Patients undergoing free flap reconstructive surgery for head and neck cancer with preoperative radiotherapy will be randomized to either remote ischemic preconditioning (RIPC) group or control group. On the day of surgery, after induction of anesthesia, RIPC, consisting of 4 cycles of 5-min ischemia (using pneumatic cuff pressure of 200 mmHg) followed by 5-min reperfusion at the upper arm, or sham-RIPC (pressure < 10 mmHg) will be induced in the RIPC or control group, respectively. Before completion of surgery, RIPC or sham-RIPC will be repeated. Tissue oxygen saturation and skin temperature of the flap will be recorded until postoperative day 1.~As a sub-study, blood samples will be obtained before and after RIPC/sham-RIPC. From them, plasma dialysate will be prepared to use for Langendorff isolated heart model. Myocardial infarct size of Langendorff rat heart will be compared between the groups to evaluate organ protective effects of RIPC during free flap reconstructive surgery.
Remote ischemic preconditioning (RIPC) has shown organ-protective effects in many clinical settings including patients with ischemic heart disease. However its protective role in head and neck cancer patients with preoperative radiotherapy undergoing free flap reconstructive surgery has not yet been evaluated. The purpose of the current study is to evaluate the effect of RIPC on tissue oxygen saturation and skin temperature of the flap, as well as its organ-protective effects using Langendorff isolated heart ischemia-reperfusion model.