Establishment of Featal Heart Surgery with an Improvement of the Placental Blood Flow in Cardiopulmonary Bypass Using Fetal Lamb Model / 대한흉부외과학회지

ABSTRACT

BACKGROUND: We tested the effect of indomethacine and total spinal anesthesia on the improvement of placental flow during cardiopulmonary bypass on fetal lamb. MATERIAL AND METHOD: Twenty fetuses at 120 to 150 days of gestation were subjected to bypass via trans-sternal approach with a 12 G pulmonary arterial cannula and 14 to 18 F venous cannula for 30 minutes. All ewes received general anesthesia with ketamine. In all the fetuses, no anesthetic agents were used except muscle relaxant. Ten served as a control group in which placenta was worked as an oxygenator during bypass (Control group). The remainder worked as an experimental group in which pretreatment with indomethacine and total spinal anesthesia was performed before bypass with the same extracorporeal circulation technique as control group (Experimental group). Observations were made every 10 minutes during a 30-minute bypass and 30-minute post bypass period. RESULT: Weights of the fetuses ranged from 2.2 to 5.2 kg. In Control group, means of arterial pressure decreased from 44.7 to 14.4 mmHg and means of PaCO2 increased from 61.9 to 129.6 mmHg at each time points during bypass. Flow rate was suboptimal (74.3 to 97.0 ml/kg/min) during bypass. All hearts fibrillated immediately after the discontinuation of bypass. On the contrary, in Experimental group, means of arterial pressure reamined higher (45.8 to 30 mmHg) during bypass (p<0.05). Means of PaCO2 were less ranging from 59.8 to 79.4 mmHg during bypass (p<0.05). Flow rates were higher (78.8 to 120.2 ml/ kg/min) during bypass (p<0.05). There were slower deterioration of cardiac function after cessation of bypass. CONCLUSION: In this study, we demonstrated that the placental flow was increased during fetal cardiopulmonary bypass in the group pretreated with indomethacine and total spinal anesthesia. However, further studies with modifications of the bypass including a creation of more concise bypass circuit, and a use of axial pump are mandatory for the clinical application.