The heart rate following edrophonium-atropine and edrophonium-glycopyrrolate mixtures

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

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 microg kg(-1)) and high (80 microg 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 microg 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 microg kg(-1)) administered 5 minutes later. Administered first, atropine (80 microg 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 microg kg(-1)) caused the mildest HR changes without ECG and noncardiac AN disturbances, and is recommended for the antagonism of NMB in sheep.

Effects of four anticholinesterase-anticholinergic combinations and tracheal extubation on QTc interval of the ECG, heart rate and arterial pressure

BACKGROUND

Imbalance in cardiac sympathetic tone causes prolongation of the QTc interval of the ECG. On the other hand, impairment of the parasympathetic control of the heart rate caused by anticholinesterase-anticholinergic combinations might also affect the cardiac sympathetic tone and hence the QTc interval of the ECG. The main purpose of the present study was to compare the effects of four anticholinesterase-anticholinergic combinations used for the antagonism of the neuromuscular block on the QTc interval of the ECG, heart rate and arterial pressure.

METHODS

Eighty-four ASA class I-II patients with a mean age of 32 to 37 yr undergoing otolaryngological surgery were randomly allocated to one of the following groups: neostigmine 40 microg/kg+glycopyrronium 8 microg/kg (Ne-Glyc), neostigmine 40 microg/kg+atropine 20 microg/kg (Ne-Atr), edrophonium 200 microg/kg+atropine 300 microg (Edr-Atr (1)), edrophonium 500 microg/kg+atropine 7 microg/kg (Edr-Atr (2)). QTc interval and heart rate were measured by a signal processing method based on an IBM/PC/xT-compatible microcomputer and arterial pressure with a sphygmomanometer at 1-min intervals up to 10 min after the injection of the drugs and immediately and 2 min after extubation. The ECG, lead II, was continuously recorded. Neuromuscular block was measured by a Datex relaxograph.

RESULTS

In all groups, the most pronounced increase in both QTc interval, heart rate and arterial pressure occurred 1 min after the study drugs and immediately after extubation. In all groups, the mean QTc intervals at 1 and 2 min after the study drugs and after extubation were longer than the upper limit of the normal range (440 ms). Junctional rhythm occurred in 1 to 3 patients in all other groups with the exception of the Edr-Atr(1) group in which no cardiac arrhythmias occurred. At 1 min, the heart rate in the Ne-Atr group was at a significantly higher level than that in the Ne-Glyc group. From 3 to 6 min, the heart rate in the Edr-Atr(2) group and at 3 min in the Edr-Atr(1) group was at a lower level than the heart rate in the Ne-Glyc group.

CONCLUSIONS

On the basis of the present results, anticholinesterase-anticholinergic combinations should be avoided in patients having a long QT interval syndrome or a prolonged QT interval from other causes. In addition, the cardiovascular stimulation caused by tracheal extubation should also be avoided in these patients.

Reversal of residual neuromuscular block with neostigmine at one to four hours after a single intubating dose of vecuronium

The purpose of this study was to measure the degree of residual neuromuscular block at different times after a single dose of vecuronium, and to evaluate the effectiveness of two different doses of neostigmine in antagonizing this residual block. Train-of-four (TOF) ratios were examined for up to 4 h after a single dose of vecuronium, 0.1 mg/kg, in 60 patients during nitrous oxide/isoflurane/fentanyl anesthesia. The effect of neostigmine, 40 micrograms/kg, was studied at 1,2,3, or 4 h. The effect of neostigmine, 20 micrograms/kg, was studied at 2 or 4 h after the vecuronium. Before neostigmine administration, the TOF ratio was less than 0.75 in 17 patients (including one patient at 4 h). Neostigmine produced an increase in TOF ratio in 52 patients and a decrease in 8. The TOF ratio decreased after neostigmine only, at 2,3, or 4 h after vecuronium, when the TOF ratio was > or = 0.9 and when neostigmine 40 micrograms/kg was administered. One patient, at 1 h, had a TOF ratio of 0.00 and this did not reach 0.75 until 57 min after neostigmine, 40 micrograms/kg. There was a high incidence (50%) of adverse cardiovascular effects after both doses of neostigmine. In making the decision as to whether neostigmine should be administered, the risk to the patient of residual neuromuscular block must be balanced against the adverse cardiovascular effects of the neostigmine.

Autonomic and cardiovascular effects of neuromuscular blockade antagonism in the dog

Autonomic and cardiovascular changes were studied when neuromuscular blockade was antagonized in 96 dogs with one of eight anticholinesterase-antimuscarinic drug combinations. Neostigmine (50 or 100 micrograms/kg) was administered before or after atropine (40 micrograms/kg) or glycopyrrolate (10 micrograms/kg). The high dose of neostigmine (100 micrograms/kg) caused bradyarrhythmias, salivation, and signs of bronchosecretion when used with either antimuscarinic agent and irrespective of the administration sequence. The heart rate increased, but not significantly, when atropine was injected before either dose of neostigmine. This did not occur when this administration sequence was reversed. Arrhythmias and cardiovascular and autonomic changes did not occur when glycopyrrolate was injected before or after neostigmine at 50 micrograms/kg.

Comparison of the combined effects of atropine and neostigmine with atropine and edrophonium on the lower oesophageal sphincter

In two groups (n = 11) of healthy patients, we have measured gastric, lower oesophageal and barrier pressures before and after antagonism of neuromuscular block during anaesthesia with nitrous oxide and isoflurane. In one group, atropine 1.2 mg and neostigmine 2.5 mg were given and in the second group atropine 0.6 mg with edrophonium 1 mg/kg. One minute after administration of the reversal agents, there was a significantly greater reduction in barrier pressures in the neostigmine and atropine group than in the edrophonium and atropine group, but subsequently, there was no significant difference between the two groups. We conclude that there is no clinical difference between the two reversal mixtures in terms of the risk of regurgitation in the immediate period after reversal.

Antagonism of neuromuscular blockade. The cardiovascular effects in children of the combination of edrophonium and glycopyrronium

Glycopyrronium 5 or 10 micrograms/kg was administered either simultaneously with, or 1 minute before, edrophonium 1 mg/kg in order to antagonise competitive neuromuscular blockade in 80 children. Both doses of glycopyrronium given before the edrophonium resulted in an initial significant (p less than 0.01) increase in heart rate. Heart rate decreased significantly (p less than 0.01) in all groups after the edrophonium was given, and only glycopyrronium 10 micrograms/kg administered before edrophonium prevented a substantial decrease below baseline. Initial heart rate responses to glycopyrronium or edrophonium are rapid, and measurements at intervals of 30 seconds may be necessary to record these changes.

Edrophonium-hyoscine butylbromide mixture for reversal of neuromuscular blockade: heart rate changes in infants and children

The effectiveness of hyoscine butylbromide in the prevention of edrophonium-induced bradycardia was assessed in 50 infants and children. A mixture of edrophonium (1.0 mg/kg) and either atropine (0.01 mg/kg) or hyoscine butylbromide (0.4 mg/kg) was administered to reverse the effects of tubocurarine. An initial bradycardia followed the injection of the edrophonium-atropine mixture. In contrast there was no initial decrease in heart rate after the administration of the edrophonium-hyoscine butylbromide mixture. Hyoscine butylbromide can be used with advantage as a substitute for atropine in edrophonium reversal in infants and children.