僧帽弁狭窄ならびに先天性心疾患における肺換気機能に関する研究—右心カテーテル法所見との対比

Ventilatory Function and Its Relation to Pulmonary Circulatory Dynamics in Mitral Stenosis and Congenital Heart Disease

序論

　体動時の軽度の呼吸困難から，安静時の呼吸困難，起坐呼吸，あるいは心臓喘息にいたるまで，種々の程度の，呼吸に関する愁訴が，心疾患の主要な徴候の一つであることは申すまでもない。これらは心臓に原因する2次的な肺機能異常によるものであるが，この点に関しての詳細な研究は，最近の肺生理学，肺機能検査法の進歩，ならびに右心カテーテル法の導入に負うことが多い。著者は僧帽弁狭窄症と先天性心畸形について肺換気機能と肺循環の両面を比較検討したので，その成績を報告し，いささか考察を試み度い。

Ventilatory function and pulmonary circulatory dynamics were comparatively examined in 34 cases of mitral stenosis and 38 cases of congenital heart disease, and following results were obtained.

I) Mitral Stenosis

1) In mild cases with pulmonary capillary pressure below 20mmHg and pulmonary arterial pressure below 30mmHg, lung volume and maximum breathing capacity showed normal values in the majority of cases. In cases with pulmonary capillary pressure above 20mmHg and pulmonary arterial pressure above 30mmHg, decrease of vital capacity, increase of the ratio of residual volume to total lung capacity, and decrease of maximum breathing capacity were generally obvious.

2) There was significant negative correlation between vital capacity and pulmonary capillary pressure or pulmonary arterial pressure (r=-0.628, -0.642: p<0.01). This correlationship became closer by excluding those cases with extremely long or short duration of symptoms.

3) There was no significant correlation between the maximum breathing capacity and pulmonary capillary or pulmonary arterial pressure (r=-0.502, -0.353: p>0.05).

4) Air velocity index was 0.77~1.49, the average value being 1.11.

II) Congenital Heart Disease

1) Congenital heart disease with left-right shunt

(ⅰ) In cases with distinct increase of pulmonary blood flow but without elevation of pulmonary arterial pressure, lung volume and maximum breathing capacity generally showed normal values. On the other hand, (ⅱ) in cases with marked increase of pulmonary blood flow and distinct elevation of pul-monary arterial pressure, decreased vital capacity, increased ratio of residual volume to total lung capa-city, and decreased maximum breathing capacity were observed in the majority of cases. (ⅲ) In a case which showed marked elevation of pulmonary arterial pressure but no increase of pulmonary blood flow, being accompanied by right-left shunt chiefly, there was no distinct change in lung volume and maximum breathing capacity.

2) In pulmonary stenosis and tetralogy of Fallot, there was no distinct change in lung volume and maximum breathing capacity. In some of these cases showing cyanosis, there was marked increase in minute ventilation.