Objectives: Patients suffering from congenital pulmonary or heart lesions often may not follow classical standardized cardiopulmonary exercise test (CPET) on a treadmill or bicycle due to insufficiency or mental or physical disability
Methods: We developed a new CPET for these patients based on a 6MWT allowing individual speed combined with a mobile telemetric spiroergometry. In addition to 6MWT-distance and Borg dyspnea index, oxygen uptake, CO2-production as well as heart frequency, breathing frequency and -minute volume, pulse oxymetry and ECG could be recorded.
Results: In a pilot study we strained 26 healthy volunteers both by regular treadmill CPET (DGPK protocol) and our modified 6MWT in random order on 2 subsequent days. The setup was validated by 28 patients recruited from our outpatient clinic.
Biometrical data (mean±SD). No significant differences
| No | Gender | Age [years] | Height [cm] | Weight [kg] | |
| Volunteers | 26 | 12m 14f | 24.3±4.4 | 175±8 | 70.69±12.1 |
| Patients | 28 | 14m 14f | 23.1±7.4 | 171±12 | 66.5±16.4 |
Test data: (mean±SD)
| VO2/kg/minAT [ml/kg/min] | VO2/kg/minmax [ml/kg/min] | O2/HRAT [ml] |
OUES | HR AT [/min] |
BFAT [/min] |
VEAT [l/min] |
|
| Treadmill | 24.4±7.2 | 41.2±11.1 | 12.1±3.8 | 2.89±0.96 | 137.2±22.0 | 25.3±6.7 | 40.5±15.1 |
| 6MWT | 23.2±6.9 | 32.1±10.3 | 11.3±3.7 | 2.94±1.17 | 141.9±24.6 | 32.0±9.3 | 44.8±16.1 |
| r | 0.67 | 0.74 | 0.74 | 0.81 | 0.52 | 0.53 | 0.54 |
In linear regression analysis, best correlation was found for oxygen uptake efficiency slope (OUES), oxygen uptake (VO2/kg/min) at anaerobic threshold and maximum.
Conclusion: Although our modified 6MWT is a test at submaximal effort at anaerobic threshold, it correlates well to classical treadmill test enabling CPET even in physically or mentally handicapped patients, and may serve as substitute for treadmill test.