Pulse oximetry in cyanotic congenital heart disease

Abstract

Transcutaneous oximetry allows for both noninvasive and continuous assessment of arterial oxygenation. Transcutaneous oxygen partial pressure (PO 2) monitoring has been shown to correlate sufficiently well with arterial oxygen pressure to be used clinically in inpatients and outpatients with congenital heart disease and chronic lung disease. 1 However, this technique is limited by the nonlinear relation between arterial oxygen pressure and oxygen content created by the oxyhemoglobin dissociation curve and interindividual variability in P 50. 2 Pulse oximetry allows for the noninvasive assessment of oxygen saturation, thus improving the ability to estimate oxygen content. Prior studies suggested that although there is a good correlation between transcutaneous and arterial oxygen saturation, this technique can overestimate oxygen saturation at lower levels. 3–6 Because patients with cyanotic congenital heart disease generally have chronic hypoxemia of greater severity than do those with lung disease, this overestimation may have clinical significance. We evaluated the reliability of transcutaneous pulse oximetry in patients with congenital heart disease in the cardiac catheterization laboratory and in clinical settings to determine the usefulness of this technique in clinical practice.