Recurarization with magnesium sulfate administered after two minutes sugammadex reversal: A randomized, double-blind, controlled trial

Study objective: The current study tested the hypothesis that magnesium sulfate after reversal with sugammadex causes recurarization.Design: A single-center, prospective, randomized, double-blind, controlled trial.Setting: Terciary care hospital in Rio de Janeiro, Brazil.Patients: Included 60 patients undergoing for elective otolaryngological surgery.Interventions: All patients received total intravenous anesthesia and a single dose of rocuronium (0.6 mg/kg). In 30 patients, the neuromuscular blockade was reversed with sugammadex (4 mg/kg) at the reappearance of one or two posttetanic counts (deep-blockade series). In 30 other patients, sugammadex (2 mg/kg) was administered at the reappearance of the second twitch of the train-of-four (moderate-blockade series). After the normalized train-of-four ratio recovered to & GE;0.9, the patients in each series were randomized to receive intravenous magnesium sulfate (60 mg/kg) or placebo for 10 min. Neuromuscular function was measured by acceleromyography.Measurements: The primary outcome was the number of patients who exhibited recurarization (normalized train of-four ratio < 0.9). The secondary outcome was rescue with an additional dose of sugammadex after 60 min. Main results: In the deep-blockade series, a normalized train-of-four ratio < 0.9 occurred in 9/14 (64%) patients receiving magnesium sulfate and 1/14 (7%) receiving placebo, RR 9.0 (95% CI: 62-1.30), and (p = 0.002), with four rescues with sugammadex. In the moderate-blockade series, neuromuscular blockade recurred in 11/15 (73%) patients receiving magnesium sulfate and in 0/14 (0%) receiving placebo (p < 0.001), with two rescues. The absolute differences in recurarization were 57% and 73% in the deep-blockade and moderate-blockade, respectively.Conclusions: Single-dose magnesium sulfate led to a normalized train-of-four ratio < 0.9, 2 min after recovery from rocuronium-induced deep and moderate neuromuscular blockade using sugammadex. Additional sugammadex reversed prolonged recurarization.

Automated summary

The objective of this study was to test the hypothesis that magnesium sulfate after reversal with sugammadex causes recurarization. The study was designed as a single-center, prospective, randomized, double-blind, controlled trial. The results showed that in the magnesium sulfate group, 64% of patients with deep blockade and 73% of patients with moderate blockade experienced recurarization, while in the placebo group, only 7% and 0% of patients experienced recurarization, respectively. This study demonstrated that a single dose of magnesium sulfate led to recurarization in patients who had recovered from rocuronium-induced deep and moderate neuromuscular blockade using sugammadex, and additional sugammadex could reverse prolonged recurarization.