• Skip to content
  • Skip to primary sidebar
  • Collections
  • ECG Library
  • Top 100
  • PART ONE
  • CASES
  • CCC
  • Tox Library

Life in the Fast Lane • LITFL • Medical Blog

Emergency medicine and critical care medical education blog

Critical Care Compendium | Ventilator Associated Lung Injury (VALI)

Ventilator Associated Lung Injury (VALI)

by Chris Nickson, Last updated April 12, 2016

OVERVIEW

  • mechanical ventilation with application of pressure to the lung, whether positive or negative, can cause damage known as ventilator-associated lung injury (VALI)
  • VALI may occur in previously normal lungs or worsen pre-existing ARDS
  • About 1 in 4 mechanically ventilated patients develop VALI, the risk is likely higher in ARDS patients
  • Ventilator induced lung injury (VILI) is sometimes used as a synonym for VALI, but strictly speaking VILI is VALI when mechanical ventilation is the proven cause of lung injury

TYPES OF VALI

Ventilator Associated Lung Injury (VALI) can occur due to:

  • volutramua
  • barotrauma
  • biotrauma
  • recruitment/ derecruitment injury (atelectotrauma)
  • shearing injury
  • oxygen toxicity

Ventilated patients are also at risk of ventilator associated pneumonia (VAP)

MECHANISMS AND MINIMISATION STRATEGIES

Injury Mechanism  Minimisation Strategy
Volutrauma
  • Non-homogenous lung injury
  • Over-distension of normal alveolar units to trans- pulmonary pressures above ~30 cm H2O (that corresponds to approximate total lung volume) causes basement membrane stretch and stress on intracellular junctions.
  • Avoid over-distending the “baby lung” of ARDS:
    (a) Maintain Plateau Airway pressure under 30 cm H20
    (b) Use Tidal volumes 6ml/kg (4- 8ml/kg)
  • Good evidence to support this strategy (ARDSNet ARMA trial)
Barotrauma
  • Increasing the trans-pulmonary pressures above 50 cm H2O will cause disruption of the basement membranes with classical barotrauma
Biotrauma
  • Mechanotransduction and tissue disruption leads to upregulation and release of chemokines and cytokines with subsequent WBC attraction and activation resulting in pulmonary and systemic inflammatory response and multi-organ dysfunction
  • Protective lung ventilation strategies
  • Use of neuromuscular blockers may ameliorate (ACURASYS trial)
Recruitment / Derecruitment Injury
aka atelectotrauma
  • The weight of the oedematous lung in ARDS contributes to collapse of the dependant portions of the lung
  • Repeated alveolar collapse and expansion (RACE) with tidal ventilation will contribute to lung injury.
  • Consider recruiting collapsed lung +/- employing an open lung ventilation strategy.
  • This may be achieved by:
    (a) Ventilation strategies: Sigh / APRV / “Higher PEEP”
    (b) A recruitment manoeuvres: e.g. CPAP 40/40, or stepwise PCV
    (c) Prone Positioning (gravitational recruitment manoeuvre)
  • Good theoretical support and case series / few trials inconclusive outcomes / meta-analysis supports high PEEP / proning supported by PROSEVA trial
Shearing injury
  • This occurs at junction of the collapsed lung and ventilated lung. The ventilated alveoli move against the relatively fixed collapsed lung with high shearing force and subsequent injury.
Oxygen toxicity
  • Higher than necessary FiO2 overcomes the ability of the cells to deal with free oxygen free radicals and leads to oxygen related free radical related lung injury.
  • High FiO2 may contribute to collapse through absorption atelectasis.
  • Limit FiO2 through the use of recruitment, higher PEEP and accepting SaO2 / PaO2 that correspond the the “shoulder” of the oxyhaemoglobin dissociation curve (SaO2 88-94)

References and Links

LITFL

  • CCC — Volutrauma
  • CCC — Protective lung ventilation
  • CCC — Open Lung Approach to Ventilation

Journal articles

  • Frank JA, Matthay MA. Science review: mechanisms of ventilator-induced injury. Crit Care. 2003 Jun;7(3):233-41. Epub 2002 Oct 16. Review. PubMed PMID: 12793874; PubMed Central PMCID: PMC270664.
  • Gajic O, Dara SI, Mendez JL, Adesanya AO, Festic E, Caples SM, Rana R, St Sauver JL, Lymp JF, Afessa B, Hubmayr RD. Ventilator-associated lung injury in patients without acute lung injury at the onset of mechanical ventilation. Crit Care Med. 2004 Sep;32(9):1817-24. PubMed PMID: 15343007.
  • Mead J, Takishima T, Leith D. Stress distribution in lungs: a model of pulmonary elasticity. J Appl Physiol. 1970;28:596–608. [PubMed]
  • Pinhu L, Whitehead T, Evans T, Griffiths M. Ventilator-associated lung injury. Lancet. 2003 Jan 25;361(9354):332-40. Review. PubMed PMID: 12559881
  • Rocco PR, Dos Santos C, Pelosi P. Pathophysiology of ventilator-associated lung injury. Curr Opin Anaesthesiol. 2012 Apr;25(2):123-30. doi: 10.1097/ACO.0b013e32834f8c7f. Review. PubMed PMID: 22395439.

Share this:

  • Facebook
  • LinkedIn
  • Twitter

About Chris Nickson

FCICM FACEM BSc(Hons) BHB MBChB MClinEpid(ClinTox) DipPaeds DTM&H GCertClinSim

Chris is an Intensivist at the Alfred ICU in Melbourne and is an Adjunct Clinical Associate Professor at Monash University. He is also the Innovation Lead for the Australian Centre for Health Innovation and the Chair of the Australian and New Zealand Intensive Care Society (ANZICS) Education Committee. He has a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia's Northern Territory, Perth and Melbourne. He has since completed further training in emergency medicine, clinical toxicology, clinical epidemiology and health professional education. He coordinates the Alfred ICU's education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the 'Critically Ill Airway' course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of Lifeinthefastlane.com, the RAGE podcast, the Resuscitology course, and the SMACC conference. His one great achievement is being the father of two amazing children. On Twitter, he is @precordialthump.

Reader Interactions

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Primary Sidebar

All LITFL posts by EMAIL or RSS

LITFL Weekly review by EMAIL or RSS

Frivolous Friday Five by EMAIL or RSS

Copyright © 2007 - 2019 · Powered by vocortex and iSimulate

We use cookies to understand site usage and to improve the content and offerings on our sites. If you continue using our website, we'll assume that you are happy to receive all cookies on this website.