A Study on CO Diffusing Capacity with Reference to Pulmonary Hemodynamics and Ventilatory Functions in Patients with Cardiac or Chronic Pulmonary Disease

Abstract

The pulmonary diffusing capacity (DL) is a value relating to the flow rate of gas across the alveolo-capillary membrane to the pressure gradient. In patients with cardio-pulmonary diseases, an impediment of DL is caused by many factors. The relationship between DL and plumonary hemodynamics or ventilatory functions was studied in order to clarify these f actors. Material and Methods In 14 normal subjects, 20 patients with cardiac valvular disease (mitral valvular disease 13 and aortic valvular disease 7), 15 patients with essential hypertension and 30 patients with chronic pulmonary disease (emphysema 9, asthma 16 and others), the pulmonary diffusing capacity for carbon monoxide (DLco) was measured by FILLEY'S steady state method. Right heart catheterization was performed simultaneously. Ventilatory functions were measured by 13.5 L Benedict-Roth respirometer. Results The average value of DLCO for 14 normal subjects was 15cc per minute per mmHg. These DLco values were divided by body surface area (DLco/M²), because DLco Was cor-related with BSA. Normal values for DLco/M² were in a range from 9 to 11cc per minutes per mmHg per squaremeter BSA. A. DLco in patients with various cardiopulmonary diseases 1) Cardiac valvular diseases a) mitral stenosis and mitral insufficiency DLco was slightly decreased in all patients with mitral stenosis and mitral insufficiency (7∼9cc/min/mmHg/M²). b) mitral steno-insufficiency DLco Was markedly decreased in all patients except for one patient (4.3∼5.9cc/min/mm Hg/M²). c) aortic steno-insufficiency DLco was within normal limits in 3 patients and slightly decreased in 4 patients (6.5∼8.5 cc/min/mmHg/M²). 2) Essential hypertension DLco was within normal limits in 6 patients, slightly decreased in 8 patients (6.8∼8.9cc/ min/mmHg/M²) and moderately decreased in one patient (5.7 cc/min/mmHg/M²).