Histamine release by neuromuscular blocking agents.

Histamine release by neuromuscular blocking agents Sir,—The design of the study by Naguib and colleagues [1] on the histamine releasing potencies of various neuromuscular blocking drugs resulted in cardiovascular changes which were profound, adverse and predictable. For example, the data sheet for mivacurium suggests administration over 5–15 s. The authors chose 5 s, despite quoting references which showed potential adverse haemodynamic changes caused by rapid administration of some benzylisoquinolinium neuromuscular blockers. Three minutes after administration of mivacurium, the control mean arterial pressure (MAP) of 76.0 mm Hg had decreased to a mean of 58.1 mm Hg, 2 SD below which gives an MAP of 43.7 mm Hg. Hypotension and tachycardia represents the worst possible combination of cardiovascular variables for myocardial perfusion, already compromised by covert coronary atherosclerosis at 60 yr of age, the maximum age in the study sample. El-Bakry AK. Histamine-release haemodynamic changes produced by rocuronium, vecuronium, mivacurium, atracurium and tubocurarine. Sir,—The design of our study [1] was not different from that of similar studies. For example, Basta and colleagues [2] and Moss and colleagues [3] administered atracurium and dimethyl-tubocurarine and tubocurarine, respectively, as a single rapid (5 s) bolus. Administration of mivacurium over 5 s is still within the recommendations of the manufacturer. However, slower administration of larger doses of benzylisoquinolinium compounds such as mivacurium 0.25 mg kg 91 , for example over 60 s, results in no significant changes in histamine concentrations or haemodynamic variables [4]. Therefore, with slower administration, the inherent differences between the neuromuscu-lar blocking drugs studied could not have been elicited. The dramatic scenario created by Dr Todd in his letter does not match our data. The patients in the mivacurium group were aged 20–41 (mean 28.4) yr. The ranges of mean arterial pressure and heart rate observed in this group were, respectively, 47–70 mm Hg and 76–93 beat min 91. For those patients who may be compromised cardiovascularly, it is clear that selecting a drug with less histamine release may be an appropriate choice. El-Bakry AK. Histamine-release haemodynamic changes produced by rocuronium, vecuronium, mivacurium, atracurium and tubocurarine. effects of mivacurium chloride (BW B1090U) in patients receiving nitrous oxide–opiate–barbiturate anesthesia. Sir,—I was surprised to find that reference No. 46 in the article by Phillips, Daborn and Hatch [1] concerning the osmolality of feeding mixtures during experimental injections of milk into tracheas was a reference more than 40 yr old. I would have hoped that …