The Berlin Definition of ARDS
Online Supplement:
Assesment of Left Atrial Hypertension (Pg 2-3)
Chest X-Ray Interpretation for the Diagnosis of ARDS (Pg 4-16)
Niall D Ferguson, Eddy Fan, Luigi Camporota, Massimo Antonelli, Antonio Anzueto,
Richard Beale, Laurent Brochard, Roy Brower, Andrés Esteban, Luciano Gattinoni, Andy Rhodes,
Arthur S Slutsky, Jean-Louis Vincent, Gordon D Rubenfeld*, B Taylor Thompson*, and V Marco
Ranieri*
An initiative of the European Society of Intensive Care Medicine endorsed by the American
Thoracic Society, the Society of Critical Care Medicine and the European Respiratory Society
* These authors contributed equally to this work as co-chairs of the Task Force
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Assessment of left atrial hypertension
Despite the evolution of monitoring technology, the assessment of cardiovascular status and the
physiologic goals for these parameters remains a significant challenge in the care of critically ill
patients. The Berlin ARDS definition recognizes these practical challenges and incorporates
recent data to shift the focus from excluding patients with left atrial hypertension to excluding
patients with only left atrial hypertension as an explanation for their clinical syndrome. The clinical
data that support this are: ARDS and left atrial hypertension frequently co-exist, left ventricular
dysfunction is common in patients with sepsis, pulmonary artery catheters are not routinely used in
the care of ARDS patients, and the chest radiograph, BNP, and troponin T are not accurate in
critically ill patients for distinguishing cardiogenic from non-cardiogenic causes of respiratory
failure. Patients with a clinical syndrome compatible with ARDS are likely to present on a spectrum
from clear cardiogenic edema to clear ARDS, with many cases existing in the middle. These case
vignettes are meant to illustrate this spectrum and guide clinicians in their thinking about similar
cases.
Vignette 1
A 53 year old man presents to the emergency department with substernal chest pain and dyspnea
of 2 hours duration. On examination he is afebrile and tachypneic, and auscultation of the lungs
discloses bilateral rales. The SpO2 on 100% oxygen delivered by a non-rebreather mask is 96%.
The EKG shows antero-lateral ischemia and the CXR demonstrates pulmonary edema. A rapid
troponin T assay is 0.10 ug/L (upper limit of normal 0.03 ug/L). An emergent echocardiogram
shows decreased left ventricular function with focal wall motion abnormality. An attempt at noninvasive ventilation fails as the patient becomes hemodynamically unstable. After intubation, the
PaO2/FiO2 ratio on FiO2 0.60 is 230.
Discussion
This patient meets the hypoxemia and radiographic criteria for mild ARDS. However, there is no
identifiable risk factor for ARDS and clear evidence of left ventricular dysfunction from cardiac
ischemia. This is not ARDS.
Vignette 2
A 74 year old man with a history of COPD and congestive heart failure has a 4 day prodrome of
fever, productive cough, chest pain, and dyspnea which is worse when supine. On presentation to
the emergency department he is dyspneic, the temperature is 40.1 C, the heart rhythm is atrial
fibrillation with a rate of 140 beats per minute, the blood pressure is 90/60 mmHg and the SpO 2 is
92% on supplemental oxygen of 50% via face mask. He has decreased breath sounds at the right
base and diffuse rales and wheezes. The serum lactate is 5 mmol/L. An EKG shows inverted T
waves across the precordial leads. An echocardiogram shows global reduction in left ventricular
function. A chest radiograph reveals hyperinflated lungs with a dense right lower lobe
consolidation. Two liters of saline are rapidly infused with a transient increase in blood pressure
and reduction in heart rate but oxygenation worsens and the patient is intubated and placed on a
norepinephrine infusion. On transfer to the ICU, the post-intubation chest radiograph shows the
right lower lobe opacity, a right pleural effusion, and evolving left sided infiltrates. A central venous
line placed for resuscitation shows a central venous pressure of 15 mmHg and an ScvO 2 of 55%.
The arterial blood gas after intubation reveals a PaO2/FiO2 ratio of 180 on FiO2 0.6. The troponin
T is 0.06 ug/L.
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Discussion
This case is a common scenario for intensivists. The patient meets oxygenation and radiographic
(the infiltrates, while asymmetric, are bilateral) criteria for moderate ARDS. Clearly, the patient has
pneumonia and likely has pre-existing left ventricular dysfunction. Elevations of troponin are not
uncommon in patients with severe sepsis. The evolution of bilateral opacities might indicate a
degree of left atrial hypertension, but this does not exclude a diagnosis of ARDS. This is ARDS;
probably with a component of hydrostatic edema.
Vignette 3
A 43 year old otherwise healthy woman is taken to the operating room for a routine laparoscopic
cholecystectomy. The trocar perforates the inferior vena cava. The injury is identified immediately
and a laparotomy is performed. As vascular control is obtained the patient goes into shock and
has a brief episode of pulseless electrical activity. She is resuscitated with 1 mg of epinephrine, 10
liters of crystalloid and 6 units of packed red cells. At the end of the case she is brought to the
post-anesthesia care area intubated with a blood pressure of 160/90 mmHg without vasopressors.
The serum lactate is 7 mmol/L, a CXR shows bilateral opacities and the arterial blood gas reveals
a PaO2/FiO2 ratio of 180. The central venous pressure is 20 mmHg.
Discussion
The patient meets oxygenation and radiographic criteria for moderate ARDS. She has risk factors
for ARDS including transfusion and hypovolemic shock. However, she may simply have
hydrostatic pulmonary edema as a result of the significant volume resuscitation. On presentation it
may be difficult to distinguish these. If her oxygenation, lactic acidosis, and radiograph improve
rapidly with diuresis, this favors hydrostatic edema. However, if they fail to completely resolve,
then this is ARDS. It would be reasonable to use lung protective ventilation targets in a patient like
this, however enrolling them in a clinical trial for ARDS would be problematic until the diagnosis is
clearer.
Vignette 4
A 19 year old woman is ejected from her car after a single vehicle crash. She is found face down
in water with multiple injuries including traumatic brain injury, rib and sternal fractures, pulmonary
contusions, and a positive ultrasound screen of her abdomen for free fluid. She is intubated in the
field and brought to the emergency department where she is hypotensive and subsequently taken
immediately to the operating room. She receives 14 units of packed red cells, 8 units of fresh
frozen plasma, and pooled platelets in addition to 7 liters of crystalloid. On evaluation in the ICU
she has a PaO2/FiO2 ratio of 150 on FiO2 0.50, and a chest radiograph with bilateral opacities.
Because of ongoing concerns about hypotension an echocardiogram is performed which shows a
hyperdynamic small left ventricle and no pericardial effusion.
Discussion
This patient meets the hypoxemia and radiographic criteria for moderate ARDS. The patient has
multiple risk factors for ARDS including severe trauma, potential aspiration, and blood products.
There is no evidence of left ventricular dysfunction and, if anything, that the patient is somewhat
intravascularly depleted. This is ARDS.
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Chest X-Ray Interpretation for the Diagnosis of ARDS
The following set of 12 chest x-rays were evaluated by the panel for the presence of bilateral
opacities consistent with pulmonary edema (may be very mild, patchy, and asymmetric) that are
not fully explained by pleural effusions, pulmonary nodules or masses, or lobar/lung collapse (i.e.,
radiographically consistent with the diagnosis of ARDS). Other common reasons that opacities
may be misinterpreted as being consistent with pulmonary edema and ARDS, when they are not,
include the following:
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Vascular redistribution or indistinct vessels alone are not consistent with pulmonary edema
and ARDS
Radiographs of patients with extrathoracic opacities (e.g., cooling blankets, backboards)
may be difficult to interpret for opacities consistent with pulmonary edema and ARDS
Radiographs in severely obese patients are difficult to interpret for opacities consistent with
pulmonary edema and ARDS
Poor inspiration may accentuate all lung markings, both normal and abnormal
Opacities that are known to be chronic are not consistent with ARDS
No chest radiographic pattern is diagnostic of ARDS, as the syndrome requires additional clinical
criteria. Possible radiographic interpretations are: consistent, inconsistent, and equivocal for the
diagnosis of ARDS.
For patients with an equivocal chest x-ray for the diagnosis of ARDS, the context (e.g., medical
history, presence of risk factors) and evolution of the patient’s clinical condition and chest x-ray
over time (e.g., 8-12 hours) may be helpful to ascertain whether there are opacities consistent with
pulmonary edema and ARDS. Depending on the mechanism of action and risks of a considered
intervention, clinicians and researchers may want to include (e.g., low tidal volume ventilation) or
exclude (e.g., higher risk biologic agent) such patients. Although we have little data on the clinical
differences in outcome or response to therapy, there is some evidence that intermediate
phenotypes might yield a smaller signal in mechanistic studies [Shah CV, Lanken PN, Localio AR,
et al. (2010) An alternative method of acute lung injury classification for use in observational
studies. Chest 138:1054-61]. Therefore, some investigators may choose to include or exclude
patients with equivocal radiographs in their study populations and report this in the methods.
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CXR #1 – CONSISTENT WITH ARDS
This is an example of a patient with bilateral infiltrates consistent with pulmonary edema. The left
hemidiaphragm is visible, arguing against left lower lobe atelectasis. Typical or classic
radiographic findings of ARDS have been characterized as bilateral confluent opacities as
demonstrated in this radiograph. However, the AECC definition expanded the scope of
radiographic opacities that are consistent with ARDS to include bilateral opacities that are simply
consistent with pulmonary edema, even if patchy and inhomogeneous.
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CXR #2 – INCONSISTENT WITH ARDS
The opacities in the right lower lobe are likely due to a pleural effusion, while there is evidence of
either atelectasis in the left lower lobe or a left pleural effusion. There is no convincing evidence of
opacities in the mid- or upper-lung zones consistent with pulmonary edema.
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CXR #3 – INCONSISTENT WITH ARDS
Although this chest x-ray is underpenetrated, the opacifications of both lower lobes are likely due to
pleural effusions and/or atelectasis. There does not appear to be convincing evidence of bilateral
opacities consistent with pulmonary edema.
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CXR #4 – EQUIVOCAL FOR ARDS
This chest x-ray demonstrates some equivocal findings for bilateral infiltrates consistent with
pulmonary edema. There may be opacifications in left mid-lung field consistent with edema. Loss
of the left hemidiaphragm may be due to left lower lobe atelectasis or pleural effusion. The
opacities and abnormalities in the right hemithorax may be primarily due to a pleural effusion.
Given the equivocal nature of this chest x-ray, the context (e.g., medical history, presence of risk
factors) and evolution of the patient’s clinical condition and chest x-ray over time (e.g., 8-12 hours)
may be helpful to ascertain whether there are opacities consistent with pulmonary edema.
Depending on the mechanism of action and risks of a considered intervention, clinicians and
researchers may want to include (e.g., low tidal volume ventilation) or exclude (e.g., higher risk
biologic agent) such patients.
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CXR #5 – CONSISTENT WITH ARDS
This is an example of a patient with bilateral infiltrates consistent with pulmonary edema.
Although there is poor inspiration, which tends to accentuate all markings (both normal and
abnormal), there is clear evidence of opacification in both lungs, consistent with pulmonary edema.
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CXR #6 – CONSISTENT WITH ARDS
This is an example of a patient with bilateral infiltrates consistent with pulmonary edema. There is
clear evidence of confluent airspace opacities which are not fully explained by effusions, nodules,
masses, or lobar/lung collapse.
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CXR #7 – INCONSISTENT WITH ARDS
The opacifications in both upper lung fields may be due to prominent first rib costochondral
junctions. Although there appear to be prominent vascular markings of both lungs, there is no
evidence of bilateral opacities that are clearly consistent with pulmonary edema. Radiographs of
patients with extrathoracic opacities like cooling blankets or backboards may be difficult to interpret
for opacities consistent with pulmonary edema and ARDS.
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CXR #8 – EQUIVOCAL FOR ARDS
There is evidence of bilateral interstitial opacities, without any significant airspace opacities, which
appear chronic in nature and are not clearly consistent with pulmonary edema. Given the
equivocal nature of this chest x-ray, the context (e.g., medical history, presence of risk factors) and
evolution of the patient’s clinical condition and chest x-ray over time (e.g., 8-12 hours) may be
helpful to ascertain whether there are opacities consistent with pulmonary edema. Depending on
the mechanism of action and risks of a considered intervention, clinicians and researchers may
want to include (e.g., low tidal volume ventilation) or exclude (e.g., higher risk biologic agent) such
patients.
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CXR #9 – CONSISTENT WITH ARDS
There is evidence of bilateral airspace opacities which are consistent with pulmonary edema,
including dense right upper lobe opacification, with additional opacifications and air bronchograms
in right lower, as well as the left mid-lung zone. Lobar opacities are considered to be consistent
with pulmonary edema.
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CXR #10 – INCONSISTENT WITH ARDS
Despite the limited exposure of this chest x-ray, both hemidiaphragms are visible and there is no
clear evidence of bilateral opacities consistent with pulmonary edema. Radiographs in severely
obese patients are difficult to interpret for opacities consistent with pulmonary edema and ARDS.
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CXR #11 – EQUIVOCAL FOR ARDS
The opacities in both lower lung fields could be from atelectasis and/or pleural effusion. There is
no evidence of opacities in the mid- to upper-lung fields consistent with pulmonary edema. Given
the equivocal nature of this chest x-ray, the context (e.g., medical history, presence of risk factors)
and evolution of the patient’s clinical condition and chest x-ray over time (e.g., 8-12 hours) may be
helpful to ascertain whether there are opacities consistent with pulmonary edema. Depending on
the mechanism of action and risks of a considered intervention, clinicians and researchers may
want to include (e.g., low tidal volume ventilation) or exclude (e.g., higher risk biologic agent) such
patients.
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CXR #12 – EQUIVOCAL FOR ARDS
There is evidence of some opacities in the left lower lobe, which could be due to atelectasis, and is
not clearly consistent with pulmonary edema. The focal opacities in right upper lung field may be
due to a confluence of the first rib and prominent blood vessels, but could be consistent with
pulmonary edema. Given the equivocal nature of this chest x-ray, the context (e.g., medical
history, presence of risk factors) and evolution of the patient’s clinical condition and chest x-ray
over time (e.g., 8-12 hours) may be helpful to ascertain whether there are opacities consistent with
pulmonary edema. Depending on the mechanism of action and risks of a considered intervention,
clinicians and researchers may want to include (e.g., low tidal volume ventilation) or exclude (e.g.,
higher risk biologic agent) such patients.
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