In patients with bidirectional cavopulmonary anastomosis (BCPA) the superior vena cava connects directly to the pulmonary artery. Its function is to provide an improved pulmonary blood flow and volume load on the ventricle.

BCPA is a useful palliative procedure for selected patients. However, the effects of BCPA on cardiovascular physiology are complex. Several studies have suggested that different ventilatory techniques might influence cardiovascular outcomes. For example, hyperventilation, which stimulates the respiratory center, has been shown to be ineffective.

In addition to cardiovascular effects, mechanical ventilation can also be detrimental to patient health. In particular, hypercapnia with respiratory acidosis results in a decrease in pulmonary blood flow (PBF) and a higher rate of CBF. These changes can also lead to deep sedation and paralysis.

Consequently, BCPA is not suitable for all patients. Those who have a high risk of pulmonary venous obstruction should receive positive pressure ventilation.

The British Cardiac Patients Association (BCPA) recently commissioned a nationwide survey of cardiologists to identify cardiac surgeons who would consider performing BCPA. All patients were provided with informed consent and enrolled in the study.

A total of 23 patients with a median age of 10 months were included in the study. Median weight was 6.2 kg. Two patients had a ventricular septal defect, two had bilateral superior vena cavae and four had tricuspid atresia.

Before the BCPA, all patients were evaluated by cardiac catheterization. The results showed that echocardiographic criteria were favorable in 17 of the 23 patients. Among these, the echocardiographic parameters that were favorable were: a normal proximal branch pulmonary artery size, no ventricular outflow tract obstruction, moderate to less atrioventricular regurgitation, and good ventricular function.