18213
document
A comparison of the effects of anticholinergic and beta 2-agonist and combination therapy on respiratory impedance in COPD . The effects of three different regimens of inhaled bronchodilators on spirometry and respiratory impedance as measured with the technique of forced oscillations were compared in a double-blind crossover study in 22 patients with stable chronic obstructive pulmonary disease ( FEV1 less than 70 percent predicted ) . On three trial days , patients inhaled , in random order , 40 micrograms ipratropium bromide , 200 micrograms fenoterol hydrobromide , or a combination of 40 micrograms ipratropium and 100 micrograms fenoterol from a powder inhaler , followed by a second dose of the same drug after 60 min . The effects were measured at baseline and 20 , 40 , 60 , and 120 min after the first inhalation . No significant decrease in total respiratory resistance at 8 Hz ( Rrs [ 8 ] ) was observed after ipratropium , whereas Rrs ( 8 ) decreased significantly 20 min after fenoterol and 40 min after the combination regimen ( p less than 0.05 ) . All three studied drugs resulted in a significant increase in the reactance ( p less than 0.01 ) and decrease in resonant frequency . Both fenoterol ( delta FEV1 34 percent , p less than 0.0001 ) and the combination regimen ( delta FEV1 38 percent , p less than 0.0001 ) resulted in a significantly larger increase in FEV1 than ipratropium alone ( delta FEV1 17 percent , p less than 0.0001 ) . A second dose of fenoterol and of the combination regimen resulted in a further significant increase in FEV1 after 120 min ( p less than 0.05 ) . A second dose of ipratropium did not result in a further significant increase in FEV1 . The changes in respiratory impedance were qualitatively similar for all three drug regimens , but larger in absolute terms after fenoterol and the combination regimen than after ipratropium . The similar effect of these drugs on the reactance can be explained by an increase in the capacitance of the respiratory system , and in combination with a decrease in frequency dependence of resistance , by assuming a decrease in peripheral airway resistance .
18214
Intervention_Pharmacological
anticholinergic and beta 2-agonist
18215
Intervention_Pharmacological
combination therapy
18216
Intervention_Pharmacological
inhaled bronchodilators
18217
Intervention_Pharmacological
ipratropium bromide
18218
Intervention_Pharmacological
fenoterol hydrobromide
18219
Intervention_Pharmacological
combination of 40 micrograms ipratropium and 100 micrograms fenoterol
18220
Intervention_Pharmacological
ipratropium
18221
Intervention_Pharmacological
fenoterol
18222
Intervention_Pharmacological
combination regimen
18223
Intervention_Pharmacological
combination regimen
18224
Intervention_Pharmacological
ipratropium
18225
Intervention_Pharmacological
fenoterol
18226
Intervention_Pharmacological
combination regimen
18227
Intervention_Pharmacological
ipratropium
18228
Intervention_Pharmacological
fenoterol
18229
Intervention_Pharmacological
combination regimen
18230
Intervention_Pharmacological
ipratropium
18231
Outcome_Physical
total respiratory resistance at 8 Hz ( Rrs [ 8 ] )
18232
Outcome_Physical
reactance ( p less than 0.01 )
18233
Outcome_Physical
resonant frequency
18234
Outcome_Physical
FEV1
18235
Outcome_Other
second dose
18236
Outcome_Physical
A second dose of ipratropium did not result in a further significant increase in FEV1 .
18237
Outcome_Physical
capacitance of the respiratory system
18238
Participant_Condition
COPD
18239
Participant_Sample-size
22
18240
Participant_Condition
stable chronic obstructive pulmonary disease
18241
Participant_Condition
FEV1 less than 70 percent predicted