The hemodynamic and respiratory effects of Remote Ischemic Preconditioning on patients undergoing lower limb orthopaedic surgery

Aim and Arterial tourniquets are used widely for extremity orthopedic surgeries with regional or general anesthesia to reduce blood loss، but the harmful effect of ischemia and reperfusion is not clear yet. In this clinical trial 40 patients scheduled for lower extremity surgery with pneumatic tourniquet were randomized into 2 groups: a remote ischemic preconditioning (RIP group، n=20)، in which patients received three “5 minutes” cycles of ischemia، alternating with 5 minutes of reperfusion before extended use of tourniquet and a control group (n=19). Hemodynamic variables prior to inflation of tourniquet and every 30 minutes during the surgery and 10 minutes after tourniquet deflation and arterial blood gas sample prior to and after surgery were compared between groups. In comparison with the baseline values، systemic blood pressure was increased in all patients، however in control group it was significantly more than baseline values and also higher than the RIP group (p=0. 03 and p=0. 032 respectively). There was no significant change in heart rate and O2 saturation and Spontaneous respiratory rate between the groups and in comparison with baseline values. Tourniquet application in limb surgery can cause hemodynamic changes and remote ischemic preconditioning can not attenuate these effects such as variation of blood pressure، heart rate and changes of respiatory rate and arterial O2 saturation. However RIP can reduce inceases in systolic blood pressure and acidosis.