Bronchodilator delivery by metered-dose inhaler in ventilator-supported patients

The optimal dose and technique for administration of bronchodilators with a metered-dose inhaler (MDI) in mechanically ventilated patients have not been established. We studied the efficacy and safety of 10 puffs (90 micrograms/puff) of albuterol administered by an MDI in seven mechanically ventilated patients with chronic obstructive pulmonary disease (COPD). Rapid airway occlusions at constant flow inflation were performed before and at 5-min intervals after administration of albuterol for 60 min. Significant decreases in maximum (Rrsmax; p < 0.01) and minimum inspiratory resistance (Rrsmin; p < 0.01) were present at 5 min and persisted for 60 min after administration of albuterol (p < 0.01 for both parameters). Rrsmax indicates maximal inspiratory resistance while Rrsmin represents the ohmic flow resistance. Intrinsic positive end-expiratory pressure decreased significantly (p < 0.05) 15 min after albuterol administration. Heart rate, blood pressure, and arterial oxygenation did not show significant change after albuterol. In summary, 10 puffs of albuterol given by an MDI and spacer produced significant bronchodilation in ventilator-supported patients with COPD, without producing side effects. In conclusion, higher doses of albuterol given by an MDI and spacer could be used routinely in mechanically ventilated patients with COPD.