High‐frequency, high‐intensity TENS compared to standard treatment with opioids for postoperative pain relief after laparoscopic cholecystectomy: A multicentre randomized controlled trial

Abstract Background Adverse effects of opioids could prolong the duration of stay in the post‐anaesthesia care unit (PACU). This study aimed to assess time in the PACU and the pain‐relieving effect of high‐frequency, high‐intensity transcutaneous electrical nerve stimulation (HFHI TENS) versus standard treatment with intravenous (IV) opioids. Methods Patients undergoing laparoscopic cholecystectomy at two Swedish hospitals were invited to participate. Patients reporting postoperative pain intensity ≥3 according to the Numeric Rating Scale (NRS) in the PACU were randomized to receive standard treatment with IV opioids or HFHI TENS, administered with an intensity of 40–60 mA for 1 min, repeated once if insufficient pain relief. If NRS remained ≥3 after two TENS stimulation the patients received IV opioids. Results In total, 163 patients were randomized to receive HFHI TENS ( n = 85) or IV opioids ( n = 78). There was no difference between the HFHI TENS group versus the opioid group regarding time in the PACU (138 min [SD 69] vs. 142 min [SD 95], mean difference −4.42 [95% CI–30:22], p = 0.74), time to pain relief NRS < 3 (median 10 min) and pain intensity at PACU discharge (NRS 1.7 [SD 1.45] vs. 1.6 [SD 1.20], p = 0.58). In the HFHI TENS group, 39 patients (46%) needed additional treatment with IV opioids. Mean opioid consumption was significantly lower in the HFHI TENS group than in the opioid group (4.5 vs. 11.0 morphine equivalents; p < 0.001). Conclusions HFHI TENS may be an opioid‐sparing alternative for postoperative pain relief. Significance Statement In this multicentre, RCT time in the PACU and the pain‐relieving effect of HFHI TENS was compared to standard treatment with IV opioids. There were no differences between the groups regarding time in the PACU, time to pain relief and side effects but opioid consumption in the HFHI TENS group was significantly lower. Both groups reported high satisfaction with pain treatment and care. In summary, HFHI TENS should be considered a safe, fast‐onsetting, opioid‐sparing option for postoperative pain relief.