Carbon Dioxide, Oxygen and Mean Arterial Pressure After Cardiac Arrest and Resuscitation

Carbon Dioxide, Oxygen and Mean Arterial Pressure After Cardiac Arrest and Resuscitation - Targeting High vs. Low Normal Values

The COMACARE trial is a pilot multicenter randomized trial to assess the feasibility and effect on brain injury markers of targeting low or high normal arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2) and mean arterial pressure (MAP) in comatose, mechanically ventilated patients after out-of-hospital cardiac arrest. Using factorial design, participants are randomized at admission to intensive care unit to one of eight groups targeting either low or high normal values of PaO2, PaCO2 and MAP for 36 h. In this way, investigators will be assessing the feasibility and effect of all three variables at the same time.

The primary outcome is serum concentration of neuron-specific enolase (NSE) at 48 h after cardiac arrest. Feasibility outcome is between-group separation in PaO2, PaCO2 and MAP levels. Secondary outcomes include continuous monitoring of cerebral oxygenation, EEG and ECG for 48 h, the levels of NSE, S100B and cardiac troponin at randomization and 24, 48 and 72 h after cardiac arrest and neurological assessment at 6 months after cardiac arrest.

Inclusion Criteria:

• Witnessed out-of-hospital cardiac arrest with ventricular fibrillation (VF) or ventricular tachycardia (VT) as the initial rhythm
• Delay of return of spontaneous circulation (ROSC) 10-45 min from the start of the arrest
• Confirmed or suspected cardiac origin
• Mechanical ventilation
• Markedly impaired level of consciousness (no response to verbal commands and Glasgow coma scale [GCS] motor score < 5)
• Deferred consent possible or likely
• Active intensive care initiated, including targeted temperature management (33-36 C)

Exclusion Criteria:

• Probable withdrawal of active ICU care due to terminal illness or poor prognosis because of severely reduced functional status before cardiac arrest
• Confirmed or suspected intracranial pathology and/or suspicion of raised intracranial pressure
• Pregnancy
• Severe oxygenation problem (PaO2 / FiO2 < 100 mmHg)
• Severe COPD