Dexamethasone concentration affecting rocuroniuminduced neuromuscular blockade and sugammadex reversal in a rat phrenic nerve-hemidiaphragm model: An ex vivo study

Background: The concentration range of dexamethasone that inhibits neuromuscular blockade (NMB) and sugammadex reversal remains unclear. Objective: To evaluate the effects of dexamethasone on rocuronium-induced NMB and sugammadex reversal. Design: Ex vivo study. Setting: Asan Institute for Life Sciences, Asan Medical Center, Korea, from July 2015 to November 2015. Animals: One hundred sixty male Sprague-Dawley rats. Interventions: We assessed the effect of four concentrations of dexamethasone [0, 0.5, 5 (clinical concentrations) and 50mgml-1 (experimental concentration)] on partial NMB on 40 phrenic nerve-hemidiaphragm preparations (n = 10 per concentration). Once the first twitch of train-offour (TOF) had been depressed by 50% with rocuronium, dexamethasone was administered. To assess the effect of dexamethasone on sugammadex reversal, 120 phrenic nerve-hemidiaphragm preparations were used in three subexperiments (n = 40 per experiment), using three administration regimens of rocuronium-equimolar sugammadex: a single dose, a split-dose (split 1/2 and 1/2) and a reduced split-dose (split 1/2 and 1/4). After complete NMB was achieved, dexamethasone and sugammadex were administered. Main Outcome Measures: The change in the first twitch height, the recovery time to a TOF ratio at least 0.9, and the TOF ratio at 30 min were evaluated. Results: There were no significant differences in the first twitch height among groups (P = 0.532). With a single dose of sugammadex, dexamethasone did not affect the recovery time to a TOF ratio at least 0.9 (P = 0.070). After using a split-dose of sugammadex, the recovery time to a TOF ratio at least 0.9 was delayed only at a concentration of 50mgml-1 of dexamethasone. With a reduced split-dose of sugammadex, the TOF ratio at 30 min was lowered only by a concentration of 50mgml-1 of dexamethasone (P<0.010). Conclusion: Acute bolus administration of dexamethasone at clinical concentrations had no effect on NMB or on sugammadex reversal.