Correlation between arterial blood pressure and oxygenation in tetralogy of fallot

To examine the relationship between arterial blood pressure and oxygenation in patients undergoing complete surgical correction of tetralogy of Fallot, a retrospective study of 16 patients was first performed, looking at the correlation between mean arterial blood pressure (MAP) and arterial oxygen tension (PaO₂ The correlation between phenylephrine-induced changes in MAP (Δ MAP) and those in PaO₂ (Δ PaO₂ was investigated prospectively in seven patients. In the retrospective study, there was a significant correlation between MAP and (PaO₂ (n = 66; r = 0.55; P < 0.01), and most data points with a PaO₂ <50 mm Hg were associated with a MAP <60 mm Hg. In the seven patients who received phenylephrine, 10 μg/kg, a significant correlation was found between Δ MAP and Δ (PaO₂ (n = 10; r = 0.95; P < 0.01). These results suggest that in tetralogy of Fallot arterial blood pressure is a determinant of arterial oxygenation, and that the risk of serious hypoxia is significant when MAP is <60 mm Hg.