[Isoproterenol continuous nebulization for childhood status asthmaticus. I. Efficacy and side effects of high-dose method].

We investigated the efficacy and the side effects of "high-dose isoproterenol continuous nebulization" for childhood status asthmaticus. Subjects were 34 children who were hospitalized and underwent the nebulization therapy. The 50 ml solution of 0.5% dl-isoproterenol was diluted in 500 ml of normal saline and nebulized through an ultrasound nebulizer. The period of continuous nebulization was 25.5 +/- 16.0 hours. The Wood's clinical score clearly decreased in 32 cases, the average score changing from 7.7 +/- 0.8 to 2.9 +/- 1.3. Heart rate was elevated significantly during the first 3 hours (156 +/- 25/min at the start of the nebulization, 180 +/- 20/min at 1 hour, 171 +/- 23 at 3 hours), and then it decreased gradually to 122 +/- 25/min at the cessation of the nebulization. Serum GOT, LDH, CPK, and potassium were elevated after the nebulization compared with the values before the treatment, though the changes were not statistically significant. CPK-MB fraction after the nebulization was higher than normal range in 12 of 13 subjects. Of 34 subjects, 11 (32%) complained nausea or vomited, 2 showed arrhythmia on ECG (ventricular premature conduction), 1 developed myocardiac infarction, and 1 developed possible heart failure, some of which might be attributable to the pharmacological side effects of isoproterenol nebulization. We conclude that "high-dose isoproterenol continuous nebulization" is an effective method for childhood status asthmaticus, but there is some risk of serious side effects. This method was originally developed as a method indicated for the case of respiratory failure or threatened respiratory failure following status asthmaticus, and we should not extend the indication of this method thoughness.