The MASTER Trial has successfully addressed requirements of protocols for large trials.

ter, during the insertion of a catheter into the radial artery, the patient became agitated with involuntary, spasmodic movements of both arms (myoclonic jerks). While unresponsive to verbal commands, he was hemodynamically stable and breathing spontaneously (SaO2 96% with O2 delivered at 3 L/min through a face mask). Interpreted as a paradoxical response to midazolam, intravenous boluses of propofol were given resulting in upper airway obstruction necessitating endotracheal intubation (thiopental 200 mg, rocuronium 40 mg, fentanyl 100 g). Anesthesia was maintained with desflurane and nitrous oxide. The surgery was uneventful. On emergence from anesthesia, the myoclonic jerks were observed again and the trachea remained intubated. In the recovery room, further examination of previous blood tests showed a low magnesium level of 0.52 mmol/L prompting the administration of 2 g magnesium over 15 min. The myoclonic jerks resolved and the trachea was extubated. The neurological examination on the next day was normal. We propose that the unusual occurrence of myoclonic jerks in this patient was a manifestation of metabolic encephalopathy (hypomagnesemia and chronic renal failure) combined with central sensory deafferentation from neuraxial blockade and midazolam.