• Critical care medicine · Sep 2016

    Role of Strain Rate in the Pathogenesis of Ventilator-Induced Lung Edema.

    • Alessandro Protti, Tommaso Maraffi, Marta Milesi, Emiliano Votta, Alessandro Santini, Paola Pugni, Davide T Andreis, Francesco Nicosia, Emanuela Zannin, Stefano Gatti, Valentina Vaira, Stefano Ferrero, and Luciano Gattinoni.
    • 1Dipartimento di Anestesia, Rianimazione ed Emergenza Urgenza, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Milan, Italy.2Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi, Milan, Italy.3Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy.4Centro di Ricerche Chirurgiche Precliniche, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Università degli Studi, Milan, Italy.5U.O.C. Anatomia Patologica, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Milan, Italy.6Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi", Milan, Italy.7Dipartimento di Scienze Biomediche, Chirurgiche e Odontoiatriche, Università degli Studi, Milan, Italy.
    • Crit. Care Med. 2016 Sep 1; 44 (9): e838-45.

    ObjectiveLungs behave as viscoelastic polymers. Harms of mechanical ventilation could then depend on not only amplitude (strain) but also velocity (strain rate) of lung deformation. Herein, we tested this hypothesis.DesignLaboratory investigation.SettingAnimal unit.SubjectsThirty healthy piglets.InterventionsTwo groups of animals were ventilated for 54 hours with matched lung strains (ratio between tidal volume and functional residual capacity) but different lung strain rates (ratio between strain and inspiratory time). Individual strains ranged between 0.6 and 3.5 in both groups. Piglets ventilated with low strain rates had an inspiratory-to-expiratory time ratio of 1:2-1:3. Those ventilated with high strain rates had much lower inspiratory-to-expiratory time ratios (down to 1:9). Respiratory rate was always 15 breaths/min. Lung viscoelastic behavior, with ventilator setting required per protocol, was "quantified" as dynamic respiratory system hysteresis (pressure-volume loop [in Joules]) and stress relaxation (airway pressure drop during an end-inspiratory pause [in cm H2O]). Primary outcome was the occurrence of pulmonary edema within 54 hours.Measurements And Main ResultsOn average, the two study groups were ventilated with well-matched strains (2.1 ± 0.9 vs 2.1 ± 0.9; p = 0.864) but different strain rates (1.8 ± 0.8 vs 4.6 ± 1.5 s; p < 0.001), dynamic respiratory system hysteresis (0.6 ± 0.3 vs 1.4 ± 0.8 J; p = 0.001), and stress relaxation (3.1 ± 0.9 vs 5.0 ± 2.3 cm H2O; p = 0.008). The prevalence of pulmonary edema was 20% among piglets ventilated with low strain rates and 73% among those ventilated with high strain rates (p = 0.010).ConclusionsHigh strain rate is a risk factor for ventilator-induced pulmonary edema, possibly because it amplifies lung viscoelastic behavior.

      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…