Why is "selection of mode" important during initiation and throughout the course of the mechanical ventilator?

Use the values of the oxygen partial pressure on both sides of the resistance membrane(Po2 = 100, Pco2 = 40.) to find the value of the diffusing capacity (DL). (Use cm3 oxygen, mmHg, min units)

During maximal aerobic exercise, exercise-induced arterial hypoxemia may result in elite endurance athletes due to which of the following?     reduced venous return leads to decreased pulmonary capillary flow rate     transit time through the pulmonary capillaries is much shorter     oxygen diffusion capacity is no longer calculated using capillary mean PO2     lower venous O2 content increases the PO2 gradient

Explain how the pressure flow mechanism works and describe what it is used for