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Biomedical subjects

Paolo Palange

Publications and source records attributed to Paolo Palange.

5 recordsLinked to original sources
PubMed2005

Supplemental oxygen and heliox: 'new' tools for exercise training in chronic obstructive pulmonary disease.

PURPOSE OF REVIEW: Chronic obstructive pulmonary disease (COPD) is a condition characterized by airflow obstruction only partially reversible with usual bronchodilator therapy. Inability of gas to move freely in and out of the lungs causes dyspnea and exercise intolerance. Putative mechanisms of exercise limitation under these conditions are the occurrence of expiratory airflow limitation and dynamic lung hyperinflation developing with the increase in minute ventilation during exercise. This review will examine the results of recent studies using nonpharmacological interventions to improve exercise tolerance in COPD and their relevance to rehabilitation programs. RECENT FINDINGS: Decreasing ventilatory demands and/or gas density have been recently shown to be beneficial to improve exercise tolerance, symptoms, and quality of life. For instance, breathing supplemental oxygen was capable of reducing exercise ventilation, thus allowing expiratory flow limitation within the tidal breathing range to be minimized, and operational lung volumes to be accommodated at lower levels. As a result, dyspnea was decreased for the elastic work of breathing was decreased, and patients were able to increase exercise intensity and/or duration. Manipulating gas density has also been shown to be beneficial in relieving symptoms and improving exercise capacity, for it facilitates gas emptying during expiration. As a result, the amount of expiratory flow limitation and operational lung volumes decreased, thus ultimately leading to greater exercise tolerance. SUMMARY: Nonpharmacological interventions aimed at modifying physical gas properties appear to open new perspectives in exercise rehabilitation programs for COPD.

Administration, Inhalation↗
PubMed2004

Effect of heliox on lung dynamic hyperinflation, dyspnea, and exercise endurance capacity in COPD patients.

We tested the hypothesis that heliox breathing, by reducing lung dynamic hyperinflation (DH) and dyspnea (Dys) sensation, may significantly improve exercise endurance capacity in patients with chronic obstructive pulmonary disease [n = 12, forced expiratory volume in 1 s = 1.15 (SD 0.32) liters]. Each subject underwent two cycle ergometer high-intensity constant work rate exercises to exhaustion, one on room air and one on heliox (79% He-21% O2). Minute ventilation (VE), carbon dioxide output, heart rate, inspiratory capacity (IC), Dys, and arterial partial pressure of CO2 were measured. Exercise endurance time increased significantly with heliox [9.0 (SD 4.5) vs. 4.2 (SD 2.0) min; P < 0.001]. This was associated with a significant reduction in lung DH at isotime (Iso), as reflected by the increase in IC [1.97 (SD 0.40) vs. 1.77 (SD 0.41) liters; P < 0.001] and a decrease in Dys [6 (SD 1) vs. 8 (SD 1) score; P < 0.001]. Heliox induced a state of relative hyperventilation, as reflected by the increase in VE [38.3 (SD 7.7) vs. 35.5 (SD 8.8) l/min; P < 0.01] and VE/carbon dioxide output [36.3 (SD 6.0) vs. 33.9 (SD 5.6); P < 0.01] at peak exercise and by the reduction in arterial partial pressure of CO2 at Iso [44 (SD 6) vs. 48 (SD 6) Torr; P < 0.05] and at peak exercise [46 (SD 6) vs. 48 (SD 6) Torr; P < 0.05]. The reduction in Dys at Iso correlated significantly (R = -0.75; P < 0.01) with the increase in IC induced by heliox. The increment induced by heliox in exercise endurance time correlated significantly with resting increment in resting forced expiratory in 1 s (R = 0.88; P < 0.01), increase in IC at Iso (R = 0.70; P < 0.02), and reduction in Dys at Iso (R = -0.71; P < 0.01). In chronic obstructive pulmonary disease, heliox breathing improves high-intensity exercise endurance capacity by increasing maximal ventilatory capacity and by reducing lung DH and Dys.

Administration, Inhalation↗
PubMed2003

Non-invasive evaluation of gas exchange during a shuttle walking test vs. a 6-min walking test to assess exercise tolerance in COPD patients.

Walking tests, such as the "shuttle" incremental walking test (SWT) and the 6-min walking test (6'WT), are commonly utilized in evaluating exercise intolerance in patients with chronic obstructive pulmonary disease (COPD) and the distance covered is the variable usually considered. Because lung gas exchange indexes are not measured, little is known about the physiological response elicited by different walking protocols. We compared exercise adaptation during the 6'WT and SWT in 13 male stable COPD patients [mean (SE) age: 70 (1) years; forced expiratory volume in 1 s (FEV(1)): 1.2 (0.1) l; arterial O(2) tension (PaO(2)): 72 (2) mmHg; arterial CO(2) tension (PaCO(2)): 41 (1) mmHg]. Oxygen uptake (.VO(2)), CO(2) output (.VCO(2)), minute ventilation (.V(E)), and heart rate (HR) were monitored by a portable telemetric system. During the SWT a linear response in lung gas exchange indexes was observed while, during the 6'WT, the response was exponential. During the 6'WT, .VO(2), .VCO(2), .V(E), and HR values at steady-state (SS) were significantly lower compared to SWT peak values. For SWT, distance covered correlated with .VO(2PEAK), (R=0.86, p<0.001), .VCO(2PEAK), (R=0.87, p<0.001) and .V(EPEAK) (R=0.74, p<0.01); moreover, distance and .VO(2PEAK) were significantly correlated with peak .VO(2) values obtained during cycle ergometer incremental exercise (R=0.72, p<0.01 and R=0.92, p<0.0001, respectively). For 6'WT, the distance covered did not correlate with any pertinent physiological index. The two walking protocols reveal substantial differences in pathophysiologic adaptations and provide evidence that SWT is more accurate than the 6'WT in the evaluation of maximal exercise tolerance in COPD patients.

Adaptation, Physiological↗