Berlin et al. Automated expiratory ventilation assistance through a small endotracheal tube can improve venous return and cardiac output. Intensive Care Med Exp. 2019, 7(1), 6

Prof Heerdt and co-workers showed in a porcine model that EVA ventilation with a Negative End Expiratory Pressure (NEEP; -8 mbar) improved hemodynamics during normovolemia and during hypovolemia after hemorrhage as compared with VCV with PEEP. Before hemorrhage EVA-NEEP  increased stroke volume (+27%; p=0.003) and cardiac output (+21%; p=0.023), and reduced central venous pressure (-30%; p=0.013) compared with Volume Controlled Ventilation with PEEP (4 mbar). After hemorrhage during hypovolemia the effects were more pronounced leading to an 41% increased cardiac output, higher mean arterial pressure and increased venous return for EVA – NEEP ventilation as compared with VCV-ZEEP (0 mbar). For this study a prototypical small automated ventilator based upon the EVA principle was used to generate a controlled period of negative EEP. Commented by: L. Böttinger and J.W.A. van der Hoorn. Negative pressure ventilation – a special application of expiratory ventilation assistance. Intensive Care Med Exp 2019, 7(1), 22