title: Effect of heliox on lung dynamic hyperinflation, dyspnea, and exercise endurance capacity in COPD patients.
abstract: 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.
authors.affiliation: Dipartimento di Medicina Clinica, Servizio di Fisiopatologia Respiratoria, Università La Sapienza, v. le Università 37, 00185 Rome, Italy. paolo.palange@uniroma1.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Palange
authors.forename: Gabriele
authors.initials: G
authors.lastname: Valli
authors.forename: Paolo
authors.initials: P
authors.lastname: Onorati
authors.forename: Rosa
authors.initials: R
authors.lastname: Antonucci
authors.forename: Patrizia
authors.initials: P
authors.lastname: Paoletti
authors.forename: Alessia
authors.initials: A
authors.lastname: Rosato
authors.forename: Felice
authors.initials: F
authors.lastname: Manfredi
authors.forename: Pietro
authors.initials: P
authors.lastname: Serra
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D004417:Dyspnea / Q000209:etiology / Q000503:physiopathology; D015444:Exercise; D006371:Helium / Q000008:administration & dosage* / Q000494:pharmacology; D006801:Humans; D007320:Inspiratory Capacity / Q000187:drug effects*; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000008:administration & dosage* / Q000494:pharmacology; D010807:Physical Endurance / Q000187:drug effects*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology*; D011659:Pulmonary Gas Exchange / Q000187:drug effects; D015656:Respiratory Mechanics / Q000187:drug effects
chemical_list: D006371:Helium; C038949:heliox; D010100:Oxygen