Most studies evaluating bronchodilation in flow-volume spirometry have been conducted in adult patients with obstructive airways diseases (COPD: Journal of Chronic Obstructive Pulmonary Disease, 5:310–318), but less is known about bronchodilation responses in pediatric patients.
We analysed 578 occasions from 59 patients: 31 non-transplant obliterative bronchiolitis (BO), 273 tests, 18 men, median age 16,8 (8–35) years and 28 severe asthma(SA), 305 tests, 20 men, median age 15,47 (10–19) years, with flow-volume spirometry using 0.2 mg of inhaled salbutamol aerosol with a spacer device for bronchodilation.
In the BO sample, the average increase of forced expiratory volume in one second (FEV1) from baseline after inhaled salbutamol was 92,8ml (95% confidence interval (CI): 80.5; 105.1) or 7.9% (95% CI:6.8, 9.1) and in the SA group 234,7 ml (95% CI: 214.2; 255.3) or 13,8% (95% CI:11.85, 14.3); (p < 0.01).The change of FEV1 correlated significantly with baseline FVC and baseline FEV1 (p < 0.01) in SA patients. The ratio of FEV1 to forced vital capacity (FEV1/FVC) at baseline was the strongest influencing factor for bronchodilation response in asthma patients but loosed weight in the multilevel analysis. In BO patients no significant correlation was found except for the weight z-score.
As expected results showed a significant increase of FEV1 from the baseline bronchodilation test in the SA pediatric patients. Low baseline FEV1/FVC, reflecting airflow limitation, was a strong determinant for FEV1 response to bronchodilation. In BO patients the increase of FEV1 from the baseline showed no difference from that reported in the normal population and the only correlation found was patient weight.
Our results indicate that the increase of FEV1 from baseline bronchodilation test shows statistically significant heterogeneity between non-transplant obliterative bronchiolitis and severe asthma across ages in childhood. These findings suggest that bronchodilation can be a useful tool to discriminate both diseases in pediatric patients.
Teresa Bandeira, No Financial Disclosure Information; No Product/Research Disclosure Information