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Comparison of recorded values from six pulse oximeters
H Choe1, C Tashiro, K Fukumitsu
1Department of Anesthesiology, Chonbuk University Medical School, Korea.
Critical Care Medicine
|July 1, 1989
Summary
Noninvasive pulse oximeters show varied oxygen saturation (SpO2) readings, with some estimating functional arterial oxygen saturation (SaO2) and others fractional oxygen saturation (%HbO2). A standardized calibration is needed for accurate dyshemoglobin measurements.
Area of Science:
- Biomedical Engineering
- Medical Device Technology
- Clinical Measurement
Background:
- Noninvasive pulse oximetry is widely used for monitoring oxygen saturation.
- Variations in pulse oximeter calibration can affect measurement accuracy.
- Dyshemoglobinemia (e.g., carboxyhemoglobin, methemoglobin) can interfere with pulse oximetry readings.
Purpose of the Study:
- To compare oxygen saturation (SpO2) values from six noninvasive pulse oximeters against a cooximeter.
- To assess the impact of dyshemoglobin levels on pulse oximeter accuracy.
- To investigate potential calibration differences among pulse oximeter devices.
Main Methods:
- Six noninvasive pulse oximeters and a cooximeter were used for simultaneous measurements.
- Eight healthy volunteers were subjected to controlled hypoxia (SpO2 > 70%).
- Cooximetry determined functional arterial oxygen saturation (SaO2), fractional SaO2 (%HbO2), carboxyhemoglobin (HbCO), and methemoglobin (MetHb).
Main Results:
- Significant differences were observed between SaO2 and %HbO2 due to HbCO and MetHb presence.
- Two pulse oximeters closely approximated %HbO2, while others correlated with SaO2.
- The maximum SpO2 difference among instruments was 2.7%.
Conclusions:
- Some pulse oximeters may be calibrated for SaO2, while others target %HbO2.
- Standard two-wavelength pulse oximeters cannot accurately measure %HbO2 or SaO2 in the presence of dyshemoglobin.
- Manufacturers should establish a standardized calibration method for pulse oximeters.