Fig. 2. Simulated airway Pco2, Paco2, mixed venous Pco2, arterial Pco2, and airway and pulmonary capillary carbon dioxide flux for the 10th rebreathing cycle for simulated cardiac outputs of 4 l/min. Rebreathing time: 50 s; rebreathing dead space: 150 ml. Dashed line = airway Pco2; thickest line = Paco2; thin line = arterial Pco2; thick line = venous Pco2; line with open square = airway carbon dioxide flux; line with open circle = pulmonary carbon dioxide flux.