Comparison of Outcome Measures Pre- and Post-Treatment
Mean values for the study outcome measures recorded immediately prior to
the study drug treatment and 30 minutes after treatment completion are
summarized in Table 2. Average EF75 values improved with all study
therapies, with statistically significant differences observed for
saline placebo (3.9L/min ± 2.0 vs. 4.4L/min ± 2.4, p=0.04) and 1.25mg of
albuterol (3.8L/min ± 1.7 vs. 4.5L/min ± 2.2, p<0.001). The
differences for 2.5mg of albuterol approached but did fulfill the cutoff
for significance (3.9L/min ± 1.9 vs. 4.2L/min ± 2.1, p=0.06). Among the
secondary study outcomes, both dose levels of albuterol led to modest
but statistically significant reduction in peak inspiratory pressure and
increase in minute ventilation but were also associated with a small
rise in average heart rate (Table 2). Of the 414 administered drug
doses, 31 were associated with a greater than 20% post-treatment
increase in heart rate. Stratified by drug therapy, 14% (19/132) of
administered 2.5mg doses of albuterol were followed by a
>20% rise in heart rate compared with 6% (8/144) of
1.25mg albuterol doses and 3% (4/138) of aerosolized saline treatments
(p=0.001 for 3-way chi square comparison). All heart rate changes were
self-limited and did not necessitate subsequent discontinuation of study
drug therapy.