Figure 4. Impact of nitrogen excretion and increasing dead space fraction on lung clearance index.

The impact of increasing deadspace on true LCI is shown by the lower curve (grey diamonds). The impact of nitrogen (N₂) excretion on measured LCI is shown by the open circles, using true FRC. Measured LCI using measured FRC is also shown (black circles). The percent error in the measured LCI using measured FRC is shown by the black diamonds (right axis).