Denis E. O’Donnell

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Chronic obstructive pulmonary disease (COPD) is known to elicit intrinsic abnormalities in male skeletal muscle. However, it is unclear to what extent these changes occur in women and whether they are fiber-type specific. We investigated fiber-type specific differences in selected histochemical properties in muscle obtained from women with moderate to(More)
BACKGROUND To have a better understanding of the mechanisms of exercise limitation in mild-to-moderate chronic obstructive pulmonary disease (COPD), we compared detailed respiratory physiology in patients with COPD and healthy age- and sex-matched controls. METHODS Data were collected during the pre-treatment, patient characterization phase of a(More)
Respiratory mechanical abnormalities in patients with chronic obstructive pulmonary disease (COPD) may impair cardiodynamic responses and convective oxygen delivery during exercise, resulting in slower ventilatory, pulmonary gas exchange (PGE), and heart rate (HR) kinetics compared with normal. We reasoned that bronchodilators and the attendant reduction of(More)
RATIONALE Exacerbations of COPD are defined clinically by worsening of chronic respiratory symptoms. Chronic respiratory symptoms are common in the general population. There are no data on the frequency of exacerbation-like events in individuals without spirometric evidence of COPD. AIMS To determine the occurrence of 'exacerbation-like' events in(More)
We examined the contribution of alterations in central ventilatory control, static and dynamic respiratory mechanics and their interaction to exertional breathlessness in healthy human pregnancy. Detailed ventilatory, respiratory mechanical/muscular and perceptual responses to incremental cycle exercise were compared in the third trimester (TM3) and again(More)
Dyspnea, exercise intolerance, and activity restriction are already apparent in mild chronic obstructive pulmonary disease (COPD). However, patients may not seek medical help until their symptoms become troublesome and persistent and significant respiratory impairment is already present; as a consequence, further sustained physical inactivity may contribute(More)
In chronic obstructive pulmonary disease (COPD), worsening expiratory flow limitation together with alteration in the elastic properties of the lung are associated with progressive lung hyperinflation and gradual decline in the resting inspiratory capacity over time. Dynamic hyperinflation (DH) refers to the variable increase in end-expiratory lung volume(More)
BACKGROUND Long-term oxygen therapy (LTOT) is the only component of the management of chronic obstructive pulmonary disease (COPD) that improves survival in patients with severe daytime hypoxemia. LTOT is usually provided by a stationary oxygen concentrator and is recommended to be used for at least 15-18 h a day. Several studies have demonstrated a(More)
BACKGROUND The relationship between patient-reported symptoms and objective measures of lung function is poorly understood. AIM To determine the association between responsiveness to bronchodilator and respiratory symptoms in random population samples. METHODS 4669 people aged 40 years and older from 8 sites in Canada completed interviewer-administered(More)