OBJECTIVE: To investigate the maximum dose of continuous mivacurium infusion for intraoperative neuromonitoring (IONM) and observe the adverse reactions during thyroid surgery under total intravenous anesthesia (TIVA). METHODS: Thirty patients undergoing IONM during thyroid surgery received continuous infusion of mivacurium at the initial rate of 14.97 μg · kg RESULTS: The EC CONCLUSIONS In patients undergoing thyroid surgery under TIVA, the EC
Anesthesia, Intravenous ; Humans ; Mivacurium ; Propofol ; Remifentanil ; Thyroid Gland

BACKGROUND: The timing principle entails administration of a single bolus of non-depolarizing muscle relaxant, followed by an induction agent at the onset of neuromuscular blockade. Three different mivacurium dose regimens were compared to determine its safety and efficacy for rapid tracheal intubation in Filipinos METHODS: Sixty ASA I or II patients, 20-65 years old, surgery requiring orotracheal intubation were randomly allocated into three groups. Group I received 0.20 mg/kg, Group II 0.25 mg/kg, and Group III 0.30 mg/kg mivacurium over for twenty seconds. At the onset of 3-5 percent change in TOF, considered as the onset time, anesthesia was induced with thiopental at 5 mg/kg; laryngoscopy was accomplished at 95 percent neuromuscular blockade. Intubating conditions were assessed according to the Copenhagen Consensus Conference CCC rating scale RESULTS: The mean onset times for Groups I to III were 64.5 +/- 16.6 seconds, 47.5 +/- 10.8 seconds and 21.5 +/- 7.96 respectively, while the time to 95 percent blocks were 85.5 +/- 30.7 seconds, 57.8 +/- 9.8 seconds, and 35.0 +/- 9.9 seconds. Intubating conditions were either good or excellent in all patients. All patients were satisfied with the manner of induction of anesthesia CONCLUSION: Mivacurium at a dose of 0.3 mg/kg using the timing principle consistently provided good to excellent intubating conditions, 35-45 seconds after induction of anesthesia and is an acceptable alternative to succinylcholine for rapid tracheal intubation. (Author)
Human ; Aged ; Middle Aged ; Adult ; Young Adult ; Adolescent ; INTUBATION, TRACHEAL ; ANESTHESIA ; LARYNGOSCOPY ; HEMODYNAMIC ; SUCCINYLCHOLINE ; MIVACURIUM ; NEUROMUSCULAR BLOCKADE

OBJECTIVE: To determine the maximum dose of continuously infused mivacurium for intraoperative neuromonitoring and observe its adverse effects in thyroid surgery. METHODS: Twenty-eight patients undergoing thyroid surgery with intraoperative neuromonitoring received continuous infusion of mivacurium at the initial rate of 5.43 μg?kg?min, and the infusion rate for the next patient was adjusted based on the response of the previous patient according to the results of neurological monitoring. The depth of anesthesia was maintained with sevoflurane and remifentanil during the surgery. The LD50 and 95% of mivacurium were calculated using Brownlee's up-and-down sequential method. RESULTS: The LD50 of continuously infused mivacurium was 8.94 μg?kg?min (95% : 8.89- 8.99 μg?kg?min) during thyroid surgery, which did not affect neurological function monitoring. Transient chest skin redness occurred after induction in 9 patients (32.1%). None of the patients experienced intubation difficulties or showed intraoperative body motions during the surgery. CONCLUSIONS In patients undergoing thyroid surgery under anesthesia maintained by inhalation and intravenous infusion, the LD50 of mivacurium was 8.94 μg?kg?min (95% : 8.89-8.99 μg?kg?min) for continuous infusion, which does not cause serious adverse effects during the operation.
Anesthesia ; Anesthetics, Inhalation ; Anesthetics, Intravenous ; Humans ; Intraoperative Neurophysiological Monitoring ; methods ; Lethal Dose 50 ; Mivacurium ; administration & dosage ; adverse effects ; Neuromuscular Nondepolarizing Agents ; administration & dosage ; adverse effects ; Remifentanil ; Sevoflurane ; Thyroid Gland ; surgery