Kouji Matsuzaki

Preoperative Autologous Blood Donations in Pediatric Cardiac Surgery

BACKGROUND Preoperative autologous blood donation is one of the most effective methods to avoid homologous blood transfusion in cardiac operations. However, there have been few reports about the safety and efficacy of autologous blood donation in children. METHODS Since 1986, we have instituted a blood conservation program including preoperative autologous blood donations in children. Eighty children as young as 3 years old (mean +/- SD, 8.6 +/- 3.9 years) and weighing as little as 12.3 kg (29.2 +/- 14.5 kg) were enrolled in the program, and 735 +/- 388 mL of blood was donated during an average of 3.1 +/- 1.5 phlebotomies before the operations. RESULTS Two episodes of mild vasovagal reaction were observed in 2 patients as a complication of the phlebotomy. Seventy-six percent of the collected blood was stored by cryopreservation; the remaining 24% was preserved by liquid storage. Seventy-eight of these patients (97.5%) underwent operations using cardiopulmonary bypass. Seventy-five patients (94%) were operated on successfully without the need for a homologous blood transfusion. As for the other 5 patients, 2 received only platelet concentrate. CONCLUSION Preoperative autologous blood donation is a safe and effective method to avoid homologous blood transfusion in pediatric cardiac operations.

Veno-venous bypass to prevent myocardial ischemia during right heart bypass operation in PA, IVS, and RV dependent coronary circulation

There is a risk of myocardial ischemia in patients with pulmonary atresia and intact ventricular septum associated with right ventricle dependent coronary circulation, especially during open heart operation. Cardiopulmonary bypass unloads the right ventricle, and thereby reduces the coronary perfusion pressure in an area that is wholly or partly dependent on the right ventricle. We present a veno-venous bypass technique to keep the right ventricle beating and ejecting to supply the oxygenated blood into the right ventricle dependent myocardium and consequently to prevent myocardial ischemia during right heart bypass operation.

Tranexamic acid reduces blood loss after cardiopulmonary bypass

To evaluate the effect of tranexamic acid (TA) on blood loss after cardiopulmonary bypass (CPB), 157 patients who underwent elective valve replacement operations were studied, with one group of 90 patients receiving tranexamic acid (Group TA) and 67 patients serving as the control group (Group N). In group TA, 50 mg/kg of tranexamic acid was administered just before and after CPB, and every 90 minutes during CPB. The activated coagulation time was maintained at more than 450 seconds during CPB in both groups. There was no significant difference in the CPB time between the groups (163 +/- 32 min in group N and 152 +/- 38 min in group TA:NS). The time required for hemostasis was shortened in group TA, which resulted in a shorter operation time (6.7 +/- 1.5 hrs vs 6.0 +/- 1.5 hrs in group N and group TA, respectively: p = 0.006). The amount of chest tube drainage within 12 hours after surgery was significantly reduced (225 +/- 129 ml vs. 180 +/- 118 ml in group N and group TA, respectively: p = 0.026). The chest tube was able to be removed earlier in group TA, and the total blood loss was significantly smaller in group TA (402 +/- 292 ml) than in group N (631 +/- 609 ml; p = 0.004). The authors thus conclude that antifibrinolytic therapy during CPB with tranexamic acid reduces postoperative blood loss, and shortens the operation time due to an improvement in hemostasis.

A new aspect of coronary artery spasm induced by cardiac surgery

Five patients developed coronary artery spasm during open heart surgery in our institute between 1984 and 1988. One patient was undergoing coronary artery bypass grafting and the other four valvular surgery or surgery for congenital heart disease. In one of the patients undergoing non-coronary surgery, the preoperative induction of right coronary artery spasm by ergonovine had been documented angiographically while the remaining three patients did not possess organic or functional coronary disease. All five patients exhibited a sudden onset of hemodynamic collapse with ventricular tachyarrhythmias or ST elevation during the early period of reperfusion, the time to onset being 89.2±84.8 minutes after unclamping of the aorta. In addition, contraction of the right ventricular free wall was severely impaired. Although one patient died due to left ventricular rupture caused by direct cardiac massage, the early mortality thus being 20 per cent, the other four were successfully treated with the intravenous administration of nitroglycerin and diltiazem. Three patients required the assistance of intraaortic balloon pumping for severe cardiac failure. Thus, during open heart surgery, coronary artery spasm can occur even in patients without organic coronary lesions and the possible mechanisms of this condition are discussed herein.