1. Ventilator Induced Lung Injury

2. Ventilator Induced Lung Injury
Barotrauma
Volutrauma
Stretch Injury
Biochemical Injury

3. Ventilator Induced Lung Injury
Barotrauma
Air leaking into pleural space
Air leaking into interstitial space (PIE)
Tearing at Bronchio-Alveolar Junction as lung is recruited and allowed to collapse
Most occurs in dependent lung zones (transition zone)

4. Effect of 45 cmH2O PIP
Control min min

5. Ventilator Induced Lung Injury
Stretch Injury
Alters capillary transmural pressures
Changes in transmural pressure causes breaks in capillary endo and epithelium
Increases leak of proteinacious material
Promotes Atelectasis

6. Ventilator Induced Lung Injury Stretch Injury
Alveolar Space
A-C Membrane

7. Ventilator Induced Lung Injury
Rodents ventilated with three modes:
High Pressure
(45 cmH2O), High Volume
Low Pressure (negative pressure ventilator), High Volume
(45 cmH2O), Low Volume (strapped chest and abdomen)
Dreyfuss,D ARRD 1988;137:1159

8. Ventilator Induced Lung Injury
Volutrauma
Caused by cycling of the lung (change in surface area), independent of pressure required
Alters Surfactant function
Promotes Atelectasis
Increases capillary leak of proteinacious material
Dreyfuss,D ARRD 1988;137:1159

9. Ventilator Induced Lung Injury
Hyaline Membrane Disease is not really a disease, it’s the result of volume cycling the lungs
CMV produces consolidation, over inflation and hyaline membrane formation
HFOV uniformly inflates the lung without hyaline membrane formation
Meredith K, JAP 1989; 66:2150

10. Ventilator Induced Lung Injury
Premature baboon model
Coalson J. Univ Texas San Antonio

11. Ventilator Induced Lung Injury
Premature baboon model
Coalson J. Univ Texas San Antonio

12. Alveolar Edema and Hyaline Membrane

13. Hemorrhage and Edema

14. Adult ARDS HFOV - Caring for the Baby in Adults
Baby Lung Sitting on Top of a Consolidated Lung
Tidal Volumes of 6-10 ml/kg based on weight
Tidal Volumes of ml/kg based on open lung units
Histology is similar to infant lung injury

15. Ventilator Induced Lung Injury
Adult Acute Respiratory Failure
Atelectasis
Overdistended airways and alveoli
Cellular accumulation
Hyaline Membranes
Lamy ARRD 1976; 114:267

16. Ventilator Induced Lung Injury
Adult ARDS late stage lung structural changes
Enlarged air space
Septal destruction
Fibrotic lesions

17. ARDS Pulmonary Injury Sequence
Phase 1 Early Exudative Treatment
Endo/Epithelial Damage
Type 1 Alveolar Cell Injury and/or Loss
Capillary Congestion
Interstitial/Alveolar Edema, Hemorrhage
Protein Accumulation
Surfactant Deactivation
Atelectasis
Hyaline Membrane Formation
Inflammatory Cell Migration
Volutrauma - Increased Protein Leak, Atelectasis, etc.

18. ARDS Pulmonary Injury Sequence
Phase 2 Proliferative (Day 5-10)
Proliferation of Type 2 Cells
Fibroblast Migration
Interstitial Collagen Formation
Increased Dead Space
Decreased Compliance
Increased Pulmonary Vascular Resistance

19. ARDS Pulmonary Injury Sequence
Phase 3 Fibrotic (Day 10-14)
Lung Destruction
Emphysematous Changes
Fibrosis
Pulmonary Vascular Obliteration
Chronic Lung Disease

20. Ventilator Induced Lung Injury
Biochemical Injury
Biochemical agents (mediators) attack the lung
Recruit fibrotic proliferation cells to the lung
Atelectasis promotes release of chemical mediators
Mediators released in the lung can attack other organ systems
Cells
Macrophages
Endothelial and Epithelial Cells
Platelets
Neutrophils
Mediators
Cytokines
Leukotrienes
PAF (Platelet Activating Factor)
Thromboxane
TNF (Tumor Necrotizing Factor)
Complement Proteins
Interleukin-1,8

21. Ware and Matthay NEJM 342 (18): 1334

22. Pulmonary Injury Sequence
There are two injury zones during mechanical ventilation
Low Lung Volume Ventilation tears adhesive surfaces
High Lung Volume Ventilation over-distends, resulting in “Volutrauma”
The difficulty is finding the “Sweet Spot”
Froese AB, Crit Care Med 1997; 25:906

23. Ventilator Induced Lung Injury
Twenty Years of One Year Follow Up of Lung Function (DLCO) in ARDS Survivors
Suchyta MR, ERS 1997

24. Ventilator Induced Lung Injury
HFOV with Surfactant as Compared to CMV with Surfactant in the Premature Primate
HFOV resulted in
Less Radiographic Injury
Less Oxygenation Injury
Less Alveolar Proteinaceous Debris
Jackson C AJRCCM 1994; 150:534

25. Ventilator Induced Lung Injury
High Lung Volume Strategies with HFOV
Extended Surfactant Activity
Normalized Lamellar Body Phospholipid levels
Improved lung mechanics
All Conventional Ventilator Strategies
Resulted in Death or Decreased Surfactant Performance
Froese A, ARRD 1993; 148:569

26. Ventilator Induced Lung Injury

27. Ventilator Induced Lung Injury
Control animal histology
Sugiura M, JAP 1994; 77:1355

28. Ventilator Induced Lung Injury
HFOV animal histology
Sugiura M, JAP 1994; 77:1355

29. Ventilator Induced Lung Injury
CMV animal histology
Sugiura M, JAP 1994; 77:1355

30. Ventilator Induced Lung Injury
HFOV Stimulates Significantly Less Neutrophil Activity Than CMV
Neutrophil Activity Has a Role in the Genisis of ARDS, Releasing Active Oxygen Species, Proteinases and Arachidonic Acid Metabolites.
Sugiura M, JAP 1994; 77:1355

31. Ventilator Induced Lung Injury
HFOV produces less inflammatory markers than CMV
Imai Y, AJRCCM 1994; 150:1550

32. Ventilator Induced Lung Injury
Activation of alveolar macrophages and pro-inflammatory cytokines play a pivotal role in Ventilator Induced Lung Injury
Takata M, AJRCCM 1997; 156:272

33. Risk Factors for ARDS Trauma Shock Syndromes - Sepsis, Cardiogenic
Gastric Aspiration
Burns
Diffuse Pneumonias
Near Drowning
Drug Overdose
Metabolic Events - Pancreatitis, Uremia
Systemic Mediator Release Associated Diseases
Disseminated Intravascular Coagulopathy
Cardiopulmonary Bypass Anaphylaxis
Extrapulmonary Infection Transfusion Reaction

34. Lung Inflation Patterns Multi-Scan CT (10 scans/sec)
30 kg Pig
Pre Lavage
Pressure Control Ventilation
Paw 13 cmH2O PEEP 5 cmH2O
Weiler N. et al, 1999, personal communication

35. Lung Inflation Patterns Multi-Scan CT (10 scans/sec)
30 kg Pig
Pre Lavage
Pressure Control Ventilation
Paw 23 cmH2O PEEP 15 cmH2O
Weiler N et al, 1999, personal communication

36. Lung Inflation Patterns Multi-Scan CT (10 scans/sec)
30 kg Pig
Post Lavage
Pressure Control Ventilation
Paw 13 cmH2O PEEP 5 cmH2O
Weiler N et al, 1999, personal communication

37. Lung Inflation Patterns Multi-Scan CT (10 scans/sec)
30 kg Pig
Post Lavage
Pressure Control Ventilation
Paw 23 cmH2O PEEP 15 cmH2O
Weiler N et al, 1999, personal communication

38. Lung Inflation Patterns Multi-Scan CT (10 scans/sec)
30 kg Pig
Post Lavage
Pressure Control Ventilation
Paw 33 cmH2O PEEP 25 cmH2O
Weiler N et al, 1999, personal communication

39. Lung Inflation Patterns Multi-Scan CT (10 scans/sec)
30 kg Pig
Post Lavage
HFOV
Paw 23 cmH2O
Weiler N. Heinrichs W, et al 1999

40. “Open up the lung up and keep it open!”
Burkhard Lachmann, 1992