Retinal oxygen saturation as a non-invasive estimate for mixed venous oxygen saturation and cardiac output

Abstract

Purpose: To investigate the correlation between retinal vessel oxygen saturation and mixed venous oxygen saturation (SvO 2-mixed ) and cardiac output (CO). Methods: Retinal arterial (SaO 2-retinal ) and venous (SvO 2-retinal ) oxygen saturation were measured non-invasively with dual-wavelength retinal oximetry in subjects receiving invasive measurements of SvO 2-mixed and CO through right heart catheterization. Correlations were analysed using Spearman's rank correlation coefficients and linear regression models. Results: Fourteen patients (median age 62.7 years, range: 21–77) were included in the analysis. When adjusted for age, SvO 2-retinal showed a positive correlation with SvO 2-mixed (β = 0.80, p = 0.003). Retinal arteriovenous oxygen saturation difference was significantly correlated with the inverse of CO (Spearman's ρ = 0.59, p = 0.026). Conclusion: This pilot study provides proof of concept for the use of retinal oximetry as a non-invasive tool to assess systemic cardiovascular function.