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Indian Journal of Clinical Anaesthesia 2022;9(1):37–41
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Indian Journal of Clinical Anaesthesia
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Original Research Article
Incidence, prevalence and prognostic implications of right-sided heart failure in
acute respiratory distress syndrome: A prospective observational study
Sonika Agarwal1,*, Pankaj Rana1, Sushant Khanduri2, Mukta Singh1,
Reshma Kaushik3
1Dept. of Anesthesia, Himalayan Institute of Medical Sciences, S. R. H .U, Dehradun, Uttarakhand, India
2Dept. of Pulmonary Medicine, Himalayan Institute of Medical Sciences, S. R. H .U, Dehradun, Uttarakhand, India
3Dept. of Medicine, Himalayan Institute of Medical Sciences, S.R.H.U, Dehradun, Uttarakhand, India
ARTICLE INFO
Article history:
Received 06-09-2021
Accepted 30-12-2021
Available online 12-02-2022
Keywords:
Acute respiratory distress syndrome
Acute cor pulmonale
Echocardiography
Mechanical ventilation
ABSTRACT
Objective: Acute respiratory distress syndrome is a heterogeneous disease which involves both the alveoli
and pulmonary vessels. Acute cor pulmonale was initially considered as a marker of severity but its impact
on outcome is still controversial.
Materials and Methods: This was a prospective observational study conducted over a period of nine
months in ICU of a tertiary care center in India. Out of 2028 patient admitted in ICU 64 patients with
ARDS (Berlins definition) underwent transthoracic echocardiography within 3 days of admission after
diagnosis.
Result: Acute cor pulmonale(ACP) was detected in 23 (36%) patients. Patients with ACP have greater the
severity of disease and higher APACHE score as compared to those without ACP.Ph, PCO2and P/F ratio
appears to be the independent risk factor in patients for ACP in ARDS.Patients with ACP in ARDS had a
higher incidence of shock and mortality(43.5%).
Conclusion: ACP is quite common in ARDS. Due to its effect on the outcome, it appears to be a major
factor in deciding ventilatory strategy in patients with ARDS. Right ventricle protective approach of
ventilation keeps lung and heart connected.
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1. Introduction
Acute respiratory distress syndrome(ARDS) is
heterogeneous and challenging disease with various
pathophysiologic mechanisms responsible for different
degrees of severity. Substantial progress has been made
in the understanding of the pathogenesis of the disease
and different treatment strategies have been proposed
accordingly.
ARDS was considered mainly as a disease of alveoli,
so “opening the lung” and targeting the arterial oxygen
saturation and restricted fluid therapy are considered the
* Corresponding author.
E-mail address:sonikakatiyar@srhu.edu.in (S. Agarwal).
mainstay of management. The ventilatory management and
protocols for ARDS has been regularly modified with the
enhancement of our knowledge of the physiopathology of
ARDS, the mortality of ARDS still remains significant.1,2
Even though the most hypoxemic patient has the greatest
mortality,1,3 but still the severity of hypoxemia per se does
not reliably predict the outcome.4A possible reason for this
could be an under-recognized involvement of the pulmonary
vasculature and the right side of the heart in ARDS.
Zapol and Snider first described that ARDS which
affects both the alveoli and the pulmonary circulation.5
The pulmonary vessels are high capacitance and low
resistance system and the right ventricle provides blood
https://doi.org/10.18231/j.ijca.2022.009
2394-4781/© 2022 Innovative Publication, All rights reserved. 37
38 Agarwal et al. / Indian Journal of Clinical Anaesthesia 2022;9(1):37–41
flow at low pressure to pulmonary vasculature.6Right
ventricle(RV) is thin-walled and works against low-pressure
pulmonary circulation. ARDS causes inflammation, edema,
vasoconstriction, micro-thrombi, and vascular remodeling
of the pulmonary vasculature.7Other factors which
increase RV after-load are ARDS induced reduction in
lung compliance which increases pleural pressures, trans-
pulmonary pressures, mechanical ventilation and positive
end-expiratory pressure (PEEP) induced an increase in
intrathoracic pressures.8This elevated RV after load
further increases right ventricle stroke-work index which
progresses to RV dysfunction and cor pulmonale.9
The incidence of ACP has reduced with the
implementation of lung protective ventilation which
was around 60% in the 1990s to 20% - 25%.10 Mortality
of ARDS remains high so the hemodynamic management
in ARDS especially on the protection of RV appears to
be the way to reduce mortality. So the primary objective
of the prospective study was to determine the incidence,
prevalence, prognostic implication and the outcome of
patients with cor pulmonale in ARDS.
2. Materials and Methods
This was a prospective observational study conducted in
tertiary care hospital intensive care unit (ICU) with 40
bedded capacity. After taking approval by the ethical and the
research committee of our institute, informed and written
consent was taken from the patients relative. Between
June 2016 and January 2017 all patients (> 10 years of
age), who develop ARDS as defined by Berlins definition3
and who underwent trans thoracic echocardiography(TTE)
within 3 days of ICU admission were included in this
study. Exclusion criteria were chronic pulmonary diseases,
chronic cor pulmonale, cardiogenic pulmonary edema and
age<10 yrs. Cardiogenic pulmonary edema was ruled by
doing an echocardiographic assessment and finding low LV
filling pressures. The lung protective strategy of mechanical
ventilation using low tidal volume was used keeping plateau
pressure target ≤30 cm H2O.
TTE examinations were performed by the cardiologist
or the intensivist highly trained in critical care
echocardiography using the “Philips Clearvue 350”
machine. Briefly, the following echocardiographic views
were examined: four-chamber long-axis view to assess the
end-diastolic right ventricle/left ventricle (RV/LV) area ratio
and LV ejection fraction; para-sternal short-axis view of the
LV to evaluate the motion of the interventricular septum
during end systole.ACP was identified by a combination
of RV enlargement with septal dyskinesia. RV dilatation
will be defined by an RV end-diastolic area (RVEDA)/left
ventricular end-diastolic area (LVEDA) with both measured
at the end diastole 0.6.11
2.1. Statistical analysis
The data were collected and entered in MS Excel 2010.
Statistical analysis was performed using SPSS software
version 22. The one-sample Kolmogorov-Smirnov test was
employed to determine whether the data sets differed from
a normal distribution. Descriptive statistics were calculated
for variables like age, sex, etc. Mean ±SD for continuous
variables and frequency (%) for quantitative variables were
calculated. Normally distributed data were a analyzed using
the unpaired t-test for continues variables and categorical
variables were analyzed using the chi-square test.
If p<.05, then the hypothesis is said to be statistically
significant.
3. Result
Out of 2028 patients who were admitted in ICU over 8
months period 64 patients were included in the study with
a mean age of 40 with 29 males and 35 females. 23(36%)
of patients with ARDS had cor pulmonale. The group with
or without cor pulmonale were not significantly different in
various demographic parameters like age, sex or cause of
ARDS as shown in Table 1.
The patients who had cor pulmonale had more severe
disease with higher APACHE 2 score, more acidosis, higher
PaCO2and lower PaO2/FiO2ratio as compared to patients
without cor pulmonale which was statistically significant as
shown in Table 2. Mortality was higher in cor pulmonale
group(43.5%) as compared to non Cor pulmonale group
(14.6%) though not statistically significant.
4. Discussion
ARDS is a challenging disease which is a major cause of
morbidity and mortality in ICUs throughout the world.
Suter at al defined the best ventilatory strategy in ARDS
as the one which allows the best oxygen delivery.12 He
showed that while increasing the PEEP from 0 to 7 cm H2O
the compliance increased in parallel with oxygen transport
and dead space decreased, whereas further increasing PEEP
from 7 cm H 2 O to 13 cm H 2 O, compliance decreased
in parallel with a decrease in oxygen transport and an
increase in dead space. From here the concept of heart-lung
interaction and its impact of ventilatory settings on it were
introduced. Unfortunately, most of the guidelines focus on
lung even though the mortality remains unchanged.13 A new
area to decrease mortality appears to be focusing on ARDS
induced pulmonary vascular injury, its effects on the right
ventricle, and finally its effect on hemodynamics.
In the past, the Pulmonary artery catheter was used
to diagnose ACP but now with the development of non-
invasive critical care echocardiography, echocardiography
now appears as the “gold standard” to diagnose ACP. 14
Transesophageal echocardiography(TEE) is considered
to be a more effective approach but both the approaches,
Agarwal et al. / Indian Journal of Clinical Anaesthesia 2022;9(1):37–41 39
Table 1: General profile of patients
Without cor pulmonale With cor pulmonale P value
No. of patients n(%) 41(64%) 23(36%)
Age groups(Yrs)
10-20 5(12.2%) 1(4.3%)
21-30 14(34%) 5(21.7%)
31-40 7(17.1%) 6(26.1%)
41-50 6(14.6%) 7(30.4%) .477
51-60 2(4.9%) 2(8.7%)
61-70 5(12.2%) 28(7%)
>70 2(4.9%) 1(4.3%)
Male sex n(%) 18(43.9%) 11(47.8%) .798
Cause of ARDS
Pneumonia 4(9.8%) 7(30.4%)
Sepsis 11(26.8%) 7(30.4%)
Scrub typhus 23(56.1%) 5(21.7%)
Dengue fever 1(2.4%) 2(8.7%) .20
Trauma 2(4.9%) 1(4.3%)
Aspiration 1(4.3%)
Malaria
Apache 2
Mean±SD 15.83±2.9 18.61±4.26 .003
Severity of ARDS
Mild 6(14.63%) 2(8.69%)
Moderate 24(58.53%) 7(30.43%) .027
severe 11(26.8%) 14(60.86%)
PH Mean±SD 7.33±.10 7.25±.16 .021
P/F ratio Mean±SD 138.5±50.05 98.7±46 .003
PCO2 39.8 ±3.8 45 ±5.32 <.02
PEEP Mean±SD 9.87±1.33 10.73±1.57 .038
NIV Support n(%) 4(9.75%) 1(4.34%)
Mechanical ventillation n(%) 37(91.25%) 22(95.66%)
Table 2: Outcome of patients
Without corpulmonale With corpulmonale p-value
Shock 12(29.3%) 16(69.6%) .003
Proning 2(4.9%) 2(8.7%) .614
Mechanical ventilation days (mean) 4.65 5.81 .284
Icu stay days(mean) 5.90 7.43 .165
Outcome
Improved 31(75.6%) 10(43.5%)
LAMA* 4(9.8%) 3(13%) . 024
Expired 6(14.6%) 10(43.5%)
*left against medical advise
transesophageal and transthoracic, can be used for
diagnosis.10 In some studies cardiac MRI is considered as
the gold standard for diagnosing ACP but it is practically
difficult in critically ill patients.15 In our study we used
transthoracic echocardiography as a modality to diagnose
ACP. The cor pulmonale was detected in 36% out of 64
ARDS ventilated with lung protective ventilation, which
was slightly higher than other studies which reported the
incidence of 20-25%.16
The ventilatory strategies have an indirect effect on
pulmonary circulation by their effect on oxygenation and
ventilation. Higher the carbon dioxide levels more are the
pulmonary vasoconstriction and so more right ventricle
load.17 PaO2/FiO2ratio and PaCO2appears to be an
independent factor for ACP in our study which is similar
to other studies.16 So the ventilatory support should focus
on the improvement of oxygenation and at least to some
extent control hypercapnia to decrease the right ventricular
load. Circulatory failure is common in ARDS. A European
survey performed during the era of protective mechanical
ventilation, such circulatory failure is either related to the
septic shock for half of the patients or for the other half
40 Agarwal et al. / Indian Journal of Clinical Anaesthesia 2022;9(1):37–41
to another cause, which could be right ventricular (RV)
failure-related ARDS, also named acute cor pulmonale.1
In our study higher incidence of shock was seen in ACP
patients which were 69.6% patients as compared to non-
ACP patients. Similarly Boissier et al.16 also showed that
in 226 ARDS patients, ACP was associated with a higher
incidence of shock. In another study by Lhéritier G et al
done on 200 patients with ARDS, 64% of patients with ACP
required norepinephrine infusion as compared to 49% of
patients without ACP.10 Pulmonary embolism which is also
a reason for cor pulmonale was not present in both the group
in our study.
Cor pulmonale was associated with higher mortality
which was 43.5% in our study. The study by Boissier et al. 16
also showed that ACP was independently associated with
Mortality and the result were similar in an observational
study by Todd M et al.18 These the finding differs from a
landmark study by Lheritier et al.10 as they applied airway
pressure limitation measures to correct cor pulmonale, so
it did not affect mortality. Increased mortality may be
attributed to more incidence of shock in cor pulmonale
group and the oxygenation compromise in our study. Prone
positioning which is considered as a rescue ventilatory
strategy for refractory hypoxemia was more frequently done
in the patients with cor pulmonale in our study.19
5. Limitation
The facility of TEE is not available in our institute, so we
rallied on TTE. We did only a single TTE while serial TEE
is required for the management of patients. The number of
patients included in the study were only 64 which were also
less.
6. Conclusion
RV function should be identified early for the ventilatory
management of ARDS as it has an impact on mortality.
The echocardiography of the ventilated patients should be
done bedside and various measures to reduce RV after-
load should be taken. Lungs and RV are interconnected
and what is good for the lung is good for RV and vice
versa should always be taken into account. The French
Society of Intensive Care Medicine has recognized the
need for monitoring the right ventricle in patients with
ARDS. Further studies are required to consider it as a
standard of care. The valuable information is provided
by echocardiography for hemodynamic monitoring for
optimizing ventilatory strategies in ARDS.
7. Source of Funding
None.
8. Conflict of Interest
The authors declare no conflict of interest.
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Agarwal et al. / Indian Journal of Clinical Anaesthesia 2022;9(1):37–41 41
Author biography
Sonika Agarwal, Associate Professor
Pankaj Rana, N.P.C.C. Student
Sushant Khanduri, Associate Professor
Mukta Singh, Assistant Professor
Reshma Kaushik, Professor
Cite this article: Agarwal S, Rana P, Khanduri S, Singh M, Kaushik R.
Incidence, prevalence and prognostic implications of right-sided heart
failure in acute respiratory distress syndrome: A prospective
observational study. Indian J Clin Anaesth 2022;9(1):37-41.
