beta(2)-agonist bronchodilators delivered by metered-dose inhalers (MD
I) are commonly used in the treatment of bronchospasm in both intubate
d and nonintubated patients. Substantial data support the effectivenes
s of MDI delivery systems in nonintubated patients. However, few studi
es have examined the effectiveness of MDIs in intubated, mechanically
ventilated patients. MDIs are often used in conjunction with a spacing
device that may enhance delivery of drug to the airways, but few in v
ivo data have demonstrated efficacy of this delivery method in ventila
ted patients. We studied ten critically ill patients who had a peak (P
-peak) to pause (P-pause) gradient of more than 15 cm H2O during sedat
ed, quiet breathing on assist control ventilation. We administered 5,
10, and 15 puffs (90 mu g per puff) of MDI albuterol through a specifi
c spacer (Aerovent) at 30-min intervals, while measuring resistive pre
ssure (defined as P-peak-P-pause) before and after treatments. Resisti
ve airway pressure after 5 puffs decreased in nine of ten patients, fr
om 25.1+/-7.2 to 20.8+/-5.6 cm H2O (p<0.12). The addition of 10 more p
uffs further reduced resistive pressure in nine of nine patients from
20.8+/-5.6 to 19.0+/-4.4 (p<0.01). Fifteen more puffs (30 cumulative p
uffs) did not result in further improvement (p>0.5). A toxic reaction
occurred in one patient (systolic blood pressure decreased 20 mm Hg) a
fter 5 puffs of albuterol. We conclude that MDI administered through t
his specific spacer is effective in mechanically ventilated patients i
n doses up to 15 puffs, and that therapy should be titrated to effecti
veness and toxicity.