Differential pulmonary functional recovery from severe COVID-19
and impaired diffusion function in recovered severe COVID-19 patients
Among the 64 patients with pulmonary functional test, 39 ( 60.9% ) were
males and 25 ( 39.1% ) were females, with an average ( 49.31 ± 14.98 )
years old, 20 cases ( 31.3% ) of smokers. There were 20 cases ( 31.2%
) with pulmonary ventilation dysfunction, including 15 cases ( 23.4% )
with restrictive ventilation dysfunction and 5 cases ( 7.8% ) with
obstructive ventilation dysfunction ; and 23 cases ( 35.9% ) with
diffusion dysfunction ( Table 3 ) . Table 3 showed a significant
difference in ventilation dysfunctions among the different groups of
severity, for restrictive ventilation, which accounted for 0% in mild
illness, 16.1% in moderate and 43.5% in severe group, respectively (
p=0.028 ) in moderate and severe groups; for obstructive ventilation
dysfunction, which accounted for 30% in mild illness, 6.45% in
moderate and 0% in severe group, respectively ( p=0.022 ) in mild and
severe groups; Similarly, diffusion dysfunction was observed among
different groups, which accounted for 30% in mild illness,22.6% in
moderate and56.5% in severe group, respectively ( p=0.021 ) in moderate
and severe groups. Small airway function accounted for 40% in mild
illness, 41.94% in moderate and 30.43% in severe group, respectively (
p=0.678 ) ( Table 3 ) . This trend of the gradual decrease in level of
DLCO among patients was identical with the varying degree of severity.
In the severe group, DLCO% pred was ( 78.93 ± 17.48 ) %, which was
lower than the average of the three groups, indicating that the
diffusion dysfunction in the severe group is more significant. The
pulmonary dysfunction of the three groups was statistically significant
( P<0.05 ) ( Table 3 and Figure 1 ) .The value of TLC % pred
in severe group was much less than that of moderate or mild groups,
suggesting the higher impairment of lung volume in severe COVID-19
patients. Thus, the difference in diffusion dysfunction is statistically
significant between the moderate group and severe group, especially the
diffusion dysfunction was decreased in the severe group.
Male was positively
correlation with diffusion dysfunction and the oxygen therapy was mildly
correlated with diffusion dysfunction in severe patients
In order to explore the factors correlation with the decrease in the
diffusion dysfunction in all the convalescent COVID-19 patients, the
pulmonary function of 56 cases were divided into 5 groups: 0 )
completely normal; 1) diffusion dysfunction; 2) obstruction ventilatory
dysfunction; 3) restrictive ventilatory dysfunction; 4) obstruction
ventilation dysfunction and diffuse dysfunction. We observed no
significant association of age, smoking, comorbidities and oxygen
therapy with diffusion impairment.
Male has the more risk factor with
impaired diffusion impairment (P = 0.037, Table 4).
Further, the pulmonary function of 18 severe cases were divided into two
groups with the decrease in the diffusion dysfunction. There were no
significant association of age, smoking, comorbidities, hormone,
antiviral, convalescent plasma and immunoglobulin with diffusion
impairment. The oxygen therapy has
the mild correlated with impaired diffusion in severe patients (P=0.040,
Table 5).