Alterations in Myocardial-Specific Creatine Phosphokinase in Children with Severe Reactive Airway Disease Treated with Intravenous Isoproterenol

Objective To describe the pattern of alterations in creatine phosphokinase (CPK) and creatine phosphokinase-myocardial isoenzyme (CPK-mb) levels and electrocardiogram (ECG) changes in children treated with intravenous infusion of isoproterenol, as determined by elevation of CPK-mb levels/indices and/or ischemic ECG changes. Design Prospective observational study. Setting A pediatric intensive care unit of a university teaching hospital. Subjects Twenty-two critically ill children (age: 3 months—17 years) with severe reactive airway disease who required intravenous isoproterenol. Interventions None. Measurements and Main Results Twenty-two children with severe reactive airway disease [pH 7.25 (7.01-7.54), Paco2 55 (23-113), and Pao2 92 (54-361)] were enrolled in the study. Baseline ECGs prior to intravenous isoproterenol were unremarkable. Baseline CPK-mb levels/indices were found to be abnormally elevated in 5 children prior to intravenous isoproterenol. Four of these children manifested a decrease in CPK-mb levels/indices while on isoproterenol infusion. Seventeen of 22 children had normal CPK-mb levels/indices prior to isoproterenol infusion. Only 4 of these children experienced abnormal elevations during intravenous isoproterenol. CPK-mb levels/indices returned to normal in all children within 6 h of discontinuation of intravenous isoproterenol. No dysrhythmias or deaths were noted in patients who received intravenous isoproterenol. Conclusion Intravenous isoproterenol is an appropriate therapeutic modality for children with severe reactive airway disease unresponsive to conventional therapy.