Regional tissue oxygen saturation (rSO₂) monitoring through near-infrared spectroscopy (NIRS) has been reported as a non-invasive strategy to estimate the adequacy of matching between oxygen delivery (DO₂) and oxygen consumption. The rSO₂ monitoring is also reliable in non-pulsatile blood flow states, such as during veno-arterial extracorporeal life support (ECLS).

Renal rSO₂ has been specifically advocated as a useful monitoring tool in neonatal and pediatric patients on ECLS,¹ and could also be applied in adults, provided that the depth of the kidney is consistent with the reliability of the measurement.^2,3 Renal rSO₂ may be used as a surrogate of the level of renal oxygenation,² potentially predicting risk of developing acute kidney injury.³

We monitored continuously the periprocedural renal rSO₂ through multi-wavelength sensors and NIRS technology (O3 Regional Oximeter, Masimo Corporation, Irvine, CA) in two controlled donors after circulatory determination of death undergoing abdominal normothermic regional perfusion (A-NRP)