The Impact of Non-pulsatile Blood Flow on CO2-Reactivity

The Impact of Non-pulsatile Perfusion on Cerebral Blood Flow and Brain Oxygenation

The investigators hypothezised that CO2-reactivity of cerebral vessels is affected by systemic non-pulsatile blood flow. Patients undergoing elective cardiac surgery with CPB were enrolled in this prospective case control study. Blood flow velocity in the middle cerebral artery as well as regional cerebral oxygenation was determined during step changes of PaCO2 between 30, 40, and 50 mmHg. Measurements were conducted intraoperatively during non-pulsatile as well as postoperatively after admission to the ICU under pulsatile blood flow.

Inclusion Criteria:

• undergoing elective cardiac surgery with cardiopulmonary bypass

Exclusion Criteria:

• Carotid artery stenosis (> 50%)
• Neurological pathologies
• COPD with CO2 retention
• Women of childbearing age