[Clinical study of the effect to myocardial protection with crystalloid cardioplegic solution during open heart surgery in infants under age 3 months].

We investigated the effect to myocardial protection with crystalloid cardioplegic solution (Kurume solution I (S-I)) during open heart surgery in 21 infants less than 3 months old. The mortality was 28.6% (6 cases) including 2 patients having peroperative severe acidosis or shock. It was suggested that about half of them died of inadequate myocardial preservation. Comparing factors in the deaths with the survivors, there were significant differences between them in extracorporeal circulation time (ECCT) (196.7 +/- 50.1 min versus 133.2 +/- 45.8 min, p less than 0.01) and aortic-cross clamping time (ACCT) (120.0 +/- 45.8 min versus 78.3 +/- 30.5 min, p less than 0.05). In survivors, 86.7% of them required the effective dose (more than 6 micrograms/kg/min) of catecholamine and 33.3% presented low cardiac output syndrome (with the dose of more than 10 micrograms/kg/min and more than for 48 hours). The incidence of LOS was related to ECCT and ACCT. Thus it seemed that infant was more susceptible than older patient to the effects of ECC and the operation was carried out safely with ECCT less than 150 minutes and ACCT under age 3 months, it is necessary to use the cardioplegic solution fitting immature myocardium and to design operative technique and assist device for open heart surgery to shorten ECCT and ACCT.