Cerebral Energy State in Cardiac Surgery

Continuous Monitoring of Cerebral Energy State During Cardiac Surgery - A Novel Approach Utilizing Intravenous Microdialysis

Impaired cerebral function remains an important complication of cardiopulmonary bypass (CPB) during cardiac surgery. The aim of the present study is to investigate whether the lactate to pyruvate (LP) ratio obtained by microdialysis (MD) of the cerebral venous outflow reflects a derangement of global cerebral energy state during cardiopulmonary bypass.

Patients undergoing primary, elective coronary artery bypass grafting were blindly randomized to usual range MAP (40 to 60 mmHg; n = 5) or intervention group MAP (60 to 80 mmHg; n = 5) during CPB. MD catheters were positioned in a retrograde direction in the internal jugular vein and a reference catheter was inserted into the brachial artery. The relations between LP ratio, MAP, data obtained from bi-frontal NIRS and neurological outcome measures were assessed.

Inclusion criteria:

• Elective CABG on CPB

Exclusion criteria:

• Acute patients or reoperations
• Patients with epidural catheter
• Previous stroke
• Stenotic carotids
• Ejection fraction (EF) < 50 %
• Estimated per operative risk > 5%