, end diastolic velocity, mean velocity, pulsatility index and resistance index.

Measurements will be performed on comatose participants at 0-6 hours, 20-28, 44-52 and 66-72 hours after enrolment on both eyes using ultrasound and include the following: optic nerve sheath diameter of right and left side and mean optic nerve sheath diameter.

"Continuous 4-channel EEG will be established on participants as soon as possible within 0-6 hours. EEG will be stopped at successful extubation or when 72 hours has passed since study inclusion.~EEG Reactivity will be performed on comatose participants at the following times: 0-6, 20-28, 44-52 and 66-72 hours after study inclusion. Reactivity includes 7 standardized stimuli, including 1 visual, 3 auditive and 3 pain stimuli.~EEG data will be reviewed in Stratus EEG Analysis (Kvikna Mediacal ehf. version 5.1). Timestamps for EEG-reactivity will be manually inserted in the file. EEG Reactivity will be analysed quantitatively by power spectrum analyses performed in LabVIEW 2016 (National Instruments) according to the principles of a previous method (PMID: 36041343). Background activity within 5 minutes following reactivity stimuli, prioritizing time periods without artifacts, will be analysed by power spectrum analyses, Mindray quantitative analysis and manually analyzed by experts."