FIGURE 6

The corresponding VE/VCO2 relationships related to figure 5. Note the depressed VE/VCO2 profile consequent to the progressive PaCO2 increase (circles, dashed curve), compared with that obtaining with arterial CO2 tension (PaCO2) constrained not to increase (squares, solid curve). As a result, VE/VCO2min was decreased in the former condition.