Intubating conditions and neuromuscular block after divided dose mivacurium or single dose rocuronium

Abstract

Purpose: To evaluate the tracheal intubating conditions and neuromuscular blocking charactenstics of divided dose mivacurium or single dose rocuronium. Methods: Thirty-two patients undergoing elective surgery were studied. Anaesthesia was with propofol 2 mg.kg -~ , followed by an infusion of 150/t/g.kg-l-min -I. Patients were randomized to receive either mivacurium-0.15 mg'kg -~ followed 30 sec later by 0. I mg-kg -I, or rocuronium-0.9 mg'kg -I, followed 30 sec later by placebo. Tracheal intubating conditions were assessed 90 sec after the initial dose of relaxant by an anaesthetist who was unaware of patient group. The electromyographic (EMG) response of the first dorsal interosseus muscle to ulnar nerve train-of-four was measured. Results: Successful tracheal intubation was performed in all patients after both mivacurium and rocuron~um. Intubating conditions (jaw relaxation, open visible vocal cords) were judged to be good-excellent in all but one patient before insertion of the tracheal tube. However, patients receiving mivacurium were more likely to experience coughing and bucking after tracheal tube insertion (10/I 6 patients) than those receiving rocuronium (3/I 6 patients, P < 0.05). No patient in the rocuronium group experienced moderately vigorous coughing and bucking after insertion of the tracheal tube vs six patients in the mivacurium group (P < 0.05). Time to I 0 and 25% recovery of neuromuscular function was faster (P < 0.05) after divided dose mivacunum (20 + I and 23 -+-I min, respecttvely) than after rocuronium (45 +--5 and 57 4-8 min, respectively). Conclusion: The results suggest that, during conditions of the study, dMded dose mivacurium is not recommended for a 90-sec tracheal intubation in patients where moderate coughing and bucking is deemed unacceptable. Obj 9: I~valuer les conditions de I'intubation de la tract'~e et les caract&istiques du bloc neuromusculaire au mivacurium ,5 dose fractionn~e et au nocuronium i~ dose unique. M~thodes : Cette ~tude r~unissait 22 patients programrr~s pour une chirurgie non urgente. I'anestl%sie ~tait r~alis~e avec du propofol 2 mg'kg -I, sum d'une perfusion de 150/Jg.kg -P.min -~. Les patients recevaient al~atoire-ment soit du mivacurium 0,15 mg'kg -~ sum 30 sec plus tard par 0, I mg.kg -I, soit du rocuronium 0,9 mg.kg -~, suivi 30 sec plus tard d'un placebo. Les conditions d'intubation de la trachf_~e ~taient ~valu~_~es 90 sec aprcSs la dose initiale de myorelaxant par un anesth~siste ignorant le groupe auquel le patient appartenait. La r~ponse ~lectromyo-graphique (EMG) ,~ la stimulation au train-de-quatre (TOF) du premier muscle interosseux dorsal ~tait mesur~ae. l~.sultats : I'intubation de la trach~e a ~t~ r~Jssie chez tous les patients des deux groupes. Les conditions d'intubation (relaxation de la m~choire, visualisation de cordes vocales b~antes) avant I'insertion de la canule trach6ale ~taient jug~es de bonnes ,~ excellentes chez tousles patients ~ rexception d'un seul. Cependant, les patients sous mivacurium ~ataient plus sujets i~ la toux et a...

Intubating conditions and blockade after mivacurium, rocuronium and their combination in young and elderly adults

“…It is likely that smaller doses would have produced longer onset times and poorer intubating conditions. For rocuronium, the lowest dose reported to be consistent with acceptable intubating conditions, or 0.6 mg·kg -1 , [17][18][19] was used, because larger doses are associated with a prolonged duration of action. 18 The combination dose was based on the reported value of 62% for the synergism between both drugs, that is 31% of each drug given together produces an effect equivalent to 100% of either drug given alone.…”

“…To obtain a fast onset, one could increase the dose of rocuronium to 0.9 mg·kg -1 , but the duration of action would be increased considerably. 19,20 Intubating conditions were assessed at 2.5 min in the present study. The time chosen for this procedure appears rather arbitrary, as intervals varying between one minute and three minutes have been chosen by various investigators.…”

“…The time chosen for this procedure appears rather arbitrary, as intervals varying between one minute and three minutes have been chosen by various investigators. 15,17,[19][20][21][22][23] It is expected that intubating conditions would have been less optimal if a shorter interval had been used. Conditions reported here might appear worse than in most published studies.…”

Onset of vecuronium-induced neuromuscular block after a long priming interval

“…However, in previous studies in which the time of onset of rocuronium-or mivacurium-induced neuromuscular block was investigated, the definitions of the onset time differed to some extent. Patel et al [8], Cooper et al [4], and Pühringer et al [9] defined the onset of neuromuscular block as the state in which the T1/control value was 0, was minimum, and was 0.05, respectively. Only Patel et al [8] regarded the onset of neuromuscular block as a T1/control value of 0, as in our study.…”

“…Patel et al [8], Cooper et al [4], and Pühringer et al [9] defined the onset of neuromuscular block as the state in which the T1/control value was 0, was minimum, and was 0.05, respectively. Only Patel et al [8] regarded the onset of neuromuscular block as a T1/control value of 0, as in our study. They noted that the times to the onset of rocuronium 0.9 mg·kg Ϫ1 -and mivacurium 0.25 mg·kg Ϫ1 -induced neuromuscular block were 108 s and 183 s, respectively.…”