Anesthesia and cardiopulmonary bypass for congenital heart surgery.

The neonate has a limited respiratory reserve and is prone to ventilatory failure and hypoxemia. They are mechanically disadvantaged by increased chest wall compliance, reliance on the diaphragm as the main muscle of respiration and a reduction in functional residual capacity (FRC) with an increase in closing capacity. Because of an increased metabolic rate, oxygen consumption is two to three times the adult level, yet their oxygen reserve is diminished due to a reduction in FRC. An increased proportion of total oxygen consumption is directed at the work of breathing and they have a relative fixed tidal volume and rate-dependent minute ventilation.