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DOI: 10.1055/s-0039-1679087
Evaluation of a Modified 6-Minute Walk Test with Mobile Spiroergometry
Publication History
Publication Date:
28 January 2019 (online)
Objectives: Cardiopulmonary exercise testing (CPET) is an important tool for evaluation of exercise capacity and clinical significance for resurgery in patients with congenital heart disease.
Classical 6-minute walk test (6mWT) results only in the walking distance but is patient self-controlled for workload intensity. Treadmill-spiroergometry delivers precise parameters such as oxygen-uptake (VO2), oxygen-pulse (O2/HR), and parameters of breathing (i.e., minute volume [MV]). However, patients have to follow a definite protocol rising the workload, but not all of them can physically or mentally follow such a distinct protocol.
The combination of classical 6mWT with a mobile CPET system (JAGER Oxycon mobile) gives additional telemetric information about VO2, O2/HR, MV, SpO2, and 12-channel ECG continuously during the test. In a pilot study, parameters at anaerobic threshold (AT V-slope) were compared of both tests.
Methods: To evaluate the correlation of modified 6mWT with normal treadmill-CPET in a pilot study, we have recruited 26 healthy volunteers (12 males and 14 females), age 18 to 45 years, weight 70.7 ± 12.1 kg, and height 173.5 ± 7.7 cm who walked sequentially by chance either 6mWT or treadmill-CPET (DGPK protocol) on two following visits.
Results: Mean + SD, range at AT.
|
VO2/kg/min (mL/kg/min) |
VO2/HR (mL) |
VE (L/min) |
HR (/min) |
|
|---|---|---|---|---|
|
Treadmill DGPK |
28.4 ± 7.9 (10.3–42.7) |
13.1 ± 4.0 (4.6–21) |
50 ± 21 (16–112) |
153 ± 19 (113–181) |
|
Modified 6mWT |
24.7 ± 6.8 (14.1–35.7) |
11.6 ± 3.9 (6.4–22.4) |
49 ± 16 (28–92) |
150 ± 26 (53–180) |
Discussion and Conclusion: There was a good correlation of r = 0.59 for VO2/kg/min at AT and a linear regression of VO2–6mWT = 12.34 + (0.438 × VO2-treadmill) with a significant difference (p = 0.019, paired t-test); however, there was no significant difference for VO2/HR (0.06), VE (0.05), and HR (0.06).
In spite of the necessity of high motivation of the volunteers and prospectively patients, both tests provided comparable data.
Thus, the modified 6mWT in combination with mobile spiroergometry may provide more safety (online SpO2, 12-channel ECG) for those (handicapped) patients, contributing additional data on VO2/HR and VO2/kg/min for exercise tolerance and hemodynamics prior to resurgery.