The Cardiac Effects of Prolonged Hypothermia After Cardiac Arrest

The PhD-study contains 3 sub studies:

• Study 1 estimates the extend of myocardial damage resulting from the primary arrest and from the reperfusion injuries: Area under the curve of cTnT and CK-MB as 12 repeated measurements and NT-proBNP as 4 measurements post arrest

-Hypothesis: There is a statistically significantly greater release of the cardiac biomarkers cTnT and NT-proBNP quantified by the area under the curve in the 24 versus the 48 hours group in the intervention period from 24 to 72 hours.

• Study 2 investigates MTH´s influence on systolic and diastolic function by standard and Tissue Doppler (TDI) echocardiography after 24, 48 and 72 hours. The primary endpoint is mitral annular systolic velocity ("S´ max")

-Primary hypothesis: There is statistically significant improvement in S' max from the time T24 to T72 in the 48 versus the 24 hours group.

-Secondary hypothesis: There is statistically significantly better systolic function at T48 measured in terms of individual S' max-change in the 48 hours group (still hypothermic) versus the 24 hours group (reached normothermia).

• Study 3 investigates MTH´s influence on the need for vasopressor or inotrope and the duration of arrhythmias during the first 72 hours post arrest.

• Primary hypothesis: There is a statistically significantly increased tendency of arrhythmias in the 48 versus the 24 hours group measured in the period from T0 to T72.
• Secondary hypothesis: There is a statistically significantly reduced need for inotropes in the 48 versus the 24 hours group measured by cumulative vasopressor index in the period from T0 to T72.

Inclusion criteria

• Resuscitated after cardiac arrest outside hospital with suspected cardiac triggering cause (and stabile circulation for at least 20 minutes after return of spontaneous circulation,
• Glasgow coma score < 8 and
• Age ≥ 18 years and < 80 years.

Exclusion criteria

• Cardiac arrest of suspected non-cardiac triggering cause (e.g. trauma, aortic dissection, massive bleeding, hypoxia or accidental hypothermia),
• >60 minutes from cardiac arrest to ROSC,
• Time from cardiac arrest until start of cooling >4 hours,
• Terminal illness,
• Coagulopathy (medical anticoagulation treatment including thrombolysis is not a contraindication),
• Unwitnessed arrests with asystolia as presenting rhythm,
• Pregnancy,
• Persistent cardiogenic shock,
• Systolic blood pressure <80 mmHg despite vasoactive treatment and intra-aortic balloon pump
• CPC 3-4 before the cardiac arrest,
• Suspected/confirmed acute intra cerebral hemorrhage or stroke,
• Acute CABG or other operation in connection with performing CPR,
• Lack of consent from the relatives,
• Lack of consent from the GP and
• Lack of consent from the patient if he/she wakes up and is relevant.