Ephedrine and phenylephrine induce opposite changes in cerebral and paraspinal tissue oxygen saturation, measured with near-infrared spectroscopy: a randomized controlled trial.

While the effects of phenylephrine (PE) and ephedrine (E) on cerebral oxygen saturation (rSO) already has been studied, the effect on paraspinal oxygen saturation (rSO) is still unexplored. This study aims to assess the effect of PE and E on rSO and rSO, measured with near-infrared spectroscopy. A randomized 4-treatment cross-over trial was designed in 28 patients under BIS-titrated anaesthesia with sevoflurane.