Peri-operative comparison of different transient external shunt techniques in bidirectional cavo-pulmonary shunt

Objective: In patients with functional single ventricular physiology, the avoidance of cardiopulmonary bypass offers many advantages including earlier extubation, decreased necessity of inotropic support, improved hemodynamical status and reduced likehood of post-operative prolonged pleural effusion. We believe that the bidirectional cavopulmonary anastomosis operations may be performed with transient external shunt techniques. The purpose of this prospective study is the peri- and post-operative comparison of different transient external shunt methods used in bidirectional cavopulmonary shunt operations. Methods: Between years 1997 and 2000, 30 patients have undergone bidirectional cavo-pulmonary shunt operation by using three different types of external shunt. The mean patient age was 13 months (range, 3 months–3 years). Previous operations had been performed in ten patients (33%). All patients were divided into three groups according to type of external shunt used. In group A (ten patients), the transient external shunt was constructed between superior vena cava and right atrium by uniting two standard venous cannulas with a Y-connector. In group B (ten patients), the external shunt was performed with a single short venous cannula constructed between superior vena cava and right atrium. In group C (ten patients), the external shunt was constructed between superior vena cava and left pulmonary artery by using a single short venous cannula. During operation, central venous pressure (CVP), arterial O2 saturation and mean arterial blood pressure were recorded continuously. Results: All operations are completed without the establishment of cardiopulmonary bypass. Hospital mortality was 3.3%. One patient in group A died because of low cardiac output at the end of postoperative day 2. All patients were extubated within 4 h. In groups A–C mean superior vena caval pressures were measured 28, 24 and 21 mmHg, respectively during superior vena cava-right pulmonary artery anastomosis. In both groups A and B patients, arterial O2 saturation decreased to a minimum 53±2 and 53±2%, respectively during the operation. In the group C, minimum arterial O2 saturation was measured 82±2%. Although mean arterial pressure decreased in all groups during clampage; in group C patients, this drop is not significant. Conclusion: Based on the study presented here, bidirectional cavo-pulmonary anastomosis can be carried out by using different types of transient external shunt. The best