Effect of Shenmai injection, a traditional Chinese medicine, on pulmonary dysfunction after tourniquet-induced limb ischemia-reperfusion.

Background: Tourniquet has been considered as a recognized cause of lower limb ischemia-reperfusion injury in the orthopedic field. This study investigates pulmonary function after tourniquet deflation and the protective effect of Shenmai injection (SMI), a traditional Chinese medicine.

Methods: Twenty-eight patients undergoing lower extremity surgery were randomized into a control group (group C) and a SMI group (group S), 14 patients in each group. Blood gas and circulating indicators (malondialdehyde, interleukin [IL]-6, and IL-8) were measured immediately before tourniquet inflation and at 0.5 hour, 2 hours, 6 hours, and 24 hours after tourniquet deflation.

Results: Plasma levels of malondialdehyde, IL-6, and IL-8 in group C were significantly increased over baselines from 2 hours to 24 hours after tourniquet deflation and the levels reached their peaks at 6 hours after tourniquet deflation, when arterial partial pressures of oxygen and arterial-alveolar oxygen tension ratio were decreased, whereas alveolar-arterial oxygen difference was increased significantly. Both the changes in blood gas variables and plasma mediators were attenuated in group S.

Conclusion: Pulmonary gas exchange is impaired after lower limb ischemia-reperfusion induced by clinical tourniquet application. Pretreatment with SMI, a traditional Chinese medicine, attenuates lipid peroxidation and systemic inflammatory response and mitigates pulmonary dysfunction.