Table 2

Effect of salmeterol on lung function and respiratory muscle strength

PlaceboSalmeterolMean difference (95% CI)Drug effect p value
Values are mean (SD) or mean treatment differences with 95% confidence intervals. Respiratory muscle strength tests are measured in cm H2O.
FEV1 = forced expiratory volume in 1 second; VC = vital capacity; TLC = total lung capacity; RV = residual volume; Pimax = maximum inspiratory pressure; Pdi = diaphragmatic pressure; Poes = oesophageal pressure.
*Significant period × treatment interaction.
FEV1 (l)0.74 (0.22)0.78 (0.26)−0.21 (−0.40 to 0.02)0.07*
VC (l)2.26 (0.78)2.38 (0.79)−0.54 (−1.40 to 0.30)0.19*
FEV1/VC (%)35.0 (11.5)33.9 (10.1)−1.1 (−3.6 to 1.3)0.34
TLC (l)6.56 (1.47)6.45 (1.44)−0.11 (−0.30 to 0.08)0.22
RV (l)4.30 (0.82)4.08 (0.90)−0.23 (−0.48 to 0.03)0.08
RV/TLC (%)66.2 (0.05)63.6 (0.07)−2.6 (−4.91 to −0.33) 0.03
Pimax81.6 (14.5)77.4 (12.2)−4.2 (−9.5 to 1.2)0.12
Sniff Pdi99.9 (10.7)97.8 (16.3)−2.1 (−8.7 to 4.5)0.52
Sniff Poes79.6 (12.4)78.8 (12.9)−0.8 (−4.7 to 3.1)0.66