Ventilation–perfusion effects of negative-pressure ventilation: insights from an experimental rat model

The results indicate that compared with PPV, NPV enhances gas exchange and ventilation-perfusion matching in healthy lungs. Although NPV causes fewer ventilation-perfusion inequalities and reduced dead space ventilation, its efficacy may be limited by increased intrapulmonary shunting during excessive negative end-expiratory pressure levels. These results provide mechanistic support for the physiological benefits of subatmospheric ventilation and may provide a basis for further studies on the refinement of noninvasive and lung-protective ventilation strategies in clinical settings with impaired ventilation-perfusion matching, such as acute respiratory failure, postoperative care, and ventilator weaning.