The analgesic efficacy of forearm versus upper arm intravenous regional anesthesia (Bier's block): A randomized controlled non-inferiority trial

Abstract

Study objectiveThis study aimed to assess if a forearm (FA) intravenous regional anesthesia (IVRA) with a lower, less toxic, local anesthetic dosage is non-inferior to an upper arm (UA) IVRA in providing a surgical block in patients undergoing hand and wrist surgery. DesignObserver-blinded, randomized non-inferiority study. SettingOperating room. Patients280 patients undergoing hand surgery were randomly assigned to UA IVRA (n = 140) or FA IVRA (n = 140). InterventionsForearm IVRA or upper arm IVRA in patients undergoing hand and wrist surgery. MeasurementsThe primary outcome was block success rate of both techniques. Block success was defined as no need of additional analgesics. A second, alternative non-inferiority outcome was defined as no need of conversion to general anesthesia. A difference in success rate of <5% was considered non-inferior. Secondary endpoints were tourniquet pain measured with a Numerical Rating Scale (0−10), satisfaction of patients and surgeons, onset time, surgical time and total OR time. Main resultsNon-inferiority of block success rate, defined as no need of additional analgesics or conversion to general anesthesia was inconclusive (5.24%, 95% CI:-4.34%,+14.82%). Non-inferiority of no need of conversion to general anesthesia was confirmed (+0.73%, 95% CI:-0.69%,+2.15%). No differences were observed in onset time (FA: 5 (5, 8) vs UA: 6 (5, 7) min, p = 0.74), surgical time (FA: 8 (5, 12) vs UA: 7 (5, 11) min, p = 0.71), nor total OR stay time (FA: 34 (27, 41) vs UA: 35 (32, 39) min, p = 0.09). Tourniquet pain after 10 min was significantly lower after FA IVRA compared to UA IVRA (FA: 2.00 (0.00, 4.00) vs UA: 3.00 (1.00,5.00) min, p = 0.003). ConclusionWe failed to demonstrate non-inferiority of forearm IVRA with a lower dosage of LA in providing a surgical block without rescue opioids and LA. Non-inferiority of no need of conversion to general anesthesia was confirmed.