慢性左心疾における肺循環ならびに換気 : 呼吸機能障害の検討

Pulmonary circulatory and ventilatory-respiratory disturbance were studied in 108 patients with mitral and aoric valvular disease. The following conclusions were obtained. 1) The elevation of wedge pressure (WP) elicited the increment of pulmonary arterial mean pressure (PAm) and pulmonary vascular resistance index (PVRI) proportionally. The increasing rate of PAm and PVRI for Wp above 25 mmHg in WP was larger compaired to below 25 mmHg.. 2) Following the elevation of WP, total ventilation (V^^・E) and effective alveolar ventilation (V^^・A) increased, whereas predicted per cent vital capacity and pulmonary compliance decreased. These changes become more evident when WP exceed the critical value of 25 mmHg. 3) With the elevation of WP, per cent dead space and alveolar-arterial oxygen tension differrence (A-^<a>Do_2) increased, whereas CO pulmonary diffusing capacity (DL_co) decreased. As a result, arterial oxygen saturation (SaO_2) was lowerd. These results seemed to indicated that sustained pulmonary hypertension (when above 25 mmHg) gave to not only vasoconstrictive responce of pulmonary artery, but also organic changes of pulmonary arterial wall, alveolar wall and interstitial tissues.