[Is stairclimbing a maximal exercise test for COPD patients?]

Is the Short and Fast Step Test a safe and feasible tool for exploring anaerobic capacities of individuals with coronary heart disease in clinical practice?

BACKGROUND

While its importance in daily living, the anaerobic metabolism is not taken into account in clinical practice. The lack of validated functional performance tests for patients with chronic disabilities may explain this defect. In this context, the Short and Fast Step Test (SFST) was recently developed and validated in healthy volunteers.

AIM

The purpose of this study was to investigate the safety, feasibility and reliability of the SFST, a functional test exploring anaerobic metabolism in coronary patients during cardiac rehabilitation.

DESIGN

This study was a monocentric prospective study.

SETTINGS

This study took place in the rehabilitation center of the University Hospital Center of Dijon, France.

POPULATION

44 coronary patients, addressed for a first cardiac rehabilitation, were included in this protocol.

METHODS

All participants performed three SFST: T1 and T2 (including respiratory gas exchange) the first day of the program and T3 after 3 to 7 days. SFST consists of walking up and down a 17.5cm-high step as many times as possible in 1 minute. Safety was assessed by the percentage of patients who performed the SFST without reporting a fall, or muscular or cardiovascular events. Feasibility was evaluated by the percentage of patients who succeeded in doing the SFST. Reliability was assessed with the number of raised steps in same condition (T1-T3) and different conditions (T1-T2) using a 2-way intraclass correlation coefficient (ICC). Values were given with their 90% confidence interval [90%CI].

RESULTS

The safety was 95.2% [85.8;99.2] for T1, 88.1% [76.6;95.2] for T2 and 90.4% [79.5;96.7] for T3. 100% [93,1;100] of participants completed T1 and T2, 92.9% [82.6;98] T3. An ICC of 0.74 [0.60;0.84] was observed between T1 and T3 and of 0.87 [0.79;0.92] between T1 and T2.

CONCLUSIONS

This study demonstrates the good safety, feasibility and reliability of the SFST to assess anaerobic metabolism in coronary patients in a rehabilitation program.

CLINICAL REHABILITATION IMPACT

These results show that the SFST seems suitable for the evaluation of brief submaximal functional capacity in daily activities. It offers a real possibility to assess such capacity during the cardiac rehabilitation routine.

Portable Oxygen Therapy: Is the 6-Minute Walking Test Overestimating the Actual Oxygen Needs?

The appropriate titration for the personalized oxygen needs of patients with chronic obstructive pulmonary disease (COPD) and severe hypoxemia is a determining factor in the success of long-term oxygen therapy. There are no standardized procedures to assist in determining the patient’s needs during the physical activities of daily life. Despite that effort tests are a wide broad approach, further research concerning the development of protocols to titrate O₂ therapy is needed. The main objective of this study was to assess whether the level of oxygen titrated through the 6-minute walking test (6MWT) for patients with COPD and exertional hypoxemia is adequate to meet the patients’ demand during their activities of daily living. Physiological and subjective variables were estimated for a study population during two walking tests: a 6MWT and a 20-minute walking circuit (20MWC), designed ad-hoc to reproduce daily physical activities more truthfully. The results indicate that in a significant proportion of patients, the 6MWT might not accurately predict their oxygen needs at a domiciliary environment. Therefore, the titration of the portable O₂ therapy could not be optimal in these cases, with the detrimental impact on the patient’s health (hyperoxia episodes), the autonomy of the oxygen device, and the decrease of time out of the home.

Stair-Climbing Capacity as a Marker of Improvement Following Pulmonary Rehabilitation

PURPOSE

The aim of this study was to explore the potential and safety of a stair-climbing test as a tool to monitor improvement following pulmonary rehabilitation (PR) in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Stair-climbing capacity was assessed in 139 patients with COPD before and after a comprehensive 8-week PR program, which included stair-climbing training. Stair-climbing capacity was assessed as the total number of flights of stairs climbed without stopping. A constant work rate endurance test (CET) was also performed before and after PR. Change in stair-climbing after PR (Δstairs) was compared and correlated to the change in endurance time (ΔCET) and, for 40 patients, to the change in COPD assessment test (ΔCAT) score.

RESULTS

Most patients had moderate to severe COPD (mean forced expiratory volume in 1 second = 54% ± 20% predicted). Stair-climbing capacity, endurance time, and CAT score improved after PR (2.8 ± 1.4 vs 8.3 ± 3.3 flights, 408 ± 272 vs 717 ± 415 seconds, and 20.0 ± 6.4 vs 17.6 ± 6.6 units, respectively; P value for all < .001). Δstairs was moderately correlated to ΔCET (r = 0.49; P < .001) and well correlated to ΔCAT (r = -0.71; P < .001). Patients with greater change in Δstairs had better baseline resting lung function and aerobic capacity. No adverse events were reported during stair-climbing.

CONCLUSION

Stair-climbing is responsive to training in patients with COPD and is correlated to the change in CAT score following PR. Although the test requires further standardization, it could eventually be used as a simple and safe way to assess improvement following interventions in COPD.

Can we use the 6-minute step test instead of the 6-minute walking test? An observational study

OBJECTIVE

To verify whether or not heart rate is maintained below the calculated submaximal level in healthy, sedentary subjects when they perform the 6-minute step test (6MST) and the 6-minute walking test (6MWT), and to compare the maximal heart rate achieved by the subjects at the end of each test.

DESIGN

Observational, cross-sectional study.

SETTING

One tertiary centre.

PARTICIPANTS

Two hundred and fifty-three participants from a pool of 330 healthy and sedentary subjects between 20 and 80 years of age.

INTERVENTIONS

Both the 6MWT and the 6MST were performed in accordance with the American Thoracic Society's statement. Dyspnoea, blood pressure, oxygen saturation and heart rate were measured before and after each test.

RESULTS

Mean heart rate immediately after the 6MST was significantly higher than mean heart rate immediately after the 6MWT {125 [standard deviation (SD) 19] vs 111 (SD 17) beats/minute; mean difference 13 (95% confidence interval of the difference 10 to 16); P<0.001}. Moreover, mean heart rate during (3minutes after commencement) the 6MST [118 (SD 18) beats/minute] was statistically higher than mean heart rate at the end of the 6MWT [111 (SD 18) beats/minute; P<0.001]. None of the subjects achieved the calculated submaximal heart rate.

CONCLUSIONS

The 6MST and 6MWT are safe and produce submaximal effort in healthy participants. However, they are not interchangeable, and the 6MST requires more energy than the 6MWT.