Normothermic retrograde continuous cardioplegia for myocardial protection during cardiopulmonary bypass. A modified technique.

Normothermic retrograde continuous cardioplegia is a revolutionary development for myocardial preservation in cardiac surgery. Despite excellent reports regarding this technique, the surgical community has expressed concern over technical problems encountered. The method of normothermic retrograde continuous cardioplegia in current use requires both large total crystalloid volumes and large potassium loads to deliver adequate cardioplegia. We have developed a technique that eliminates these problems. The heart is stopped by an initial infusion of normothermic cardioplegic solution through a coronary sinus catheter. The infusate is then converted to normothermic pump blood. Small boluses of potassium chloride are added intermittently to maintain cardiac arrest. We applied this technique to 35 patients undergoing cardiac valve surgery. The average volume of crystalloid cardioplegia required was 125 mL (range, 40 to 155 mL), and the average total potassium load was 52 mEq (range, 2 to 100 mEq). Clinically significant sequelae were noted in 4 patients (11%), and 1 (3%) died of pneumonia on the 28th postoperative day. The method we describe is a safe and effective alternative to the current technique of normothermic retrograde continuous cardioplegia and offers both physiologic and technical advantages to patients undergoing cardiac valve procedures.