Ventilator Induced Lung Injury. VIASYS Healthcare, Inc. Ventilator Induced Lung Injury Barotrauma Volutrauma Stretch Injury Biochemical Injury

Ventilator Induced Lung Injury

VIASYS Healthcare, Inc.


• Barotrauma

• Volutrauma

• Stretch Injury

• Biochemical 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)


Effect of 45 cmH2O PIP

Control 5 min 20 min Control 5 min 20 min



• Stretch Injury• Alters capillary

transmural pressures• Changes in transmural

pressure causes breaks in capillary endo and epithelium

• Increases leak of proteinacious material

• Promotes Atelectasis


Ventilator Induced Lung InjuryStretch Injury

AlveolarSpace

A-CMembrane



• Rodents ventilated with three modes:• High Pressure

(45 cmH2O), High Volume

• Low Pressure (negative pressure ventilator), High Volume

• High Pressure (45 cmH2O), Low Volume (strapped chest and abdomen)

Dreyfuss,D ARRD 1988;137:1159



• 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

• Promotes Atelectasis

Dreyfuss,D ARRD 1988;137:1159



• 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



Premature baboon model

Coalson J. Univ Texas San Antonio



Premature baboon model

Coalson J. Univ Texas San Antonio


Alveolar Edema and Hyaline Membrane


Hemorrhage and Edema


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 20-50 ml/kg based on open lung units

• Histology is similar to infant lung injury



• Adult Acute Respiratory Failure– Atelectasis– Overdistended

airways and alveoli

– Cellular accumulation

– Hyaline Membranes Lamy ARRD 1976; 114:267



• Adult ARDS late stage lung structural changes• Enlarged air

space• Septal

destruction• Fibrotic lesions


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.



• 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



• Phase 3 Fibrotic (Day 10-14)• Lung Destruction• Emphysematous Changes• Fibrosis• Pulmonary Vascular Obliteration• Chronic Lung Disease



• 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


Ware and Matthay NEJM 342 (18): 1334


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



Twenty Years of One Year Follow Up of Lung Function (DLCO) in ARDS Survivors

Suchyta MR, ERS 1997



• 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

Alveolar Protein

0%

5%

10%

15%

20%

25%

30%

CM

V

CM

V-S

HF

OV

HF

OV

-S

Mode

Per

cen

t D

ebri

s



• 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





Control animal histology

Sugiura M, JAP 1994; 77:1355



HFOV animal histology

Sugiura M, JAP 1994; 77:1355



CMV animal histology

Sugiura M, JAP 1994; 77:1355



• 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



• HFOV produces less inflammatory markers than CMV Imai Y, AJRCCM 1994; 150:1550



• Activation of alveolar macrophages and pro-inflammatory cytokines play a pivotal role in Ventilator Induced Lung Injury

Takata M, AJRCCM 1997; 156:272


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


Lung Inflation PatternsMulti-Scan CT (10 scans/sec)

Weiler N. et al, 1999, personal communication

30 kg Pig

Pre Lavage

Pressure Control Ventilation

Paw 13 cmH2O PEEP 5 cmH2O



Weiler N et al, 1999, personal communication

30 kg Pig

Pre Lavage


Paw 23 cmH2OPEEP 15 cmH2O




30 kg Pig

Post Lavage


Paw 13 cmH2O PEEP 5 cmH2O




30 kg Pig

Post Lavage






30 kg Pig

Post Lavage




Lung Inflation PatternsMulti-Scan CT(10 scans/sec)

30 kg PigPost LavageHFOV Paw 23 cmH2O

Weiler N. Heinrichs W, et al 1999


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

Documents

Ventilator Induced Lung Injury. VIASYS Healthcare, Inc. Ventilator Induced Lung Injury Barotrauma Volutrauma Stretch Injury Biochemical Injury