Effects of postural change on oxygen saturation and respiration in patients after the Fontan operation: platypnea and orthodeoxia.

The aim of this study was to assess whether platypnea and orthodeoxia occur in Fontan patients. We divided 14 Fontan patients into 2 groups: 8 patients who had pulmonary arteriovenous fistulas and/or intra-atrial shunts (group A) and 6 patients who had neither pulmonary arteriovenous fistulas nor intra-atrial shunts (group B). They were compared with 9 controls (group C). Arterial oxygen saturation, minute ventilation per body weight and ventilatory equivalent for carbon dioxide were measured in the supine and then sitting positions. In group A, 1 patient had platypnea and 3 patients had orthodeoxia (changes in the saturation from the supine position to the sitting position were -4% to -7%) accompanied with slight hyperpnea, and all 4 patients had both pulmonary arteriovenous fistulas and intra-atrial shunts. Contrary, patients in group B had neither platypnea nor orthodeoxia. The saturation was significantly lower and the minute ventilation was significantly higher in the sitting position than in the supine position in group A (p < 0.05). The other groups showed no significant difference in the saturation or the minute ventilation between the 2 positions. All groups showed the ventilatory equivalent was significantly higher in the sitting position than in the supine position (p < 0.05 to 0.01). We demonstrated platypnea and orthodeoxia in Fontan patients with pulmonary arteriovenous fistulas and intra-atrial shunts. We believe platypnea and orthodeoxia should be regard as a complication in Fontan patients with pulmonary arteriovenous fistulas and/or intra-atrial shunts.