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Method comparison of two non‐invasive dual‐wavelength spectrophotometric retinal oximeters in healthy young subjects during normoxia
Author(s) -
Told Reinhard,
Boltz Agnes,
Schmetterer Leopold,
Garhöfer Gerhard,
Sacu Stefan,
SchmidtErfurth Ursula,
Pollreisz Andreas
Publication year - 2018
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/aos.13719
Subject(s) - earlobe , medicine , pulse oximetry , confidence interval , repeatability , retinal , oxygen saturation , ophthalmology , limits of agreement , standard deviation , anesthesia , surgery , nuclear medicine , oxygen , mathematics , chemistry , statistics , organic chemistry
Purpose Spectrophotometric retinal oximetry is a non‐invasive technology for measuring oxygen saturation in arterioles and venules (SaO 2 , SvO 2 ). We compared two commercially available systems: the Oxymap T1 (Oxymap ehf., Reykjavik, Iceland) and the Dynamic Vessel Analyzer ( DVA , Imedos, Jena, Germany). Methods Twenty healthy adults were included after giving informed consent. Two measurement cycles 30 min apart, including Oxymap T1, DVA , arterialized capillary blood draw of the earlobe (ScO 2 ) and peripheral oxygen saturation using finger pulse oximetry (SpO 2 ) were scheduled. Results SaO 2 (p > 0.0004) but not SvO 2 (p < 0.05) was statistically significantly different between the retinal oximeters used. Agreement between devices using repeated SO 2 measurements resulted in a standard deviation ( SD ) of differences of 3.5% in retinal arterioles and 4.8% in venules. Bland–Altman plot using the mean of a participant's two measurements from each device showed an average mean difference of 4.4% (95% confidence limits of agreement: −8.6 to 17.4) and −3.3% (95% confidence limits of agreement: −28.8 to 22.2) for SaO 2 and SvO 2 , respectively. Comparison of mean SaO 2 and SvO 2 with mean ScO 2 and SpO 2 indicated that SO 2 measurements were generally higher in ScO 2 and SpO 2 . Conclusion This study shows very good repeatability for both devices, which is consistent with the literature. However, it does not show sufficient concordance between SaO 2 measurements from both devices, indicating that patients should be followed by one device only. Differences in absorbance wavelengths used and image post‐processing may explain the differences.