This document provides definitions and criteria for acute respiratory distress syndrome (ARDS) according to various consensus definitions: 1) The American-European Consensus Conference in 1994 defined ARDS as acute onset hypoxemia, bilateral pulmonary infiltrates on chest x-ray, and pulmonary artery wedge pressure ≤ 18 mmHg. 2) More recent definitions such as the Delphi consensus require a PaO2/FiO2 ratio ≤ 200 mmHg with PEEP > 5 cm H2O and radiographic criteria involving more than two lung quadrants. 3) Definitions have evolved over time to better characterize the heterogeneities in ARDS and improve reliability, but criteria such as hypoxemia and radiographic

1. ARDS- BERLIN DEFINITION
DR PRASHANT BHATIA

2. Guru Brahma Gurur Vishnu
Guru Devo Maheshwaraha
Guru Saakshat Para Brahma
Tasmai Sree Gurave Namaha
Meaning:Guru is verily the representative of Brahma, Vishnu and
Shiva. He creates, sustains knowledge and destroys the weeds of
ignorance. I salute such a Guru.

3. Stages of ARDS
Exudative (acute) phase
Proliferative phase
Fibrotic phase

4. STAGES
 Acute, exudative
phase
◦ rapid onset of respiratory
failure after trigger
◦ diffuse alveolar damage
with inflammatory cell
infiltration
◦ hyaline membrane
formation
◦ capillary injury
◦ protein-rich edema fluid in
alveoli
◦ disruption of alveolar
epithelium
Expansion of
interstitium with
macrophages
and
inflammation
Hyaline
Membra
nes
Alveolar
Filling

5.  Proliferative phase:
◦ persistent hypoxemia
◦ development of hypercarbia
◦ fibrosing alveolitis
◦ further decrease in pulmonary compliance
◦ pulmonary hypertension
 Chronic phase / Recovery phase
◦ obliteration of alveolar and bronchiolar
spaces and pulmonary capillaries
◦ gradual resolution of hypoxemia
◦ improved lung compliance
◦ resolution of radiographic abnormalities

6. ARDS causes
 Direct Lung Injury:
a) PNA and aspiration of gastric contents
or other causes of chemical
pneumonitis
b) pulmonary contusion, penetrating lung
injury
c) fat emboli
d) near drowning
e) inhalation injury
f) reperfusion pulm edema after lung
transplant

7. ARDS causes
 Indirect lung injury
a) sepsis
b) severe trauma w/ shock
hypoperfusion
c) drug over dose
d) cardiopulmonary bypass
e) acute pancreatitis
f) transfusion of multp blood products

9. WHAT IS A DEFINITION
A definition is a thorough description of
the meaning of a lexical unit

10. WHY DEFINITION
 FACILITATES RESEARCH
 PATHOGENESIS AMPLIFIED AND
NOTIFIED
 COMPARISION OF VARIOUS CLINICAL
TRIALS
 EARLY INSTITUTION OF
STANDARDISED CARE
 OUTCOME PROGNOSTICATION
 MEASURE THE IMPACT (ECONOMIC,
SOCIAL) ETC

11. DEFINITION OF ALI/ARDS
 AMERICAN-EUROPEAN CONSENSUS
CONFERENCE 1994
 ALI CRITERIA
Timing: acute onset
Oxygenation: PaO₂/FIO₂≤ 300 MM Hg
(regardless of peep)
Chest Radiograph: bilateral infiltrates
seen on frontal chest radiograph
Pulmonary artery wedge:≤ 18 mm Hg
when measured or no clinical evidence
of left atrial hypertension

12. DEFINITION OF ALI/ARDS
 ARDS CRITERIA
Timing: acute onset
Oxygenation: PaO₂/FIO₂≤ 200 MM
Hg (regardless of peep)
Chest Radiograph: bilateral infiltrates
seen on frontal chest radiograph
Pulmonary artery wedge:≤ 18 mm Hg
when measured or no clinical
evidence of left atrial hypertension

15. MURRAY LIS
 No Lung Injury Score 0
 Mild To Moderate Lung Injury Score 1-
2.5
 Severe Lung Injury > 2.5

16. DELPHI CONSENSUS
DEFINITION
 PEEP (>10) PaO₂/FIO₂≤ 200 MM Hg
 RADIOGRAPHIC CRITERIA > 2
QUADRANTS
 QUANTITATIVE PULMONARY
COMPLIANCE ABNORMALITIES
OR
 PREDISPOSING CONDITION
 NON CARDIOGENIC PULMONARY
OEDEMA CHARACTERISATION
EITHER BY PAC OR TTE

17. OXYGENATION INDEX
 OI = MAP × FIO₂ × PaO ₂ /100
 OI > 30 HAS BEEN ASSOCIATED
WITH POOR OUTCOME

18. HETEROGENITIES
 INCITING CAUSE
 PHASE
 TIMING RELATIVE TO ONSET OF
MECHANICAL VENTILATION
 VARIABILITY IN MECHANISM

19. RELIABILITY AND VALIDITY
 RELIABILITY INTEROBSERVER
INTRAOBSERVER
 VALIDITY FACE
CONTENT
CRITERION
CONCURRENT
PREDICTIVE
CONSTRUCT
CONVERGENT
DISCRIMINANT

20.  Face Validity Do the diagnostic criteria
appear to describe the disease entity in
question
 Criterion Validity Do the diagnostic criteria
correlate with gold standard
 Predictive Validity Does this predict a
certain outcome or response to therapy

21. HYPOXEMIA
 VARIES WITH FIO₂
 EFFECT OF PEEP
 CONFOUNDING FACTORS
ATELECTASIS
LOW
C.O
SHUNT
 VENTILATORY SETTINGS
 TIME PERIOD

22. EFFECT OF SHUNT

23. INFILTRATES
 INTEROBSERVER VARIABILITY
 EFFECT OF HIGH MEAN AIRWAY
PRESSURE
 CT SCAN IS RELIABLE

24. LEFT ATRIAL
HYPERTENSION
 PAOP MEASUREMENT-
INTEROBSERVER
RELIABILIY
 TRANSMITTED AIRWAY
PRESSURES
 FLUID RESUSCITATION

25. ACUTE ONSET
 SPECIFICATION OF TIMELINES OF
‘ACUTE’

26. HYPOXEMIA PaO₂/FIO₂≤ 201-
300 WITH
PEEP/CPAP≥5
PaO₂/FIO₂≤ 200
WITH
PEEP/CPAP≥5
PaO₂/FIO₂≤ 100
PEEP/CPAP≥10
TIMIMING ACUTE ONSET WITHIN 1 WEEK OF A KNOWN CLINICAL
INSULT OR NEW/WORSENING RESPIRATORY SYMPTOMS
Mild Moderate Severe
ORIGIN OF
OEDEMA
RESPIRATORY FAILURE NOT EXPLAINED BY CARIAC
FAILURE OR FLUID OVERLOAD
RADIOLOGIC
ABNORMALITIES
BILATERAL
OPACITIES
BILATERAL
OPACITIES
OPACITIES
INVOLVING AT
LEAST THREE
QUADRANTS
ADDITIONAL
PHYSIOLOGIC
DERANGEMENTS
N/A N/A
VEcorr>10L/MIN
OR
Crs ≤ 40 ml/cm H₂О
ARDS

27. RECURITABLE LUNGS
 30-40 cm H₂O AIR WAY PRESSURE FOR
30-40 SECS
 PEEP BY 10 cm H₂O TO A MAXIMUM OF
20 cm H₂O
 POTENTIAL HIGH POTENTIAL
LOW
SpO₂> 5% MARGINAL
EFFECT
PaCO₂ PaCO₂
Compliance
Compliance

28. RESCUE THERAPIES
 High peep levels
 Lung recruitment maneuvers
 High frequency ventilation
 Airway pressure release ventilation
 Prone positioning
 Extracorporeal life support

29. NONVENTILATORY
STRATEGIES
 Neuromuscular Blocking Agents
 Inhaled Nitric Oxide
 ECLS
 Conservative Fluid Management
 Corticosteroid Therapy
 Nutritional Supplementation Therapy

32. We are constantly misled
by the ease with which our
minds fall into the ruts of
one or two experiences.
Sir William Osler