Open AccessNon-invasive assessment of cerebral oxygenation: A comparison of retinal and transcranial oximetry
Author(s) -
Karel Van Keer,
Jan Van Keer,
João Barbosa–Breda,
Vahid Nassiri,
C. De Deyne,
Cornelia Genbrugge,
Luís Abegão Pinto,
Ingeborg Stalmans,
Evelien Vandewalle
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0190612
Subject(s) - retinal , medicine , oxygenation , confidence interval , transcranial doppler , ophthalmology , cardiology
Background To investigate the correlation between cerebral (SO 2-transcranial ), retinal arterial (SaO 2-retinal ) and venous (SvO 2-retinal ) oxygen saturation as measured by near-infrared spectroscopy (NIRS) and retinal oximetry respectively. Methods Paired retinal and cerebral oxygen saturation measurements were performed in healthy volunteers. Arterial and venous retinal oxygen saturation and diameter were measured using a non-invasive spectrophotometric retinal oximeter. Cerebral oxygen saturation was measured using near-infrared spectroscopy. Correlations between SO 2-transcranial and retinal oxygen saturation and diameter measurements were assessed using Pearson correlation coefficients. Lin’s concordance correlation coefficient (CCC) and Bland-Altman analysis were performed to evaluate the agreement between SO 2-transcranial as measured by NIRS and as estimated using a fixed arterial:venous ratio as 0.3 x SaO 2-retinal + 0.7 x SvO 2-retinal . The individual relative weight of SaO 2-retinal and SvO 2-retinal to obtain the measured SO 2-transcranial was calculated for all subjects. Results Twenty-one healthy individuals aged 26.4 ± 2.2 years were analyzed. SO 2-transcranial was positively correlated with both SaO 2-retinal and SvO 2-retinal (r = 0.44, p = 0.045 and r = 0.43, p = 0.049 respectively) and negatively correlated with retinal venous diameter (r = -0.51, p = 0.017). Estimated SO 2-transcranial based on retinal oximetry showed a tolerance interval of (-13.70 to 14.72) and CCC of 0.46 (95% confidence interval: 0.05 to 0.73) with measured SO 2-transcranial . The average relative weights of SaO 2-retinal and SvO 2-retinal to obtain SO 2-transcranial were 0.31 ± 0.11 and 0.69 ± 0.11, respectively. Conclusion This is the first study to show the correlation between retinal and cerebral oxygen saturation, measured by NIRS and retinal oximetry. The average relative weight of arterial and venous retinal oxygen saturation to obtain the measured transcranial oxygen saturation as measured by NIRS, approximates the established arterial:venous ratio of 30:70 closely, but shows substantial inter-individual variation. These findings provide a proof of concept for the role of retinal oximetry in evaluating cerebral oxygenation.