Small Airway Impairment and Bronchial Hyperresponsiveness in Asthma Onset

PURPOSE: Our study tried to find a relationship between baseline FEF25-75% and airway hyperresponsiveness (AHR) and whether a greater FEF25-75% impairment may be a marker of a more severe hyperresponsiveness in subjects with normal FEV1 and FEV1/FVC and suggestive asthma symptoms. Besides, we tried to asses a FEF25-75% cut-off value to identify hyper-reactive subjects. METHODS: 4,172 subjects (2,042 M; mean age: 38.3+/-14.9; mean FEV1 % predicted: 100.5+/-12.7 and FEV1/FVC: 85.4+/-6.8) were examined after performing a methacholine (Mch) test. All subjects reported a symptom onset within 3 years before the test. Subjects with PD20400 microg were arbitrarily considered affected by moderate/severe and borderline AHR, respectively. RESULTS: PD20 values were 213 (IQR:86-557), 340 (IQR:157-872) and 433 (IQR:196-1032) microg in subjects with baseline FEF25-7570% respectively (P70%. The hyperreactive subjects percentage, was higher in those with FEF25-7570% (P70%) was a higher AHR risk factor, especially in subjects with moderate/severe AHR (OR: 2.18 [IQR:1.41-3.37]; P50 and 70% levels were similar both in normoreactive and hyperreactive subjects. CONCLUSIONS: At asthma onset, reduced baseline FEF25-75 values with normal FEV1 and FEV1/FVC may predict AHR. Detectable predictive cut-off values do not exist because even normoreactive subjects can show lower FEF25-75 values. Furthermore, a greater FEF25-75 reduction may be associated to a more severe AHR, suggesting a possible FEF25-75 role in the management of asthma when FEV1 and FEV1/FVC are normal.

Comparison of the protective effect amongst anticholinergic drugs on methacholine-induced bronchoconstriction in asthma.

The protective effect of inhaled anticholinergic drugs in the methacholine-induced bronchospasm is well-known. The objective of this study was to assess if any possible differences may be found among Ipratropium (IB), Oxitropium (OXI) and Tiotropium (TIO) pre-treatments to obtain the protective effect. Forty-four patients with intermittent bronchial asthma and PD(20)FEV(1) < 200 microg were selected (24 M, 20 F; mean age 32 +/- 8.8). On the baseline, they had mean FEV(1)%: 98.8 +/- 8.54 of theoretical and mean PD(15)FEV(1) 111.8 +/- 61.04 microg. After 72 hours, all patients underwent a second methacholine challenge and were given Ipratropium (40 microg by MDI in 14 pts) or Oxitropium (200 microg by MDI in 14 pts) or Tiotropium (18 microg by Handihaler in 16 pts) sixty minutes before the test. Sixty minutes after the bronchodilator inhalation, the FEV(1)% increase was higher (p < 0.05) in OXI (6.7 +/- 4.83%) and TIO groups (6.11 +/- 2.54%) than in the IB group (3.8 +/- 1.96%). In the IB group PD(15)FEV(1) and PD(20)FEV(1) were obtained in all patients, while in the OXI group they were obtained in 12 and 5 pts respectively and in the TIO group in 14 and 5 pts respectively. Normal hyperreactivity was obtained in 2 patients, in both OXI and TIO groups. In OXI and TIO, the PD(15) obtained after drug pre-medication, was similar (respectively 1628 +/- 955.7 and 1595.5 +/- 990 microg), but higher (p < 0.0001) in comparison to the PD(15) measured in the IB group (532.2 +/- 434.8 microg). Also, the dose-response slope (decline percentage of FEV(1)/cumulative methacholine dose) after PD(15) was similar in both OXI and TIO groups but different in the IB group. A significant relationship (p < 0.01) was found between PD(15)FEV(1) (obtained in 40 pts) and the increase in FEV(1)% obtained 60 minutes after bronchodilator inhalations (r = 0.53). In conclusion, with a standard dose, both Oxitropium and Tiotropium seem to have the same protective effect in bronchial asthma but higher than Ipratropium. It's probable that the best dose of Ipratropium should be a higher one than the usual dose taken.