Atropine and the electrical activity of the heart during induction of anaesthesia in children

The effect of atropine on rhythm and conduction disturbances during 322 critical care intubations

OBJECTIVES

Our objectives were to describe the prevalence of arrhythmia and conduction abnormalities before critical care intubation and to test the hypothesis that atropine had no effect on their prevalence during intubation.

DESIGN

Prospective, observational study.

SETTING

PICU and pediatric/neonatal intensive care transport.

SUBJECTS

All children of age less than 8 years intubated September 2007-2009. Subgroups of intubations with and without atropine were analyzed.

INTERVENTION

None.

MEASUREMENT AND MAIN RESULTS

A total of 414 intubations were performed in the study period of which 327 were available for analysis (79%). Five children (1.5%) had arrhythmias prior to intubation and were excluded from the atropine analysis. Atropine was used in 47% (152/322) of intubations and resulted in significant acceleration of heart rate without provoking ventricular arrhythmias. New arrhythmias during intubation were related to bradycardia and were less common with atropine use (odds ratio, 0.14 [95% CI, 0.06-0.35], p < 0.001). The most common new arrhythmia was junctional rhythm. Acute bundle branch block was observed during three intubations; one Mobitz type 2 rhythm and five ventricular escape rhythms occurred in the no-atropine group (n = 170). Only one ventricular escape rhythm occurred in the atropine group (n = 152) in a child with an abnormal heart. One child died during intubation who had not received atropine.

CONCLUSIONS

Atropine significantly reduced the prevalence of new arrhythmias during intubation particularly for children over 1 month of age, did not convert sinus tachycardia to ventricular tachycardia or fibrillation, and may contribute to the safety of intubation.

Cardiac arrest after oxymetazoline nasal spray

Oxymetazoline nasal spray is a potent alpha 1-adrenergic agonist commonly used to vasoconstrict blood vessels in the nasal mucosa. In this incident, oxymetazoline nasal spray 0.025% was administered to a 2-year-old patient during general anesthesia for nasal endoscopy. Severe hypertension with reflex bradycardia progressed to sinus arrest and was successfully treated with alropine and cardiopulmonary resuscitation. Decreasing the dose of oxymetazoline and pretreatment with an anticholinergic is recommended.

Should the routine use of atropine before succinylcholine in children be reconsidered?

It is common practice to administer atropine before a first dose of succinylcholine in infants and children. However, the administration of succinylcholine without atropine has not been investigated in children. This study was designed to compare cardiovascular changes after the administration of either atropine with succinylcholine or succinylcholine alone. In 41 ASA I or II patients aged from 1 to 12 yr anaesthesia was induced with thiopentone 5 mg.kg-1. Patients were randomly allocated to receive either atropine 20 micrograms.kg-1 and succinylcholine 1.5 mg.kg-1 (n = 20) or succinylcholine 1.5 mg.kg-1 alone (n = 21). Heart rate and rhythm were recorded continuously from two minutes before induction until two minutes after tracheal intubation. Blood pressure was measured non-invasively before and after induction of anaesthesia and both immediately and two minutes after laryngoscopy. One self-limiting episode of bradycardia was recorded during laryngoscopy in a child who received atropine. Heart rate increased in both groups compared with baseline values (108 +/- 25), with a greater increase in patients who had received atropine (150 +/- 13) than in those who had not (128 +/- 18) (P < 0.05). There was no difference in mean arterial pressure or incidence of arrythmias between the two groups. No recorded arrythmias were judged to be clinically important by a cardiologist. The incidence of bradycardia after succinylcholine in the absence of atropine in children aged from 1 to 12 yr appears to be lower than previously estimated. The use of atropine before a single dose of succinylcholine in children deserves to be reconsidered.

The cardiovascular effects of anticholinergic agents administered during halothane anaesthesia in children

The cardiovascular effects of anticholinergic agents administered during halothane anaesthesia were studied in 31 children aged 1-12 years undergoing peripheral orthopaedic surgery. Either normal saline, glycopyrrolate (10 micrograms.kg-1) or atropine (20 micrograms.kg-1) was administered in randomized double-blind fashion during the induction of anaesthesia with halothane while the electrocardiogram was continuously recorded. After induction, the children were paralyzed with atracurium, intubated, and ventilated. Anaesthesia was maintained with N2O/O2 and halothane (up to 2.5% inspired). The concentrations of expired CO2 and halothane were measured continuously using mass spectrometry. Sixty-one percent (19/31) of the children developed one or more dysrhythmias. Junctional rhythm occurred in 74% (14/19) of the children with dysrhythmias, developed early during induction (mean +/- s.d. time = 2.29 +/- 2.0 min after commencement of induction), and usually resolved before the administration of the study drug (8/14). All dysrhythmias initially occurred before or during induction and none developed during intubation, during incision, during the maintenance of anaesthesia, or after the administration of anticholinergic agents. The data suggest that: 1) a combination of factors present during halothane induction is highly dysrhythmogenic especially for junctional rhythm; 2) junctional rhythm will resolve spontaneously; 3) the administration of an anticholinergic agent during halothane induction is safe but may be unnecessary in children greater than 1 year of age; and 4) the dysrhythmogenic factors present during induction are attenuated during the maintenance of halothane anaesthesia.

A method for prevention of cardiovascular reactions to laryngoscopy and intubation

A technique of nebulizing lidocaine in the upper airways was developed and its effectiveness in preventing cardiovascular responses to laryngoscopy and intubation was documented. In ten pre-treated patients the average percentage-rise in systolic blood pressure was 10.3 per cent and there were no arrhythmias. The pulse rate increased by 16.8 per cent. In ten control patients, the systolic blood pressure increased by 56 per cent and the incidence of arrhythmias was 40 per cent. The pulse rate increased by 38.8 per cent. The significance and application of these results is discussed and compared to other available methods. The opinion is expressed that the effect of the aerosol, especially as it relates to the suppression of arrhythmias, is partly due to systemic absorption of lidocaine.