Pulmonary haemodynamic changes in patients with severe COPD.

Worsening gas exchange during exercise and during exacerbations of COPD contributes to systemic hypoxaemia and reduces quality of life. However, pulmonary haemodynamic changes under such conditions are not well understood. Right heart catheterization was performed in six patients with severe COPD (%FEV(1) < 50%) during rest, exercise and during an exacerbation. Pulmonary artery pressure (Ppa) was slightly elevated at rest. The Ppa, as well as pulmonary artery wedge pressure (Pawp) and cardiac index were significantly increased during bicycle ergometer exercise. In contrast, pulmonary vascular resistance increased significantly during an exacerbation accompanied by a slightly increased Ppa. Supplemental oxygen resulted in significant decreases in Ppa and Pawp during exercise and Ppa during exacerbations. In patients with COPD, haemodynamic changes in the pulmonary circulation may differ during exercise and with exacerbations. Supplementary oxygen is beneficial and associated with reductions in pulmonary arterial pressures.