Operational Evaluation of Pulse Oximetry in NICU Patients with Arterial Access

OBJECTIVE: To investigate pulse oximetry in neonates who require arterial access as represented by the clinical data recorded to manage their care. STUDY DESIGN: Analysis of simultaneous SpO 2 and SaO 2 from: 7-year historical NICU data ( N =31,905); 4-month prospective NICU data ( N =566); verification data using two hemoximeters ( N =52); and NICU data from two collaborating centers ( N =95 and 168). The bias function (SpO 2 −SaO 2 ) was regressed against the measured “gold” standard, SaO 2 . RESULTS: A significant negative correlation was found for each of the data sets between the bias function and SaO 2 . This bias was similar for devices from several manufacturers (Datex-Ohmeda, Masimo, Nellcor, and Spacelabs). Maximum operational performance occurred with peaks between 92 and 97% SaO 2 , but declined markedly above and below this narrow range. In all, 71 to 95% of patients exhibited data with significant bias . CONCLUSION: These operational data suggest that with the methodology and devices currently in use, SpO 2 values in most all neonates who require arterial lines inaccurately correlate with measured arterial saturation.