Bronchodilator therapy with metered-dose inhaler and spacer versus nebulizer in mechanically ventilated patients: comparison of magnitude and duration of response.

OBJECTIVE: Four-hour comparison of the bronchodilator response of albuterol administered via metered-dose inhaler (MDI) with spacer versus small-volume nebulizer (SVN) to mechanically ventilated patients with chronic obstructive pulmonary disease (COPD).

DESIGN: Prospective randomized clinical trial.

SETTING: Medical intensive care unit in a university hospital.

PATIENTS: Thirteen mechanically ventilated COPD patients.

INTERVENTION: Albuterol administration of 4 puffs (0.4 mg) or 10 puffs (1.0 mg) via MDI with spacer or 2.5 mg via SVN to mechanically ventilated patients in order to assess the bronchodilator response over 4 hours.

MEASUREMENTS AND RESULTS: Mechanically ventilated patients were enrolled in a randomized crossover study wherein one group received 4 puffs (0.4 mg) or 2.5 mg of albuterol and another group received 10 puffs (1.0 mg) or 2.5 mg of albuterol on separate days. Respiratory mechanics measurements were obtained over 4 hours. Total airway resistance declined by 14.4 +/- 3.8% after 4 MDI puffs, 18.3 +/- 1.8% after 10 MDI puffs, or 13.7 +/- 2.6% after 2.5 mg via SVN, compared to baseline (p < 0.01). After albuterol delivery, airway resistance remained improved for 90-120 minutes (p < 0.05) and returned to baseline by 4 hours with all treatments.

CONCLUSION: The airway response to albuterol administration via MDI and SVN to mechanically ventilated patients was similar in magnitude and duration, returning to baseline by 240 minutes. In stable, mechanically ventilated COPD patients, albuterol may be administered via MDI with spacer or via SVN every 4 hours.