Figure 1.

Desaturation distance ratio.

Notes: First, the desaturation area was calculated as the total area above the curve created using SpO₂ values observed at each minute during the 6MWT, thereby summing up the difference between SpO₂ of 100% and the patient’s SpO₂ at each minute. Next, the DDR was obtained using the ratio of the desaturation area to the 6MWD.

Abbreviations: 6MWD, 6-minute walk distance; 6MWT, 6-minute walk test; DA, desaturation area; DDR, desaturation distance ratio; SpO₂, peripheral oxygen saturation.