Influence of CPB Temperature on CABG Morbidity

To compare three accepted modes of myocardial preservation, warm, tepid, and cold blood cardioplegia, coinciding with normothermic (37 degrees centigrade), tepid (32 degrees centigrade) and hypothermic (8 to 10 degrees centigrade) cardiopulmonary bypass (CPB) to define differences in neurologic function in coronary artery bypass graft (CABG) patients. BACKGROUND: A pilot study of warm versus cold perfusion and preservation was completed in 32 patients prior to the ongoing study. The findings of the pilot study showed 53 percent of patients had evidence of new neurologic disturbance at postoperative day four. Only the neurologic dysfunction could be correlated with warm versus cold perfusion (37.5 percent warm versus 75 percent cold, P less than 0.05). The changes in neurologic function had abated or clearly improved by one month of follow-up, and the distinction in neurologic dysfunction grading was no longer apparent between the two groups. DESIGN NARRATIVE: Patients were randomly assigned to cold, tepid, or warm blood cardioplegia, coinciding with normothermic, tepid, and hypothermic cardiopulmonary bypass. All patients received a standard anesthetic protocol combining narcotic and inhalational anesthesia. Each patient entering the study had extensive clinical data collected prospectively incorporating most aspects of measurable determinants related to myocardial preservation. Additionally, neurologic tests were performed by a blinded neurologist and rated by an objective scoring system, the Mathew scale. The studies were performed preoperatively, on the third or fourth postoperative day, and at one month following surgery. Hematologic data were measured for fibrinolytic potential.