The effect of rapid volume expansion on hypoxemia in patients with tetralogy of fallot

I MMEDIATE AND clinically significant decreases in arterial oxygen saturation have been observed in patients with tetralogy of Fallot when, before the start of cardiopulmonary bypass, approximately 4 mL/kg of blood was withdrawn through the aortic cannula in order to remove air. Arterial oxygen saturation returned to control values after replacement of the withdrawn blood. The rapid improvement in arterial oxygen saturation suggested that volume expansion could be useful in the treatment of hypoxemic spells in patients with tetralogy of Fallot. Clinical experience with the effect of volume expansion on oxygen saturation in six patients with tetralogy of Fallot who developed a decrease in oxygen saturation to less than 75% is reported.