Pulmonary function studies were made on 292 patients with pulmonary tuberculosis.
All patients were divided into four groups, namely, those with normal ventilation (NV)
restrictive ventilatory insufficiency (RVI) obstructive ventilatory insufficiency (OVI) and
mixed ventilatory insufficiency(MVI) based upon vital capacity, timed vital capacity and
air velocity index, and the functional characteristics of each group were compared. The
incidence of NV has progressively decreased and that of MVI has progressively
increased as the extent of the disease process progressed, as expected, and this was
particularly true in female patients. However, the incidence of OVI was higher among
male patients whereas that of RVI was higher among female patients regardless of the
extent of the disease process. Vital capacity was within normal range in patients with
NV and OVI but it was significantly decreased in those with RVI and MVI. Timed vital
capacity in those with NV . and RVI showed no deviation from that of normal value
but significant decrease was noted in those with OVI and MVI. Air velocity index was
within normal range or even higher than normal in patients with NV and RVI but it
was lower in those with OVI and MVI. However, even in patients with OVI and MVI
the mean values of air velocity index were well above the lower limit of the normal,
suggesting that this test is not a very sensitive one for the detection of air trapping.
Maximal breathing capacity was within normal limits in patients with NV but
moderately decreased in the remaining groups, particularly in those will MVI. Also noted
was a greater decrease in maximal breathing capacity in patients will RVI in
comparison to those with OVI, thus suggesting that a decrease in the ventilating area of
the lung rather than airway obstruction played a more significant role in the production
of ventilatory insufficiency in pulmonary tuberculosis. Changes in breathing reserve ratio
and ventilatory factor according to each type of ventilation were very similar to those of
maximal breathing capacity. And the decreases in breathing reserve ratio and ventilatory
factor were caused in most of cases by a decrease in maximal breathing capacity. Air
trapping index and Leslie´s index not only showed no close correlation to limed vital
capacity and air velocity index but even some controversy was present. It was felt that
air trapping index and Leblie´s index were not valuable tests for the diagnosis of air
trapping. Changes in capacity ratio according to each type of ventilation were very
similar to those of air velocity index. Minute ventilation, oxygen consumption, ventilation
equiva1ent and oxygen diffusion were approximately of the same range regardless of the
type of ventilatory insufficiency.
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