Proceedings

Consistent Two to Four Degree Crystalloid Potassium Cardioplegia

Division of Cardiovascular and Thoracic Surgery, Department of Surgery, The University of Texas Medical Branch, Galveston, Texas 77550

^* Address correspondence to: Benjamin Schneider, C.C.P., Division of Cardiovascular and Thoracic Surgery, University of Texas Medical Branch, Galveston, Texas 77550

Abstract

The use of hypothermic crystalloid potassium cardioplegia in open heart surgery has been shown to be effective in arresting the heart and protecting it from ischemic injury during aortic crossclamping. A perfusion technique for the routine delivery of 2-4° centigrade (C) crystalloid potassium cardioplegia has been employed in 116 consecutive coronary artery bypass graft procedures between October 1980 and October 1981. The cardioplegic solution is infused with a low flow roller pump through a polyvinyl chloride tubing coil immersed in an ice bath which serves as the cooling device and a Sarns pediatric bubble trap. The planned initial dose of cardioplegia is 450 ml/m² body surface area. With the initial cardioplegia infusion, the mean myocardial temperature was lowered to 14.4 ± 0.4°C (S.E.). Myocardial temperataure is maintained at less than 20°C at all times. A total of 2524 ± 73 ml of cardioplegia was administered for each patient with a mean crossclamp time of 83.6 ± 2.2 minutes and a total bypass time of 156 ± 3.6 minutes.

CPK-MB and SGOT values were minimally elevated in the immediate postoperative period, but returned to normal on the second and third postoperative day respectively. Two patients in the study group died with an operative mortality of 1.7 percent. The cardioplegia infusion system we have employed assured the delivery of crystalloid potassium cardioplegia to the myocardium at 2-4°C, provided continuous profound myocardial hypothermia, and resulted in good myocardial protection as determined by clinical variables followed postoperatively.