Intermittent positive pressure ventilation increases diastolic pulmonary arterial pressure in advanced COPD.

OBJECTIVES: To measure the impact of intermittent positive pressure ventilation (IPPV) on diastolic pulmonary arterial pressure (dPAP) and pulmonary pulse pressure in patients with advanced COPD.

BACKGROUND: The physiological effects of raised intrathoracic pressures upon the pulmonary circulation have not been fully established.

METHODS: 22 subjects with severe COPD receiving IPPV were prospectively assessed with pulmonary and radial arterial catheterization. Changes in dPAP were assessed from end-expiration to early inspiration during low and high tidal volume ventilation.

RESULTS: Inspiration during low tidal volume IPPV increased the median [IQR] dPAP by 3.9 [2.5-4.8] mm Hg (P < 0.001). During high tidal volume, similar changes were observed. The IPPV-associated change in dPAP was correlated with baseline measures of PaO2 (rho = 0.65, P = 0.005), pH (rho = 0.64, P = 0.006) and right atrial pressure (rho = -0.53, P = 0.011).

CONCLUSIONS: In severe COPD, IPPV increases dPAP and reduces pulmonary pulse pressure during inspiration.