Jugular venous bulb oxygen saturation in patients with preexisting diabetes mellitus or stroke during normothermic cardiopulmonary bypass

Background: The authors hypothesized that patients with cerebrovascular abn ormalities or metabolic disorders may experience abnormality in cerebral ci rculation more frequently than patients without these risks. The current st udy attempted to assess jugular venous bulb oxygen saturation (Sjv(O2)) in patients with preexisting diabetes mellitus or stroke undergoing normotherm ic cardiopulmonary bypass. Methods: Thirty-nine patients undergoing elective coronary artery bypass gr aft surgery were studied, including 19 age-matched control patients, 10 dia betic patients, and 9 patients with preexisting stroke A 8.0-French fiberop tic oximetry oxygen saturation catheter was inserted into the right jugular bulb to continuously monitor internal Sjv(O2). Hemodynamic parameters and arterial and jugular venous blood gases were measured at seven time points: (1) after the induction of anesthesia and before the start of surgery, (2) just after the beginning of cardiopulmonary bypass, (3) 20 min after the b eginning of bypass, (4) 40 min after the beginning of bypass, (5) 60 min af ter the beginning of bypass, (6) just after the cessation of bypass, and (7 ) at the end of the operation. Results: No significant differences were seen in mean arterial pressure, ar terial carbon dioxide tension (Pa-CO2), or hemoglobin concentration among t he three groups during the study. The Sjv(O2) value did not differ among th e three groups after anesthesia induction and before surgery, just after th e beginning of cardiopulmonary bypass, 60 min after the beginning of bypass , just after the end of bypass, or at the end. of the operation. Significan t differences between the control group and the diabetic and stroke groups were observed, however, at 20 min and 40 min after the beginning of bypass (at 20 min: control group 62.2 +/- 6.8%, diabetes group 48.4 +/- 5.1%, stro ke group 45.9 +/- 6.3%; at 40 min: control group 62.6 +/- 5.2%, diabetes gr oup 47.1 +/- 5.2%, stroke group 48.8 +/- 4.1% [values expressed as the mean +/- SD]; P < 0,05), Also, values In the diabetes and stroke groups were de creased at 20 min and 40 min after the beginning of bypass compared with be fore the start of surgery. Conclusions: A reduced Sjv(O2) value was observed more frequently in patien ts with preexisting diabetes mellitus or stroke during normothermic cardiop ulmonary bypass. It is possible that cerebral circulation during normotherm ic bypass is altered in patients with risk factors for cerebrovascular diso rder.