The Accuracy of Noninvasive Peripheral Pulse Oximetry After Palliative Cardiac Surgery in Patients With Cyanotic Congenital Heart Disease

Abstract

Background: Children with cyanotic congenital heart disease (CCHD) live with oxyhemoglobin saturations that are typically expressed as percentages in the range of 70s and 80s. Peripheral pulse oximetry (measurement of SpO2) performs poorly in this range and yet is widely used to inform clinical decisions in these patients. The reference standard is co-oximetry of arterial samples (SaO2). Methods: In this study, 515 paired measurements of SpO2 and SaO2 were taken from 19 children who had undergone palliative cardiac surgery. Results: SpO2 (Masimo SET LNCS Neo pulse oximeter) overestimated oxyhemoglobin saturation in 82% of measurements (mean 4.6% ± 6.6%). There was a strong negative correlation between mean bias and SaO2 ( r = −.96, P = .002, 95% confidence interval: −0.99 to −0.68). Conclusion: The results raise a concern that critical hypoxemia may go undetected and untreated if pulse oximetry is relied upon as the primary means of assessing oxyhemoglobin saturation in children with CCHD. Strong preference must be given to co-oximetry of arterial samples.