Lung function and nitrix oxide (NO) gas exchange in normal subjects and patients with asthma at baseline, during exacerbation and following recovery
| Normal control 57±9 years n=40 | Stable baseline asthma F250/S50 57±13 years n=15 | Asthma exacerbation F250/S50 n=15 | Asthma recovery F250/S50 plus oral corticosteroid n=15 | ||||
| FVC (litres) pre/post 180 μg of albuterol | 3.6±1.0 | ↔ | 3.2±0.9/3.3±0.9, p=0.2 | ↔ | 2.5±0.9/2.8±0.9, p=0.004/p=0.14 | ↔ | 3.2±0.8/3.2±0.7, p=0.005/p=0.19 |
| FVC % predicted pre/post | 97±13 | 88±20/94±22, p=0.2 | 66±17/74±17, p=0.001/p=0.001 | 80±17/88±22, p<0.001/p=0.06 | |||
| FEV1 (litres) pre/post | 2.8±0.7 | 2.1±0.8/2.2±0.8, p=0.009 | 1.5±0.7/1.8±0.7, p<0.001/p<0.001 | 2.1±0.7/2.2±0.6, p<0.001/p=0.1 | |||
| FEV1 % predicted pre/post | 93±14 | 71±23/78±26, p=0.004 | 49±20/57±20, p<0.001/p=0.02 | 68±21/77±24, p<0.001/p=0.02 | |||
| FEV1/FVC % pre/post | 79±5 | 66±13/68±14, p=0.005 | 61±13/64±13, p=0.06/p=0.4 | 70±12/70±12, p=0.07/p=0.2 | |||
| FENO at 50 ml/s (ppb) | 22±10 | 40±23 p=0.01 | 90±47 p=0.003 | 44±19 p<0.001 | |||
| FENO at 100 ml/s (ppb) | 14±9 | 24±11 p=0.005 | 53±27 p<0.001 | 27±9 p=0.001 | |||
| Large airway NO (nl/s) | 1.0±0.6 | 1.7±1.1 p=0.02 | 4.2±2.8 p=0.004 | 2.0±1.0 p=0.01 | |||
| Large airway NO (nl/s) corrected | 1.7±1.0 | 3.0±1.8 p=0.02 | 7.2±4.8 p=0.004 | 3.4±1.7 p=0.01 | |||
| Small airway/alveolar NO (ppb) | 3.9±2.4 | 5.6±3.0 p=0.04 | 11±6 p=0.001 | 5.9±2.2 p=0.01 | |||
| Small airway/alveolar NO (ppb) corrected | 1.9±2.3 | 2.2±2.7 p=0.2 | 2.6±4.3 p=0.8 | 1.9±2.4 p=0.4 | |||
| Statistical comparison | Baseline asthma vs age-matched normals | Exacerbation vs stable asthma | Recovery vs exacerbation |
Lung function and NO results are mean±SD. Measurements of NO gas exchange were obtained prior to spirometry. Spirometry obtained in patients with asthma are before and after 180 μg of albuterol by metered dose inhaler. Corrected indicates the NO gas exchange values in this table have been corrected for axial NO back-diffusion.22
F250/S50, fluticasone propionate 250 μg/salmeterol 50 μg; FENO, fraction expired nitric oxide; FEV1, forced expiratory volume in 1 s; FVC, forced expiratory volume; ppb, parts per billion.