Korean J Thorac Cardiovasc Surg.  2002 Oct;35(10):712-723.

The Clinical Effects of Normocapnia and Hypercapnia on Cerebral Oxygen Metabolism in Cardiopulmonary Bypass

• Kim SR
• Choi SC
• Choi KL
• Park SS
• Choi KJ
• Yoon YC
• Jun HJ
• Lee YH
• Haung YH
• Cho KH

Abstract

BACKGROUND: Substantial alterations in cerebral blood flow(CBF) are known to occur during cardiopulmonary bypass(CPB). Many investigators have speculated that these changes may be responsible for both minor and major cerebral damages after CPB. More recently, these changes in CBF have been observed to be intimately related to the arterial carbon dioxide tension(PaCO2) maintained during CPB. The present study was prospectively designed to investigate the clinical effects of normocapnic and hypercapnic CPB on the cerebral oxygen metabolism in cardiac surgery. MATERIAL AND METHOD: Thirty-six adult patients scheduled for elective cardiac surgery were randomized to either normocapnic group (PaCO2 35~40 mmHg, n=18) or hypercapnic group(PaCO2 45~55 mmHg, n=18) with moderately hypothermic nonpulsatile CPB(nasopharyngeal temperature of 29~30degrees C). In each patient, middle cerebral artery blood flow velocity(VMCA), cerebral arteriovenous oxygen content difference (C(a-v)O2), cerebral oxygen extraction(COE), cerebral metabolic rate for oxygen(CMRO2), cerebral oxygen transport(TEO2), TEO2/CMRO2 ratio, cerebral desaturation(internal jugular bulb blood oxygen saturationCONCLUSION
These findings suggest that hypercapnic CPB may have salutary effects on the cerebral oxygen metabolism and postoperative neurologic outcomes in cardiac surgery.

Keyword

Cardiopulmonary bypass; Carbondioxide; Cerebral perfusion; Metabolism

MeSH Terms

Adult
Carbon Dioxide
Cardiopulmonary Bypass*
Humans
Hypercapnia*
Incidence
Metabolism*
Middle Cerebral Artery
Oxygen*
Prospective Studies
Research Personnel
Thoracic Surgery
Carbon Dioxide
Oxygen