Efficacy and cost comparisons of bronchodilatator administration between metered dose inhalers with disposable spacers and nebulizers for acute asthma treatment.

BACKGROUND: Despite demonstration of equivalent efficacy of beta agonist delivery using a metered dose inhaler (MDI) with spacer vs. nebulizer in asthma patients, use of a nebulizer remains standard practice. OBJECTIVES: We hypothesize that beta agonist delivery with a MDI/disposable spacer combination is an effective and low-cost alternative to nebulizer delivery for acute asthma in an inner-city population. METHODS: This study was a prospective, randomized, double-blinded, placebo-controlled trial with 60 acute asthma adult patients in two inner-city emergency departments. Subjects (n = 60) received albuterol with either a MDI/spacer combination or nebulizer. The spacer group (n = 29) received albuterol by MDI/spacer followed by placebo nebulization. The nebulizer group (n = 29) received placebo by MDI/spacer followed by albuterol nebulization. Peak flows, symptom scores, and need for rescue bronchodilatator were monitored. Median values were compared with the Kolmogorov-Smirnov test. RESULTS: Patients in the two randomized groups had similar baseline characteristics. The severity of asthma exacerbation, median peak flows, and symptom scores were not significantly different between the two groups. The median (interquartile range) improvement in peak flow was 120 (75-180) L/min vs. 120 (80-155) L/min in the spacer and nebulizer groups, respectively (p = 0.56). The median improvement in the symptom score was 7 (5-9) vs. 7 (4-9) in the spacer and nebulizer groups, respectively (p = 0.78). The median cost of treatment per patient was $10.11 ($10.03-$10.28) vs. $18.26 ($9.88-$22.45) in the spacer and nebulizer groups, respectively (p < 0.001). CONCLUSION: There is no evidence of superiority of nebulizer to MDI/spacer beta agonist delivery for emergency management of acute asthma in the inner-city adult population. MDI/spacer may be a more economical alternative to nebulizer delivery.

Room air entrainment during beta-agonist delivery with heliox.

Studies of the efficacy of heliox in patients with severe asthma have shown mixed results. Among the factors that are responsible for variable outcomes, the failure of heliox delivery systems to prevent room air entrainment (RAE) during beta-agonist delivery is probably the most critical. While keeping the rotameter flow rate (FR) of heliox mixed 70:30 to a nebulizer at 10 L/min, the FR of heliox from a second gas source to a T-connector (TC) was increased during the delivery of the beta-agonist with a conventional T-nebulizer delivery system (TNDS). A negative peak inspiratory flow (pneumotachometer reading) or a helium concentration of < 70% (quadralizer reading) were indicators of RAE. RAE was tested during spontaneous tidal breathing and acute asthma. A rotameter FR of 10 L/m to the nebulizer with no flow from a second gas source to a TC (conventional TNDS) resulted in a significant drop in helium concentration during tidal breathing (46.2%) and acute asthma (27.5%) due to RAE. This degree of helium dilution can negate the beneficial effects of heliox to lung mechanics almost completely. A rotameter FR of 10 L/m each to a nebulizer and a TC resulted in a helium concentration 69.8% during tidal breathing (no RAE), but 49% (significant RAE) during asthma events. A rotameter FR of 15 L/m (pressure regulator setting, 100 lbs per square inch) to a TC, while maintaining a rotameter FR of 10 L/m to a nebulizer prevented RAE during asthma (helium concentration, 69.9%). Conventional TNDS may be used to deliver the beta-agonist with heliox during asthma without RAE.

Regular vs ad-lib albuterol for patients hospitalized with acute asthma.

STUDY OBJECTIVES: Inhaled, short-acting beta-agonists and systemic corticosteroids form the mainstay of therapy in acute asthma exacerbation. Asthma, however, is an inflammatory disease of the airways, and its underlying pathology is not impacted by short-acting beta-agonists. While the efficacy of ad-lib beta-agonist administration in outpatient management of asthma symptoms is well established, little data exist to support this strategy in patients with acute, severe asthma. We postulate that as long as patients hospitalized with severe asthma exacerbation receive systemic corticosteroids, regular, scheduled administration of short-acting beta-agonists is unnecessary. Similar therapeutic outcomes can be achieved with the ad-lib administration of the short-acting beta-agonists. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: Pulmonary floor of a 600-bed municipal hospital. PATIENTS OR PARTICIPANTS: Sixty-two patients hospitalized for acute asthma. INTERVENTIONS: Patients were randomized to receive either albuterol nebulizations (regular albuterol group) or saline solution nebulizations (ad-lib group) every 4 h with management of breakthrough symptoms with albuterol metered-dose inhaler or nebulizations for both groups. All patients received systemic corticosteroids. Peak expiratory flows, asthma symptoms, and need for rescue bronchodilator were followed up on each patient until discharge. RESULTS: There was no significant difference in the length of hospitalization (median length, 48 h for ad-lib group vs 57.5 h for regular albuterol group, p = 0.82), rate of improvement in peak flow, or symptoms between the two groups. Ad-lib beta-agonist use compared to regular albuterol scheduled use resulted in a significant reduction in the total number of albuterol treatments administered (median, 7 treatments vs 19 treatments, p = 0.001) during hospitalization. CONCLUSIONS: In the management of asthma exacerbation, ad-lib administration of albuterol is therapeutically as effective as regular, scheduled administration. This method of drug administration also reduces the total dose of beta-agonists received by the hospitalized patient.