A comparison between the adductor pollicis muscle and the abductor digiti minimi muscle using electromyography AF-201P in rocuronium-induced neuromuscular block: a prospective comparative study

Abstract

Background: The AF-201P, a new electromyography (EMG)-based neuromuscular monitor has been developed recently. The aim of this clinical study was to compare two ulnar nerve innervated muscles: the adductor pollicis (AP) muscle and the abductor digiti minimi (ADM) muscle during the recovery from rocuronium-induced neuromuscular block by using EMG AF-201P.

Methods: Twenty patients undergoing surgery with general anesthesia were enrolled in the study. During total intravenous general anesthesia, train-of-four (TOF) and post-tetanic counts (PTC) responses following 0.9 mg/kg rocuronium administration were concurrently monitored at the AP and the ADM muscles with EMG AF-201P on the opposite arms. At the end of the surgery, sugammadex 2 mg/kg was administered when TOF counts of 2 (TOFC2) was observed at both muscles. The primary outcome of the study was time from administration of rocuronium to first appearance of PTC response (first PTC). The secondary outcomes of the study were time from administration of rocuronium to TOF count of 1 (TOFC1), time from first PTC to TOFC1 (PTC-TOF time), time to TOFC2, and time from administration of sugammadex to TOF ratio ≥ 0.9. Agreement between the two muscles was assessed using the Bland-Altman analysis. Data are expressed as mean ± standard deviation.

Results: Nineteen patients were included in the analysis. Time to first PTC was significantly faster at the ADM muscle than the AP muscle (24.4 ± 11.4 min vs 32.4 ± 13.1 min, p = 0.006). PTC-TOF time was significantly longer with the ADM muscle than the AP muscle (19.4 ± 7.3 min vs 12.4 ± 10.6 min, p = 0.019). There were no significant differences in time to TOFC2 and sugammadex-facilitated recovery between the two muscles. Bland-Altman analyses showed acceptable ranges of bias and limits of agreement of the two muscles.

Conclusions: The ADM muscle showed a good agreement with the AP muscle during rocuronium-induced neuromuscular block but faster recovery of PTC response when using EMG.

Trial registration: UMIN-CTR (Registration No. UMIN000044904 ). Registered 19 July 2021 -Retrospectively registered, https://center6.umin.ac.jp/cgi-bin/ctr_e/ctr_view.cgi?recptno=R000051290 .

Keywords: Abductor digiti minimi muscle; Adductor pollicis muscle; Electromyography; Neuromuscular monitoring; Rocuronium; Sugammadex.

Fig. 1

Set up of the electromyography (AF-201P, Nihon-Kohden, Tokyo, Japan). A Monitoring the abductor pollicis (AP) muscle. B Monitoring the abductor digiti minimi (ADM) muscle

Fig. 2

Bland–Altman plot illustrating the differences of A onset time, B time to first post-tetanic count (PTC) response, C time to train-of-four (TOF) count of 1, D PTC-TOF time, E time to TOF counts of 2, and F recovery time between the adductor pollicis (AP) muscle and the abductor digiti minimi (ADM) muscle as a function of the two measurements. Onset time is defined as time from rocuronium administration to TOF count of 0. Time to first PTC is defined as time from rocuronium administration to first appearance of PTC response. Time to TOF count of 1 is defined as time from rocuronium administration to first reappearance of TOF count of 1. PTC-TOF time is defined as time from first appearance of PTC to first reappearance of TOF count of 1. Time to TOF counts of 2 is defined as time from rocuronium administration to TOF counts of 2. Recovery time is defined as the time from sugammadex administration to TOF ratio ≥ 0.9. Solid horizontal line represents the bias and dotted horizontal lines represent the upper and lower limits of agreement with 95% confidence intervals