Albuterol via metered-dose inhaler and nebulizer equivalent in adults - Patient-Oriented Evidence that Matters

Journal of Family Practice, July, 2002 by Lisa Sanches Fuentes, Jane Huntington

Newman KB, Milne S, Hamilton C, Hall K. A comparison of alburerol administered by metered-dose inhaler and spacer with albuterol by nebulizer in adults presenting to an urban emergency department with acute asthma. Chest 2002; 121:1036-41.

* BACKGROUND Historically, nebulizers have been preferred over metered dose inhalers (MDIs) for the treatment of asthma exacerbations, although numerous studies have shown their equivalence. A systematic review of 21 randomized trials supported the equivalence of an MDI with spacer and a nebulizer; the method of albuterol delivery did not affect hospital admission rates, length of stay in the emergency department, or measures of pulmonary function. (1) Advantages of MDIs may include lower costs, less excess drag exposure, and easier use for patients and physicians.

* POPULATION STUDIED The study population consisted of all patients older than 18 years who presented to an emergency department over a 2.5 year period with an asthma exacerbation (2342 visits, 1429 patients). Most patients were African American (75.4%). Most were women (58.6%), and the mean age was 35.5 [ or -] 13.5 years.

* STUDY DESIGN AND VALIDITY The study was a large, prospective, unblinded, and nonrandomized trial consisting of 2 phases. For the first 12 months, physicians, using standard National Institutes of Health guidelines, began treatment with a nebulizer (913 visits). Then for the next 18 months, physicians began treatment with albuterol delivered via MDI and spacer (1429 visits). The dose was 5 puffs, then 3 to 5 puffs every 20 minutes as needed. At the time of discharge from the emergency department during the MDI phase of the study, patients received a peak flow meter, an MDI and spacer, an inhaled corticosteroid, written materials, and counseling by emergency department nurses.

This study was fairly weak. It was not randomized or blinded, and the patient population could have differed between the 2 phases of the study, although measurement of demographic characteristics and pre-albuterol peak expiratory flow rate (PEFR) and oxygen saturation level (Sa[O.sub.2]) revealed that the study groups were comparable. Because extent of breathing difficulty was not assessed, it is unknown if study results apply to patients with severe asthma. Moreover, physicians broke protocol by using nebulizers in 22.6% of the patients in the MDI phase if the physicians thought the treatment would benefit the patient's physical or mental status. In addition to different routes of administration of albuterol, the intervention also differed in that inhaled steroids were given in the MDI-treated group but not the nebulizer-treated patients. This intervention con[d have' contributed to the decreased relapse rate seen in the MDI-treated group.

* OUTCOMES MEASURED The outcomes measured were PEFR, Sa[O.sub.2], heart and respiratory rates, total albuterol dose, and the more patient-oriented outcomes of rate of hospital admission, relapse rate, time in the emergency department, and costs.

* RESULTS In the MDI phase, post-albuterol PEFR was 11.0% higher (342 L/min vs 308 L/min; P = .001) and change in PEFR was 13.3% higher (127 L/min vs 112 L/min; P = .002). Change in Sa[O.sub.2] was significant (P = .043), and the total albuterol dose was significantly less in the MDI group (1125 [micro]g vs 6700 [micro]g; P = .001). However, these differences did not result in significantly lower hospital admission rates. Relapse rates were significantly lower at both 14 and 21 days in the MDI phase (6.6% and 10.7% vs 9.6% and 13.5%; P < .01 and P < .05). Patients treated with MDIs spent 6.5% less time in the emergency department (163.6 min vs 175.0 min; P = .007). The difference in visit charges was not significant.

RECOMMENDATIONS FOR CLINICAL PRACTICE

This study is yet another to show that delivery of albuterol by MDI and spacer is as effective as delivery by nebulizer in adults with asthma presenting to the emergency department. Patients treated with an MDI and spacer had greater improvement in peak flow, and hospital admission rates did not differ. This trial was not well designed, but its results echo the many other studies, using tighter methods, that show equivalence. (1) Although there may be some patients and practice situations for which the nebulizer is preferred, the MDI and spacer can safely be a first-line treatment much of the time. Incorporating MDI use in the treatment of acute asthma exacerbations may help dispel the misconception of many patients that the nebulizer is a more "powerful" way of treating asthma.

REFERENCE

(1.) Cares CJ, Rowe BH, Bara A, Holding chambers versus nebulisers for beta agonist treatment of acute asthma (Cochrane Review). In: The Cochrane Library, Issue 2, 2002. Oxford, England: Update Software.

Liza Sanchez Fuentes, MD; and Jane Huntington, MD
Department of Family Medicine
University of Washington
Seattle
E-mail: efuentes@u.washington.edu