The document outlines a comprehensive approach to managing Acute Respiratory Distress Syndrome (ARDS), detailing definitions, pathophysiology, and ventilatory strategies with specific case examples. It emphasizes lung protective ventilation techniques, recruitment maneuvers, and the significance of optimal PEEP settings to improve patient outcomes. The progression of a specific patient's case illustrates various treatment adjustments and their impact on oxygenation and ventilation parameters over time.

1. Ventilatory strategy in ARDS
Dr. Chandan Kumar Sheet
MD(Pulmonary Medicine),Fellowship in Interventional Pulmonology
Consultant Pulmonary Medicine, Critical Care & Sleep disorders
Calcutta Heart Clinic & Hospital, Saltlake, Kolkata

2. Contents
 Berlin Definition
 Cause of ARDS
 Stage & Pathophysiology of ARDS
 Ventilatory management
 Rescue maneuver
 Recruitment
 Prone Ventilation

3. • 41 year male, 70 kg
• No comorbidities
• Dry cough for 5 days
• Fever for 4 days
• SOB for last 12 hours
Temperature Pulse Respiration Blood pressure SPO2
102.4 °F 112 b/min 32 b/min 100/60 mmHg 90 %
• Chest : Bilateral coarse
inspiratory crepitations

4. ABG
• FiO2 -30%
• PH-7.38
• PaO2- 56
• PaCO2 - 38
• HCO3-22
What is the diagnosis?
Multilobar pneumonia with AHRF

5.  Stared with antibiotics Piptaz + Doxy
 Oxygen supplementation @2 l/min
 CPAP with 6 cm H2O
 Fluid therapy
 Sepsis protocol followed
 ECG & Echocardiography- WNL
Multi-lobar pneumonia
with ARDS

6. What is ARDS

7. ARDS new global definition 2023

8. Cause of ARDS

9. Pathology of ARDS

10. Stages of ARDS

11. Next Day (D2)
 Worsening ARDS
 P/F ~100
 Severe ARDS
 Increased tachypnea & Tachycardia
 Increased Oxygen requirement
 Persisting Fever
 Hemodynamically stable
ABG
• FiO2 -50%
• PH-7.36
• PaO2- 50
• PaCO2 - 45
• HCO3- 20
Ventilated

12. Post Ventilation HRCT

13. Indications for Mechanical Ventilation in ARDS
 Increased work of breathing
 Oxygenation impairment
 Impending Ventilatory failure
 Acute Ventilatory failure

14. Ventilation in ARDS – Lung Protective Ventilation
FIRST STAGE
1. Calculate Predicted body weight
Male : PBW = 50 + [2.3 x (Height in inch – 60)]
Female : PBW = 45.5 + [2.3 x (Height in inch – 60)]
2. Mode : VCV
3. Set initial tidal volume (VT) at 8 mL/kg PBW.
4. PEEP at 5 cm H2O ( Recent Guidelines 8-20cm of H2O)
5. Lowest FiO2 that achieves an SpO2 of 88-95%.
6. RR : 20-35/min
7. Inspiratory time: 0.5-0.8 s
8. Reduce VT by 1 mL/kg every 2 hrs. until VT = 6 mL/kg.

15. Ventilation in ARDS – Lung protective ventilation
SECOND STAGE
1. When VT = 6 mL/kg measure the end-inspiratory plateau pressure (Pplat).
2. If Pplat >30 cm H2O decrease VT 1 mL/kg until Pplat < 30 cm H2O or VT = 4mL / kg
THIRD STAGE
1. Monitor arterial blood gases for respiratory acidosis.
2. If pH 7.15-7.30, increase respiratory rate (RR) until pH > 7.3 or RR = 35 bpm.
3. If pH < 7.15 increase RR to 35 bpm.
If pH is still <7.15, increase VT in 1 mL/kg increments until pH > 7.15
4. If pH is still <7.15 may add bicarbonate

16. OPTIMUM GOAL
 VT = 6mL / kg
 Pplat ≤30 cm H2O
 PEEP = 8-20 cm of H2O to achieve SPO2/PaO2 target
 Driving Pressure <15 cm of H2O
 SpO2 = 88 - 95%
 PaO2 = 55-80 mm Hg
 PaCO2: 40 mm Hg if possible
 pH = 7.20-7.40
Permissive hypercapnia to avoid high Pplat and driving pressure
Ventilation in ARDS – Lung protective ventilation

17. ARDS.net PEEP-FiO2 table
(mild ARDS)
(moderate to severe ARDS; greater potential for recruitment)

18. PEEP
 It is the positive end inspiratory pressure
 Prevents collapse of alveoli
 Important tool to improve oxygenation
 PEEP increases CVP and PAP but decreases aortic pressure and cardiac output.

19. PEEP in ARDS
 Protective effect by avoiding alveolar collapse and reopening
 Prevent surfactant loss in the airways → avoid surface film collapse
 Use of PEEP avoids end-expiratory collapse, thus Recruitment is obtained
 ATS suggest patients with moderate or severe ARDS receive higher PEEP

20. What is lung protective ventilation
 A method to prevent the lung injury during mechanical ventilation from pressure or volume
 In ARDS, lung compliance is reduced so high peak inspiratory pressure is usually required to deliver
the desired volume
 The increase in airway pressures has the potential to injure the lung that have normal or high
compliance.
 Positive pressure ventilation can also cause lung injuries such as pneumomediastinum, pneumothorax,
and subcutaneous emphysema.
 So, low PIP (50), Pplat (<35), driving pressure(<15), and tidal volume(4mg/kg) is preferred.

21. Our case Day 3
 Improved oxygenation with ventilation
 Moderate ARDS
 Sepsis with septic shock
 Day 2 or mechanical ventilation
 Hypotensive on Noradrenaline
 Febrile
 Blood Culture ESBL klebsiella
 Antibiotics escalated To Meropenem
ABG
• FiO2 -50%
• PH-7.30
• PaO2- 65
• PaCO2 - 50
• HCO3- 26
Ventilator settings
o VCV
o VT - 420 ml
o PEEP 10
o FIO2 50
o RR 24
o Pplat 30

22. Our case Day 7
 Day 6 or mechanical ventilation
 Hypotension corrected
 Afebrile
 ETA Culture ESBL klebsiella
 Antibiotics Meropenem continued
ABG
• FiO2 -60%
• PH-7.38
• PaO2- 55
• PaCO2 - 45
• HCO3- 22
Ventilator settings
• VCV
• VT - 420 ml
• PEEP - 18
• FIO2 - 65
• RR - 24
• Pplat - 38
Issue : Hypoxemia worsening (P/F<100)
High Pplat, High Driving pressure
Hemodynamically stable
Infection under control to some extent

23. Our case Day 7
Decreased VT to 4 ml
ABG
• FiO2 - 70%
• PH-7.20
• PaO2- 55
• PaCO2 - 60
• HCO3- 28
Ventilator settings
VCV
VT - 280 ml
PEEP - 18
FIO2 - 70
RR - 30
Pplat - 35
Issue : Hypercarbia (Permissive hypercapnia)
Still High Pplat despite lowest VT
More worsening hypoxemia
Hemodynamically stable

24. Mortality: Low VT Vs Traditional VT
Low VT
Traditional VT

25. Thank You
Concept of driving pressure
o Driving pressure is defined as the ratio between tidal volume and pulmonary compliance.
o Can be estimated by calculating the difference between plateau pressure and PEEP
o A multilevel mediation analysis involving 3562 patients from nine RCT revealed that decrease in driving
pressure were associated with increased survival in patients with ARDS.
o Driving pressures below 14 cm H2O are associated with better outcomes
o Since driving pressure represents the tidal volume adjusted according to the compliance of the
respiratory system, it may lead to a reduction in lung stretch, thereby reducing mortality

26.  Recruitment
 Prone Ventilation
 Inhalational Vasodilators
 ECMO- ECCOR
Rescue maneuvers

27. Recruitment
 A method of titration for optimal PEEP by setting a high PEEP and gradually decreasing the pressure
and FIO2.
Recruitment maneuver should be used on patients with severe pulmonary edema and who are most at
risk of dying from refractory hypoxemia due to ARDS.
 Recruitment maneuvers should not be done to patients with existing
- Barotraumas
- Compromised hemodynamics
- Presence of blebs or bullae
- Increased intracranial pressure.

28. Recruitment
protocol

29. Our case Day 9
 Day 8 or mechanical ventilation
 Hypotension corrected Afebrile
 No organ dysfunction except lung
 Failed Recruitment
ABG
• FiO2 -80%
• PH -7.38
• PaO2- 55
• PaCO2 - 45
• HCO3- 24
Ventilator settings
VCV
VT - 280 ml
PEEP - 20
FIO2 - 80
RR - 30
Pplat - 31
Issue : Normal Pplat & Driving pressure
Hemodynamically stable
Hypoxemia worsening more (P/F<100)

30. Our case Day 9
 Hypoxemia worsening more (P/F<100)
 Dense radiological opacities
 What Next?

32. Prone Ventilation
 A procedure to temporarily
improve oxygenation by placing
the bed and patient in a
Trendelenberg position at 15 to 30
degrees.
 Prone position places the majority
of the lower lobes in an uppermost
position.
 Candidate: PEEP >10 and FIO2>
60% to maintain supine oxygen
saturation of 90%
(Marini et al. 2004).

33. Prone Ventilation

34. Prone Ventilation: Benefits

35. Prone Ventilation protocol
• Assess the patient's hemodynamic status and oxygenation.
• Administer sedation and neuromuscular blocking agents.
• Provide eye care/lubrication if indicated.
• Ensure that the patient's tongue is inside the mouth, insert a bite block if needed.
• Empty any drainage bags
• Perform anterior skin care, and place hydrocolloid dressings on bony prominences
• Secure the airway/endotracheal tube
• Prevent tube kinking
• Reposition the patient's head hourly to prevent skin breakdown.
• Place ECG leads on the patient's posterior chest
• Assign inter-professional team member repositioning responsibilities
• Monitor the patient's response to prone positioning
• ABG within 1 hour of repositioning and then at 4-hour intervals.

36. Prone Ventilation contraindications
Relative contraindications
o Tracheostomy (within the first 24 hours)
o Ophthalmologic surgery
o Pregnancy
o Facial trauma.
o Severe hemodynamic instability
o Severe Hypercarbia
Absolute contraindications
o Severe arrhythmias
o Pelvic fracture
o Intracranial hypertension
o Spine instability
o Recent sternotomy/cardiac surgery

37. Our case Day 13
 Day 12 or mechanical ventilation
 Prone ventilation day 3
 No organ dysfunction
 No fever
ABG
• FiO2 - 40%
• PH -7.48
• PaO2- 65
• PaCO2 - 45
• HCO3- 24
Ventilator settings
o VCV
o VT - 380 ml
o PEEP - 10
o FIO2 - 40
o RR – 24
o Pplat - 25
Issue : Hypoxemia improved (P/F> 150)
Normal Pplat & Driving pressure
Hemodynamically stable

38. Our case Day 15
 Day 14 or mechanical ventilation
 Supine ventilation day 3
 No organ dysfunction
 No fever
ABG
• FiO2 - 30%
• PH -7.45
• PaO2- 65
• PaCO2 - 40
• HCO3- 20
Ventilator settings
o VCV
o VT - 400 ml
o PEEP - 8
o FIO2 - 30
o RR – 24
o Pplat - 25
Issue : Hypoxemia improved (P/F> 200)

39. Day 15

40. Our case Day 16
 Day 15 or mechanical ventilation
 PSV tolerating
 No organ dysfunction
 No fever
ABG
• FiO2 - 30%
• PH -7.45
• PaO2- 75
• PaCO2 - 40
• HCO3- 20
Ventilator settings
o PSV
o PEEP - 5
o PSV - 6
o FIO2 - 30
Issue : Hypoxemia improved (P/F> 250)

41. Day 18
 Day 17 or mechanical ventilation
ABG
• FiO2 – 25 %
• PH -7.40
• PaO2- 78
• PaCO2 - 38
• HCO3- 20
Issue : Hypoxemia improved (P/F> 300)
Extubated

42. Thank You

43. Thank You