Development Technologies for the Monitoring of Six-Minute Walk Test: A Systematic Review

In the pandemic time, the monitoring of the progression of some diseases is affected and rehabilitation is more complicated. Remote monitoring may help solve this problem using mobile devices that embed low-cost sensors, which can help measure different physical parameters. Many tests can be applied remotely, one of which is the six-minute walk test (6MWT). The 6MWT is a sub-maximal exercise test that assesses aerobic capacity and endurance, allowing early detection of emerging medical conditions with changes. This paper presents a systematic review of the use of sensors to measure the different physical parameters during the performance of 6MWT, focusing on various diseases, sensors, and implemented methodologies. It was performed with the PRISMA methodology, where the search was conducted in different databases, including IEEE Xplore, ACM Digital Library, ScienceDirect, and PubMed Central. After filtering the papers related to 6MWT and sensors, we selected 31 papers that were analyzed in more detail. Our analysis discovered that the measurements of 6MWT are primarily performed with inertial and magnetic sensors. Likewise, most research studies related to this test focus on multiple sclerosis and pulmonary diseases.

Six minute walk test in Italian children with cystic fibrosis aged 6 and 11

Six Minute Walk Test (6MWT) is a field exercise test widely used in clinical practice, both in adults and in pediatric patients. The primary aim of the study is to evaluate the physical performance of the subjects and compare them with the predicted Italian values. The secondary aim is to verify the possible relationship between the 6MWT distance (6MWD) and the clinical variables of the sample. Italian children between 6-11 years affected by CF were recruited from 9 regional centres for CF. Short questionnaire assessments about their health state and physical activity routine was administered. Anthropometric characteristics were measured before the test and, peripheral oxygen saturation (SpO2), heart and respiratory rate were measured before and after a 6-minute walk test. The tests were performed according to the American Thoracic Society (ATS) guidelines. 6MWD was compared with the predicted distance calculated by the reference equation for healthy subjects of the same age.A total of 132 children were recruited (70 male) and completed the assessment. The mean (±SD) for 6MWD was 557.4(±69.9), male = 551.4(±80.0), female = 560.4(±63.3), however the predicted distance mean was 605m. A total of 101(76.5%) subjects practice regular physical activity. A total of 31(23%) had a FEV1 lower than their Lower Limits of Normal (LLN). Functional performance on the 6MWT was poorer among the CF patients than among the predicted distance estimated with Italian values. The correlation with the amount of physical activity and 6MWD has been verified.

Changes in physiological variables in patients with diffuse interstitial lung disease in the six-minute walk test

Objective: Diffuse Interstitial Lung Disease (DILD) is a pathology with a high mortality rate in Colombia as well as around the world. Linking patients to pulmonary rehabilitation programs is essential to improve their quality of life and aerobic capacity; thus, all patients perform the six-minute walk test (6-MWT). This study aimed to describe the changes in physiological and aerobic capacity-related variables in patients with DILD in the 6-MWT at admission to a pulmonary rehabilitation program and determine possible differences between patients with idiopathic pulmonary fibrosis (IPF) and other DILDs. Methods: This is a cross-sectional descriptive study on patients with DILD who performed the 6-MWT between January 2017 and February 2019. Sociodemographic, clinical, physiological, and exercise tolerance variables were taken into account at four different times of the 6-MWT: Rest time, the end, and the first and the fifth minute after the end of the test. The Human Ethics Committee endorsed the study, and all participants signed the informed consent form. Results: There were 64 patients with DILD. The average age was 60.84 years, 53.1% were female, 73.4% required home oxygen, and 53.1% had a diagnosis of IPF. There were no statistically significant differences in the heart rate (HR), respiratory rate (RR), peripheral oxygen saturation (SpO2), Borg scale, and fatigue in lower limbs at the four evaluated moments of the test for both groups of patients with DILD (p=0.000); moreover, the FEV1/FVC ratio for patients with other DILD was higher (p=0.000). The distance traveled for IPF was 339.26±124.84, while for other DILDs, it was 365.63±113.00 (p=0.382). Conclusions: Patients with other DILDs have better FEV1/FVC and travel longer distances with less dyspnea and fatigue than patients with IPF during the 6-MWT. Both groups' HR, RR, SpO2, Borg, and fatigue variables presented significant changes during the 6-MWT.

6 Minute Walk Test (6-MWT) as a Tool for Predicting Post Operative Pulmonary Complications in Abdominal Surgeries

Background: Post operative pulmonary complications (PPC) contribute to increased morbidity and mortality. Thus pre operative assessment is required. Six minute walk test (6-MWT) is a simple and reliable test which is recently being included in pre operative evaluation. Objectives: The objective of this study is to determine the value of the six minute walk test as a reliable tool in detecting post operative pulmonary complications in patients undergoing abdominal surgery. Materials and Methods: It is a prospective observational study conducted in a tertiary care centre for a period of 3 months. 66 patients in the age group of 40-60 years undergoing elective abdominal surgery under general anaesthesia were included in this study based on universal sampling method. Patients with recent coronary syndrome, uncontrolled hypertension, cardiac diseases, pregnancy and conditions which impair walking (eg. Arthiritis) were excluded from the study. 6 minute walk test was performed before the surgery. The procedure was explained to the patients and consent was obtained. The test was conducted on a flat surface of 20m near our pre anaesthetic clinic and the patient was asked to walk for a period of 6 minutes in their own comfortable pace. The distance covered by the patients in the 6 minutes was noted. Vitals such a SpO2, heart rate, systolic and diastolic blood pressures were recorded before and after the test. The patients were followed up for the development of pulmonary complications in the post operative period. Results: Out of the 66 patients included in the study, 35 patients did not develop PPC (Group 1) and 31 patients developed PPC (Group2) including one death due to respiratory failure. The six minute walk distance in the PPC group was significantly less (p=0.0001) when compared to that of the non PPC group. Patients in the PPC group also required prolonged hospital stay. Pneumonia was the most commonly developed post operative pulmonary complication. Conclusion: Six minute walk test is a useful tool in predicting post operative pulmonary complication in patients undergoing abdominal surgery.

Phenotyping Adopters of Mobile Applications Among Patients With COPD: A Cross-Sectional Study

Effectiveness of technology-based interventions to improve physical activity (PA) in people with COPD is controversial. Mixed results may be due to participants' characteristics influencing their use of and engagement with mobile health apps. This study compared demographic, clinical, physical and PA characteristics of patients with COPD using and not using mobile apps in daily life. Patients with COPD who used smartphones were asked about their sociodemographic and clinic characteristics, PA habits and use of mobile apps (general and PA-related). Participants performed a six-minute walk test (6MWT), gait speed test and wore an accelerometer for 7 days. Data were compared between participants using (App Users) and not using (Non-App Users) mobile apps. A sub-analysis was conducted comparing characteristics of PA–App Users and Non-Users. 59 participants were enrolled (73% Male; 66.3 ± 8.3 yrs; FEV1 48.7 ± 18.4% predicted): 59% were App Users and 25% were PA-App Users. Significant differences between App Users and Non-App Users were found for age (64.2 ± 8.9 vs. 69.2 ± 6.3yrs), 6MWT (462.9 ± 91.7 vs. 414.9 ± 82.3 m), Gait Speed (Median 1.5 [Q1–Q3: 1.4–1.8] vs. 2.0 [1.0–1.5]m/s), Time in Vigorous PA (0.6 [0.2–2.8] vs. 0.14 [0.1–0.7]min) and Self-Reported PA (4.0 [1.0–4.0] vs. 1.0 [0.0–4.0] Points). Differences between PA–App Users and Non-Users were found in time in sedentary behavior (764.1 [641.8–819.8] vs. 672.2 [581.2–749.4] min) and self-reported PA (4.0 [2.0–6.0] vs. 2.0 [0.0–4.0] points). People with COPD using mobile apps were younger and had higher physical capacity than their peers not using mobile apps. PA-App Users spent more time in sedentary behaviors than Non-Users although self-reporting more time in PA.

Heart rate and oxygen uptake kinetics obtained from continuous measurements with wearable devices during outdoor walks of patients with COPD: Validation study (Preprint)

BACKGROUND Continuous physiological measurements during a laboratory-based exercise test can provide physiological biomarkers, such as heart rate (HR) and oxygen uptake (V̇O2) kinetics, that carry clinically relevant information. In contrast, it is not yet clear how continuous data generated during daily life routines by wearable devices could provide meaningful biomarkers that, in turn, could improve telemonitoring applications. OBJECTIVE To determine whether valid HR and V̇O2 kinetics can be obtained from measurements with wearable devices during outdoor walks in patients with chronic obstructive pulmonary disease (COPD). As a secondary objective, we aimed to determine whether the amount of valid kinetics and kinetic model performance was comparable between outdoor walks and a conventional, laboratory-based exercise test. METHODS Eight patients with COPD measured HR (Polar Belt) and V̇O2 (METAMAX 3B) during three outdoor walks of different intensities and a six-minute walk test. For every patient and walk/test, HR and V̇O2 data were extracted after the following physical activity transitions: (i) starting a walk/test, (ii) finishing a walk/test and (iii) walking upstairs. An additional, averaged HR and V̇O2 response during outdoor walks was generated for each type of transition of every patient. Kinetic models were used to describe every separate and averaged HR and V̇O2 response when participants started a walk, finished a walk and walked upstairs. HR and V̇O2 kinetics were considered valid if the response magnitude and model fit were adequate, and model parameters were reliable. Kinetic model performance was assessed by model fit and standard errors of the parameter estimates. RESULTS Most HR kinetics were valid when starting (range 75% to 100% for separate walks; 100% for the averaged response) or finishing (range 63% to 88% for separate walks; 100% for the averaged response) an outdoor walk, but not when walking upstairs (≤29%). Many V̇O2 kinetics were valid when finishing (range 63% to 100% for separate walks; 100% for the averaged response), but not when starting an outdoor walk (range 38% to 50% for separate walks; 88% for the averaged response) or when walking upstairs (0%). The amount of valid kinetics, and kinetic model performance (P>.05), when starting/finishing an outdoor walk was comparable to starting (HR: 100%; V̇O2: 50%) or finishing (HR: 88%; V̇O2: 75%) a laboratory-based six-minute walk test. CONCLUSIONS Continuous measurements with wearable devices can provide valid HR kinetics when starting or finishing, and valid V̇O2 kinetics when finishing, an outdoor walk in patients with COPD. The amount of valid kinetics and kinetic model performance was comparable between outdoor walks and a conventional, laboratory-based exercise test. We envision that telemonitoring applications for patients with COPD could be improved by incorporating regular assessments of HR (and possibly V̇O2) kinetics, as obtained from continuous measurements with wearable devices during outdoor walks.

APLICABILIDADE DO TESTE DE CAMINHADA DE SEIS MINUTOS PARA QUANTIFICAR O DESEMPENHO CARDIOVASCULAR DO PACIENTE PÓS-INFARTO DO MIOCÁRDIO

O teste de caminhada de seis minutos (TC6) foi usado como ferramenta para quantificar as alterações geradas pela reabilitação. O objetivo desta pesquisa foi estimar as respostas cardíacas após infarto do miocárdio e os benefícios da reabilitação. Utilizou-se um circuito oval, onde foram realizados três testes em dias alternados, foi estabelecida a média dos testes, em que a pressão arterial, frequência cardíaca, frequência respiratória, saturação de oxigênio, escala subjetiva de Borg e a metragem durante a distância percorrida foram verificados. Foram avaliados três participantes com, aproximadamente, 69,3±4,93 anos. O teste ocorreu em duas etapas, a primeira foi a avaliação e, a seguir, a aplicação do protocolo com cargas variando de 40 a 50% da frequência cardíaca (FC) submáxima por idade e, na segunda, ocorreu a repetição do protocolo de avaliação. Os sinais vitais apresentaram alterações fisiologicamente esperadas, a pressão arterial sistólica (PAS) evoluiu 4,54%, a pressão arterial diastólica (PAD)14,28%, após o repouso, a PAS diminuiu para -0,8%, enquanto a PAD sofreu alterações importantes. A FC teve um percentual de evolução de 19,44%, diminuindo para -3,12%. A saturação de oxigênio teve aumento máximo de 2% e -1% de declínio, a maior metragem foi de 515,11 metros e a menor 235,5 metros. O TC6 é um teste confiável para estimar o desempenho cardiovascular de indivíduos após infarto do miocárdio. APPLICABILITY OF THE SIX-MINUTE WALK TEST TO QUANTIFY THE CARDIOVASCULAR PERFORMANCE OF PATIENTS AFTER MYOCARDIAL INFARCTION ABSTRACT The six-minute walk test (6MWT) was used as a tool to quantify the changes generated by rehabilitation. The purpose of this research was to estimate the cardiac responses after myocardial infarction and the benefits of rehabilitation. An oval circuit was used, where three tests were performed on alternate days, the average of the tests was established, in which blood pressure, heart rate, respiratory rate, oxygen saturation, Borg's subjective scale, and the footage over the distance traveled were checked. Three participants with approximately 69.3±4.93 years old were evaluated. The test occurred in two stages, the first was the evaluation and then the application of the protocol with loads varying from 40 to 50% of submaximal heart rate (HR) by age and, in the second, there was the repetition of the evaluation protocol. The vital signs showed physiologically expected changes, the systolic blood pressure (SBP) evolved 4.54%, the diastolic blood pressure (DBP)14.28%, after resting, the SBP decreased to -0.8%, while the DBP suffered important changes. The HR had a percentage of evolution of 19.44%, decreasing to -3.12%. The oxygen saturation had a maximum increase of 2% and -1% decline, the longest distance was 515.11 meters and the shortest 235.5 meters. The 6MWT is a reliable test to estimate the cardiovascular performance of individuals after myocardial infarction. Keywords: Six-minute Walk Test, Elder, Myocardial Infarction.