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Citation: Patil Shital et al (2021). “Role of Spirometry in Lung Function Assessment in Post COVID-19 Pneumonia Cases: Correlation
with CT Severity, Duration of Illness, Oxygen Saturation and Ventilatory Support in Critical Care Setting in Tertiary Care Setting in
India.”. Saudi J Med, 6(12): 441-448.
441
Saudi Journal of Medicine
Abbreviated Key Title: Saudi J Med
ISSN 2518-3389 (Print) |ISSN 2518-3397 (Online)
Scholars Middle East Publishers, Dubai, United Arab Emirates
Journal homepage: https://saudijournals.com
Original Research Article
“Role of Spirometry in Lung Function Assessment in Post COVID-19
Pneumonia Cases: Correlation with CT Severity, Duration of Illness,
Oxygen Saturation and Ventilatory Support in Critical Care Setting in
Tertiary Care Setting in India.”
Patil Shital1*, Uttareshvar Dhumal2, Abhijit Acharya3
1Associate Professor, Pulmonary Medicine, MIMSR Medical College, Latur, India
2Associate Professor, Department of Radiodiagnosis, MIMSR Medical College, Latur, India
3Associate Professor, Department of Pathology, MIMSR medical college, Latur, India
DOI: 10.36348/sjm.2021.v06i12.008 | Received: 13.11.2021 | Accepted: 21.12.2021 | Published: 26.12.2021
*Corresponding Author: Dr. Shital Patil, MD
Abstract
Background: Although Lung is the primary target organ involvement in corona virus disease-19 (COVID-19), post-
covid lung pathology and its impact on lung functions is still uncertain. Material and methods: Prospective multicentric
study conducted during May 2020 to September 2021, to find pulmonary function assessment in post-COVID-19
recovered pneumonia cases irrespective of their symptoms, included 600 cases in symptomatic and asymptomatic group
and subjected to inclusion and exclusion criteria. All cases were subjected to Spirometry analysis. Statistical analysis was
done by using chi-test. Results: In Spirometry assessment of post-COVID-19 pneumonia cases at 12 weeks post
discharge form hospital, abnormal lung function in 77.5% post covid-19 pneumonia cases; restrictive pattern was
predominant type and documented in 43.33% cases, normal lung functions were documented in 22.5% cases. In age and
gender assessment in normal and abnormal lung functions assessment, statistically significant association in males
90/150 versus females 45/315 [p<0.00001]; and in age of population in study cases as below 50 years 110/300 versus
above 50 years 25/165 [p<0.0001]. CT severity score has shown negative impact on lung function after recovery at 12
weeks post-discharge; cases with score <8, 8-15 and >15 documented normal and abnormal lung functions as in 36/54,
60/80 and 39/331 respectively of total 600 study cases [p<0.00001]. Duration of illness has associated negative impact on
lung function; <7 days, 8-15 days and >15 days of onset of symptoms documented normal and abnormal lung functions
in 108/132, 22/168 and 5/165 cases respectively [p<0.00001]. Low oxygen saturation at entry point has negative impact
on overall outcome on lung function; cases with oxygen saturation <75%, 75-90% and >90% observed as normal and
abnormal lung functions in 92/18, 35/135 and 6/314 cases respectively [p<0.00001]. Timing of BIPAP/NIV has
significant association in attaining normal lung functions after post-COVID19 pneumonia recovery; cases received
BIPAP/NIV at entry point <1 day, 3-7 days and after 7 days of hospitalization were documented normal and abnormal
lung functions in 30/150, 40/35 and 5/50 cases respectively [p<0.00001]. Conclusions: Pulmonary functions abnormality
in post-COVID-19 pneumonia cases has been documented and should be assessed cautiously to have successful
treatment outcome. Restrictive lung disease is the predominant lung function impairment in post-COVID 19 recovered
lung pneumonia cases. Age above 50 years, male gender, Diabetes, High CT severity, longer duration of illness, proper
timing of initiation of BIPAP/NIV therapy, has documented significant impact on post covid lung functions at 12 weeks
assessment.
Keywords: Pulmonary functions, spirometry, post-COVID-19, Restrictive pattern.
Copyright © 2021 The Author(s): This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International
License (CC BY-NC 4.0) which permits unrestricted use, distribution, and reproduction in any medium for non-commercial use provided the original
author and source are credited.
INTRODUCTION
On March 11, 2020, the World Health
Organization (WHO) declared coronavirus disease 2019
(COVID-19) to be a pandemic, with approximately
20% of patients infected requiring hospitalization and
6% in critical care and needing invasive ventilatory
assistance [1]. Early epidemiological reports showed
that 8.2% of total cases presented with rapid and
progressive respiratory failure, similar to acute
respiratory distress syndrome (ARDS) [2].
Patil Shital et al.; Saudi J Med, Dec, 2021; 6(12): 441-448
© 2021 |Published by Scholars Middle East Publishers, Dubai, United Arab Emirates 442
COVID-19 is a heterogeneous disease with
most patients experiencing mild illness and spontaneous
recoveries, but a relevant subgroup of individuals
requires hospitalization for pneumonia and other
complications. In the initial reports from Wuhan, China,
up to one third of patients developed severe pneumonia
with acute respiratory distress syndrome (ARDS) [3].
Previous coronavirus infections include severe
acute respiratory syndrome (SARS) and Middle East
respiratory syndrome (MERS). Similar to COVID-19,
SARS and MERS typically begin with an acute illness
from which most patients recover after two weeks.
However, up to one third of SARS patients developed
severe pulmonary complications and ARDS [4]. A
subgroup of SARS survivors developed persistent lung
parenchymal abnormalities, including pulmonary
fibrosis [5, 6]. The appearance of pulmonary fibrosis
correlated with severity and duration of the acute illness
[7, 8] and radiological features of fibrosis persisted in
approximately 30% of patients after three and six
months [9, 10]. Older age, and male sex were identified
as risk factors for poor outcomes and development of
lung fibrosis [9, 11]. With the anticipation of potential
long-term sequelae after COVID-19, follow-up
strategies have been proposed by several groups from
the US, Great Britain, China, and India [12-15].
In present study, we have evaluated lung
function assessment at 12 weeks post-discharge in
treated cases of covid-19 pneumonia, and correlated
with CT severity at entry point, oxygenation status at
entry point, total duration of illness at hospitalization,
and use of BIPAP/NIV during course of hospitalization.
MATERIALS AND METHODS
Prospective multicentric observational study
conducted in Venkatesh chest hospital, and Pulmonary
Medicine, MIMSR medical college Latur during May
2020 to June 2021, to find out lung function assessment
of post-COVID-19 recovered pneumonia cases after 12
weeks of discharge from hospital. Total 600 cases were
enrolled in study after IRB approval and written
informed consent of patient.
Inclusion criteria
1. All treated and recovered cases of COVID-19
pneumonia cases above 18-year age, admitted in
indoor unit has been enrolled in study
2. Recovered cases of COVID-19 pneumonia
irrespective of CT severity were enrolled in study
3. Recovered cases of COVID-19 pneumonia
irrespective oxygen saturation was enrolled in
study
4. Recovered cases of COVID-19 pneumonia with
comorbidity like Diabetes Mellitus, IHD, CVD,
CKD, COPD were enrolled in study
5. Recovered cases of COVID-19 pneumonia cases
willing to undergo spirometry test were enrolled in
study
Exclusion criteria
1. Recovered cases of COVID-19 pneumonia cases
not willing to undergo spirometry test
2. Recovered cases of COVID-19 pneumonia cases
not able to perform spirometry test
3. Recovered cases of COVID-19 pneumonia cases
with neurological issues like hemiparesis or
hearing difficulty and having co-ordination
problem during spirometry
4. Recovered cases of COVID-19 pneumonia cases
with tachypnea or tachycardia and cases with
oxygen supplementation at rest were excluded from
study
5. Recovered cases of COVID-19 pneumonia below
18 years of age
6. Recovered cases of COVID-19 pneumonia in
pregnant females (any trimester was excluded)
All study cases were undergone following assessment
before enrolling in study
1. Clinical assessment as- vital parameters like heart
rate, respiratory rate, blood pressure and
documentation of respiratory adventitious sounds
2. Laboratory parameters- hemoglobin, renal
functions, blood sugar level, kidney functions,
ECG
3. Spirometry
METHODOLOGY OF SPIROMETRY
Subsequently spirometry evaluation was done
by a portable spirometer, SPIROLAB II (manufactured
by Medical International Research, Italy); and meets
American Thoracic Society and European Respiratory
Society standards (ATS & ERS), before and fifteen
minutes after administration of 400 microgram
salbutamol using pressurized metered-dose inhaler
(pMDI) with small-volume spacer device. All patients
were instructed not to use any bronchodilator on the
preceding night and on day of procedure. Spirometry
procedure was carried out as per ATS/ERS task force
recommendation for standardization of lung function
testing [17]. Subjects who were found to have post-
bronchodilator FEV1 (Forced Expiratory Volume in
first second)/FVC (Forced Vital Capacity) <0.7 were
taken up for final analysis as this value indicates the
cut-off for diagnosis of obstructive airway disease
according to GOLD guideline. Bronchodilator
Reversibility (BDR) was defined as an improvement in
FEV1 by at least 12% and 200 ml over pre-
bronchodilator value. FEV1/FVC ≥0.7 were excluded
as those patients had either a normal spirometry or a
purely restrictive ventilatory abnormality. Also, the
individuals who failed to fulfil acceptability and
reproducibility criteria of spirometry were excluded.
FVC, FEV1, and FEV1/FVC ratio values for case
patients were compared with gender-specific and race-
specific adult predicted normative population values
and the control group [16, 20].
Patil Shital et al.; Saudi J Med, Dec, 2021; 6(12): 441-448
© 2021 |Published by Scholars Middle East Publishers, Dubai, United Arab Emirates 443
The British Thoracic Society (BTS) guidelines
recommends the evaluation of PFTs at three months‟
post-discharge, especially at follow-up with patients
suspected of having an interstitial disease [20].
Interpretive algorithms were used in
determining restrictive or obstructive patterns and
spirometry results were analyzed and categorized in
four groups as [16-19].
1. Normal- FEV1/FVC ratio of >70% and an FVC of
> 80% predicted
2. Obstructive-Airway obstruction was defined as an
FEV1/FVC ratio of <70% and an FVC of > 80%
predicted
3. Mixed-combined defects were FVC of < 80%
predicted and an FEV1/FVC ratio of<70%
4. Restrictive-restrictive defects as an FEV1/FVC
ratio of >70% with an FVC of < 80% predicted
The statistical analysis was done using chi-
squared test. Significant values of χ2 were seen from
probability table for different degree of freedom
required. P value was considered significant if it was
below 0.05 and highly significant in case if it was less
than 0.001.
Observation and Analysis
In this study, total 600 post-COVID-19
recovered pneumonia cases were enrolled, between age
group 18-95 years of age; age above 50 years were 60%
(360/600) and age below 50 were 40% (240/600). In
gender distribution in study group, male population was
68.33 % (410/600) and females were 31.66% (190/600).
Main symptoms in study group were shortness of breath
in 79% cases, cough especially dry in 48% cases, and
fatigability in 79% cases, Tachycardia in 72% cases,
Tachypnea in 24% cases and oxygen desaturation on 6
min walk in 21% cases.
Table-1: Spirometry assessment of post-COVID 19 pneumonia cases at 12 weeks of discharge from hospital (n=600)
Total cases (n=600)
Percentage (%)
Normal
135
22.5
Obstructive
85
14.16
Mixed
120
20
Restrictive
260
43.33
In Spirometry assessment of post-COVID 19
pneumonia cases at 12 weeks post discharge form
hospital, restrictive pattern was predominant type
documented in 43.33% cases, normal lung functions
were documented in 22.5% cases [Table 1].
Table-2: Age and gender distribution in post-COVID-19 pneumonia cases (n=600) with Lung Function patterns
Age of study
population
Normal Lung Functions
(135/600)
Abnormal Lung functions
(465/600)
P value
<50 years (n=240)
90
150
χ2= 51.61
P <0.00001
>50 years (n=360)
45
315
Gender
Normal Lung Functions (135/600)
Abnormal Lung Functions
(465/600)
Male (n=410)
110
300
χ2= 13.91
P <0.0001
Female (n=190)
25
165
We observed abnormal lung function in 77.5%
post covid-19 pneumonia cases, and statistically
significant association in males (90/150) versus females
(45/315) normal and abnormal lung functions
respectively [p<0.00001]; similar observation also
documented in age of population in study cases as
below 50 years (110/300) versus above 50 years
(25/165) [p<0.0001] [Table2].
Table-3: Correlation of CT severity (at entry point) and lung function assessment by spirometry in post-covid-19
pneumonia cases after 12 weeks post discharge from hospital
CT severity
Normal lung functions
(n=135)
Abnormal lung functions
(n=465/600)
Analysis
<8 score (n=90)
36
54
χ2=79.42
P <0.00001
9-15 (n=140)
60
80
>15 (n=370)
39
331
CT severity score has shown negative impact
on lung function after recovery at 12 weeks post-
discharge; cases with score <8, 8-15 and >15
documented normal and abnormal lung functions as in
36/54, 60/80 and 39/331 respectively of total 600 study
cases [p<0.00001] [Table3].
Patil Shital et al.; Saudi J Med, Dec, 2021; 6(12): 441-448
© 2021 |Published by Scholars Middle East Publishers, Dubai, United Arab Emirates 444
Table-4: Duration of illness at entry point during hospitalization and its effect on Lung functions at 12 weeks of
discharge in post-COVID-19 pneumonia cases
Duration of illness
Normal lung functions
(n=135)
Abnormal lung
functions (n=465)
Analysis
<7 days (n=240)
108
132
χ2 =119.96
P <0.00001
8-15 days (n=190)
22
168
>15 days (n=170)
5
165
Duration of illness has associated negative
impact on lung function; <7 days, 8-15 days and >15
days of onset of symptoms documented normal and
abnormal lung functions in 108/132, 22/168 and 5/165
cases respectively [p<0.00001] [Table 4].
Table-5: Oxygen saturation at entry point and its effect on lung function at 12 weeks of discharge in post-COVID-
19 pneumonia cases
Oxygen saturation
Normal lung functions
(n=135)
Abnormal lung functions (n=465)
Analysis
<75% (n=110)
92
18
χ2 =317.52
P < 0.00001
75-90% (n=170)
35
135
>90% (n=320)
6
314
Low oxygen saturation at entry point has
negative impact on overall outcome on lung function;
cases with oxygen saturation <75%, 75-90% and >90%
observed as normal and abnormal lung functions in
92/18, 35/135 and 6/314 cases respectively [p<0.00001]
[Table5].
Table-6: BIPAP/NIV initiation time at entry point and its effect on lung function at 12 weeks of discharge in post-
COVID-19 pneumonia cases (n=310)
BIPAP used (n=310) with duration of illness
Normal lung functions
Abnormal lung
functions
Analysis
Entry point < 1days (n=180)
30
150
χ2 =47.12
P < 0.00001
3- 7 days (n=75)
40
35
After 7 days (n=55)
5
50
Timing of BIPAP/NIV has significant
association in attaining normal lung functions after
post-COVID19 pneumonia recovery; cases received
BIPAP/NIV at entry point <1 day, 3-7 days and after 7
days of hospitalization were documented normal and
abnormal lung functions in 30/150, 40/35 and 5/50
cases respectively [p<0.00001] [Table 6].
DISCUSSION
1. Pattern of Spirometry analysis in study cases:
In present study, spirometry assessment of
post-COVID 19 pneumonia cases at 12 weeks post
discharge form hospital, restrictive pattern was
predominant type documented in 43.33% cases, normal
lung functions were documented in 22.5% cases. Guler
SA et al. [21] demonstrated lower lung volumes (TLC,
FVC, and FEV1) in patients after severe/critical
COVID-19, the higher FEV1/FVC ratio in the
severe/critical subgroup suggests a tendency toward a
restrictive physiology, and the lack of difference in
respiratory muscle strength suggest a lung parenchymal
rather than a respiratory muscle issue. Mo et al. [23]
reported an impairment of diffusion capacity followed
by restrictive ventilatory defects, which are both
associated with the severity of the disease. You J et al.
[24] published first reports on lung function related to
COVID-19 indicated that patients have a restrictive
defect and a small airways dysfunction that can be
persistent and not related to the disease severity.
Seven studies Frija-Masson et al. [25], Huang
et al. [29], Li et al. [27], Liu et al. [26], Mo et al. [23]
You et al., [24] Zhao et al. [28] reported the spirometry
test in post-covid cases and documented reported
variable prevalence of restrictive pattern in severe
COVID-19 infection that ranges from (10.53%) to
(50%). All studies showed forced vital capacity (FVC),
forced expiratory volume in the first second (FEV1),
and FEV1/FVC ratio. Liu et al. [26] did not report
patterns of PFT abnormality; six studies [23-25, 27-29]
found a prevalent restrictive pattern in 59% and
obstructive pattern in 16% post-covid pneumonia cases.
Similarly, in our study, we have documented restrictive
pattern in 43.33% and obstructive pattern in 14.16%
cases.
R. Torres-Castro et al. [30] done systematic
review and meta-analysis of Respiratory function in
post-COVID-19 cases and observed altered diffusion
capacity, restrictive pattern and obstructive pattern were
found in 39%, 15% and 7% of patients, respectively.
Salem et al. [31] in their study documented finding of
restrictive lung impairment in about 50% of post-
COVID-19 pneumonia survivors is in line with several
Patil Shital et al.; Saudi J Med, Dec, 2021; 6(12): 441-448
© 2021 |Published by Scholars Middle East Publishers, Dubai, United Arab Emirates 445
previous studies. A recent study done by Fumagalli et
al. [32] found a significant incidence of a restrictive
pattern in 10 (76%) out of 13 patients after 6 weeks
from recovery in covid pneumonia cases. These
variations in the prevalence of restrictive lung defect
among COVID-19 pneumonia survivors could be
explained by the differences in the time of assessment
which range from close to discharge to three months
after discharge. These studies suggest that patients
affected by COVID-19 pneumonia are at increased risk
of developing restrictive pulmonary diseases after
recovery from the acute illness.
Timing of spirometry analysis was important
in follow-up post-covid cases, as ongoing inflammation
till one month of duration of illness has negative impact
on real time lung function assessment by spirometry.
We have followed BTS recommendations [20] as for 3
months‟ post discharge in all post-covid cases. All
above mentioned studies [23-29] have performed
spirometry analysis in one-month post discharge.
However, lesions of COVID-19 are more
likely to impact bilateral pulmonary and multiple lobs
than those of SARS. Previous studies have been
reported that SARS have long-term effects on lung
function, chest CT scans, and related physiological
characteristics in part of survivors, even at one year
after discharge [9, 33-35].
2. Age and gender distribution with lung function
patterns in post-COVID-19 pneumonia cases
We observed abnormal lung function in 77.5%
post covid-19 pneumonia cases, and statistically
significant association in males (90/150) versus females
(45/315) normal and abnormal lung functions
respectively [p<0.00001]; similar observation also
documented in age of population in study cases as
below 50 years (110/300) versus above 50 years
(25/165) [p<0.0001] AM Salem et al. [31] observed that
the female sex was an independent predictor for
impaired lung diffusion using multivariable logistic
regression (P = 0.024), and No significant predictor for
the restrictive pattern was detected. Seven studies [23-
29] documented most affected age groups as Frija-
Masson et al. as 54 years (46-62 years), Huang et al. as
46.7 13.7 years, Li et al. doesn‟t documented age
group affection in their study, Liu et al. as 69.1 7.8
years, Mo et al as 49.1 14.0, You et al. as 50.7 12.1
years, Zhao et al. as 47.7 15.5 years reported in their
study.
3. Is there any correlation between CT severity (at
entry point) and lung function assessment by
spirometry in post-covid-19 pneumonia cases
after 12 weeks post discharge from hospital?
In present study, CT severity score has shown
negative impact on lung function after recovery at 12
weeks post-discharge; cases with score <8, 8-15 and
>15 documented normal and abnormal lung functions
as in 36/54, 60/80 and 39/331 respectively of total 600
study cases [p<0.00001].
This is the first study included large number of
post-covid cases and documenting the effect of CT
Severity illness score when patient was hospitalized to
indoor unit and its impact on overall pulmonary
functions outcome at 12 weeks of discharge from
hospital.
Lewis et al. [40] in their study included mild
and moderate disease with 20% of patients being severe
or critical disease. Based on the small numbers of
critically ill patients, a trend towards worsening lung
function, there is likely a component of lung fibrosis
and destruction of alveoli causing reduced PFT values.
4. Does duration of illness at entry point during
hospitalization and its effect on Lung functions
at 12 weeks of discharge in post-COVID-19
pneumonia cases?
In present study, duration of illness has
negative impact on lung function at 12 weeks of
discharge; as duration <7 days, 8-15 days and >15 days
of onset of symptoms documented normal and
abnormal lung functions in 108/132, 22/168 and 5/165
cases respectively [p<0.00001].
This is the first study included large number of
post-covid cases and documenting the effect of duration
of illness when patient was hospitalized to indoor unit
and its impact on overall pulmonary functions outcome
at 12 weeks of discharge from hospital.
5. Oxygen saturation at entry point and its effect
on lung function at 12 weeks of discharge in
post-COVID-19 pneumonia cases
In present study, Low oxygen saturation at
entry point has negative impact on overall outcome on
lung function; and cases with oxygen saturation <75%,
75-90% and >90% observed as normal and abnormal
lung functions in 92/18, 35/135 and 6/314 cases
respectively [p<0.00001].
This is the first study included large number of
post-covid cases and documenting the effect of hypoxia
(oxygen saturation at entry point) during hospitalization
in indoor unit and its impact on overall pulmonary
functions outcome at 12 weeks of discharge from
hospital.
6. Does BIPAP/NIV initiation time at entry point
has any effect on lung function at 12 weeks of
discharge in post-COVID-19 pneumonia cases
(n=310)?
In present study, timing of BIPAP/NIV has
significant association in attaining normal lung
functions after post-COVID19 pneumonia recovery.
Covid-19 pneumonia cases received BIPAP/NIV at
entry point <1 day, 3-7 days and after 7 days of
Patil Shital et al.; Saudi J Med, Dec, 2021; 6(12): 441-448
© 2021 |Published by Scholars Middle East Publishers, Dubai, United Arab Emirates 446
hospitalization were documented normal and abnormal
lung functions in 30/150, 40/35 and 5/50 cases
respectively [p<0.00001] Guler SA et al. [21]
documented negative correlation between the duration
of mechanical ventilation during the acute disease and
pulmonary function at 4-month follow-up. This might
be due to a prolonged impairment after very severe
COVID-19 or related to more severe disease course in
susceptible patients. Alternatively, Herridge MS et al.
[22] proposed ventilator induced lung-injury is a well-
described challenge post-ARDS, which can impact on
pulmonary function after recovery from the acute
illness. Faverio P [39] et al. documented radiological
abnormalities and abnormal lung functions in up to 58%
of patients with COVID-19, which was present as
pulmonary sequelae, although of mild entity in the
majority of cases, at 6-month follow-up, the need for
invasive ventilatory support during hospitalization is a
risk factor for detection of radiological abnormalities,
but not for DLCO impairment, at follow-up.
7. Other important observations in present study
A). Inhaled corticosteroids (ICS) given to post-
covid patients at the time of discharge were having
symptomatic improvement in terms of dyspnea index,
although head-to-head comparison of lung functions
assessment before and after ICS were not available as
we have performed spirometry after 12 weeks of
discharge and initial spirometry assessment was not
available.
B). Inhaled Ciclesonide doesn‟t show any
symptomatic benefit as compared to inhaled budesonide
or fluticasone at any point during course of covid
pneumonia from evolution to resolution.
C) Although Higher CT severity scores were
associated with higher proportion of lung parenchymal
abnormalities, Lung function assessment (spirometry)
shows mixed pattern (mixed obstructive-restrictive) in
20 % study cases, and we assume rational for these
observations may be „mosaic type‟ with „parenchymal
fibrosis‟ i.e. heterogeneous lung involvement; and
majority of these cases shown slowly resolving over 12
weeks. In these categories of mixed spirometry function
abnormality (20 % cases), significant symptomatic
improvement was documented with inhaled budesonide
and formoterol and we repeated after 3 months of
therapy and documented near complete resolution of
lung functions after prompt evaluation and targeted
these patients with conventional lung anti-fibrotics,
pirfenidone and Nintedanib over 12 weeks with inhaled
bronchodilators with inhaled corticosteroids. The exact
mechanism of the injury of the lungs by COVID-19 is
still a new subject that is under debate. Studies [36-38]
that included autopsies of COVID-19 patients described
an acute lung injury with diffuse alveolar damage
associated with fibrotic changes and microthrombi in
the pulmonary vasculature.
D) Limitations of study- DLCO assessment
were not available at our center and it was not done in
study cases. DLCO assessment in post covid cases will
help in documenting micro-thrombosis and macro-
thrombosis in pulmonary vasculature in post covid
setting, also it will help in predicting response to
anticoagulants and antiplatelets and need for same in
follow up settings. We have used D-dimer assessment,
and resting plus exertional heart rate (heart rate after 6
min walk) as alternative option to DLCO in predicting
need of anticoagulation, while antiplatelets we
continued for 12 weeks in all cases and recommended
to use for one year in co-morbid cases, especially in
presence of DM, HTN, recent stroke, obesity,
malignancy and COPD.
CONCLUSIONS
COVID-19 pneumonia is heterogeneous
disease with variable effect on lung parenchyma,
airways and vasculature leading to long term effects on
lung functions. Spirometry is cost effective, non-
invasive, easily available, sensitive tool for assessment
lung function in post covid care setting and it will help
management of these cases by assessing response to
treatment. Pulmonary functions abnormality in post-
COVID-19 pneumonia cases has been documented and
should be assessed cautiously to have successful
treatment outcome. Restrictive lung disease is the
predominant lung function impairment in post-COVID
19 recovered lung pneumonia cases. Age above 50
years, male gender, Diabetes mellitus, High CT
severity, longer duration of illness, proper timing of
initiation of BIPAP/NIV therapy, has documented
significant impact on post covid lung functions at 12
weeks assessment. All post covid cases needs lung
functions assessment by spirometry to predict course of
underlying lung pathology and targeting interventions
accordingly.
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