Dependence of bronchoconstrictor and bronchodilator responses on thoracic gas compression volume

作者：Pellegrino Riccardo^*; Antonelli Andrea; Crimi Emanuele; Gulotta Carlo; Torchio Roberto; Dutto Luca; Pedersen Ole F; Brusasco Vito

来源：Respirology, 2014, 19(7): 1040-1045.

DOI：10.1111/resp.12349

• absolute lung volume
• alveolar pressure
• asthma
• chronic obstructive pulmonary disease
• forced expiratory volume

Background and objectiveDuring forced expiration, alveolar pressure (P-ALV) increases and intrathoracic gas is compressed. Thus, 1-s forced expiratory volume measured by spirometry (FEV1-sp) is smaller than 1-s forced expiratory volume measured by plethysmography (FEV1-pl). Thoracic gas compression volume (TGCV) depends on the amount of gas within the lung when expiratory flow limitation occurs in the airways. We therefore tested the hypothesis that bronchoconstrictor and bronchodilator responses using FEV1-sp are biased by height and gender, which are major determinants of lung volume.
MethodsWe studied 54 asthmatics during methacholine challenge and 55 subjects with airway obstruction (FEV1-sp increase >200mL and >12% after salbutamol) measuring at the same time FEV1-sp or FEV1-pl.
ResultsDuring methacholine challenge, TGCV increased more in males than females, correlated with P-ALV, total lung capacity (TLC) and height, and the provocative dose was lower using FEV1-sp than FEV1-pl. With salbutamol, FEV1-pl increased <200mL and <12% in 28 subjects, predominantly tall males, with larger TLC, TGCV and P-ALV.
ConclusionsBronchoconstrictor and bronchodilator responses are overestimated by standard spirometry in subjects with larger lungs because of TGCV.
Spirometry is used to assess FEV1 at the mouth. This technique depends on airway resistance and lung size; thus, it gives a smaller volume than that measured by plethysmography. Since gender and body size major determinants of lung size, FEV1 is overestimated in tall, male subjects.

• 出版日期2014-10