Negative-pressure-assisted ventilation lowers driving pressure and mechanical power in an ARDS model

Increased lung heterogeneity from regional alveolar collapse drives ventilator-induced lung injury in patients with acute respiratory distress syndrome (ARDS). New methods of preventing this injury require study. Our study objective was to determine whether the combination of temporary transvenous diaphragm neurostimulation (TTDN) 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 h postinjury using volume-control mode at 8 mL/kg, positive end-expiratory pressure (PEEP) 5 cmH(2)O, with respiratory rate and FIO2 set to achieve normal arterial blood gases. Two groups received TTDN, either every second breath [mechanical ventilation (MV) thorn TTDN50%, n = 6] or every breath (MV thorn 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 (A-a) gradient was lowest for MV thorn TTDN100% (P < 0.05). MV thorn 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, postinjury, and study-end in MV thorn TTDN100% ( P < 0.05). The total exposure to transpulmonary driving pressure, mechanical power, and mechanical work was the lowest in MV thorn TTDN100% (P < 0.05). Lung injury score and total inflammatory cytokine concentration in lung tissue were the lowest in MV thorn TTDN100% (P < 0.05). Volume-control ventilation plus transvenous diaphragm neurostimulation on every breath improved Pa-O2/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. NEW & NOTEWORTHY Combining temporary transvenous diaphragm neurostimulation with volume-control ventilation on every breath, called negative-pressure-assisted ventilation, improved gas exchange and alveolar homogeneity in a preclinical model of moderate ARDS. Transpulmonary driving pressure, mechanical power, and mechanical work reductions were observed and resulted in lower lung injury scores and tissue cytokine concentrations in the every-breath-neurostimulation group compared with volume-control ventilation only. Negative-pressure-assisted ventilation is an exciting new potential tool to reduce ventilator-induced lung injury in patients with ARDS.