2. 2
Outline
• Introduction
• Fighting strategy :
▫ Low tidal volume ventilation
▫ PEEP optimization
▫ Lung recruitment
▫ Prone positioning
▫ Neuromuscular blocking agent
▫ ECMO
▫ Summary of evidences
• Practical points
▫ PEEP selection and recruitment
▫ NIV and nasal high flow ?
▫ Prone CPR ?
▫ ARDS with pneumothorax
• Q&A / Take home messages
3. 3
Case scenario
• A 52 year old male patient with known case
HT presented to the ER with severe dyspnea
for 1 day with high grade fever and
worsening productive cough for 3 days
(SpO2 with mask with bag 6 lpm = 72%).
• He was intubated, chest radiograph was
shown as below and ER physician consult
you about ICU transfer.
• You know your night is just begin.
7. 7
Introduction
• Diagnosis in real world practice
• “40% of ARDS patients were missed”
• Of 29,144 patients admitted to
participating ICUs, 3022 (10.4%) fulfilled
ARDS criteria.
Lung SAFE Study. JAMA 2016;315(8):788-800
8. 8
Clinical presentation
• Acute onset
▫ Often within 12-48 hrs
after predisposing event
• Decrease Lung compliance
▫ Increase work of breathing
▫ Tachypnea
▫ Rapid shallow breathing
• Hypoxemia
▫ Resistant to general oxygen therapy
▫ V/Q Mismatch and shunt
Fan, et la. JAMA 2005
9. 9
Precipitating factors
Fan, et al. JAMA 2005
Direct cause Indirect cause
Pneumonia Sepsis/septic shock
Aspiration Trauma with multiple fx
Toxic inhalation Acute pancreatitis
Lung contusion Burn injury
Near drowning Blood transfusion
Toxic ingestion
Drugs
10. 10
Pathophysiology
N Engl J Med 2000; 342:1334-1349
Insult (direct/indirect)
Activation of inflammatory
cells and mediators
Damage to alveolar capillary
membrane
Increase permeability of
alveolar capillary membrane
Influx of protein rich fluid
lead to shunt;
vasoconstriction, vascular
leakage, impaired diffusion
11. 11
Phases of ARDS : Exudative
N Engl J Med 2017; 377:3562-72
▫ Damaged alveolar
endothelial and
epithelial
▫ Protein-rich
edema fluid
▫ Alveolar
macrophage
▫ Inflammatory
cytokine
12. 12
Phases of ARDS : Proliferative
N Engl J Med 2017; 377:3562-72
▫ Repair process
▫ Reestablished
epithelial integrity
▫ “Hyaline membrane”
▫ Reabsorption of
alveolar edema
13. 13
Phases of ARDS : Fibrotic phase
N Engl J Med 2017; 377:3562-72
▫ Persistent alveolar
edema
▫ Extensive fibrosis
▫ Does not occur in
all patients
▫ Associated with
poor outcomes :
Prolonged
mechanical
ventilation and
increased mortality
18. 18
Specific Treatment
▫ Treatment of the underlying cause
▫ Correct precipitating factors
▫ Sepsis-associated ARDS
Early resuscitation
Appropriate antibiotic agents
Source control
B. Taylor Thompson, M.D.,ARDS. NEJM 2017
19. 19
Fighting strategy
ARDS mx
Specific Tx
Supportive
Tx
Ventilatory
mx
Non-
ventilatory
mx
Medical mx
Non-
medical mx
- Low tidal volume
ventilation
- Optimal PEEP
- Recruitment
maneuver
20. 20
Low tidal volume strategy
▫ First strategy to improve survival
in ARDS
▫ ↓ VILI, ↓ Barotrauma, ↓ Pneumothorax
▫ Recommend Tidal volume (VT)
= 4-6 ml/kg predicted BW
▫ Predicted BW
Male : 50 + 0.91x(Ht in cm - 152.4)
Female : 45.5 + 0.91x(Ht in cm – 152.4)
B. Taylor Thompson, M.D.,ARDS. NEJM 2017
21. 21
Low tidal volume strategy
▫ Keep plateau pressure < 30 cmH2O
▫ Avoid respiratory acidosis
▫ Adjust set RR (reach to 35/min) to
maintain MV
▫ Permissive hypercapnia
B. Taylor Thompson, M.D.,ARDS. NEJM 2017
23. 23
Low tidal volume strategy
“ARMA Study” NEJM. 2000
Mortality rate was 39.8 >> 31.0%
in lower tidal volume group
(P=0.007)
24. 24
Low tidal volume strategy
Eddy Fan. MD. PhD. ARDS advance in diagnosis and treatment. JAMA 2018
25. 25
Low tidal volume strategy
Papazian et al. Ann. Intensive Care (2019) 9:69
26. 26
Low tidal volume strategy
Mark J D Griffiths et al, Guidelines on the management of acute
respiratory distress syndrome. BMJ Open RS research (2019)
Monitor continuously ; 6-8 ml/kg or even 10 !
27. 27
How to get a Ppla?
VCV mode >> select square wave form
Tool >> Insp hold
28. 28
How to get a Ppla?
VCV mode >> select square wave form
Tool >> Insp hold
30. 30
PEEP Optimization
N Engl J Med 2004; 351:327-336
▫ PEEP table (ARDSNet)
▫ Suggested PEEP, FiO2 to combat hypoxemia
Mod to severe ARDS
Mild to mod ARDS
31. 31
PEEP Optimization
Allan J. Walkey, Higher PEEP vs Lower PEEP Strategies -- Systematic review. Ann ATS 2017
No significant difference in mortality
32. 32
PEEP Optimization
Matthias Briel, Higher PEEP vs Lower PEEP in ARDS -- Systematic review. JAMA 2010
Subgroup : Patient with ARDS
(P/F ratio <200), higher PEEP
group were less likely to die in
hospital (34.1% vs 39.1% RR 0.91
(5% CI 0.81-1.00 p =.049)
33. 33
PEEP Optimization
▫ Overall High PEEP was not associated with
survival
▫ High PEEP were associated with improved
survival and weaning in subgroup of ARDS
(PF ratio < 200)
▫ “Higher PEEP in moderate to severe
ARDS”
▫ Keep : PaO2 ≥ 55 mmHg and SpO2 ≥ 88%
Eddy Fan. MD. PhD. ARDS advance in diagnosis and treatment. JAMA 2018
35. 35
PEEP Optimization
• How to choose a proper PEEP?
“PEEP Titration methods”
▫ Incremental PEEP
▫ Decremental PEEP with recruitment
▫ Stress index (SI)
▫ Esophageal pressure guide
▫ PV loops
▫ Thoracic electric impedance tomography and
lung ultrasound
Will be demonstrated in practical section…
36. 36
Lung recruitment
▫ Lung recruitment maneuvers are
interventions that increase airway
pressures to open collapsed lung units.
▫ Dynamic, transient increasing of
transpulmonary pressure
▫ Improve oxygenation
▫ With Decremental PEEP titration
▫ Adverse effects :
Hypotension : ↓ Venous return / CO
Desaturation
↓ Cerebral perfusion
Barotrauma
Arrhythmia .. And more.
Eddy Fan. MD. PhD. ARDS advance in diagnosis and treatment. JAMA 2018
38. 38
Lung recruitment
ART : Effect of Titrated vs Low Positive End-Expiratory Pressure (PEEP) on Mortality in ARDS. JAMA 2017
Do not support the routine use of lung
recruitment maneuver and PEEP
titration
39. 39
Lung recruitment
Papazian et al. Ann. Intensive Care (2019) 9:69
Eddy Fan. MD. PhD. ARDS advance in diagnosis and treatment. JAMA 2018
41. 41
Neuromuscular
blocking agent
▫ Cisatracurium
▫ ↓ VILI, Improve patient-ventilator synchrony,
▫ ↓ Pneumothorax
▫ Consider in
Early ARDS
Moderate to severe ARDS : PF ratio < 150 mmHg
▫ Infusion for 48 hrs or longer
“ACURASYS”. NEJM 2010
Cisatracurium compare to
placebo, 90-day mortality
31.6% in Cis group and 40.7% in
placebo group.
42. 42
Neuromuscular
blocking agent
• Indication for NMBA
▫ P/F ratio < 150
• Contraindication for NMBA
▫ Pregnancy
▫ Obesity
▫ Increased ICP
▫ Severe COPD
▫ Severe liver disease
▫ Bone marrow transplantation
▫ Chemotheapy-induced neutropenia
▫ Pneumothorax
“ACURASYS”. NEJM 2010
44. 44
Fighting strategy
ARDS mx
Specific Tx
Supportive
Tx
Ventilatory
mx
Non-
ventilatory
mx
Medical mx
Non-
medical mx
- Prone
position
- Restrictive
fluid strategy
- ECMO
45. 45
Prone positioning
Guidance For Prone Positioning in Adult Critical Care. Intensive care society 2019
Low pul vascular perfusion pressure
High transpulmonary pressure
High pul vascular perfusion pressure
Low transpulmonary pressure
46. 46
Prone positioning
▫ Effect of prone
Redistribution of ventilation to dorsal area
Improve V/Q mismatching
Elimination of lung compression by heart
↓ VILI
▫ Adverse effect
↑ Risk of pressure sore
Need heavy sedation
Risk of tube/catheter dislodgement
Caution If hemodynamic instability
Eddy Fan. MD. PhD. ARDS advance in diagnosis and treatment. JAMA 2018
47. 47
Prone positioning
▫ P/F ratio < 150
▫ Receiving Prone position ≥ 16 hrs
▫ Reduced 28 and 90-day mortality
“PROSEVA trial”. NEJM 2013
48. 48
Prone positioning
• Indication (current)
▫ Moderate to severe ARDS with PaO2:FiO2 ratio
< 150 mmHg and FiO2 ≥ 0.6
▫ Early within the course of the disease (ideally
< 48 hours) following 12-24 hours of
mechanical ventilation allowing for treatment
optimization.
▫ Best outcomes achieved using tidal volumes of
6ml/kg predicted body weight and consider the
use of neuromuscular blocking drugs if there
is evidence of ventilator dys-synchrony.
Guidance For Prone Positioning in Adult Critical Care. Intensive care society 2019
50. 50
Prone positioning
• When to stop prone?
▫ PF ratio > 150 after 4 hrs of supination
▫ (PEEP < 10 and FiO2 < 0.6)
Guidance For Prone Positioning in Adult Critical Care. Intensive care society 2019
51. 51
Prone positioning
Papazian et al. Ann. Intensive Care (2019) 9:69
Mark J D Griffiths et al, Guidelines on the management of acute
respiratory distress syndrome. BMJ Open RS research (2019)
52. 52
Restrictive fluid mx
▫ Mild to moderate ARDS with stable
hemodynamic : Diuretic with or without
albumin may improve gas exchange and
oxygenation
▫ Restrictive fluid : CVP < 6 cmH2O
▫ No mortality benefit
Fan, et la. JAMA 2005
53. 53
Restrictive fluid mx
Mark J D Griffiths et al, Guidelines on the management of acute
respiratory distress syndrome. BMJ Open RS research (2019)
56. 56
ECMO in ARDS
▫ ECMO to rescue lung injury in severe ARDS
(EOLIA) trial
▫ Disease severity criteria (Despite optimal care)
PF ratio < 50 mmHg for > 3 hrs
PF ratio < 80 for > 6 hr
ABG : pH < 7.25 with PaCO2 ≥ 60 mmHg > 6hr
“EOLIA trial” NEJM 2018
57. 57
ECMO in ARDS
Papazian et al. Ann. Intensive Care (2019) 9:69
Mark J D Griffiths et al, Guidelines on the
management of acute respiratory distress
syndrome. BMJ Open RS research (2019)
58. 58
Mx in ARDS
(Evidence sum)
▫ Improve survival !
Low TV ventilation
Prone position
Early neuromuscular blocking agent
ECMO
▫ Not improve survival but oxygenation.
Optimal or Higher PEEP
Recruitment maneuver
Permissive hypercapnia
Restrictive fluid strategy
Mark J D Griffiths et al, Guidelines on the
management of acute respiratory distress
syndrome. BMJ Open RS research (2019)
59. 59
Other Mx in ARDS
(Evidence sum)
▫ HFOV Strongly against
▫ Inhaled vasodilators Weakly against
▫ Corticosteroid Research rec
▫ ECCO2R Research rec
▫ Driving pressure No recommendation
Mark J D Griffiths et al, Guidelines on the management of acute
respiratory distress syndrome. BMJ Open RS research (2019)
60. 60
Other Mx in ARDS
Dexamethasone
Jesús Villar et al, Dexamethasone treatment in ARDS. Lancet Respir Med 2020;8: 267–76
▫ P : Moderate to severe ARDS (P/F<200)
▫ I : Dexamthasone 20 mg IV OD
▫ C : Conventional tx
▫ O : Primary – ventilator free days at 28 D
Secondary – Mortality at 60 D
62. 62
NIV/NHFC uses in ARDS
▫ Mild ARDS (P/F 200-300)
▫ Close monitoring, if deteriorate >>
intubation (esp. first 1-2 hrs)
Gasperstad E, et al. Chest 2007; 132:711-20
Indication
• Need ventilation support
• Moderate to severe RS distress
(PF 200-300)
• Tachypnea
• Accessory muscle use or
abdominal paradox
• pH< 7.35, PaCO2 > 45
mmHg or PF < 300
Contraindication
• Cardiac arrest
• Medical instability
• Risk for aspiration or upper
airway obstruction
• Uncorrected pneumothorax
• Recent head and neck or
esophageal trauma or Sx
• Large amount of sputum
• Uncooperative
63. NIV/NHFC uses in ARDS
• P : Patient with hypoxic
RS failure
• I : HFNC
• C : Standard O2, NIV
• O : Intubation in 28 D
63
“FLORALI trial”. NEJM 2015; 372:2185-96
64. 64
How to recruit lung and
select a proper PEEP?
Example : Decremental method titration
▫ Full sedation and Nimbex
▫ Stable vital signs
▫ Dull some alarm ranges
▫ VCV mode VT 6-8 ml/kg PEEP 18-20 cmH2O
(or event 25 in some cases), PF 40-60 lpm
(Constant flow) I time 0.8-1 sec,
Lower RR (approx. 20 tpm) to eliminate PEEPi
▫ Measure Pplat , Calculate Compliance
▫ Observe Vte, SpO2, BP
▫ Wait for 2 mins then decrease PEEP 2 mmH2O
▫ Find closing point (desat / decrease
compliance) then reopen at cpPEEP + 2
65. 65
How to recruit lung and
select a proper PEEP?
Driving Pressure > 15 mmHg : Increased mortality
Driving P = Pplat-PEEP
66. 66
How to recruit lung and
select a proper PEEP?
Total airway pressure (P peak) = Resistance + Elastance
Pplat – PEEP == Overcome resistance (Driving Pressure)
Pplat = Pressure when no flow (No resistance)
== Pressure to overcome Elastance
67. 67
How to recruit lung and
select a proper PEEP?
Compliance =
Δ𝑉
Δ𝑃
Compliance =
𝑉𝑡𝑒
P 𝑃𝑙𝑎𝑡−𝑃𝐸𝐸𝑃
Total airway pressure (P peak) = Resistance + Elastance
Pplat – PEEP == Overcome resistance (Driving Pressure)
Pplat = Pressure when no flow (No resistance)
== Pressure to overcome Elastance
68. 68
How to recruit lung and
select a proper PEEP?
PEEP 18 16 14 12 10 8 …
Vte 400 390 400 410 400 390
Pplat 37 31 28 24 22 22
C 21.1 26 28.6 34.2 27.9 27.9
72. 72
Cardiac arrest during prone
(Prone CPR)
Guidance For Prone Positioning in Adult Critical Care. Intensive care society 2019
73. 73
ARDS and pneumothorax
▫ Gammon et al demonstrated an overall
incidence of pneumothorax of 14%
mechanically ventilated patients, whereas
a sub-group of 29 ARDS patients had a
60% incidence of pneumothorax.
▫ The development of a pneumothorax in a
critically ill patient is associated with
mortality rates between 66% and 77%
▫ Difficult to detect ; 1/3 were missed.
▫ Can be fatal due to progression to tension
pneumothorax.
Kenneth J. Woodside et al. Pneumothorax in patients with ARDS. Intensive care med 2003
74. 74
ARDS and pneumothorax
▫ Patients on positive-pressure ventilation
with pneumothoraces require rapid
drainage, as there is a high risk of
progression to tension.
▫ Traditional treatment has been with tube
thoracostomy.
▫ Expert opinion : Prone position and Lung
recruitment still possible after ICD
placement.
Kenneth J. Woodside et al. Pneumothorax in patients with ARDS. Intensive care med 2003
