Serial cardiac troponin concentrations as marker of cardiac toxicity in children with status asthmaticus treated with intravenous terbutaline.

OBJECTIVES: The study's objectives were to evaluate serial troponin concentrations as a marker of cardiac toxicity in children receiving intravenous terbutaline for status asthmaticus and to study if troponin concentrations are affected by severity of asthma and risk factors for severe asthma.
METHODS: This was a prospective observational study in 20 consecutive patients who were admitted to a tertiary care pediatric intensive care unit for status asthmaticus and received intravenous terbutaline. Cardiac troponin I (cTnI) concentrations were measured half an hour before the bolus of intravenous terbutaline, 4 hours after terbutaline, and then every 24 hours until discontinuation of the continuous terbutaline infusion.
RESULTS: Ten patients had cTnI concentrations greater than 0.03 ng/mL. Maximum cTnI concentrations were recorded after the terbutaline bolus in 6 patients, during terbutaline infusion in 3 patients, and before terbutaline use in 1 patient. Three of these 10 (3/10) patients showed increased cTnI concentrations before the terbutaline bolus. One patient had a significant elevation in cTnI concentration (peak level of 3.79 ng/mL) with electrocardiogram (ECG) changes of myocardial injury that normalized upon discontinuation of terbutaline. All other patients with elevated cTnI concentrations had normal ECG findings.
CONCLUSIONS: Elevated cTnI concentrations were observed in 50% of patients treated with intravenous terbutaline for status asthmaticus. Clinically significant cardiotoxicity was not observed except in 1 patient in whom the abnormal ECG findings normalized upon discontinuation of terbutaline. There was no statistically significant difference in asthma severity or in the risk factors for severe asthma in children with and without elevation of cTnI concentrations.