Eligible patients who have been treated in the intensive care units of Helsinki
University Hospital are invited to participate. Controls are recruited from follow-up
clinics, and with announcements in media and websites.

The participants receive an invitation to a follow-up clinic where their experiences from
the ICU treatment and recovery will be discussed. The investigators will perform
neuropsychologic testing (6 months post-discharge), a telephone interview (3 months) and
send written questionnaires (3, 6 and 24 months) to the participants. The participants
will undergo MRI imaging of the brain and laboratory tests will be taken. The olfactory
function will be tested at a follow-up clinic. Data on the patients´ respiratory function
from clinical spirometry and diffusion capacity testing 3 and 6 months after discharge
are collected. The patients will perform a 6 min walk test.

Data on coagulation laboratory values will be registered from acute phase and 6 months
after discharge. The investigators will also analyse ApoE alleles, neurofilament light
and NAD-metabolites and study their correlation with neuropsychologic findings and long
term symptoms (up to 5 years after hospital discharge).

Participants will also undergo magnetic resonance imaging of the heart at 6-12 months
after the hospital discharge, and laboratory samples, a symptom questionnaire and
electrocardiogram are collected. Inflammatory parameters and variables associated with
regulating inflammation and coagulation will be analysed.

Clinical data from the acute and post-acute phase and demographic data are collected from
the patient data management systems.

The target patient number is 75 intensive care treated patients and 50 control persons in
each three control group.