Remote ischemic preconditioning in lower limb surgery; the hemodynamic and respiratory effects

Background: Remote Ischemic Preconditioning introduces brief episodes of ischemia and reperfusion, which reduces long term ischemia in orthopedic surgery. The aim of this study was to evaluate hemodynamic and respiratory effects of remote ischemic preconditioning in lower extremity orthopedic surgeries. Materials and Methods: In this clinical trial, 40 patients scheduled for lower extremity surgery with pneumatic tourniquet were randomly allocated to remote ischemic preconditioning (RIP) group (n=20) and the control group (n=19). Patients in RIP group received three “5 minutes” cycles of ischemia, alternating with 5 minutes of reperfusion before extending the use of tourniquet. Hemodynamic variables prior to inflation of tourniquet, every 30 minutes during the surgery and 10 minutes after tourniquet deflation and also arterial blood gas sample prior to and after surgery were recorded and compared between groups. Results: During operation blood pressure dropped in the RIP group and variations in heart rate, respiratory rate, and pulse oximeter measurements after surgical tourniquet release were not significantly different between two groups. Changes in blood gas parameters were significantly less pronounced in the RIP group. Conclusion: Remote ischemic preconditioning may not attenuate most of the adverse effects of surgical tourniquet deflation, including variations in heart rate, respiratory rate, and arterial oxygen saturation as well as blood pressure drops. However, RIP may reduce increases in systolic blood pressure and acidosis following tourniquet application.