Absence of previous respiratory complaints | + | | + | + | Childhood asthma with no asthma attack for past 10 years |
Single exposure to high levels of CBrClF2 | + | | + | + | + |
Onset of asthma symptoms within 24 hours after exposure | + | | + | + | + |
Symptoms lasting at least 3 months | + | | + | + | + |
Bronchial obstruction | Obstruction of small airways | | – | – | – |
Baseline spirometry parameters (percentage of predictive value*) | (February 1999) | | (April 1999) | (January 1999) | (April 1999) |
FVC (l) | 3.14 (86%) | | 3.21 (90%) | 4.81 (91%) | 3.36 (95%) |
FEV1 (l) | 2.55 (80%) | | 2.82 (91%) | 3.92 (90%) | 2.92 (95%) |
FEV1/FVC (%) | 81% | | 88% | 81% | 87% |
FEF25–75(l/s) | 2.41 (60%) | | 3.89 (98%) | 4.85 (105%) | 2.99 (77%) |
Bronchial hyperresponsiveness | + | | + | + | + |
Methacholine challenge† | March 2000 | April 2001 | April 1999 | February 1999 | April 1999 |
Maximum cumulative dose of methacholine | 640 μg | 1280 μg | 160 μg | 1280 μg | 640 μg |
Percentage of fall in FEV1 | −24% | −23% | −28% | −22% | −38% |
Presence of other pulmonary disease at the time of incident | – | | – | – | – |
Diagnosis of RADS‡ | Definite | | Definite | Definite | ? |