Set-up. This figure depicts the experimental model of the isolated buffer-perfused lung. The lungs are mounted in a water-heated glass-chamber ("artificial thorax") that allows for negative pressure ventilation. The negative pressure inside the chamber is measured by a transducer (Paw) and used to calculate the dynamic lung compliance. The tidal volume is calculated by integration of the flow signal of the pneumotachograph (P). The buffer solution is stored in the reservoir and equilibrated with a gas mixture that contained carbon dioxide (5%) and oxygen (6%). The solution is pumped by a roller pump and the flow is pressure-controlled regulated by a software program. The pressure transducers (arterial Pa, venous Pv) are adjusted to the height of the hilum.