Reversal of neuromuscular block with sugammadex: a comparison of the corrugator supercilii and adductor pollicis muscles in a randomized dose-response study.

BACKGROUND: Neuromuscular monitoring using the corrugator supercilii muscle is associated with a number of challenges. The aim of this study was to assess reversal of a rocuronium-induced neuromuscular blockade with sugammadex according to monitoring either using the corrugator supercilii muscle or the adductor pollicis muscle. We hypothesized that a larger dose of sugammadex would be required to obtain a train-of-four (TOF) ratio of 1.0 with the corrugator supercilii muscle than with the adductor pollicis muscle. METHODS: Forty patients aged 20-60 years and 40 patients aged ≥ 70 years were enrolled. After induction of anesthesia, we recorded the corrugator supercilii muscle response to facial nerve stimulation and the adductor pollicis muscle response to ulnar nerve stimulation using acceleromyography. All patients received 1 mg/kg rocuronium. When the first twitch (T1) of TOF recovered to 10% of control values at the corrugator supercilii, rocuronium infusion was commenced to maintain a T1 of 10% of the control at the corrugator supercilii. Immediately after discontinuation of rocuronium infusion, 2 mg/kg or 4 mg/kg of sugammadex was administered. The time for recovery to a TOF ratio of 1.0 and the number of patients not reaching a TOF ratio of 1.0 by 5 min at each dose and muscle was recorded. RESULTS: When neuromuscular block at the corrugator supercilii was maintained at a T1 of 10% of control, that at the adductor pollicis was deep (post-tetanic count ≤ 5). Sugammadex 4 mg/kg completely antagonized neuromuscular block at both muscles within 5 min. The time to a TOF ratio of 1.0 at the adductor pollicis was significantly longer in the group ≥ 70 years than the group 20-60 years (mean (SD): 178 (42.8) s vs. 120 (9.4) s, P < 0.0001). In contrast, 2 mg/kg sugammadex reversed neuromuscular blockade at the corrugator supercilii but not at the adductor pollicis, with 10 patients in the group 20-60 years and 8 patients in the group ≥ 70 years requiring an additional sugammadex (P < 0.05 vs. 4 mg/kg sugammadex). CONCLUSION: Sugammadex 4 mg/kg was required to reverse a moderate rocuronium-induced neuromuscular block when the corrugator supercilii muscle is used for monitoring.

Reversibility of rocuronium-induced profound neuromuscular block with sugammadex in younger and older patients.

BACKGROUND: This study compared the reversibility of rocuronium-induced profound neuromuscular block with sugammadex in younger and older patients. METHODS: Fifteen younger (20-50 yr) and 15 older (≥70 yr) patients were sequentially enrolled in this study. After induction of anaesthesia and laryngeal mask insertion, contraction of the adductor pollicis muscle in response to ulnar nerve stimulation was quantified using acceleromyography during 1.0-1.5% end-tidal sevoflurane and remifentanil anaesthesia. All patients initially received rocuronium 1 mg kg(-1), followed by 0.02 mg kg(-1) when a post-tetanic count (PTC) of 1 or 2 was observed. After completion of surgery, at reappearance of 1-2 PTC, the time required for a single bolus dose of 4 mg kg(-1) sugammadex to produce recovery to a train-of-four (TOF) ratio of 0.9 was recorded. RESULTS: There were no differences in the total dose of rocuronium administered between the younger [mean (sd): 93.4 (17.5) mg] and the older [97.5 (32.2) mg] groups. In all patients, adequate recovery of the TOF ratio to 0.9 was achieved after administration of sugammadex, although it was significantly slower in the older [3.6 (0.7) min, P<0.0001] than in the younger group [1.3 (0.3) min]. There were no clinical events attributable to recurarization. CONCLUSIONS: Sugammadex can adequately restore neuromuscular function in older patients, although a longer time is required to recover from profound rocuronium-induced neuromuscular block than in younger patients.

Normalization of acceleromyographic train-of-four ratio by baseline value for detecting residual neuromuscular block.

BACKGROUND: This study was designed to recognize the importance of normalizing postoperative acceleromyographic train-of-four (TOF) ratio by the baseline TOF value obtained before neuromuscular block for ensuring adequate recovery of neuromuscular function. METHODS: In 120 patients, TOF responses of the adductor pollicis to the ulnar nerve stimulation were monitored by acceleromyography (AMG) during anaesthesia using propofol, fentanyl and nitrous oxide. Control TOF stimuli were administered for 30 min. A TOF ratio measured at the end of control stimulation was regarded as a baseline value. Neuromuscular block was induced with vecuronium 0.1 mg kg(-1) and was allowed to recover spontaneously. Duration to a TOF ratio of 0.9 as calculated by AMG (DUR-raw 0.9) was compared with that of 0.9 as corrected by the baseline TOF ratio (i.e. 0.9 x baseline TOF ratio; DUR-real 0.9). RESULTS: Baseline TOF ratios ranged from 0.95 to 1.47. The average TOF ratios observed every 5 min were constant throughout control stimulation from at time zero mean (SD) [range]; 1.11 (0.09) [0.94-1.42] to at 30 min 1.13 (0.11) [0.95-1.47]. The DUR-real 0.9 was 91.0 (18.0) [51.3-131.0] min and was significantly longer than the DUR-raw 0.9 (81.2 (16.3) [41.3-123.0] min). CONCLUSIONS: Baseline TOF ratios measured by AMG are usually more than 1.0 and vary widely among patients. Therefore a TOF ratio of 0.9 displayed postoperatively on AMG does not always represent adequate recovery of neuromuscular function and should be normalized by baseline value to reliably detect residual paralysis.