Cardiovascular and autonomic nervous effects of edrophonium and atropine combinations during neuromuscular blockade antagonism in sheep

R. E. Clutton, M. A. Glasby

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Abstract

Objective To study heart rate (HR), arterial blood pressure (BP) and autonomic nervous (AN) effects of edrophonium-atropine combinations during neuromuscular blockade (NMB) antagonism in sheep. Experimental design Randomized, prospective and experimental study. Animals Seventy-eight Scottish blackface ewes; mean age: 4.5 years; mean body mass: 54 kg. Methods After induction with IV etomidate (0.5 mg kg(-1)) and midazolam (0.5 mg kg(-1)), anaesthesia was maintained with halothane and NMB produced with atracurium or mivacurium. In the first study (n = 53), the electrocardiographic (ECG), HR, BP and AN effects of low (40 mu g kg(-1)) and high (80 mu g kg(-1)) atropine doses combined with either of two edrophonium doses (0.5 or 1.0 mg kg(-1)) were investigated. These variables were also measured in a second study when edrophonium (1.0 mg kg(-1)) was administered 5 minutes before atropine (80 mu g kg(-1)) and vice versa. Data were analysed using one-way within-subjects and repeated measures ANOVA. Results In the first study, all combinations reversed NMB but significantly (p <0.001) increased HR and BP within 2 minutes without arrhythmias. In the second study, edrophonium (1.0 mg kg(-1)) significantly increased HR and BP, saliva flow (n = 1) and lung sounds (n = 3) and caused ECG changes (n = 1). Cardiovascular changes were partially reversed by atropine (80 mu g kg(-1)) administered 5 minutes later. Administered first, atropine (80 mu g kg(-1)) significantly decreased HR and BP effects which were fully (HR) and partially (BP) reversed by edrophonium (1 mg kg(-1)) administered 5 minutes later. Conclusion and clinical relevance The cardiovascular effects of edrophonium and atropine were opposite to those reported in humans and dogs. Edrophonium (0.5 mg kg(-1)) and atropine (80 mu g kg(-1)) caused the mildest HR changes without ECG and noncardiac AN disturbances, and is recommended for the antagonism of NMB in sheep.
Original languageUndefined/Unknown
Pages (from-to)191-200
Number of pages10
JournalVeterinary Anaesthesia and Analgesia
Volume35
Issue number3
DOIs
Publication statusPublished - 2008

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