Equivalence of continuous flow nebulizer and metered-dose inhaler with reservoir bag for treatment of acute airflow obstruction. Metered dose inhalers for bronchodilator delivery in intubated, mechanically ventilated patients. Metered-dose inhaler versus nebulized albuterol in mechanically ventilated patients.
Traditionally, patients with acute airflow obstruction are treated with bronchodilator aerosols delivered by continuous flow nebulizers. While bronchodilator administration with the metered dose inhaler (MDI) and reservoir or spacer attachment is as effective as administration with the nebulizer in most settings, the former has not been widely accepted for treatment of acute airway obstruction in the emergency room. We compared the efficacy of the continuous flow nebulizer to that of the MDI with InspirEase (reservoir spacer) in 75 patients (45 men and 30 women), ages 18-73 (chi 44 years) who presented to the emergency room with acute asthma and COPD. Subjects in each group (22 COPD and 53 asthma) were randomly assigned to treatment with three puffs of metaproterenol (0.65 mg/puff) via the MDI with InspirEase plus nebulizer with placebo, or placebo MDI with InspirEase plus nebulizer with 15 mg metaproterenol in double blind fashion. Either treatment was given three times at 30 min intervals. The FEV1 and dyspnea scores according to the Borg scale were measured at baseline, 30 min after the first treatment, and 30 min after the third. There was no significant outcome difference between the two treatments in either diagnostic group. There also was no significant outcome difference for patients with baseline FEV1 less than 0.9L. Serum theophylline levels, the need for concomitant therapy with corticosteroids, or additional emergency room therapy after the study, hospitalizations and treatment side effects did not differ between treatment groups. We conclude that there is no demonstrable advantage of a continuous flow nebulizer over an MDI with InspirEase for the treatment of acute airflow obstruction. We determined the relative efficacy of two bronchodilator aerosol delivery methods in 18 intubated mechanically ventilated patients with airways obstruction. Two treatment arms, consisting of albuterol 270 micrograms (three puffs) from a metered dose inhaler and albuterol 2.5 mg from a saline solution nebulized with an updraft inhaler, were compared in a single blind, randomized crossover design. Pulmonary function was evaluated using an interrupter technique. Changes in passive expiratory flow at respiratory system recoil pressures between 6 and 10 cm H2O provided the therapeutic endpoints. Paired measurements were made before and 30 minutes after drug delivery. The MDI and NEB resulted in similar improvements in iso-recoil flow (mean increase for both groups = 0.1 L/s). Treatment sequence, severity of obstruction, and bronchodilator responsiveness had no effect on relative efficacy. Albuterol caused a small but significant increase in heart rate that was similar following both delivery methods. We conclude that bronchodilator aerosol delivery with metered dose inhalers provides a viable alternative to nebulizer therapy in intubated mechanically ventilated patients and may result in a cost savings to hospitals and patients. In nonintubated patients, beta 2-agonist bronchodilators are equally effective when delivered by metered-dose inhalers (MDI) or nebulizers (NEB). The delivery of these drugs by MDI to intubated, mechanically ventilated patients has become a widespread practice. To compare the efficacy of the two delivery systems and establish optimal dosing, we prospectively randomized 10 mechanically ventilated patients, with increased airways resistance, to receive albuterol by either MDI or nebulizer in incrementally higher doses. After a 4-hr washout, patients were crossed-over to receive the drug by the alternative route of administration. Albuterol delivered by NEB to a total dose of 2.5 mg reduced the inspiratory flow-resistive pressure (peak-pause airway pressures) from 21.5 +/- 5.7 to 17.6 +/- 5.4 cm H2O (p < 0.01). Nebulized albuterol at cumulative doses of 7.5 mg led to further reductions in 8 of 10 patients (p < 0.1), but led to toxic side effects in 4 of them; in the remaining 6 patients toxicity occurred at a cumulative dose of 15.0 mg. By contrast, albuterol in cumulative doses reaching 100 puffs (9 mg) from an MDI administered into an endotracheal tube adapter did not significantly reduce resistive pressures, and produced no toxicity. We conclude that nebulized albuterol provides objective physiologic improvement, while albuterol administered by MDI through an endotracheal tube adapter has no effect in mechanically ventilated patients with airflow obstruction. Nebulizer treatments can and should be titrated to higher-than-conventional doses, using toxic side-effects and physiologic response to guide therapy.
Existing randomized controlled trials, including randomized cross-over trials where the order of the intervention was randomized, comparing nebulizer and MDI for aerosol bronchodilation in mechanically ventilated adult patients do not provide sufficient evidence to support either delivery method at this time.