Tracheal intubation conditions after one minute: rocuronium and vecuronium, alone and in combination

Abstract

SummaryRocuronium is a recently introduced nondepolarising neuromuscular blocking agent with a rapid onset and intermediate duration of action. Experimental observations have suggested that during onset it acts synergistically with other nondepolarising agents, but that at a steady state the combined action is additive. In order to investigate whether synergism during onset produces a clinical benefit we performed the following study of tracheal intubation conditions. Consenting patients presenting for elective surgery which required tracheal intubation were randomly allocated to receive a standard anaesthetic and either a twice ED 95 dose of rocuronium, or vecuronium, or an equipotent mixture of both drugs. Tracheal intubation conditions were assessed after 60 s and scored as excellent, good, poor or impossible. The conditions produced in the rocuronium and the mixture groups were similar and both were significantly better than those of vecuronium. Excellent intubation conditions were achieved in 57% of the rocuronium group, 70% of the mixture group and 27% of the vecuronium group. We conclude that a mixture of rocuronium and vecuronium acts synergistically during the early part of their action and a mixture containing one ED 95 of both agents provides comparable conditions for tracheal intubation as an equipotent dose of rocuronium. Rocuronium is a nondepolarising neuromuscular blocking drug which provides a rapid onset of action with an intermediate duration [1][2][3]. It is particularly useful for patients who require rapid tracheal intubation as it reliably provides good intubation conditions within 1 min of intravenous administration [1][2][3][4].A chance observation in an earlier study suggested that a mixture of rocuronium and vecuronium provided a faster onset of neuromuscular blockade than an equipotent dose of rocuronium alone, even though the maximum degree of blockade attained remained unaffected. Naguib reported that a mixture of rocuronium and mivacurium has an additive action at a steady state, but a review of his results supports the observation of a faster speed of onset for a combination of rocuronium with mivacurium [5]. Kim & Cho have also studied the interaction of rocuronium with mivacurium [6]. A review of their results suggests that the onset times of mixtures of mivacurium and rocuronium are shorter than would be anticipated if the two drugs had an additive action. However, their results also show that the recovery indices of the mixtures are close to that expected for an additive action of the two drugs during recovery. These studies imply that rocuronium may act synergistically with other nondepolarising agents during onset of blockade, but that when a steady state is reached the early synergistic effect is overwhelmed by an alternative mechanism of action which results in an additive effect with other nondepolarising drugs. It also implies that the quality of tracheal intubation conditions achieved after 1 min might be enhanced by using an equipotent mixture of rocuronium with anothe...

A Comparative Study of Intubating Conditions and Haemodynamic Effects Following Vecuronium, Rocuronium and Its Combination

“…Synergism of combination of rocuronium and vecuronium was also observed by England AJ and colleagues, 7 who noted excellent to good intubating conditions at 60sec in 90% of patients receiving combination of vecuronium and rocuronium. Neeti M and colleagues 8 also noted excellent to good intubating conditions at 60sec in 93.3% of patients receiving combination of vecuronium and rocuronium.…”

“…7,8 Nigrovic and colleagues 9 have postulated that the neuromuscular blocking agents belonging to different chemical groups (Isoquionoline or aminosteroid) display an inverse pattern of affinities for the two α-subunits and, when present together, produce a synergistic neuromuscular block. This hypothesis does not satisfactorily explain the synergistic behaviour of the combination of structurally similar rocuronium and vecuronium.…”

“…The proposed early presynaptic action could explain synergism between rocuronium and vecuronium developing during early stages of blockade. 7 Our study population consisted of 90 ASA grade I & II patients in the age group 20-60 years who were allocated into three groups -Group V, Group R, Group RV with the sample size of 30 in each group.…”

Neuromusular Blockade of Inj. Atracurium and Inj. Vecuronium

“…England, M. F. Morgarson and S. A. Feldman studied comparison of mixture of vecuronium and rocuronium with either vecuronium or rocuronium for quality of condition for tracheal intubation at one minute. (15) Excellent intubation conditions were achieved in 57% of the rocuronium group, 70% of mixture group and 27% of rocuronium group. Adequate intubating conditions are dependent on depth of anaesthesia, skill of endoscopist and muscle relaxation.…”

Pharmacoeconomics and Pharmacodynamic Interactions of Rocuronium and Pancuronium

“…However, Meretoja et al [23] showed synergistic interaction between atracurium and mivacurium which are structurally benzylisosquinolines. Similarly, England et al [24] showed that a mixture of rocuronium and vecuronium acts synergistically during early part of their action. e present study examined the combination of pancuronium and rocuronium to evaluate the possibility of synergism between the two.…”