Influence of acute normovolaemic haemodilution on the dose‐response and time‐course of action of atracurium^Note

Abstract

We concluded that the patients undergoing acute isovolaemic haemodilution were about 30% more sensitive to neuromuscular blockade of atracurium and had a longer duration after administration of the same dose (microg/kg) than the control patients. Care must be taken with this problem when atracurium is used as a muscle relaxant during acute haemodilution.

Influence of acute normovolemic hemodilution on the potency and time course of action of rocuronium in rabbits

“…These findings are inconsistent in the current study, but on the other hand, they are consistent with previous results [6][7][8]. After ANH, the duration of vecuronium, atracurium, and rocuronium had increased by 32%, 33%, and 28%, respectively, due to an increase in muscle relaxant potency, hemodynamic changes, and changes in plasma electrolytes [6][7][8]. We suspect that the duration is not significantly influenced by the change in volume of distribution.…”

“…The effects of muscle relaxants such as rocuronium are determined by the distribution periods rather than the clear periods [21]; therefore, we expected that reducing plasma concentration by increasing the volume of distribution would decrease the duration of rocuronium. These findings are inconsistent in the current study, but on the other hand, they are consistent with previous results [6][7][8]. After ANH, the duration of vecuronium, atracurium, and rocuronium had increased by 32%, 33%, and 28%, respectively, due to an increase in muscle relaxant potency, hemodynamic changes, and changes in plasma electrolytes [6][7][8].…”

“…The ED50 of muscle relaxants was decreased after ANH as follows; succinylcholine (64%), pancuronium (60%), tubocurarine (53%) [5], vecuronium (22%) [6], atracurium (25%) [7] and rocuronium (42%) [8]. In this study, the ED50 of rocuronium had similarly decreased by 45% and 50% in the M and S groups, respectively, compared with the control group.…”

“…In this study, the ED50 of rocuronium had similarly decreased by 45% and 50% in the M and S groups, respectively, compared with the control group. The potency of muscle relaxants was influenced by the degree of protein binding with unbound muscle relaxant [7]. In this study, after ANH, it was found that plasma protein and albumin had decreased by 28% and 34% in the M group and by 43% and 53% in the S group, respectively.…”

“…After ANH, the duration and potency of succinylcholine, pancuronium, and tubocurarine increase [5]. The dose-response curves of vecuronium [6], atracurium [7], and rocuronium [8] are shifted to the left; further, duration and potency increase, but there are no effects on the dose-response curve and the duration of cisatracurium [9]. Published reports of muscle relaxant effects have evaluated the pharmacodynamics of muscle relaxants in moderate ANH (decrease in Hct 25%-28%), but there is no data on the effects of muscle relaxants in severe ANH (decrease in Hct below 20%), which is difficult to clinical trials [10].…”