JUGULAR BULB SATURATION AND COGNITIVE DYSFUNCTION AFTER CARDIOPULMONARY BYPASS

Inadequate cerebral oxygenation during cardiopulmonary bypass may lead to postoperative cognitive dysfunction in patients undergoing cardiac operations. A psychological test battery was administered to 255 pati ents before cardiac operation and just before hospital discharge. Post operative impairment was defined as a decline of more than one standar d deviation in 20% of tests. Variables significantly (p < 0.05) associ ated with postoperative cognitive impairment are baseline psychometric scores, largest arterial-venous oxygen difference, and years of educa tion. Jugular bulb hemoglobin saturation is significant if it replaces arterial-venous oxygen difference in the model. Factors correlated wi th jugular bulb saturation at normothermia were cerebral metabolic rat e of oxygen consumption (r = -0.6; p < 0.0005), cerebral blood now (r = 0.4; p < 0.0005), oxygen delivery (r = 0.4; p < 0.0005), and mean ar terial pressure (r = 0.15; p < 0.05). Three measures were significantl y related to desaturation at normothermia and at hypothermia as well: greater cerebral oxygen extraction, greater arterial-venous oxygen dif ference, and lower ratio of cerebral blood now to arterial-venous oxyg en difference. We conclude that cerebral venous desaturation occurs du ring cardiopulmonary bypass in 17% to 23% of people and is associated with impaired postoperative cognitive test performance.