• Am. J. Respir. Crit. Care Med. · May 2011

    Lung stress and strain during mechanical ventilation: any safe threshold?

    • Alessandro Protti, Massimo Cressoni, Alessandro Santini, Thomas Langer, Cristina Mietto, Daniela Febres, Monica Chierichetti, Silvia Coppola, Grazia Conte, Stefano Gatti, Orazio Leopardi, Serge Masson, Luciano Lombardi, Marco Lazzerini, Erica Rampoldi, Paolo Cadringher, and Luciano Gattinoni.
    • Dipartimento di Anestesiologia, Terapia Intensiva e Scienze Dermatologiche, Università degli Studi di Milano, Milan, Italy.
    • Am. J. Respir. Crit. Care Med. 2011 May 15;183(10):1354-62.

    RationaleUnphysiologic strain (the ratio between tidal volume and functional residual capacity) and stress (the transpulmonary pressure) can cause ventilator-induced lung damage.ObjectivesTo identify a strain-stress threshold (if any) above which ventilator-induced lung damage can occur.MethodsTwenty-nine healthy pigs were mechanically ventilated for 54 hours with a tidal volume producing a strain between 0.45 and 3.30. Ventilator-induced lung damage was defined as net increase in lung weight.Measurements And Main ResultsInitial lung weight and functional residual capacity were measured with computed tomography. Final lung weight was measured using a balance. After setting tidal volume, data collection included respiratory system mechanics, gas exchange and hemodynamics (every 6 h); cytokine levels in serum (every 12 h) and bronchoalveolar lavage fluid (end of the experiment); and blood laboratory examination (start and end of the experiment). Two clusters of animals could be clearly identified: animals that increased their lung weight (n = 14) and those that did not (n = 15). Tidal volume was 38 ± 9 ml/kg in the former and 22 ± 8 ml/kg in the latter group, corresponding to a strain of 2.16 ± 0.58 and 1.29 ± 0.57 and a stress of 13 ± 5 and 8 ± 3 cm H(2)O, respectively. Lung weight gain was associated with deterioration in respiratory system mechanics, gas exchange, and hemodynamics, pulmonary and systemic inflammation and multiple organ dysfunction.ConclusionsIn healthy pigs, ventilator-induced lung damage develops only when a strain greater than 1.5-2 is reached or overcome. Because of differences in intrinsic lung properties, caution is warranted in translating these findings to humans.

      Pubmed     Full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…