Published in:
01-07-2010 | original Article
Influence of respiratory pressure support on hemodynamics and exercise tolerance in patients with COPD
Authors:
Cristino Carneiro Oliveira, Cláudia Regina Carrascosa, Audrey Borghi-Silva, Danilo C. Berton, Fernando Queiroga Jr., Eloara M. V. Ferreira, Luiz E. Nery, J. Alberto Neder
Published in:
European Journal of Applied Physiology
|
Issue 4/2010
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Abstract
Inspiratory pressure support (IPS) plus positive end-expiratory pressure (PEEP) ventilation might potentially interfere with the “central” hemodynamic adjustments to exercise in patients with chronic obstructive pulmonary disease (COPD). Twenty-one non- or mildly-hypoxemic males (FEV1 = 40.1 ± 10.7% predicted) were randomly assigned to IPS (16 cmH2O) + PEEP (5 cmH2O) or spontaneous ventilation during constant-work rate (70–80% peak) exercise tests to the limit of tolerance (T
lim). Heart rate (HR), stroke volume (SV), and cardiac output (CO) were monitored by transthoracic cardioimpedance (Physioflow™, Manatec, France). Oxyhemoglobin saturation was assessed by pulse oximetry (SpO2). At similar SpO2, IPS16 + PEEP5 was associated with heterogeneous cardiovascular effects compared with the control trial. Therefore, 11 patients (Group A) showed stable or increased Δ “isotime” – rest SV [5 (0–29) mL], lower ΔHR but similar ΔCO. On the other hand, ΔSV [−10 (−15 to −3) mL] and ΔHR were both lower with IPS16 + PEEP5 in Group B (N = 10), thereby reducing ΔCO (p < 0.05). Group B showed higher resting lung volumes, and T
lim improved with IPS16 + PEEP5 only in Group A [51 (−60 to 486) vs. 115 (−210 to 909) s, respectively; p < 0.05]. We conclude that IPS16 + PEEP5 may improve SV and exercise tolerance in selected patients with advanced COPD. Impaired SV and CO responses, associated with a lack of enhancement in exercise capacity, were found in a sub-group of patients who were particularly hyperinflated at rest.