Figure 2.
Percentage improvement of resistance, tidal volume and compliance after lungs were crossed over from a nitrogen-oxygen gas mixture (nitrox) to a helium-oxygen gas mixture (heliox) and from heliox to nitrox. A negative percentage improvement indicates a deterioration of lung function, i.e. an increase in resistance is depicted as a negative percentage improvement.
Orsini et al. Critical Care 1999 3:65 doi:10.1186/cc311