Specific slow tests are not mandatory in patients with extremely short standard (3.2km/hr 10% slope) test durations during exercise oximetry.

Abstract

To compare the transcutaneous oxygen pressure results observed in patients with severe walking limitation during standard procedures (3.2km/hr, 10% slope) versus during a test performed at a low speed (2km/hr, 10% slope). In 31 patients, the decrease from rest of oxygen pressure (DROP) index was measured on both buttocks, both thighs and both calves during two consecutive tests on treadmill. The maximal walking time (MWT) and the minimal DROP values (DROPmin ) observed during the 2 tests were compared with t test. Correlation of DROPmin values during the slow and standard procedure was performed with linear regression. The -15mmHg cut-off value defined for standard test interpretation was used arbitrarily for the interpretation of slow test results. MWT was 80±52s versus 376±269s at standard and slow speed, respectively (p<.001). No difference on all recorded DROPmin values at a standard (-9.5±6.9mmHg) and slow (-10.5±7.9mmHg) speed was found; n=186, p=.168. Coefficient of correlation between DROPmin s found at the two tests was r=0.820 (p<.01), with regression line close to the line of identity. With the identical -15mmHg cut-off, 166 (89.2%) of 186 the results were classified similarly after standard and slow procedures. Specific slow treadmill procedures are not mandatory in patients with extremely short test durations when performing standard (3.2km/hr 10% slope) exercise oximetry. In patients expected to be unable to walk at standard speed, the -15mmHg normal limit seems to be valid for the interpretation of tests with a slow procedure (2.0km/hr).