LAUSR

Increased lung heterogeneity from regional alveolar collapse drives ventilator-induced lung injury in ARDS patients. New methods of preventing this injury require study. Our study objective was to determine whether the combination of temporary transvenous diaphragm neurostimulation with standard-of-care volume-control mode ventilation changes lung mechanics, reducing ventilator-induced lung injury risk in a preclinical ARDS model. Moderate ARDS was induced using oleic acid administered into the pulmonary artery in pigs, which were ventilated for 12 hours post-injury using volume-control mode at 8 ml/kg, PEEP 5 cmH2O, with respiratory rate and FiO2 set to achieve normal arterial blood gases. Two groups received TTDN, either every second breath (MV+TTDN50%, n=6) or every breath (MV+TTDN100%, n=6). A third group received volume-control ventilation only (MV, n=6). At study-end, PaO2/FiO2 was highest and alveolar-arterial oxygen gradient was lowest for MV+TTDN100% (p<0.05). MV+TTDN100% had the smallest end-expiratory lung volume loss and lowest extravascular lung water at study-end (p<0.05). Static lung compliance was highest and transpulmonary driving pressure was lowest at baseline, post-injury, and study-end in MV+TTDN100% (p<0.05). The total exposure to transpulmonary driving pressure, mechanical power and mechanical work was the lowest in MV+TTDN100% (p<0.05). Lung injury score and total inflammatory cytokine concentration in lung tissue were the lowest in MV+TTDN100% (p<0.05). Volume-control ventilation plus transvenous diaphragm neurostimulation on every breath improved PaO2/FiO2, A-a gradient and alveolar homogeneity, as well as reduced driving pressure, mechanical power, and mechanical work, and resulted in lower lung injury scores and tissue cytokine concentrations in a preclinical ARDS model.