• Tae-Yun Sung, Hwang-Ju You, Choon-Kyu Cho, Hey Ran Choi, Yong Beom Kim, Yong Sup Shin, and Hong Seuk Yang.
• From the Konyang University Hospital, Konyang University College of Medicine, Daejeon (T-YS, H-JY, C-KC), Inje University Seoul Paik Hospital, Seoul (HRC), Gachon University Gil Medical Center, Incheon (YBK), Chungnam National University School of Medicine, Daejeon (YSS) and Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (HSY).
• Eur J Anaesthesiol. 2018 Mar 1; 35 (3): 193-199.

BackgroundMagnesium potentiates the effects of nondepolarising muscle relaxants. However, few studies have used magnesium chloride (MgCl2). Sugammadex reverses neuromuscular block by steroidal nondepolarising muscle relaxants.ObjectivesTo assess the effects of MgCl2 on rocuronium-induced neuromuscular blockade and its reversal by sugammadex.DesignIn-vitro experimental study.SettingAnimal laboratory, Asan Medical Center, Seoul, South Korea, from 20 March 2016 to 3 April 2016.AnimalsForty male Sprague Dawley rats.InterventionLeft phrenic nerve-hemidiaphragms from 40 Sprague Dawley rats were allocated randomly to four groups (1, 2, 3 and 4 mmol l MgCl2 group, n = 10 each). Rocuronium was administered cumulatively until the first twitch of train-of-four (TOF) disappeared completely. Then, equimolar sugammadex was administered.Main Outcome MeasuresThe effective concentration (EC) of rocuronium was obtained in each group. After administering sugammadex, recovery of the first twitch height and the TOF ratio were measured for 30 min.ResultsEC50, EC90 and EC95 significantly decreased as the concentration of MgCl2 increased (all P ≤ 0.001), except the comparison between the 3 and 4 mmol l MgCl2 groups. After administration of sugammadex, the maximal TOF ratio (%) was lower in the 4 mmol l MgCl2 group than the 1 mmol l MgCl2 group [median 91.7 interquartile range (83.4 to 95.8) vs. 98.3 interquartile range (92.2 to 103.4), P = 0.049]. The mean time (s) from sugammadex injection to achieving maximal first twitch was significantly prolonged in the 4 mmol l MgCl2 group vs. the 1 mmol l MgCl2 and 2 mmol l MgCl2 groups [1483.9 (± 237.0) vs. 1039.0 (± 351.8) and 926.0 (± 278.1), P = 0.022 and 0.002, respectively].ConclusionIncreases in MgCl2 concentration reduce the ECs of rocuronium. In addition, administering sugammadex equimolar to the administered rocuronium shows limited efficacy as MgCl2 concentration is increased.Trial RegistrationThe in-vitro study was not registered in a database.

26 keywords...

hide…