Effect of ischemic and pharmacological preconditioning of lower limb muscle tissue on tissue oxygenation measured by near-infrared spectroscopy - a pilot study

Background: Ischemic or volatile anesthetic preconditioning is defined as tissue protection from impending ischemic cell damage by repetitive short periods of tissue exposure to ischemia or volatile anesthetics. Objective of this study was to elucidate, if ischemic preconditioning and pharmacological preconditioning with sevoflurane have effects on muscle tissue oxygen saturation in patients undergoing surgical revascularization of the lower limb. Methods: In this prospective randomized pilot study ischemic and pharmacological (sevoflurane) preconditioning was performed in 40 patients with lower limb arterial occlusive disease undergoing surgical revascularization. Sevoflurane preconditioning was performed in one group (N = 20) by repetitive application of sevoflurane for six minutes interspersed by six minutes of washout. Thereafter, ischemic preconditioning was performed in all patients (N = 40) by repetitive clamping of the femoral artery for six minutes interspersed by six minutes of reperfusion. The effect of both procedures on leg muscle tissue oxygen saturation (rSO(2)) was measured by near-infrared spectroscopy during both procedures and during surgery and reperfusion (INVOS (R) 5100C Oxymeter with Small Adult SomaSensor (R) SAFB-SM, Somanetics, Troy, Michigan, USA). Results: Repetitive clamping and reperfusion of the femoral artery resulted in significant cyclic decrease and increase of muscle rSO(2) (p < 0.0001). Pharmacological preconditioning with sevoflurane resulted in a faster and higher increase of rSO(2) during postoperative reperfusion (Maximal 111% baseline +/- 20 versus 103% baseline +/- 14, p = 0.008) consistent with an additional effect of pharmacological preconditioning on leg perfusion. Conclusions: Ischemic preconditioning of lower limb muscle tissue and pharmacological preconditioning with sevoflurane have an effect on tissue oxygenation in patients with lower limb occlusive arterial disease.