Pharmacologic bronchodilation response to salbutamol in COPD patients.

BACKGROUND

Airway hyperresponsiveness (AHR) is the most characteristic feature of asthma, which is reported in COPD patients and smokers. Increased airway responsiveness to ί-agonists is also demonstrated in asthmatics as well as smokers. However, there is no report regarding AHR to ί-agonist drugs in COPD patients. Therefore, in this study pharmacologic bronchodilation response to salbutamol in COPD patients was examined.

MATERIALS AND

METHODS

The threshold concentrations of inhaled salbutamol required for a 20% change in forced expiratory flow in 1 sec (FEV 1 ) as PC 20 , or a 35% change in specific airway conductance (sGaw) as PC 35 was measured in 14 COPD patients and 14 normal subjects.

RESULTS

Airway responsiveness to salbutamol in COPD patients (PC 20 = 14.14 ± 1.62 and PC 35 = 9.70 ± 1.48 mg/l) was significantly lower than normal subjects (PC 20 = 224.57 ± 16.62 and PC 35 = 81.87 ± 8.16 mg/l, P < 0.001 for both cases). The values of FEV 1 and sGaw in COPD patients (56.43 ± 14.45 and 0.081 ± 0.120 respectively) were significantly lower than those of normal subjects (104.07 ± 5.72 and 0.194 ± 0.041 respectively), (P < 0.001 for FEV 1 and P < 0.005 for sGaw). There was a significant correlation between FEV 1 with PC 20 salbutamol (r = 0.862, P < 0.001). The correlations between PC 20 and PC 35 was also statistically significant (r = 0.862, P < 0.001).

CONCLUSION

These results showed increased airway responsiveness of most COPD patients to salbutamol which was highly correlated to airway caliber.