Table 1
Respiratory characteristics of the four patients according to Brooks and colleagues’ criteria9
| Patient (date of the incident) | |||||
|---|---|---|---|---|---|
| A1 (December 1998) | A2 (December 1998) | A3 (December 1998) | B1 (February 1999) | ||
| *The spirometric relative values were calculated using the reference values established by Quanjer et al.10 | |||||
| †The methacholine challenge was performed with an aerosol nebuliser (FDC88, Mediprom) which delivered successively increasing doses of methacholine (80 μg, 160 μg, 320 μg, 640 μg, 1280 μg, 1920 μg). Delivered doses were calculated from the flow rate of the aerosol and duration of delivery. At each methacholine dose, the FEV1 measurement was done, starting 90 seconds after the inhalation. The test was stopped when a fall of at least 20% of FEV1 was observed. Total duration of the methacholine challenge and FEV1 measurements generally lasted about 20 minutes. | |||||
| ‡RADS, reactive airways dysfunction syndrome. | |||||
| 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 | ? | |
