Comparison of the Train-of-Four Fade Profiles Produced by Vecuronium and Atracurium

Abstract

In this double-blind study, we have allocated randomly 40 ASA I-III patients to one of four groups. After a standard anaesthetic induction, patients received vecuronium 0.08 mg kg-1 or 0.10 mg kg-1, or atracurium 0.4 mg kg-1 or 0.5 mg kg-1. Using an electromyogram (Datex Relaxograph) the train-of-four (TOF) response was measured during onset of and recovery from neuromuscular block. A greater degree of fade of TOF was observed with atracurium during onset of neuromuscular block than with equivalent doses of vecuronium. During recovery of neuromuscular transmission, vecuronium was associated with more fade than atracurium. The differences in the TOF profiles of these two drugs may be important when judging the adequacy of antagonism of neuromuscular block using the TOF response.

Avaliação do bloqueio neuromuscular residual e da recurarização tardia na sala de recuperação pós-anestésica

“…Assim, a galamina e a d-tubocurarina mostraram maior fadiga do que o pancurônio, refletindo maior afinidade dos dois primeiros pelo receptor nicotínico neuronal 10 . No que tange a afinidade de ocupação do atracúrio, vecurônio, mivacúrio e rocurônio, pode-se dizer que o efeito pré-sináptico é similar entre eles 11,18 . A constatação da presença de fadiga pode ser realizada por métodos clínicos ou com o auxílio de monitores da transmissão neuromuscular.…”

Train-of-four fade and neuromuscular block in rats: a comparison between pancuronium, vecuronium, and rocuronium

“…, the greater the affinity, the greater the TOF fade. 5,10,[12][13][14] If drug-dependent differences in TOF fade are determined pharmacodynamically, as with affinity for prejunctional receptors, the experiments studying this relationship should be performed under pseudo-steady-state conditions, such as in an organ bath. An organ bath allows the drug concentration to equilibrate between the bath and the neuromuscular junction and between the prejunctional and postjunctional sites, and fails to account for differences in the rate of drug diffusion and elimination.…”

“…Although it is generally accepted that the relationship between the TOF fade and neuromuscular block is constant, 1,2 previous clinical reports have shown differences in the magnitude of the TOF fade during the recovery phase for different NBA at the same level of neuromuscular block. [3][4][5][6] While nondepolarizing NBAs act mainly at the postjunctional site, some investigators have suggested that they also have a prejunctional effect that is responsible for the TOF fade. [7][8][9][10][11] Consequently, drug-dependent differences in TOF fade are believed to be a function of their prejunctional potency.…”

“…[7][8][9][10][11] Consequently, drug-dependent differences in TOF fade are believed to be a function of their prejunctional potency. 5,10,[12][13][14] However, Storella et al . 15 suggested that the differences observed clinically may be due to pharmacokinetic differences among drugs rather than any pharmacodynamic difference in potency at the site of action.…”

Pharmacokinetic Optimisation of General Anaesthesia in Pregnancy

“…Atracurium is metabolised by spontaneous degradation and the duration of action is unaltered by disease states (Agoston et al 1992) and is not prolonged in postpartum patients (Khuenl-Brady et al 1991). Offset of action with atracurium is rapid because it is metabolised even at the neuromuscular junction and it has less fade during offset of block than vecuronium (Fletcher et al 1992). Nevertheless, a peripheral nerve stimulator should be available to monitor neuromuscular block.…”