Continuous Albuterol for Exacerbation of Asthma: End of Discussion?

ABSTRACT&COMMENTARY

A number of recent studies have attempted to demonstrate the superiority of continuous delivery of nebulized b2-agonists as compared to the intermittent delivery systems we commonly use to treat asthma in the ED. Some investigators have found continuously delivered albuterol to be advantageous in selected populations, specifically adults and children with the most severe asthma exacerbations.1-3 Khine et al explored the application of this therapy for ED treatment of asthmatic children.

Seventy children with moderate to severe asthma exacerbations were randomized to receive nebulized albuterol by either intermittent or continuous administration. The investigators and treating physicians, but not the patients, were blinded to the treatment assignment. The intermittent group received albuterol 0.15 mg/kg every 30 minutes; the continuous group received albuterol 0.3 mg/kg/h using the HEART nebulizer device. Each group, therefore, received the same total hourly dose of albuterol. All subjects received prednisone or methylprednisolone 2 mg/kg at the start of the trial.

The proportion of children requiring hospitalization (about one-quarter) did not differ between the two groups. There were no intergroup differences in peak flow rate or ED treatment time. Subgroup analysis of those children with the most severe exacerbations also failed to find any differences between the two groups. The intermittent treatment group did have a greater mean increase in heart rate (30 vs 18 beats/min); other hemodynamic parameters were uninfluenced by treatment assignment. Based on respiratory care charges, the authors estimate that the continuous therapy was slightly less expensive than intermittent therapy. (Khine H, et al. Continuous vs. intermittent nebulized albuterol for emergency management of asthma. Acad Emerg Med 1996;3:1019-1024.)

COMMENT BY DAVID J. KARRAS, MD

The weight of evidence does not appear to support the routine use of continuously delivered nebulized albuterol for exacerbations of asthma in the ED, although it may be of benefit in those patients with more severe exacerbations.1-3 It is unlikely that any significant benefit would be expected from continuous drug administration as the dose of albuterol delivered hourly by either the continuous or intermittent systems is identical. While the continuous delivery system might allow for higher doses of drug to be administered, one small study has shown that high-dose continuously delivered albuterol is poorly tolerated in adults.4

The HEART continuous nebulizer delivery system may offer some advantages over intermittent systems in ease of use. Because the device needs to be filled with medication only once an hour, there may be lower respiratory therapy charges. In many EDs, however, nebulizer treatments are prepared by nurses and physicians, and this savings may not be as noticeable. Furthermore, the HEART nebulizer is far more expensive than conventional nebulizer devices (approximately $18 vs $3), although the device is reusable. A theoretical disadvantage of continuous therapy is that the patient may be left unattended for at least an hour, while the frequency of re-dosing with conventional therapy forces at least casual re-evaluation of the patient every half-hour or so.

References

1. Papo MC, et al. A prospective, randomized study of continuous vs. intermittent nebulized albuterol for severe status asthmaticus in children. Crit Care Med 1993;21:1479-1486.

2. Lin RY, et al. Continuous vs. intermittent albuterol nebulization in the treatment of acute asthma. Ann Emerg Med 1993;22:1847-1853.

3. Rudnitsky GS, et al. Continuous vs. intermittent albuterol nebulization in the treatment of acute asthma. Ann Emerg Med 1993;22:1842-1846.

4. Lin RY, et al. High serum albuterol levels and tachycardia in adult asthmatics treated with high-dose continuously aerosolized albuterol. Chest 1993;103:221-225.