Do small doses of atropine (<0.1 mg) cause bradycardia in young children?. Issue 7 (11th March 2015)

• Record Type: Journal Article
• Authors: Eisa, Lara; Passi, Yuvesh; Lerman, Jerrold; Raczka, Michelle; Heard, Christopher
• Is Part Of: Archives of disease in childhood. Volume 100:Issue 7(2015)
• Page Start: 684
• Page End: 688
• Publication Date: 2015-03-11
• Subjects: infants -- atropine -- anticholinergic -- arrhythmia -- vagal reflex; Children -- Diseases -- Periodicals; Infants -- Diseases -- Periodicals; 618.920005
• DOI: 10.1136/archdischild-2014-307868
• Languages: English
• ISSNs: 0003-9888

Abstract

Abstract : Objective: To determine the heart rate response to atropine (&lt;0.1 mg) in anaesthetised young infants. Design: Prospective, observational and controlled. Setting: Elective surgery. Patients: Sixty unpremedicated healthy infants less than 15 kg were enrolled. Standard monitoring was applied. Anaesthesia was induced by mask with nitrous oxide (66%) and oxygen (33%) followed by sevoflurane (8%). Interventions: Intravenous (IV) atropine (5 µg/kg) was flushed into a fast flowing IV. The ECG was recorded continuously from 30 s before the atropine until 5 min afterwards. Main outcome measures: The incidence of bradycardia and arrhythmias was determined from the ECGs by a blinded observer. Results: The median (IQR) age was 6.5 (4–12) months and the mean (95% CI) weight was 8.6 (8.1 to 9.1) kg. The mean (95% CI) dose of atropine was 40.9 (37.3 to 44) µg. Bradycardia did not occur. Two infants developed premature atrial contractions and one developed a premature ventricular contraction. When compared with baseline values, heart rate increased by 7% 30 s after atropine, 14% 1 min after atropine and 25% 5 min after atropine. Twenty-nine infants (48%) experienced tachycardia (&gt;20% above baseline rate) after atropine lasting 222.7 s (range 27.9–286). The change in heart rate 5 min after atropine was inversely related to the baseline heart rate. Conclusions: The upper 95% CI for the occurrence of bradycardia in the entire population of infants based on a zero incidence in this study is 5%. These results rebut the notion that atropine &lt;0.1 mg IV causes bradycardia in young infants. Trial registration number: ClinicalTrials.gov #NCT01819064 .