The purpose of this study is to investigate, if the haemostasis is impaired in cardiac arrest patients during therapeutic hypothermia compared with normothermia.

Treatment with mild therapeutic hypothermia, 32-34 °C for 12-24 hours, has shown to improve the neurologic outcome in comatose survivors of out-of-hospital cardiac arrest. Hypothermia is suspected to inhibit haemostasis and therefore cardiac arrest patients with a risk of bleeding are not treated with therapeutic hypothermia. However, the impact on the coagulation system during mild therapeutic hypothermia, has not yet been fully investigated.

The investigators aim to investigate if mild therapeutic hypothermia influences haemostasis. We are including survivors of cardiac arrest, who are treated with hypothermia for 24-48 hours.

Blood will be sampled during hypothermia and secondly during normothermia. 30 minutes after the blood are sampled it will be analyzed using a sensitive low-tissue-factor assay with rotational thromboelastometry (ROTEM®). All the dynamic coagulation parameters obtained on the ROTEM® at hypothermia and normothermia, respectively, will be compared.

Inclusion Criteria:

• Treatment with therapeutic hypothermia, for minimum 24 and up to 48 hours, due to cardiac arrest.

Exclusion Criteria:

• age <18 years.

Patients treated with mild therapeutic hypothermia for 24-48 hours due to cardiac arrest.