Effects of electroacupuncture with different wave forms on remifentanil-induced hyperalgesia after surgery

Abstract

Objective To evaluate the effects of electroacupuncture(EA)with different wave forms on remifentanil-induced hyperalgesia after surgery. Methods A total of 80 patients, aged 18-50 yr, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, with body mass index of 18-25 kg/m2, scheduled for elective splenectomy, were divided into 4 groups(n=20 each)using a random number table method: remifentanil group(group R), disperse-dense wave plus remifentanil group(group DR), continuous wave plus remifentanil group(group CR), and intermittent wave plus remifentanil group(group IR). In CR, DR and IR groups, Hegu and Sanyinjiao acupoints were stimulated for 1 h with disperse-dense wave(1 mA, 2/15 Hz), continuous wave(1 mA, 15 Hz)and intermittent wave(1 mA, 15/0 Hz), respectively, starting from 30 min before induction of anesthesia.The needle was reserved in the acupuncture points from the end of stimulation until the end of surgery.Patient-controlled intravenous analgesia was performed for 48 h with sufentanil 150 μg and tropisetron 8 mg dissolved in 150 ml of normal saline after leaving the postanesthesia care unit.Patient-controlled analgesia pump was programmed to deliver a 1 ml bolus dose with a lockout interval of 20 min and background infusion at 2 ml/h, and visual analogue scale score was maintained<4.Decozine 5 mg was intravenously injected as rescue analgesic when visual analogue scale score≥4.The consumption of intraoperative remifentanil and consumption of sufentanil and requirement for rescue analgesic within 48 h after surgery were recorded.Patients′ comfort was assessed and scored, and the pain threshold around the incision site was recorded at 48 h after surgery. Results There were no significant differences in the consumption of intraoperative remifentanil among the four groups(P>0.05). Compared with group R, the consumption of sufentanil was significantly reduced, the comfort score and pain threshold around the incision site were increased, and the incidence of nausea and vomiting was decreased in DR, CR and IR groups, the requirement for rescue analgesic was significantly decreased in group DR(P 0.05). Conclusion EA with disperse-dense wave stimulation can provide optimal efficacy in inhibiting remifentanil-induced hyperalgesia after surgery. Key words: Electroacupuncture; Piperidines; Hyperalgesia