High respiratory rate is associated with early reduction of lung edema clearance in an experimental model of ARDS
2016 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 60, no 1, 79-92 p.Article in journal (Refereed) Published
BACKGROUND: The independent impact of respiratory rate on ventilator-induced lung injury has not been fully elucidated. The aim of this study was to investigate the effects of two clinically relevant respiratory rates on early ventilator-induced lung injury evolution and lung edema during the protective ARDSNet strategy. We hypothesized that the use of a higher respiratory rate during a protective ARDSNet ventilation strategy increases lung inflammation and, in addition, lung edema associated to strain-induced activation of transforming growth factor beta (TGF-β) in the lung epithelium.
METHODS: Twelve healthy piglets were submitted to a two-hit lung injury model and randomized into two groups: LRR (20 breaths/min) and HRR (40 breaths/min). They were mechanically ventilated during 6 h according to the ARDSNet strategy. We assessed respiratory mechanics, hemodynamics, and extravascular lung water (EVLW). At the end of the experiment, the lungs were excised and wet/dry ratio, TGF-β pathway markers, regional histology, and cytokines were evaluated.
RESULTS: No differences in oxygenation, PaCO2 levels, systemic and pulmonary arterial pressures were observed during the study. Respiratory system compliance and mean airway pressure were lower in LRR group. A decrease in EVLW over time occurred only in the LRR group (P < 0.05). Wet/dry ratio was higher in the HRR group (P < 0.05), as well as TGF-β pathway activation. Histological findings suggestive of inflammation and inflammatory tissue cytokines were higher in LRR.
CONCLUSION: HRR was associated with more pulmonary edema and higher activation of the TGF-β pathway. In contrast with our hypothesis, HRR was associated with less lung inflammation.
Place, publisher, year, edition, pages
2016. Vol. 60, no 1, 79-92 p.
Anesthesiology and Intensive Care
Research subject Anaesthesiology and Intensive Care
IdentifiersURN: urn:nbn:se:uu:diva-264211DOI: 10.1111/aas.12596ISI: 000368139400010PubMedID: 26256848OAI: oai:DiVA.org:uu-264211DiVA: diva2:859516
FunderSwedish Heart Lung FoundationSwedish Research Council, K2015-99X-22731-01-4