TY - JOUR
T1 - Lung stress and strain during mechanical ventilation
T2 - Any safe threshold?
AU - Protti, Alessandro
AU - Cressoni, Massimo
AU - Santini, Alessandro
AU - Langer, Thomas
AU - Mietto, Cristina
AU - Febres, Daniela
AU - Chierichetti, Monica
AU - Coppola, Silvia
AU - Conte, Grazia
AU - Gatti, Stefano
AU - Leopardi, Orazio
AU - Masson, Serge
AU - Lombardi, Luciano
AU - Lazzerini, Marco
AU - Rampoldi, Erica
AU - Cadringher, Paolo
AU - Gattinoni, Luciano
PY - 2011/5/15
Y1 - 2011/5/15
N2 - Rationale: Unphysiologic strain (the ratio between tidal volume and functional residual capacity) and stress (the transpulmonary pressure) can cause ventilator-induced lung damage. Objectives: To identify a strain-stress threshold (if any) above which ventilator-induced lung damage can occur. Methods: Twenty-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 Results: Initial 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 H2O, respectively. Lung weight gain was associated with deterioration in respiratory system mechanics, gas exchange, and hemodynamics, pulmonary and systemic inflammation and multiple organ dysfunction. Conclusions: In 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.
AB - Rationale: Unphysiologic strain (the ratio between tidal volume and functional residual capacity) and stress (the transpulmonary pressure) can cause ventilator-induced lung damage. Objectives: To identify a strain-stress threshold (if any) above which ventilator-induced lung damage can occur. Methods: Twenty-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 Results: Initial 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 H2O, respectively. Lung weight gain was associated with deterioration in respiratory system mechanics, gas exchange, and hemodynamics, pulmonary and systemic inflammation and multiple organ dysfunction. Conclusions: In 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.
KW - Healthy lung
KW - Lung strain
KW - Lung stress
KW - Tidal volume
KW - Ventilator-induced lung injury
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U2 - 10.1164/rccm.201010-1757OC
DO - 10.1164/rccm.201010-1757OC
M3 - Article
C2 - 21297069
AN - SCOPUS:79955472706
VL - 183
SP - 1354
EP - 1362
JO - American Journal of Respiratory and Critical Care Medicine
JF - American Journal of Respiratory and Critical Care Medicine
SN - 1073-449X
IS - 10
ER -