RT Journal Article
SR Electronic
T1 Effects of hyperoxia and helium-hyperoxia on the cardiocirculatory responses to incremental exercise in hypoxaemic patients with advanced COPD
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 1711
VO 38
IS Suppl 55
A1 Marcos Nunes
A1 Fernando Queiroga-Jr.
A1 Ethiane Meda
A1 Gaspar Chiappa
A1 Maria-Christina Machado
A1 Luiz Eduardo Nery
A1 J. Alberto Neder
YR 2011
UL http://erj.ersjournals.com/content/38/Suppl_55/1711.abstract
AB Heliox breathing might positively impact upon the haemodynamic responses to exercise in non-hypoxaemic patients with moderate-to-severe chronic obstructive pulmonary disease (COPD) (Chiappa, GR et al. Am J Respir Crit Care Med, 179:1004, 2009). There is, however, a lack of evidence of whether these beneficial effects would also be found in patients with more advanced cardiovascular impairment, i.e., hipoxaemic, GOLD stage IV patients. On a double-blind study, 13 patients (FEV1= 35.4±9.1% pred; PaO2= 57.7±7.0 mmHg) were submitted to maximum incremental cardiopulmonary exercise tests while breathing hyperoxia (HiOX= 40% O2) or helium-hyperoxia (He-HiOX= 60% He/40% O2). Stroke volume (SV, mL) and cardiac output (CO, L/min) were non-invasively monitored by impedance cardiography (PhysioFlow®, Manatec Inc, France). Peak work rate (WR) was improved with He-HiOX compared to HiOX (52±21 W vs. 46±18 W); in addition, end-expiratory lung volume (EELV) was slightly, albeit significantly, reduced (5.50±1.25 vs 5.61±1.30 L; p<0.05). At iso-WR, He-HiOX was associated with higher SV and CO than HiOX (92±8 mL vs. 84±2 mL and 9.6±1.3 L/min vs. 8.7±1.9 L/min, p<0.05). Improvement in CO with He-HiOX was negatively related to resting EELV (r= - 0.72, p= 0.01) but not with baseline CO and PaO2 (p>0.05). In conclusion, hyperoxic heliox enhances the cardiocirculatory responses to exercise compared to hyperoxia alone in less hyperinflated patients with advanced, hypoxaemic COPD. These data indicate that increased operational lung volumes are related to deleterious haemodynamic effects in this patient sub-population.