Clinical study of ischemic preconditioning in alleviating early postoperative pain in patients undergoing total knee arthroplasty

Abstract

Objective To evaluate the effect of ischemic preconditioning(IPC) on early postoperative pain in patients undergoing total knee arthroplasty. Methods A prospective randomized controlled trial of 40 patients undergoing elective total knee arthroplasty was performed in the First Affiliated Hospital of Anhui Medical University from October 2015 to April 2016.Patients (18-65 years old) with ASA grade Ⅰ-Ⅲ(American Society of Anesthesiologists), were randomly divided into control group and ischemic preconditioning(IPC) group, 20 patients in each group. In the IPC group, ischemic preconditioning was performed before the operation of completely blood block to the lower limbs of the operation side, the tourniquet was inflated for 5 min and deflated for 5 min, for a total of 2 cycles. In the control group, only the tourniquet was attached without inflation or deflation before the surgery completely blocked the lower limb blood supply. The basic information of the general clinical data, tourniquet block time and operation time of the two groups were recorded and compared. The mean arterial pressure (MAP), heart rate (HR) and oxygen saturation (SpO2) were measured before surgery, 30 minutes after the upper tourniquet, and at the end of the operation. Resting pain scores (VAS) were recorded at recovery time, 6 h after surgery, and 24 h after surgery. The number of pain remedies within 24 hours after surgery was recorded. Venous blood was collected 24 hours after surgery to detect the levels of creatine kinase(CK) and interleukin-6 (IL-6) in the blood. Results There were no significant differences in the general clinical data, tourniquet blockade time, and operation time between the two groups (P>0.05). There were no significant differences in MAP, HR and SpO2 between two groups at each time point (P>0.05). The VAS score (3.10±1.02) point in the IPC group was significantly lower than that in the control group (5.45±0.99) point (t=7.394, P 0.05). The number of pain remedies in the IPC group, was significantly lower than that in the control group at 24 hours after surgery (χ2=4.803, P 0.05). The serum IL-6 level was significantly lower in the IPC group(50.11±20.39) pg/mL than in the control group (70.80±34.82) pg/mL (t=6.628, P<0.05). Conclusions Ischemic preconditioning attenuates early postoperative pain and reduces the number of pain relief patients in total knee arthroplasty. The mechanism may be related to the reduction of inflammatory response by ischemic preconditioning. Key words: Reperfusion injury; Ischemic preconditioning; Interleukin-6; Arthroplasty, replacement, knee; Pain