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

Abstract

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.

Patient-centered Outcomes Research in Interstitial Lung Disease: An Official American Thoracic Society Research Statement

“…Drawbacks of laboratory-based tests include the requirement for patient travel, the need for specialized equipment and environments, and/or the need for highly trained personnel. There is also some debate as to whether or not the current standard walk test (6-min-walk test) is a true test of endurance in ILD (103)(104)(105). In addition, most laboratory-based tests measure functional capacity, not functional performance, often making it difficult to translate results to day-to-day living.…”

Telemonitoring of daily activities compared to the six-minute walk test further completes the puzzle of oximetry-guided interventions

“…There are studies simulating PADL in laboratory tests designed to measure oxygen desaturation 32 – 34 . For example, a recent publication comparing the 6MWT with a 20-min walking circuit 35 found that the 6MWT detected higher nadir SpO 2 and lower peak HR, but there were no results comparing activity intensity as energy expenditure between tests 35 . With SMARTREAB telemonitoring, our study further contributes with the findings that lower nadir SpO 2 and higher peak HR are detected in more intensive PADL compared to the 6MWT, such as walking, walking while carrying a weight, climbing stairs and doing household chores.…”

State of the art review on portable oxygen concentrator

“…All the subjects answered a questionnaire at the end of the trial process assessing various features of oxygen therapeutic instruments. A portable prototype of oxygen concentration converter (PVSA) was introduced in order to simplify oxygen generation processes by adopting a deep evacuation phase in place of desorption by purge[27]. This study Journal of Thermal and Fluid Science www.rame.org.in includes experimental pulse volume, width and time delay measurements of the POC under three distinct conditions and two rest and activity related breathing rates [28].…”