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Pulmonary ventilation defects in older never-smokers.
Khadija Sheikh1, Gregory A Paulin1, Sarah Svenningsen1
1Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada; Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada;
Journal of Applied Physiology (Bethesda, Md. : 1985)
|June 7, 2014
Summary
Older never-smokers often have lung ventilation defects not reversed by deep breaths or medication. These defects are linked to airway narrowing, not reduced exercise capacity or breathlessness.
Area of Science:
- Pulmonary Medicine
- Radiology
- Physiology
Background:
- Hyperpolarized helium-3 (3He) MRI shows ventilation defects in older never-smokers.
- The physiological relevance of these defects requires further investigation.
Purpose of the Study:
- To evaluate ventilation-defect percent (VDP) and its response to deep inspiration (DI) and salbutamol in older never-smokers.
- To identify determinants of VDP, including pulmonary function, exercise capacity, and smoke exposure.
Main Methods:
- Fifty-two healthy older never-smokers underwent pulmonary function tests, cardiopulmonary exercise testing (CPET), and (3)He MRI.
- Ventilation-defect percent (VDP) was assessed, along with responses to DI and salbutamol.
- Questionnaires assessed dyspnea and smoke exposure.
Main Results:
- 75% of subjects had ventilation defects, mostly irreversible by DI/salbutamol.
- Subjects with defects responding to DI/salbutamol showed greater ventilation heterogeneity and lower FEV1/FVC ratios.
- FEV1, inspiratory capacity, and airway resistance predicted VDP.
Conclusions:
- Most older never-smokers exhibit peripheral ventilation defects not improved by DI/salbutamol.
- These defects are associated with irreversible airway narrowing, not dyspnea or reduced exercise capacity.
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