Figure 3: Time-matched correlation between limb tissue oxygen saturation (rSO2) and cerebral oximetry. Linear regression analyses between timematched mean (A) non-blocked limb rSO2 or (B) blocked limb rSO2 and cerebral rSO2 with standard deviations are depicted. (A) For non-blocked limb rSO2, r2=0.364, *P<0.001. (B) For blocked limb rSO2, r2=0.003, P=NS.