Significance: Real-time information about oxygen delivery to the hepatic graft is important to direct care and diagnose vascular compromise in the immediate post-transplant period.

Aim: The current study was designed to determine the utility of visible diffuse reflectance spectroscopy (vis-DRS) for measuring liver tissue saturation in vivo.

Approach: A custom-built vis-DRS probe was calibrated using phantoms with hemoglobin (Hb) and polystyrene microspheres. Ex vivo (extracorporeal circulation) and in vivo protocols were used in a swine model (n  =  15) with validation via blood gas analysis.

Results: In vivo absorption and scattering measured by vis-DRS with and without biliverdin correction correlated closely between analyses. Lin’s concordance correlation coefficients are 0.991 for μ_a and 0.959 for μs^′. Hb measured by blood test and vis-DRS with (R²  =  0.81) and without (R²  =  0.85) biliverdin correction were compared. Vis-DRS data obtained from the ex vivo protocol plotted against the PO₂ derived from blood gas analysis showed a good fit for a Hill coefficient of 1.67 and P₅₀  =  34  mmHg (R²  =  0.81). A conversion formula was developed to account for the systematic deviation, which resulted in a goodness-of-fit R²  =  0.76 with the expected oxygen dissociation curve.

Conclusions: We show that vis-DRS allows for real-time measurement of liver tissue saturation, an indicator for liver perfusion and oxygen delivery.