The aim of this study is to determine the recovery time of moderate neuromuscular blockade with sugammadex in adults pretreated with magnesium sulfate.

Sugammadex is a novel neuromuscular blocking reversal agent. Its mechanism of action is the encapsulation of rocuronium and vecuronium molecules. Numerous studies show a potential role of magnesium in reducing anesthetic requirements, sympathetic response to surgical trauma, antinociceptive action and neuroprotective effects. However, its use is limited because magnesium potentiates non-depolarizing neuromuscular blocking agents.

Primary outcome: evaluate the effect of pretreatment with magnesium sulfate on the time reversal with sugammadex (recovery of the T4/T1 ratio = 0.9) of moderate neuromuscular blockade (two answers to a train-of-four TOF) induced by rocuronium.

Secondary outcome: evaluate severe respiratory events, the incidence of residual neuromuscular blockade in the post anesthesia recovery room and postoperative pain.

Inclusion Criteria:

• Age 18-65 years
• ASA physical status 1 or 2
• weight BMI 18.5-24.9
• otorhinolaryngological surgeries

Exclusion Criteria:

• major surgery associated with massive blood loss or fluid replacement
• any known allergy to magnesium sulphate or any other study drugs
• pregnant
• anatomical malformations expected to result in a difficult intubation;
• known or suspected neuromuscular disorders and/or significant hepatic or renal dysfunction
• administration of any medication known to interfere with neuromuscular blocking agents (such as anticonvulsants, aminoglycosides, calcium channel blockers and magnesium containing medications)
• hypomagnesemia, hypermagnesemia, hypocalcemia, hypercalcemia