Hyperbilirubinemia does not interfere with hemoglobin saturation measured by pulse oximetry

Area of Science:

• Clinical Medicine
• Biomedical Engineering
• Critical Care

Background:

• Pulse oximetry is a non-invasive method for measuring oxygen saturation.
• Hyperbilirubinemia, common in certain patient populations, can potentially interfere with spectrophotometric measurements.
• Understanding potential interferences is crucial for accurate patient monitoring.

Purpose of the Study:

• To investigate the direct impact of elevated plasma bilirubin levels on Nellcor pulse oximeter (SpO2) readings.
• To determine if hyperbilirubinemia causes spectral interference with pulse oximetry.
• To assess the influence of co-existing carboxyhemoglobin levels.

Main Methods:

• Prospective clinical study comparing 29 icteric patients with 46 healthy controls.
• Comparison of pulse oximeter SpO2 readings with co-oximeter measurements (HbO2corr) corrected for spectral error.
• Analysis of corrected carboxyhemoglobin (CoHbcorr) levels and their impact on SpO2.

Main Results:

• A statistically significant difference in bias and precision was observed between SpO2 and corrected oxyhemoglobin in icteric patients compared to controls (P < 0.03).
• Icteric patients exhibited higher corrected carboxyhemoglobin levels (P < 0.005).
• After correcting SpO2 for carboxyhemoglobin, the confidence limits were identical between groups, indicating no direct bilirubin interference.

Conclusions:

• High plasma bilirubin levels do not directly interfere with Nellcor pulse oximeter SpO2 measurements.
• The observed differences in readings were attributable to elevated carboxyhemoglobin levels in icteric patients.
• Pulse oximetry remains a reliable tool for monitoring oxygen saturation in hyperbilirubinemic patients when carboxyhemoglobin is considered.