[Hydralazine and oxygen transport in interstitial and chronic obstructive pneumopathies]

We studied the effect of hydralazine (HDL) on peripheral oxygen transport (TO2) in 8 patients with chronic obstructive lung disease (EPOC, group I) and 11 patients with chronic interstitial lung disease (NI, group II) and pulmonary arterial hypertension (HAP). Mean pulmonary artery pressure (Pp) at basal conditions were 31 +/- 3 mmHg for the EPOC group and 26 +/- 9 mmHg for NI patients. After HDL, pulmonary vascular resistance (Rp) decreased significantly only in NI patients (Rp basal = 7.1 +/- 4, Rp post HDL = 5.9 +/- 3u m2). In EPOC patients Pp increased after HDL (Pp basal = 31 +/- 3, Pp post HDL = 36 +/- 4 mmHg, p less than 0.05). This was not the case for NI patients in whom Pp did not change. Both groups showed reduction in systemic vascular resistance after HDL. PaO2, PvO2, SaO2, CvO2 and TO2 were significantly increased in both groups after HDL. TO2 change was correlated with the increasing cardiac index in both diseases and with arterial oxygen content in group II only. Our study suggest that TO2 improves in EPOC and NI patients after HDL, however only in NI was associated with a reduction in pulmonary vascular resistance.