Abstract:
Rationale: There is wide variability in mechanical ventilation settings during ECMO in
ARDS patients. Although lung rest is recommended to prevent further injury, there is no
evidence to support it.
Objectives: To determine whether near-apneic ventilation decreases lung injury in a pig
model of ARDS supported with ECMO.
Methods: Pigs (26-36kg; n=24) were anesthetized and connected to mechanical
ventilation. In 18 animals lung injury was induced by a double-hit consisting in repeated
saline lavages followed by 2 hours of injurious ventilation. Then, animals were connected
to high-flow veno-venous ECMO, and randomized into 3 groups: Non-protective (PEEP 5
cmH2O, tidal volume 10 ml/kg, respiratory rate 20 bpm); Conventional-protective (PEEP
10 cmH2O, tidal volume 6 ml/kg, respiratory rate 20 bpm); Near-apneic (PEEP 10 cmH2O,
driving pressure 10 cmH2O, respiratory rate 5 bpm). Six other pigs were used as Sham. All
groups were maintained during the 24-hour study period.
Measurements and Main Results: Minute ventilation and mechanical power were lower
in the Near-apneic group, but no differences were observed in oxygenation or compliance.
Lung histology revealed less injury in the Near-apneic group. Extensive
immunohistochemical staining for myofibroblasts and pro-collagen III was observed in the
Non-protective group, with the Near-apneic group exhibiting the least alterations. Near-
apneic group showed significantly less matrix-metalloproteinase-2 and -9 activity.
Histological lung injury and fibroproliferation scores were positively correlated with
driving pressure and mechanical power.
Description:
Originally Published in: Joaquin Araos, Leyla Alegria, Patricio Garcia, Pablo Cruces, Dagoberto Soto, Benjamín Erranz, Macarena Amthauer, Tatiana Salomon, Tania Medina, Felipe Rodriguez, Pedro Ayala, Gisella R. Borzone, Manuel Meneses, Felipe Damiani, Jaime Retamal, Rodrigo Cornejo, Guillermo Bugedo, Alejandro Bruhn. Near-Apneic Ventilation Decreases Lung Injury and Fibroproliferation in an Acute Respiratory Distress Syndrome Model with Extracorporeal Membrane Oxygenation. Am J Respir Crit Care Med. 2019;199(5):603–612.
DOI: 10.1164/rccm.201805-0869OC
Copyright © 2017 by the American Thoracic Society
The final publication is available at https://www.atsjournals.org/doi/citedby/10.1164/rccm.201805-0869OC