Comparison of four facial muscles, orbicularis oculi, corrugator supercilii, masseter or mylohyoid, as best predictor of good conditions for intubation: A randomised blinded trial

CONTEXTMonitoring of facial muscles after neuromuscular blockade can give an early indication of respiratory muscle readiness for tracheal intubation. OBJECTIVETo assess which facial muscle, the orbicularis oculi, corrugator supercilii, masseter or the mylohyoid, is the best predictor of readiness for intubation after rocuronium. DESIGNProspective, randomised, blinded trial. SETTINGSingle centreSeoul, Korea, from August 2012 to November 2012. PATIENTSTwo hundred and eighty-eight patients aged 22 to 64 years were randomised to one of eight study groupsorbicularis oculi, corrugator supercilii, masseter and mylohyoid for rocuronium 0.6 or 1.2 mg kg. INTERVENTIONThe maximum twitch depression at the eyelid (orbicularis oculi), the superciliary arch (corrugator supercilii), the cheek (masseter) and the submental triangle (mylohyoid) was assessed after rocuronium 0.6 and 1.2 mg kg. Endotracheal intubation was performed after maximal neuromuscular blockade, and intubating conditions were appraised. MAIN OUTCOME MEASURESThe onset time of rocuronium and the quality of the intubation conditions were assessed. RESULTSThe onset times in the orbicularis oculi, corrugator supercilii and masseter were significantly faster than that in the mylohyoid (P