6-minute walk testing is more sensitive than maximal incremental cycle testing for detecting oxygen desaturation in patients with COPD

Defining the role of exertional hypoxemia and pulmonary vasoconstriction on lung function decline, morbidity, and mortality in patients with chronic obstructive lung disease - the PROSA study: rationale and study design

BACKGROUND

Chronic obstructive lung disease (COPD) has diverse molecular pathomechanisms and clinical courses which, however, are not fully mirrored by current therapy. Intermittent hypoxemia is a driver of lung function decline and poor outcome, e.g., in patients with concomitant obstructive sleep apnea. Transient hypoxemia during physical exercise has been suggested to act in a similar manner. The PROSA study is designed to prospectively assess whether the clinical course of COPD patients with or without exertional desaturation differs, and to address potential pathophysiological mechanisms and biomarkers.

METHODS

148 COPD patients (GOLD stage 2-3, groups B or C) will undergo exercise testing with continuous pulse oximetry. They will be followed for 36 months by spirometry, echocardiography, endothelial function testing, and biomarker analyses. Exercise testing will be performed by comparing the 6-min walk test (6MWT), bicycle ergometry, and a 15-sec breath-hold test. Exertional desaturation will be defined as SpO2 < 90% or delta-SpO2 ≥ 4% during the 6MWT. The primary endpoint will be the rate of decline of FEV1(LLN) between COPD patients with and without exertional desaturation.

DISCUSSION

The PROSA Study is an investigator-initiated prospective study that was designed to prove or dismiss the hypothesis that COPD patients with exertional desaturation have a significantly more rapid rate of decline of lung function as compared to non-desaturators. A 20% difference in the primary endpoint was considered clinically significant; it can be detected with a power of 90%. If the primary endpoint will be met, exercise testing with continuous pulse oximetry can be used as a ubiquitously available, easy screening tool to prospectively assess the risk of rapid lung function decline in COPD patients at an early disease stage. This will allow to introduce personalized, risk-adapted therapy to improve COPD outcome in the long run. PROSA is exclusively funded by public funds provided by the European Research Council through an ERC Advanced Grant. Patient recruitment is ongoing; the PROSA results are expected to be available in 2028.

TRIAL REGISTRATION

The PROSA Study has been prospectively registered at clinicaltrials.gov (register no. NCT06265623, dated 09.02.2024).

One-minute sit-to-stand test in patients with pulmonary arterial hypertension associated with congenital heart disease: A single-center prospective study

BACKGROUND

Patients with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD) have reduced exercise capacity. Recently, the 1-minute sit-to-stand test (1MSTST), which measures the number of repetitions from sitting to standing position in 1 minute, has been proposed as an alternative test to the 6-minute walking test (6MWT). The aim of our study was to assess the safety and results of the 1MSTST in comparison to the 6MWT in patients with PAH-CHD.

METHODS

Consecutive adult patients with PAH-CHD underwent the 6MWT and the 1MSTST on the same day. The 6-minute walking distance in meters and the number of repetitions on the 1MSTST were measured. Heart rate, peripheral oxygen saturations, Borg dyspnea score, and lower limb fatigue were recorded before and immediately after testing. Correlations between both tests and clinical, laboratory, and imaging parameters were statistically analyzed.

RESULTS

The study included 40 patients (50% female, mean age 43 ± 15 years), of whom 29 (72%) had Eisenmenger syndrome and 14 (35%) had Down syndrome. The number of 1MSTST repetitions correlated significantly with 6MWT distance (r = 0.807, p = 0.000). There were no adverse events, and the 1MSTST results correlated with the WHO functional class. Heart rate increase and oxygen desaturation after both tests correlated significantly, but less desaturation was observed after 1MSTST.

CONCLUSIONS

Our study showed that the 1MSTST is a safe and easily applicable test in adult patients with PAH-CHD, including patients with Down syndrome. The results of the 1MSTST correlate significantly with the 6MWT, providing an alternative tool for exercise capacity assessment in patients with PAH-CHD.

Effects of cardiorespiratory rehabilitation program on submaximal exercise in patients with long-COVID-19 conditions: a systematic review of randomized controlled trials and recommendations for future studies

INTRODUCTION

Long-COVID-19 patients (LC19Ps) often experience cardiovascular and respiratory complications. Cardiorespiratory rehabilitation programs (CRRPs) have emerged as promising interventions to enhance exercise capacity in this population. This systematic review aimed to assess the impact of CRRPs on submaximal exercise performance, specifically the 6-minute walk test (6MWT) outcomes, in LC19Ps through an analysis of available randomized controlled trials (RCTs).

METHODS

A systematic search was conducted in PubMed/Medline and Scopus to identify relevant RCTs. Six RCTs meeting inclusion criteria were included in this review, investigating the effects of CRRPs on 6MWT outcomes in LC19Ps.

RESULTS

The findings from the included RCTs provide compelling evidence supporting the effectiveness of CRRPs in improving submaximal exercise performance in LC19Ps. These results underscore the potential of CRRPs to enhance submaximal exercise capacity and overall functional well-being in this population. However, future research is imperative to determine optimal CRRPs, including duration, intensity, and specific intervention components. Additionally, the long-term sustainability and durability of CRRP-induced improvements warrant further exploration. Future studies should prioritize patient-centric outcomes and address potential implementation barriers.

CONCLUSION

CRRPs show promise in ameliorating submaximal exercise performance among LC19Ps. Further research is needed to refine these programs and ensure their lasting impact on this patient group.

SYSTEMATIC REVIEW REGISTRATION

https://doi.org/10.17605/OSF.IO/HMN38. [Figure: see text].

The six-minute walk test - a reliable test for detection of exercise-related desaturation in patients with chronic obstructive pulmonary disease

INTRODUCTION

Exercise-induced desaturation is common in patients with moderate to severe chronic obstructive pulmonary disease (COPD). It provides additional information about physical capacity and disease evolution, and it is an important predictor of mortality.

A Multiaxial Rehabilitation Programme for Workers with COVID-19 Sequelae Using a Conventional and Technological-Robotic Approach: The Proposal of INAIL and Fondazione Don Carlo Gnocchi

The COVID-19 sequelae have been shown to affect respiratory and cardiological functions as well as neuro-psychological functions, and, in some cases, metabolic/nutritional aspects. The Italian National Institute for Insurance against Accidents at Work (Istituto Nazionale Assicurazione Infortuni sul Lavoro, INAIL) recorded that, until December 2022, 315,055 workers were affected by COVID-19; therefore, there is a need to identify an effective approach to treat such patients. Robotic and technological devices could be integrated into the rehabilitation programme of people with long COVID conditions. A review of the literature showed that telerehabilitation may improve functional capacity, dyspnoea, performance, and quality of life in these patients, but no studies were found evaluating the effects of robot-mediated therapy or virtual reality systems. Considering the above, Fondazione Don Carlo Gnocchi and INAIL propose a multi-axial rehabilitation for workers with COVID-19 sequelae. To accomplish this goal, the two institutions merged the epidemiological information gathered by INAIL, the expertise in robotic and technological rehabilitation of Fondazione Don Carlo Gnocchi, and the literature review. Our proposal aims to facilitate a multi-axial rehabilitation approach customized to meet the unique needs of each individual, with a particular emphasis on utilizing advanced technologies to address the current and future challenges of patient care.

Early Desaturation During 6-Minute Walk Test is a Predictor of Mortality in COPD

BACKGROUND

Oxygen desaturation during exercise is mainly observed in severe cases of chronic obstructive pulmonary disease (COPD) and is associated with a worse prognosis, but little is known about the type of desaturation that causes the greatest risk of mortality.

MATERIAL AND METHODS

We studied all of the 6-min walk tests performed periodically at a tertiary hospital over a period of 12 years in patients with moderate or severe COPD. We classified patients as non-desaturators if they did not suffer a drop in oxygen saturation (SpO2 < 88%) during the test, early desaturators if the time until desaturation was < 1 min, and non-early desaturators if it was longer than 1 min. The average length of follow-up per patient was 5.6 years.

RESULTS

Of the 319 patients analyzed, 126 non-desaturators, 91 non-early desaturators and 102 early desaturators were identified. The mortality analysis showed that early desaturators had a mortality of 73%, while it was 38% for non-early desaturators and 28% for non-desaturators, with a survival of 5.9 years compared to 7.5 years and 9.6 years, respectively (hazard ratio of 3.50; 95% CI 2.3-5.3; p < 0.0001).

CONCLUSIONS

The early desaturation seen in patients with chronic obstructive pulmonary disease is associated with greater mortality and is likely responsible for the poor prognosis shown globally in patients who desaturate. The survival of patients with early desaturation is almost 4 years less with respect to non-desaturators, and they, thus, require closer observation.

Nutritional status of patients with COVID-19 one year post-ICU stay: a prospective observational study

Objective

Patients discharged from the Intensive Care Unit (ICU) often suffer from physical complaints and poor nutritional intake, which negatively affect nutritional status (NS). Our aim was to describe NS of patients with COVID-19 one year post-ICU stay.

Research Methods & Procedures

Observational study of adult patients with COVID-19 one year post-ICU. NS assessment (nutrient balance, body composition and physical status) was performed. Nutritional intake and nutrition-related complaints were examined. Nutritional requirements were determined with indirect calorimetry and body composition with bio-electrical impedance. Fat-free mass index (FFMI) and fat mass index (FMI) were calculated. Physical status was determined with handgrip strength (HGS), 6-minute walk test, and 1-minute sit to stand test (1MSTST). Descriptive statistics and paired sample t-tests were used for analysis.

Results

We included 48 patients (73% male; median age 60 years [IQR 52;65]). Median weight loss during ICU stay was 13%. One year post-ICU 12% weight was regained. Median BMI was 26 kg/m² and 23% was obese (BMI>30 kg/m² and high FMI). Of the patients, 50% had high FMI and 19% had low FFMI. Median reported nutritional intake was 90% of measured resting energy expenditure. Nutrition-related complaints were seen in 16%. Percentages of normal values reached in physical tests were 92% of HGS, 95% of 6 minute walking distance and 79% of 1MSTST.

Conclusion(s)

Despite almost fully regained weight and good physical recovery in adult patients one year post-ICU stay, NS remained impaired due to elevated FMI, even though reported nutritional intake was below the estimated requirements.

Inspiratory muscle strength and function in mechanically ventilated COVID-19 survivors 3 and 6 months after intensive care unit discharge

Background

Knowledge regarding the long-term impact of invasive mechanical ventilation on the inspiratory muscles and functional outcomes in COVID-19 survivors is limited.

Methods

In this single-centre prospective cohort study, we evaluated invasively ventilated patients with COVID-19 pneumonia 3 and 6 months post-intensive care unit (ICU) discharge. Outcomes included: maximal inspiratory pressure (MIP), ultrasound parameters for diaphragm function, 6-min walk distance (6MWD), dyspnoea and quality of life. We evaluated associations between MIP and duration of mechanical ventilation with follow-up outcomes.

Results

50 COVID-19 survivors discharged from ICU between 15 October 2020 and 1 April 2021 were enrolled. Overall, survivors showed a recovery trajectory over time. However, impaired MIP remained in 24 (48%) and 12 (24%) at 3 and 6 months, respectively. Diaphragm dysfunction was not observed. At 3 months, 23 (46%) had impaired functional capacity versus 10 (20%) at 6 months. Dyspnoea persisted in 44 (88%) patients at 3 months and 38 (76%) at 6 months. Quality of life was slightly decreased at 3 months with further improvements at 6 months. MIP was correlated to 6MWD, 6MWD % predicted, dyspnoea across follow-up, and quality of life at 3 months. The duration of invasive ventilation was correlated with 6MWD and 6MWD % predicted.

Conclusion

In invasively ventilated COVID-19 survivors, inspiratory muscle strength impairments persisted 6 months after ICU discharge, while maintaining normal diaphragm function. Decreased functional capacity, dyspnoea and slightly reduced health status were observed. Early screening of survivors is of utmost importance to identify those with impairments and at risk of delayed or incomplete recovery.

Prediction of exercise-induced desaturation in COPD patients without resting hypoxemia: a retrospective study

Background

There is no universally accepted criterion for assessing exercise-induced desaturation (EID). The purpose of this study is to compare the two methods regularly used for determining EID in COPD patients, as well as to explore the risk factors and predictors related to EID.

Methods

The 6MWT was performed with continuous SpO₂ monitoring on patients with stable COPD. Using two methods (method A: “SpO_2rest–SpO_2min ≥ 4% and/or SpO_2min < 90%”, method B: “SpO_2rest–SpO_2end ≥ 4% and/or SpO_2end < 90%”) as EID determination criteria to assess the incidence of EID. The differences and consistency of the two methods are compared. Moreover, we collected data through the pulmonary function test, mMRC dyspnea score, COPD assessment test, BODE index and CT-defined emphysema. Univariate and multivariate logistic regression analyses were used to identify factors affecting the EID. For the parameters that predict EID in 6MWT, a receiver operating characteristic (ROC) curve analysis was employed.

Results

The analysis included 124 patients. The overall incidence of EID was 62.1% by using method A as the criterion and 51.6% by method B. All of the EID patients found by method B were included in the EID patients identified by method A, as well as 13 new-EID patients. The difference in diagnostic outcomes between the two approaches was not statistically significant (P > 0.05), but they were in excellent agreement (Kappa = 0.807, P = 0.001). Logistic regression analyses found that D_LCO SB% pred, D_LCO/VA% pred, CAT score, mean density, PD15, emphysema volume and %LAA were significant determinants of the EID. For predicting EID, the ROC analysis produced AUC and cutoffs of 0.689 and 50.45% (D_LCO SB% pred), 0.707 and 75.0% (D_LCO/VA% pred), 0.727 and 15 points (CAT score), 0.691 and − 955.00HU (PD15), 0.671 and − 856.46HU (mean density), 0.668 and 338.14 ml (emphysema volume) and 0.656 and 7.63% (%LAA), respectively.

Conclusions

Two methods evaluating EID in this research are in a good agreement, method A can find more EID patients by focusing on SpO_2min. When conditions are constrained, it is also sufficient to assess EID in COPD patients by method B. In terms of the predictors of EID, D_LCO SB% pred, D_LCO/VA% pred, CAT score and CT-defined emphysema are all statistically significant test variables to determine EID.

Effect of pulmonary rehabilitation on heart rate recovery in adult individuals with asthma or chronic obstructive pulmonary disease

Introduction: Heart rate recovery (HRR) after exercise is a marker of disease severity and prognosis in cardiovascular and respiratory disorders. More than 30% of adult individuals with asthma may show a slow HRR. Pulmonary rehabilitation improves exercise capacity in individuals with asthma or chronic obstructive pulmonary disease (COPD).

Aim: The study aimed to evaluate the effect of pulmonary rehabilitation on HRR in individuals with asthma as compared to those with COPD.

Methods: Retrospective analysis of HRR one minute after the six-minute walking test (6MWT) was performed before and after an exercise training program. The COPD Assessment Test (CAT), Barthel Index-Dyspnea (BI-D), Medical Research Council (MRC) score for dyspnea, and the Five-Times-Sit-to-Stand test (5STS) were also assessed as secondary outcome measures.

Results: Slow HRR prevalence was significantly lower in individuals with asthma than with COPD (29.1 vs. 46.7%, respectively: p = 0.003). Post-program HRR did not change in more than 70% of individuals in either population and improved in 16% of both populations, whereas it actually worsened in 12 and 10% of individuals with asthma and COPD, respectively. The outcome measures significantly improved in both populations, irrespective of baseline HRR.

Conclusion: In individuals with asthma or COPD, exercise training does not significantly improve HRR.

Physical recovery across care pathways up to 12 months after hospitalization for COVID-19: A multicenter prospective cohort study (CO-FLOW)

Backgroud

The sudden COVID-19 pandemic forced quick development of care pathways for patients with different needs. Trajectories of physical recovery in hospitalized patients for COVID-19 following different care pathways are unknown. We aimed to assess trajectories of physical recovery and levels of physical function reached within the different care pathways. Additionally, we assessed differences in physical function across care pathways at follow-up visits.

Methods

This multicenter prospective cohort study of adults who had been hospitalized for COVID-19 was performed in 10 centers, including 7 hospitals (1 academic and 6 regional hospitals) and 3 rehabilitation centers (1 medical rehabilitation center and 2 skilled nursing facilities), located in the Netherlands. Study visits were performed at 3, 6, and 12 months post-hospital discharge and included assessment of cardiorespiratory fitness (6 min walk test [6MWT], 1 min sit-to-stand test [1MSTST]), muscle strength (maximum handgrip strength [HGS]) and mobility (de Morton Mobility Index [DEMMI]).

Findings

We report findings for 582 patients who had been discharged from hospital between March 24, 2020 and June 17, 2021. Patients had a median age of 60·0 years, 68·9% (401/582) were male, 94·6% (561/582) had received oxygen therapy, and 35·2% (205/582) mechanical ventilation. We followed patients across four different rehabilitation settings: no rehabilitation (No-rehab, 19·6% [114/582]), community-based rehabilitation (Com-rehab, 54·1% [315/582]), medical rehabilitation (Med-rehab, 13·7% [80/582]), and rehabilitation in a skilled nursing facility (SNF-rehab, 12·5% [73/582]). Overall, outcomes in 6MWT (14·9 meters [95% CI 7·4 to 22·4]), 1MSTST (2·2 repetitions [1·5 to 2·8]), and HGS (3·5 kg [2·9 to 4·0]) improved significantly (p<0·001) from 3 to 6 months and only HGS from 6 to 12 months (2·5 kg [1·8 to 3·1]; p<0·001). DEMMI scores did not significantly improve over time. At 3 months, percentage of normative values reached in 1MSTST differed significantly (p<0.001) across care pathways, with largest impairments in Med- and SNF-rehab groups. At 12 months these differences were no longer significant, reaching, overall, 90·5% on 6MWD, 75·4% on 1MSTST, and 106·9% on HGS.

Interpretation

Overall, physical function improved after hospitalization for COVID-19, with largest improvement within 6 months post-discharge. Patients with rehabilitation after hospital discharge improved in more than one component of physical function, whereas patients without rehabilitation improved solely in muscle strength. Patients who received rehabilitation, and particularly patients with Med- and SNF-rehab, had more severe impairment in physical function at 3 months, but reached equal levels at 12 months compared to patients without follow-up treatment. Our findings indicate the importance of rehabilitation.

Funding

ZonMw, Rijndam Rehabilitation, Laurens (The Netherlands).

Swetha, Prasanth G., Sakthi Sangeetha V., V. Gangadharan. Correlation between six-minute walk test and sit-to-stand test in COPD patients

Introduction and Aim: Six Minute Walk Test (6MWT) and spirometry are commonly used tests to assess the functional status of the Chronic Obstructive Pulmonary Diseases (COPD) patients. However, many other simpler tests like Sit to Stand Test (STST) are also available. This study is done to assess the utility of STST in comparison to 6MWT to evaluate the functional status of COPD patients in our hospital.   Materials and Methods: This study is a prospective and an observational study conducted on 50 COPD patients. Each patient underwent spirometry and subjected to 6MWT and STST. Quadriceps femoris muscle powers are measured for every patient before start of study. During the test, dyspnoea grade, Pulse rate, respiratory rate, saturation and blood pressure were measured.   Results: In this study group mean age was 60.38±11.09 years, mean FEV1 55.24% ±16.18% and then 6MWT and STST were correlating with each other. On comparing parameters hemodynamic parameters before and after performing 6MWT and STST for 30 seconds. There is significant correlation between 6MWT and STST using Pearson’s correlation. However, there is a negative correlation between FEV1 and both 6MWT and  STST.   Conclusion: Sit to stand test is less time consuming, repeatable and easy to perform. STST can also determine the functional status of COPD patient similar to Spirometry and Six-minute walk test. Hence, STST can be an alternative test for Spirometry and 6MWT in COPD patients in a limited resource facility.

Heart rate recovery in adult individuals with asthma

Slow heart rate recovery (HRR) after exercise is a predictor of overall mortality in individuals with and without cardiovascular or respiratory disorders. No data on adults with asthma are available. The purpose of the study is to evaluate the prevalence of slow HRR in these individuals as compared with those with chronic obstructive pulmonary disease (COPD). We performed a retrospective analysis of baseline characteristics and physiological response to the six-minute walking distance test of stable individuals with asthma or COPD. Slow HRR was defined as HRpeak - HR at 1 minute after end exercise <12 bpm. Individuals with asthma walked significantly longer (median (IQR): 455 (385-512) vs 427 (345-485) meters; p=0.005) with a lower prevalence of slow HRR (30.3% vs 49.0%, respectively: p<0.001) than those with COPD. Individuals with asthma and slow HRR were older and walked less than those with normal HRR, without any difference in airway obstruction or in disease severity. Multivariate analysis showed that only the difference HRpeak - baseline HR (∆HR), was a predictor of slow HRR in both groups. More than 30% of adult individuals with asthma may show slow HRR. Only exercise ∆HR but no baseline characteristic seems to predict the occurrence of slow HRR.

Predictors of changes in 6-min walking distance following pulmonary rehabilitation in COPD patients: a retrospective cohort analysis

BACKGROUND

Pulmonary rehabilitation (PR) is fundamental in chronic obstructive pulmonary disease (COPD) management but not all patients may show functional benefits from PR.

AIM

The aim of this study was to identify predictors of non-response in functional capacity to PR.

DESIGN

Observational study.

SETTING

Inpatient pulmonary rehabilitation center.

POPULATION

COPD patients.

METHODS

This single center study is a retrospective analysis of data in COPD patients admitted to a PR center between January 2012 and December 2017. Post-PR change in 6-min walking distance (6MWD) was used to determine the functional response to PR. Patients characteristics and pre-PR 6-min walking test responses were analyzed to determine factors associated with post-PR changes in 6MWD.

RESULTS

Data from 835 patients were analyzed as well as a subgroup of 190 patients with additional variables available. Eighty percent of the patients showed clinically significant 6MWD improvement post-PR. The predictors of 6MWD response to PR were age, pre-PR 6MWD, pre-PR end-of-test dyspnea and long-term oxygen therapy. Older patients, longer pre-PR 6MWD, higher pre-PR end-of-test dyspnea score and the use of oxygen supplementation were associated with lesser post-PR 6MWD improvement.

CONCLUSIONS

This study identified four important clinical variables predicting a lack of 6MWD response to PR.

CLINICAL REHABILITATION IMPACT

Patients with such clinical characteristics may require specific PR modalities to improve their functional benefit.

Comparison of forehead and finger oximetry sensors during the six minute walk test

BACKGROUND

Measurement of oxygen saturation (S_pO₂) during the 6 minute walk test (6MWT) could be impacted by the measurement site.

AIMS

To compare S_pO₂ and heart rate (HR) between forehead and finger sensors during the 6MWT. Sensor readings were also to be compared for signal quality and with capillary blood gas (CBG) pre and post 6MWT.

METHOD

80 subjects with pulmonary vascular disease (PVD) and/or interstitial lung disease (ILD) performed the 6MWT. Pulse oximetry was recorded at 30 s intervals. CBG was taken pre and post 6MWT to determine capillary oxygen saturation (S_CO₂).

RESULTS

The forehead sensor recorded higher values for S_pO₂ (p < 0.001) and HR (p < 0.01) compared with the finger sensor during the 6MWT. For both sensors, the demonstrated bias compared to CBG post 6MWT was higher and more variable in subjects who desaturated. During the 6MWT there was a higher occurrence (p < 0.001) of poor signal quality in the finger sensor compared with the forehead sensor.

CONCLUSION

This study suggests that the sensor site can impact pulse oximetry readings. The variance in bias suggests pulse oximetry may not accurately reflect S_CO₂ measurements particularly in subjects who desaturate during 6MWT.

Effects of High-Intensity Interval Training on Pulmonary Function and Exercise Capacity in Individuals with Chronic Obstructive Pulmonary Disease: A Meta-Analysis and Systematic Review

INTRODUCTION

This study aimed to examine the effectiveness of high-intensity interval training (HIIT) on pulmonary function and exercise capacity in individuals with chronic obstructive pulmonary disease (COPD).

METHODS

Ten databases (PubMed, the Cochrane Library, Web of Science, EMBASE, MEDLINE, CINAHL, CNKI, Wanfang, Weipu, and CBM) were searched for relevant articles published from inception to 30 June 2020. Studies were included if they were randomized controlled trials (RCTs) comparing a HIIT group with usual care or other training groups. Quality was assessed using the Physiotherapy Evidence Database (PEDro) scale, and the overall quality of evidence was assessed using the GRADE approach. The primary outcomes were peak VO2 and FEV1% predicted, and the secondary outcomes were FEV1/FVC, peak VE, peak WR, 6MWD, dyspnea, health-related quality of life, and adverse event.

RESULTS

Twelve articles (689 patients) were included. HIIT was shown to have a positive effect on exercise capacity (peak WR, 6MWD), pulmonary function (FEV1% pred, peak VE), dyspnea, and quality of life. However, sensitivity analyses for dyspnea were unstable, and the result changed from positive to negative after removing one study (SMD = - 0.13, 95% CI [- 0.44, 0.17], P = 0.40).

CONCLUSIONS

HIIT could improve pulmonary function, exercise capacity, and quality of life but may not decrease dyspnea in patients with COPD. It can be recommended as a safe and effective exercise modality in rehabilitation programs. Given that the overall results were based on a limited number of studies with significant heterogeneity and some of the results were based on low GRADE rating evidence, more high-quality, larger sample size, multicenter, and long-term follow-up RCTs are needed to confirm the clinical efficacy of HIIT in patients with COPD.

PROSPERO REGISTRATION

CRD42020165897.

Clusters of Survivors of COVID-19 Associated Acute Respiratory Failure According to Response to Exercise

COVID-19 survivors are associated with acute respiratory failure (ARF) and show a high prevalence of impairment in physical performance. The present studied aimed to assess whether we may cluster these individuals according to an exercise test. The presented study is a retrospective analysis of 154 survivors who were admitted to two hospitals of Istituti Clinici Scientifici Maugeri network, Italy. Clinical characteristics, walked distance, heart rate (HR), pulse oximetry (SpO₂), dyspnoea, and leg fatigue (Borg scale: Borg-D and Borg-F, respectively) while performing the six-minute walking test (6MWT) were entered into unsupervised clustering analysis. Multivariate linear regression identified variables that were informative for the set of variables used for cluster definition. Cluster 1 (C1: 86.4% of participants) and Cluster 2 (C2: 13.6%) were identified. Compared to C1, the individuals in C2 were significantly older, showed significantly higher increase in fatigue and in dyspnoea, greater reduction in SpO₂, and a lower HR_peak during the test. The need of walking aids, time from admission to acute care hospitals, age, body mass index, endotracheal intubation, baseline HR and baseline Borg-D, and exercise-induced SpO₂ change were significantly associated with the variables that were used for cluster definition. Different characteristics and physiological parameters during the 6MWT characterise survivors of COVID-19-associated ARF. These results may help in the management of the long-term effects of the disease.

Exertional Desaturation Has Higher Mortality Than Non-Desaturation in COPD

Background and objectives: Exertional desaturation (ED) is often overlooked in chronic obstructive pulmonary disease (COPD). We aim to investigate the impact of ED on mortality and the predictors of ED in COPD. Materials andmethods: A cohort of COPD patients with clinically stable, widely ranging severities were enrolled. ED is defined as oxyhemoglobin saturation by pulse oximetry (SpO2) < 90% or a drop of ΔSpO2 ≥ 4% during a six-minute walk test (6MWT). Cox regression analysis is used to estimate the hazard ratio (HR) for three-year mortality. Results: A total of 113 patients were studied, including ED (N = 34) and non-ED (N = 79) groups. FVC (% of predicted value), FEV1/FVC (%), FEV1 (% of predicted value), DLCO (%), maximal inspiratory pressure, SpO2 during the 6MWT, GOLD stage, and COPD severity were significantly different between the ED and non-ED groups in univariate analysis. Low minimal SpO2 (p < 0.001) and high maximal heart rate (p = 0.04) during the 6MWT were significantly related to ED in multivariate analysis. After adjusting for age, gender, body mass index, 6MWD, FEV1, mMRC, GOLD staging, exacerbation, hs-CRP, and fibrinogen, the mortality rate of the ED group was higher than that of the non-ED group (p = 0.012; HR = 4.12; 95% CI 1.37–12.39). For deaths, the average survival time of ED was shorter than that of the non-ED group (856.4 days vs. 933.8 days, p = 0.033). Conclusions: ED has higher mortality than non-ED in COPD. COPD should be assessed for ED, especially in patients with low minimal SpO2 and high maximal HR during the 6MWT.

Effect of liuzijue qigong on patients with stable chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUNDS

Chronic obstructive pulmonary disease (COPD) is a common, preventable disease of airflow limitation that accounts for the third leading deaths of any disease process in the worldwide. Health benefits of liuzijue qigong (LQG) on patients with stable COPD has been assessed. This study was designed to perform a systemic review and meta-analysis of the effect of Liuzijue breathing exercise on patients with stable COPD.

METHODS

Published articles from 1970 to December 2020 were conducted using electronic searches. Two independents reviewers conducted data extraction. The Cochrane risk of bias assessment tool was used to evaluate the quality of the included studies.

RESULTS

A total of 16 eligible trials with 1039 patients with stable COPD were identified. Compared with control group, the pool meta-analysis of LQG showed a significant improvement in forced expiratory volume in one second (FEV1) (MD = -0.16, 95% CI [0.09, 0.23], P < .00001), FEV1% (MD = 9.71, 95% CI [8.44, 10.98], P < .00001), the ratio of forced expiratory volume to forced vital capacity in the first second (FEV1/FVC [%]) (MD = 4.81, 95% CI [2.12, 7.51], P = .0005), 6 minutes walking distance (6MWD) (MD = 21.89, 95% CI [14.67, 29.11], P < .00001), health-related quality of life (SMD = -0.84, 95% CI [-1.12,-0.55], P < .00001) and modified medical research council dyspnea scale (mMRC) (MD = -0.73, 95% CI [-0.96, -0.50], P < .00001). The observed effect was more pronounced for short term and medium-term duration interventions of study. It also showed improvements in the secondary outcome measures by LQG.

CONCLUSIONS

In this systematic review and meta-analysis, LQG can improve lung ventilation function, exercise endurance and health-related quality of life of patients with stable COPD.

ETHIC AND DISSEMINATION

This study is a systematic review and it does not involve harming to the rights of participants. Ethical approval will not be require for this study. The research results may be published in a peer-reviewed journals.

Acute effect of oxygen therapy on exercise tolerance and dyspnea perception in ILD patients

Ambulatory oxygen therapy (AOT) is commonly prescribed in Interstitial Lung Disease (ILD) patients, with the aim of reducing dyspnea and increasing exercise tolerance. Despite its frequent use and a reasonable physiological rationale, there is a lack of evidence supporting the effect of AOT on improving dyspnea during exercise. Moreover, dyspnea encompasses distinct sensory (intensity, quality) and affective (anxiety, fear) components with different underlying neurophysiological mechanisms. The aim of this study was to evaluate the effect of oxygen supplementation on exercise tolerance and dyspnea in ILD patients with exercise induced hypoxia (EIH). Forty-seven ILD patients performed a six minute walk test (6MWT) on room air (RA) and with oxygen supplementation (Ox). The 6MWT distance (6MWD) was significantly greater with oxygen supplementation (RA: 242±143 m vs Ox: 345±106 m p<0,01). With oxygen supplementation, the overall dyspnea and anxiety significantly decreased both at rest (1,1±1,4 Borg Unit (BU) vs 0,4±0,9BU , p.<0.01, and 1,1±1,6BU vs 0,5±1,3 BU, p.<0.05, respectively) and at the end of exercise (5,1±2,6 BU vs 3,7±2,5 BU, p.<0.001 and 3,4 ±2,9 vs 2,5 ±2,8, p.<0.01, respectively) despite a greater walked distance. In ILD patients with EIH, oxygen supplementation increases the exercise tolerance and reduces overall dyspnea perception and the anxiety component of breathlessness.

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

Pulmonary rehabilitation is based on a thorough patient assessment, including peripheral oxygen saturation (SpO₂) and heart rate (HR) at rest and on exertion. To understand whether exercise-field tests identify patients who desaturate (SpO₂ < 90%) during physical activities, this study compared the six-minute walk test (6MWT) and daily-life telemonitoring. Cross-sectional study including 100 patients referred for pulmonary rehabilitation. The 6MWT was performed in hospital with continuous assessment of SpO₂, HR, walked distance and calculated metabolic equivalent of tasks (METs). Patients were also evaluated in real-life by SMARTREAB telemonitoring, a combined oximetry-accelerometery with remote continuous assessment of SpO₂, HR and METs. SMARTREAB telemonitoring identified 24% more desaturators compared with the 6MWT. Moreover, there were significant mean differences between 6MWT and SMARTREAB in lowest SpO₂ of 7.2 ± 8.4% (P < 0.0005), in peak HR of - 9.3 ± 15.5% (P < 0.0005) and also in activity intensity of - 0.3 ± 0.8 METs (P < 0.0005). The 6MWT underestimates the proportion of patients with exercise-induced oxygen desaturation compared to real-life telemonitoring. These results help defining oximetry-guided interventions, such as telemedicine algorithms, oxygen therapy titration and regular physical activity assessment in pulmonary rehabilitation.

Time course of exercise capacity in patients recovering from COVID-19-associated pneumonia

Objective:

High prevalences of muscle weakness and impaired physical performance in hospitalized patients recovering from COVID-19-associated pneumonia have been reported. Our objective was to determine whether the level of exercise capacity after discharge would affect long-term functional outcomes in these patients.

Methods:

From three to five weeks after discharge from acute care hospitals (T₀), patients underwent a six-minute walk test (6MWT) and were divided into two groups according to the distance walked in percentage of predicted values: <75% group and ≥75% group. At T₀ and three months later (T₁), patients completed the Short Physical Performance Battery and the Euro Quality of Life Visual Analogue Scale, and pulmonary function and respiratory muscle function were assessed. In addition, a repeat 6MWT was also performed at T₁.

Results:

At T₀, 6MWD values and Short Physical Performance Battery scores were lower in the <75% group than in the ≥75% group. No differences were found in the Euro Quality of Life Visual Analogue Scale scores, pulmonary function variables, respiratory muscle function variables, length of hospital stay, or previous treatment. At T₁, both groups improved their exercise capacity, but only the subjects in the <75% group showed significant improvements in dyspnea and lower extremity function. Exercise capacity and functional status values returned to predicted values in all of the patients in both groups.

Conclusions:

Four weeks after discharge, COVID-19 survivors with exercise limitation showed no significant differences in physiological or clinical characteristics or in perceived health status when compared with patients without exercise limitation. Three months later, those patients recovered their exercise capacity.

A comparison between Qigong exercise and cycle ergometer exercise for the rehabilitation of chronic obstructive pulmonary disease: A pilot randomized controlled trial (CONSORT)

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease that is associated with significant morbidity and mortality. Exercise training confers health benefits to people with COPD. The purpose of this study was to compare differences in the rehabilitation of COPD between Qigong exercise (QE) and aerobic exercise using a cycle ergometer (CE).

METHODS

This study was a randomized single-blind controlled trial. Twenty six participants were recruited and randomized to either the Qigong group or the cycle ergometer group. Both interventions lasted 12 weeks and comprised a 30 minutes supervised training session performed twice a week, that is, 24 sessions in total. The primary outcome measure was the endurance capacity measured by the six-minute walk test (6MWT). The secondary outcome measures were the results of the St. George's Hospital Respiratory Questionnaire (SGRQ) and the COPD assessment test (CAT).

RESULTS

Participants in the group that performed aerobic exercise using a cycle ergometer had significantly improved 6MWT (P = .005), SGRQ (P = .029), and CAT (P = .018) results. Participants in the Qigong exercise group had significant changes in 6MWT (P = .033). However, the differences in 6MWT and SGRQ were not statistically significant between the 2 groups. The changes in CAT scores before and after the intervention were significantly different between the 2 groups (P = .020). There were no reports of adverse events during the course of the trial.

CONCLUSIONS

There was no difference in the primary outcome between groups. In particular, QE and cycle ergometer exercise had similar rehabilitation effects on the improvement of the cardiopulmonary endurance and quality of life of chronic obstructive pulmonary disease patients. In addition, cycle ergometer exercise may lead to a better trend of improvement in the quality of life and can improve the severity of the clinical symptoms of chronic obstructive pulmonary disease.

TRIAL REGISTRATION

ChiCTR-TRC-14004404.

Pulmonary rehabilitation in patients with interstitial lung diseases: Correlates of success

BACKGROUND AND AIM

Benefits of pulmonary rehabilitation in Interstitial Lung Diseases (ILD) have been reported. The aim of this large multicenter study was to identify the success predictors of pulmonary rehabilitation in a real-life setting.

METHODS

Data of 240 in-patients (110 idiopathic pulmonary fibrosis (IPF), 106 ILD other than IPF and 24 undetermined ILD) undergoing pulmonary rehabilitation in a 10-year period were retrospectively evaluated. Six minute walking distance (6MWT), body weight-walking distance product tests, dyspnoea and arterial blood gases were assessed at admission and discharge. Differences in post rehabilitation changes in outcome measures as function of baseline characteristics were evaluated.

RESULTS

After rehabilitation, patients showed improvements in all outcome measures (p < 0.05), regardless of the underlying diagnosis or disease severity. Patients needing oxygen therapy at rest showed reduced benefits. Baseline 6MWD inversely correlated with its changes at discharge. Non-significant greater benefits after rehabilitation were found in IPF patients under antifibrotic therapy. In a subset of 50 patients assessed on average 10.3 ± 3.5 months after discharge, the benefits in 6MWD were not maintained (312.9 ± 139.4, 369.7 ± 122.5 and 310.8 ± 139.6 m at admission, discharge and follow up respectively: p < 0.0001).

CONCLUSION

Pulmonary rehabilitation may improve dyspnoea, exercise capacity and fatigue in patients with ILD of different aethiologies and level of severity. The long-term effects need to be established.

[Prognostic factors in idiopathic pulmonary fibrosis in a tunisian cohort]

We present data on prognostic factors in a Tunisian cohort of people with Idiopathic pulmonary fibrosis.

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) has a poor prognosis, with a median survival in patients with the condition of only 3 to 5 years. Previous studies have identified a number of prognostic factors in this chronic pulmonary disease.

METHODS

We conducted a retrospective study, including patients with idiopathic pulmonary fibrosis (IPF) who were diagnosed at the Pneumology Department of the University Hospital Fattouma-Bourguiba, Monastir, between 1991 and 2014. The aim of this study was to compare clinical, radiological, pulmonary functional predictors of survival in IPF in a Tunisian cohort with those of previous studies.

RESULTS

This study included 126 patients. Their mean age was 66 years, with a male predominance (68.3%). Respiratory function tests revealed a restrictive ventilatory deficit in 72.6% of cases. The median survival of our study population was 22.5 months [6.7-49.5]. In univariate analysis, factors associated with a poor prognosis were: lower baseline values of TLC, FCV and DLco, level of dyspnea assessed by mMRC scale, hypoxemia at diagnosis, the degree of desaturation during exercise, a higher annual decline of FVC and DLco, acute respiratory distress and also the GAP score. In multivariate analysis, independent prognostic factors were: baseline DLco, level of dyspnea, desaturation at exertion and the annual decline of the DLco.

CONCLUSION

Lower baseline DLco, the level of dyspnea, desaturation on exercise, and annual decline in DLco are all associated with a poor prognosis in IPF.

Comparison of the cardio-respiratory response of a training session on cycloergometer or treadmill versus an Adapted Physical Activity session on Nintendo Wii, in patients with chronic respiratory disease

OBJECTIVES

During a pulmonary rehabilitation program (PRP), patients frequently report that the classically proposed activities (as cycloergometer or treadmill) are not playful. The goal of adapted physical activities is to maintain physical activity that is more playful for patients. The Nintendo Wii Gaming Console allows a playful physical activity. However, it seems important to know if this tool allows physical activity with an effective cardiorespiratory effect. The objective was to compare the cardiorespiratory response of a 30-minute training session on cycloergometer (C) and treadmill (T) versus a 30-minute training session with Wii.

METHODS

Patients admitted to the PR unit of Brest University Hospital (France) were eligible for this randomized study if they had a chronic pulmonary disease. The endpoints were heart rate (HR), pulse oxymetry, dyspnea, lower limb penibility and pleasure felt.

RESULTS

Twenty patients were prospectively included. HR was significantly higher at the end of the Wii session in comparison with C session (P=0.001); there was no significant difference in HR between Wii and T. We found no significant difference for dyspnea and lower limb penibility between Wii and C (respectively P=0.8 and P=0.7) and between Wii and T (respectively P=0.96 and P=0.5). The pleasure felt was significantly greater during Wii compared to C and T (respectively P=0.001 and P=0.001).

CONCLUSIONS

Exercise training using Wii with identifiable games require higher HR at the end of the session compared to C and a similar cardiorespiratory response compared to T with the same dyspnea and lower limb exertion and with a pleasure felt significantly higher. Wii can be used for exercise training during PRP.

[Which physical tests for which objectives in pulmonary rehabilitation?]

Chronic respiratory disease is a major cause of morbidity and mortality worldwide and an important cause of disability including a reduction of exercise, functional and muscle capacity contributing to a decreased quality of life. In the context of pulmonary rehabilitation, a thorough patient-centered outcome assessment, including not only measures of lung function, but also exercise functional and muscle capacity, is imperative for a comprehensive disease management. Assessment of these impairments and dysfunctions with appropriate and change-sensitive procedures is thus necessary for personalizing the physical interventions and assessing the short- and long-term effectiveness of the intervention. The clinician currently has a wide variety of tests and measurements available to assess the physical and functional capacity of people with chronic respiratory disease. The aim of this review is to provide a pragmatic synthesis of the physical, functional and muscle capacity tests most commonly used in pulmonary rehabilitation. Ultimately, it should help the clinician to identify the relevant evaluations according to the objectives of the patients but also according to the available resources, the setting of pulmonary rehabilitation and the specific qualities of each test.

Exercise-induced desaturation in subjects with non-cystic fibrosis bronchiectasis: laboratory-based tests versus field-based exercise tests

Objective:

To investigate the validity of field walking tests to identify exercise-induced hypoxemia and to compare cardiorespiratory responses and perceived effort between laboratory-based and field-based exercise tests in subjects with bronchiectasis.

Methods:

This was a cross-sectional study involving 72 non-oxygen-dependent participants (28 men; mean age = 48.3 ± 14.5 years; and mean FEV₁ = 54.1 ± 23.4% of the predicted value). The participants underwent cardiopulmonary exercise testing (CPET) on a treadmill and constant work-rate exercise testing (CWRET) on the same day (1 h apart). In another visit, they underwent incremental shuttle walk testing (ISWT) and endurance shuttle walk testing (ESWT; 1 h apart). Desaturation was defined as a reduction in SpO₂ ≥ 4% from rest to peak exercise.

Results:

CPET results were compared with ISWT results, as were CWRET results with ESWT results. There was no difference in the magnitude of desaturation between CPET and ISWT (−7.7 ± 6.3% vs. −6.6 ± 5.6%; p = 0.10) and between CWRET and ESWT (−6.8 ± 5.8% vs. −7.2 ± 6.3%; p = 0.50). The incremental tests showed an agreement in the magnitude of desaturation in the desaturation and no desaturation groups (42 and 14 participants, respectively; p < 0.01), as did the endurance tests (39 and 16 participants; p < 0.01). The magnitude of desaturation was similar among the participants who did or did not reach at least 85% of the maximum predicted HR.

Conclusions:

Field exercise tests showed good precision to detect desaturation. Field tests might be an alternative to laboratory tests when the clinical question is to investigate exercise-induced desaturation in subjects with bronchiectasis.

Ventilatory constraint is more severe in walking than cycling in patients with COPD

Due to its effectivity in assessing functional capacity and adding prognostic information to the staging of chronic obstructive pulmonary disease (COPD) patients, the 6-min walk test (6MWT) is extensively used in clinical evaluation. Currently, there is little information about the physiological response this test elicits in patients, especially when compared to cardiopulmonary exercise test (CPET). The aim of the study was to compare ventilatory and metabolic responses between these tests commonly used for the assessment of clinical outcome. A group of 20 patients with moderate to very severe COPD were tested for their pulmonary function (flow-volume curve, static lung volumes), occlusion mouth pressures and breath-by-breath measurement of flow, volumes, and oxygen (O₂) and carbon dioxide (CO₂) concentration during the 6MWT and CPET. All parameters measured during both exercise tests were assessed over the throughout of the tests and compared between each other at specified time points. Serially measured inspiratory vital capacity (IVC) decreased more rapidly and extensively during the walk-test (p ​< ​0,0001). This was accompanied by a limited increase in tidal volume (V_T) and minute ventilation (V_E), which were significantly lower in the course of the 6MWT (p ​= ​0,0003 and p ​= ​0,0097, respectively). We also noticed a significant decrease in hemoglobin oxygen saturation (SpO₂) during the 6MWT which was correlated to percent decrease in IVC (p ​= ​0,0206). Over the course of the 6MWT, oxygen consumption (VO₂) and V_T reached plateau within 2 ​min, while carbon dioxide production (VCO₂) and V_E within 3 ​min. During CPET, VO₂, VCO₂ and V_E rose continuously, while V_T reached plateau within 4 ​min. The 6MWT seems to be a rather endurance-based test associated with more pronounced dynamic lung hyperinflation and mechanical constraint of ventilation in comparison to cycling.

•

Various types of exercise are tolerated differently.

•

The 6MWT is, as opposed to ergometry, accompanied by a quicker increase in dynamic lung hyperinflation and desaturation.

•

It seems that pedaling, as compared to walking, is the superior way of training movement for rehabilitation purposes.

Designing a Randomized Trial with an Age Simulation Suit-Representing People with Health Impairments

Due to demographic change, there is an increasing demand for professional care services, whereby this demand cannot be met by available caregivers. To enable adequate care by relieving informal and formal care, the independence of people with chronic diseases has to be preserved for as long as possible. Assistance approaches can be used that support promoting physical activity, which is a main predictor of independence. One challenge is to design and test such approaches without affecting the people in focus. In this paper, we propose a design for a randomized trial to enable the use of an age simulation suit to generate reference data of people with health impairments with young and healthy participants. Therefore, we focus on situations of increased physical activity.

Comprehensive health assessment three months after recovery from acute COVID-19

Background

Long-term health sequelae of coronavirus disease 2019 (COVID-19) may be multiple but have thus far not been systematically studied.

Methods

All patients discharged after COVID-19 from the Radboud University Medical Center, Nijmegen, the Netherlands, were consecutively invited to a multidisciplinary outpatient facility. Also, nonadmitted patients with mild disease but with symptoms persisting >6 weeks could be referred by general practitioners. Patients underwent a standardized assessment including measurements of lung function, chest computed tomography (CT)/X-ray, 6-minute walking test, body composition, and questionnaires on mental, cognitive, health status, and quality of life (QoL).

Results

124 patients (59 ± 14 years, 60% male) were included: 27 with mild, 51 with moderate, 26 with severe, and 20 with critical disease. Lung diffusion capacity was below the lower limit of normal in 42% of discharged patients. 99% of discharged patients had reduced ground-glass opacification on repeat CT imaging, and normal chest X-rays were found in 93% of patients with mild disease. Residual pulmonary parenchymal abnormalities were present in 91% of discharged patients and correlated with reduced lung diffusion capacity. Twenty-two percent had low exercise capacity, 19% low fat-free mass index, and problems in mental and/or cognitive function were found in 36% of patients. Health status was generally poor, particularly in the domains functional impairment (64%), fatigue (69%), and QoL (72%).

Conclusions

This comprehensive health assessment revealed severe problems in several health domains in a substantial number of ex–COVID-19 patients. Longer follow-up studies are warranted to elucidate natural trajectories and to find predictors of complicated long-term trajectories of recovery.

High-Flow Oxygen Therapy During Exercise Training in Patients With Chronic Obstructive Pulmonary Disease and Chronic Hypoxemia: A Multicenter Randomized Controlled Trial

OBJECTIVE

The study aimed to evaluate whether high-flow oxygen therapy (HFOT) during training was more effective than oxygen in improving exercise capacity in hypoxemic chronic obstructive pulmonary disease (COPD).

METHODS

A total of 171 patients with COPD and chronic hypoxemia were consecutively recruited in 8 rehabilitation hospitals in a randomized controlled trial. Cycle-ergometer exercise training was used in 20 supervised sessions at iso inspiratory oxygen fraction in both groups. Pre- and post-training endurance time (Tlim), 6-minute walking distance (6MWD), respiratory and limb muscle strength, arterial blood gases, Barthel Index, Barthel Dyspnea Index, COPD Assessment Test, Maugeri Respiratory Failure questionnaire, and patient satisfaction were evaluated.

RESULTS

Due to 15.4% and 24.1% dropout rates, 71 and 66 patients were analyzed in HFOT and Venturi mask (V-mask) groups, respectively. Exercise capacity significantly improved after training in both groups with similar patient satisfaction. Between-group difference in post-training improvement in 6MWD (mean: 17.14 m; 95% CI = 0.87 to 33.43 m) but not in Tlim (mean: 141.85 seconds; 95% CI = -18.72 to 302.42 seconds) was significantly higher in HFOT. The minimal clinically important difference of Tlim was reached by 47% of patients in the V-mask group and 56% of patients in the HFOT group, whereas the minimal clinically important difference of 6MWD was reached by 51% of patients in the V-mask group and 69% of patients in the HFOT group, respectively.

CONCLUSION

In patients with hypoxemic COPD, exercise training is effective in improving exercise capacity.

IMPACT STATEMENT

The addition of HFOT during exercise training is not more effective than oxygen through V-mask in improving endurance time, the primary outcome, whereas it is more effective in improving walking distance.

Physiologic Effects of Oxygen Supplementation During Exercise in Chronic Obstructive Pulmonary Disease

Supplemental long-term oxygen therapy (LTOT) is a well-established therapy that improves mortality in patients with chronic obstructive pulmonary disease (COPD) with resting hypoxemia. In the large number of patients with COPD who do not have severe resting hypoxemia but who desaturate with exercise, the clinical benefits that can be obtained by supplemental O₂ therapy during exercise is an area of interest and active research. A summary of current evidence for benefits of supplemental O₂ therapy and a review of physiologic mechanisms underlying published observations are reviewed in this article.

Exercise-Induced Oxygen Desaturation during the 6-Minute Walk Test

The 6-minute walk test (6MWT) is not intended to document oxygen (O₂) desaturation during exertion but is often used for this purpose. Because of this, it only has modest reproducibility in determining the need for ambulatory O₂ therapy in patients with cardiopulmonary disease. The diagnostic and prognostic value of detecting exertional O₂ desaturation is still unknown. The aims of this study were to estimate the prevalence of O₂ desaturation during a 6MWT based on pulse oximetry measurements at the beginning and end of a 6MWT in a clinical population of patients with suspected cardiopulmonary disease and to determine whether the pulmonary function test (PFT) can predict exercise-induced desaturation during a 6MWT. This retrospective cohort study reviewed the results of the 6MWT and the PFT (i.e., spirometry, lung volumes, and diffusion capacity) of all patients who were evaluated for suspected cardiopulmonary disease at an academic medical center during a 5-year study period. The patients were categorized into three groups based on the change in O₂ saturation by pulse oximetry (SpO₂) from start to end of the 6MWT: (1) SpO₂ decreased by ≥3%; (2) SpO₂ unchanged (−2 ≤ Δ ≤ 0%); and (3) SpO₂ increased by ≥1%. Demographic, anthropometric, and lung function measurements were analyzed to determine which factors predicted O₂ desaturation during the 6MWT. Of the 319 patients who underwent the 6MWT and the PFT from November 2005 until December 2010 (mean age = 54 ± 0.78 years, 63% women, 58% Whites, body mass index = 29.63 ± 8.10 kg/m²), 113 (35%) had a decreased SpO₂, 146 (46%) had no change, and 60 (19%) had an increased SpO₂ from the start to end of test. Our bivariate analysis found age, spirometric measures, and diffusion capacity for carbon monoxide (DLCO) had statistically significant inverse associations with the SpO₂ change category (p < 0.001). Both a 3% and 4% drop in SpO₂ during the 6MWT were statistically significantly associated with an older age, a higher prevalence of obstruction, and reduced forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), FEV₁/FVC, DLCO and 6-minute walk distance (6MWD). Multivariable logistic regression analyses revealed that only DLCO was a significant independent predictor of the change in SpO₂ and a ≥ 4% O₂ desaturation during a 6MWT. Receiver operating curve analysis indicates DLCO cut-off of 45% is 82% sensitive and 40% specific in identifying ≥4% O₂ desaturators, with an area under the curve of 0.788 ± 0.039 (p < 0.001). The prevalence of a ≥ 3% oxygen desaturation via pulse oximetry during a 6MWT in our clinical population of patients with suspected cardiopulmonary disease was 35%. Although age, spirometric lung volumes, and DLCO had statistically significant unadjusted inverse associations with the change in SpO₂ during a 6MWT, the DLCO is the only significant independent predictor of both the magnitude of the change in SpO₂ and the occurrence of O₂ desaturation of at least 4%, respectively, during the test. Clinical Implications: A DLCO cut-off of 45% may be useful in identifying patients at risk for exertional hypoxemia during a 6MWT.

SaO2 as a predictor of exercise-induced hypoxemia in chronic obstructive pulmonary disease at moderate altitude

Background

Given the high prevalence of chronic obstructive pulmonary disease (COPD) in Bogota (2630 m above the sea), screening methods are required for COPD patients who develop exercise-induced hypoxemia (EIH).

Objective

The objective was to measure the productive capacity of basal oxygen saturation for the detection of EIH during the 6-min walking test (6MWT) in patients diagnosed with COPD in a hospital in Bogotá.

Design

This was a cross-sectional, retrospective study.

Population

Patients diagnosed with COPD with SaO₂≥88% who attended the Pneumology Section of the FSFB for a 6MWT between 2013 and 2017 were included in the study.

Measurements

Age, sex, anthropometric data, SaO₂, SaO₂ during 6MWT, and spirometry were evaluated.

Results

Ninety-two patients with EIH and 32 patients without EIH were studied. Statistically significant differences were found in SaO₂, minimum SaO₂ during 6MWT, and BMI (90.8% vs 93%, 80.3% vs 88.9%, and 26.7 kg/m² vs 23.8 kg/m², respectively). FEV1 was without statistically significant differences (74.1% vs 78.6%). The ROC curve showed a better cut-off point for detecting EIH with basal SaO₂≤92% (sensitivity 76.1%, specificity 62.5%, NPV 47.6%, and PPV 85.4%) and SaO₂≤94% as the best sensitivity point (sensitivity 94.6%, specificity 15.6%, NPV 76.3%, and PPV 50%).

Conclusion

SaO₂ is not a good screening test for EIH in COPD patients at moderate altitude.

Exercise Training Modalities for People with Chronic Obstructive Pulmonary Disease

Exercise training confers health benefits for people with chronic obstructive pulmonary disease (COPD). This article reviews the evidence for several exercise training modalities shown to be beneficial among individuals with COPD. These modalities include aerobic, resistance, nonlinear periodized, upper limb and balance training, as well as yoga, Tai Chi, inspiratory muscle training, whole body vibration training and neuromuscular electrical stimulation. The literature pertaining to each modality was critically reviewed, and information on the rationale, mechanism(s) of action (where known), benefits, and exercise prescription is described to facilitate easy implementation into clinical practice.

Using SpO2 Recovery Index after a 6-Minute Walk Test to Predict Respiratory-Related Events in Hospitalized Patients with Interstitial Pneumonia

Although the prognostic factors of interstitial pneumonia (IP) patients have been reported, IP has poor prognosis. Hospitalized patients with IP have severely impaired pulmonary diffusion capacity and prominent desaturation. We hypothesized that determining oxygen saturation recovery (SpO₂ recovery index) after the 6-minute walk test (6MWT) can provide additional prognostic information regarding rehospitalization for respiratory-related events. We evaluated 73 IP patients at our hospital for demographic characteristics, pulmonary function tests and 6MWT. The Kaplan–Meier method was used to estimate rehospitalisation for respiratory-related events using SpO₂ recovery index. Cox regression analysis revealed a relationship between SpO₂ recovery index and rehospitalisation. The optimum cutoff value of SpO₂ recovery index was 4% (sensitivity, 71.4%; specificity, 79.2%). SpO₂ recovery index was most closely related to pulmonary diffusion capacity (r = 0.684, P < 0.001). In a multivariable model, it was the strongest independent predictor of rehospitalisation for respiratory-related events (hazard ratio, 0.3; 95% confidence interval, 0.10–0.90; P = 0.032). In this study, we estimated pulmonary diffusion capacity using SpO₂ recovery index values obtained from 6MWT. A SpO₂ recovery index of <4% can be useful in predicting rehospitalisation for respiratory-related events.

A comparative study of the five-repetition sit-to-stand test and the 30-second sit-to-stand test to assess exercise tolerance in COPD patients

Purpose

The sit-to-stand test (STST) has been used to evaluate the exercise tolerance of patients with COPD. However, mutual comparisons to predict poor exercise tolerance have been hindered by the variety of STST modes used in previous studies, which also did not consider patients’ subjective perceptions of different STST modes. Our aim was to compare the five-repetition sit-to-stand test (5STS) with the 30-second sit-to-stand test (30STS) for predicting poor performance in the six-minute walking test and to evaluate patients’ subjective perceptions to determine the optimal mode for clinical practice.

Patients and methods

Patients with stable COPD performed 5STS, 30STS and the 6MWT and then evaluated their feelings about the two STST modes by Borg dyspnea score and a questionnaire. Moreover, we collected data through the pulmonary function test, mMRC dyspnea score, COPD assessment test and quadriceps muscle strength (QMS). A receiver operating characteristic curve analysis of the 5STS and 30STS results was used to predict 6-minute walk distance (6MWD) <350 m.

Results

The final analysis included 128 patients. Similar moderate correlations were observed between 6MWT and 5STS (r=−0.508, P<0.001) and between 6MWT and 30STS (r=0.528, P<0.001), and there were similar correlations between QMS and 5STS (r=−0.401, P<0.001) and between QMS and 30STS (r=0.398, P<0.001). The 5STS and 30STS score cutoffs produced sensitivity, specificity and positive and negative predictive values of 76.0%, 62.8%, 56.7% and 80.3% (5STS) and 62.0%, 75.0%, 62.0% and 75.0% (30STS), respectively, for predicting poor 6MWT performance. The 5STS exhibited obvious superiority in terms of the completion rate and the subjective feelings of the participants.

Conclusion

As a primary screening test for predicting poor 6MWD, the 5STS is similar to the 30STS in terms of sensitivity and specificity, but the 5STS has a better patient experience.

Exercise response to oxygen supplementation is not associated with survival in hypoxemic patients with obstructive lung disease

Purpose

Hypoxemia is associated with more severe lung disease and worse outcomes. In some patients with chronic obstructive lung diseases who desaturate on exertion, supplemental oxygen improves exercise capacity. The clinical significance of this exercise response to oxygen supplementation is not known.

Patients and methods

We identified chronic obstructive lung disease patients at our center who underwent a 6-minute walking test (6MWT) for ambulatory oxygen assessment and who desaturated breathing air and therefore had an additional walk test on supplemental oxygen, between August 2006 and June 2016. Responders were defined as walking ≥26 m further with oxygen. Survival was determined up to February 1, 2017. We compared survival in oxygen responders and nonresponders in patients with obstructive lung diseases.

Results

One hundred and seventy-four patients were included in the study, median age 70 years. Seventy-seven (44.3%) of the patients were oxygen responders. Borg dyspnea score improved by 1.4 (±1.4) units (P<0.0005) on oxygen. Median survival was 66 months with death occurring in 84 (48.2%) patients. Kaplan–Meier analysis revealed no survival difference between both responders and nonresponders (P=0.571). Cox regression analysis showed that more 6MWT desaturation, lower 6-minute walking distance on room air, male gender, lower hemoglobin, and body mass index were associated with higher mortality risk.

Conclusion

Acute exercise response to supplemental oxygen is not associated with long-term survival in patients with obstructive lung disease. This supports the use of ambulatory oxygen treatment for symptomatic purposes only.

Effectiveness of meditative movement on COPD: a systematic review and meta-analysis

Background

The effectiveness of meditative movement (tai chi, yoga, and qigong) on COPD remained unclear. We undertook a systematic review and meta-analysis to determine the effectiveness of meditative movement on COPD patients.

Methods

We searched PubMed, Web of Science, EMBASE, and the Cochrane Center Register of Controlled Trials for relevant studies. The methods of standard meta-analysis were utilized for identifying relevant researches (until August 2017), quality appraisal, and synthesis. The primary outcomes were the 6-minute walking distance (6MWD), lung function, and dyspnea levels.

Results

Sixteen studies involving 1,176 COPD patients were included. When comparing with the control group, the 6MWD was significantly enhanced in the treatment group (3 months: mean difference [MD]=25.40 m, 95% CI: 16.25 to 34.54; 6 months: MD=35.75 m, 95% CI: 22.23 to 49.27), as well as functions on forced expiratory volume in 1 s (FEV₁) (3 months: MD=0.1L, 95% CI: 0.02 to 0.18; 6 months: MD=0.18L, 95% CI: 0.1 to 0.26), and FEV₁ % predicted (3 months: 4L, 95% CI: 2.7 to 5.31; 6 months: MD=4.8L, 95% CI: 2.56 to 7.07). Quality of life for the group doing meditative movement was better than the control group based on the Chronic Respiratory Disease Questionnaire dyspnea score (MD=0.9 units, 95% CI: 0.51 to 1.29) and fatigue score (MD=0.75 units, 95% CI: 0.42 to 1.09) and the total score (MD=1.92 units, 95% CI: 0.54 to 3.31).

Conclusion

Meditative movement may have the potential to enhance lung function and physical activity in COPD patients. More large-scale, well-designed, multicenter, randomized controlled trials should be launched to evaluate the long-range effects of meditative movement.

The 1-minute sit-to-stand test to detect exercise-induced oxygen desaturation in patients with interstitial lung disease

BACKGROUND

Although the 6-min walk test (6MWT) is the gold standard for assessing exercise-induced impairment of gas exchange, it cannot easily be performed in a clinical office environment. The aim of this study was to compare the 1-min sit-to-stand test (1STST) with the 6MWT for the ability to assess exercise-induced oxygen desaturation in patients with interstitial lung diseases (ILDs).

METHODS

A total of 107 patients were enrolled and classified into three groups: sarcoidosis, fibrotic idiopathic interstitial pneumonia (f-IIP), and other forms of ILD. The 6MWT and 1STST were performed on the same day, and pulmonary function tests, pulse oxygen saturation (SpO2), and dyspnea and fatigue (modified Borg scale) were assessed. SpO2 desaturation was evaluated by intraclass correlation coefficient (ICC), Bland-Altman analysis, and kappa (κ) coefficient in the whole population and the patient subgroups.

RESULTS

The SpO2 nadir during the 1STST and 6MWT showed good consistency [mean ± standard deviation: 92.5% ± 5% and 90% ± 7%, respectively; ICC 0.77, 95% confidence interval (CI) 0.71-0.83] and correlated strongly ( r = 0.9, p < 0.0001). The frequency of patients with oxygen desaturation ⩾4% was also consistent for the two exercise tests ( κ = 0.68, 95% CI 0.54-0.82). The number of repetitions in the 1STST correlated with the 6MWT distance ( r = 0.5, p < 0.0001), but the dyspnea scores were higher during the 1STST than the 6MWT ( p < 0.0001). These findings did not differ for the three patient subgroups.

CONCLUSION

The 1STST can measure exercise-induced desaturation in ILD patients and could be used as an alternative test to the 6MWT in office practice.

Titrating Oxygen Requirements During Exercise: Evaluation of a Standardized Single Walk Test Protocol

BACKGROUND

Oxygen supplementation for exercise-induced hypoxemia is a common clinical practice that improves exercise tolerance. However, we know of no standardized exercise oxygen titration protocol using a single walk test. We report our experience with a protocol developed in our laboratory.

METHODS

Our protocol is based on the 6-min walk test (6MWT). Pulse oximetry readings (oxygen saturation [Spo₂]) are monitored, and supplemental oxygen is added in 2 L/min increments to keep Spo₂ > 88%. This continues for at least 6 min of walking with the Spo₂ remaining > 88% for at least 3 min. The records of consecutive patients over 4 months undergoing this procedure were reviewed for test performance, oxygen titration results, and adverse events.

RESULTS

Two hundred twenty-two patients were tested; only two prematurely terminated the protocol because of intractable dyspnea. One hundred fifty-six patients (38%) required oxygen supplementation, with the first titration most commonly occurring between 1 and 2 min of walking. Nine of the patients had the first titration after 5 min of walking. The average test duration was 7 min (maximum, 15 min). The average number of titrations was 2.2 (maximum six). Sixteen patients could not maintain Spo₂ > 88% for 3 min despite administration of 15 L/min of supplemental oxygen (maximal dose).

CONCLUSIONS

Our protocol was easily performed as a modification of a standard 6MWT with no serious adverse events. Because it is based on a widely accepted measurement of functional capabilities, and because it determined a stable final oxygen dose for ≥ 3 min of walking in most patients, we believe this protocol can be easily adapted for clinical use.

Cardiorespiratory Response to Different Exercise Tests in Interstitial Lung Disease

INTRODUCTION

The 6-min stepper test (6MST) has been used as an alternative to the 6-min walk test (6MWT) to assess exercise tolerance in patients with interstitial lung disease (ILD). Recent data suggest that the tests may involve different energy pathways and cardiorespiratory responses. We thus aimed to compare the cardiorespiratory responses of ILD patients during the 6MWT and the 6MST.

METHODS

Thirty-one patients with ILD were randomized to perform both tests in the order 6MST → 6MWT (n = 16) or 6MWT → 6MST (n = 15). Gas exchange, HR, and pulse O2 saturation (SpO2) were measured continuously, and dyspnoea, leg discomfort, and blood lactate concentration were assessed before and immediately after each test.

RESULTS

Oxygen uptake (V˙O2) was lower (P = 0.002) and respiratory equivalent ratio for O2 (V˙E/V˙O2) and RER were higher (both P < 0.001) during the 6MST compared with the 6MWT. The 6MST was also associated with higher blood lactate concentrations (6MST, 4.16 ± 1.95 mmol·L; 6MWT, 2.84 ± 1.17 mmol·L; P = 0.01), higher leg discomfort scores (6MST 5 ± 3 points, 6MWT 3 ± 2 points; P < 0.001), and smaller decreases in SpO2 (6MST -5% ± 5%, 6MWT -9% ± 6%; P < 0.001).

CONCLUSIONS

ILD patients exhibited greater ventilatory responses and lower arterial O2 desaturation during the 6MST compared with the 6MWT. The higher lactate concentrations and perceived muscle fatigue observed during the 6MST may indicate the presence of intertest differences in active muscle metabolism that could contribute to the distinct cardiorespiratory responses.

Assessment of dyspnea and dynamic hyperinflation in male patients with chronic obstructive pulmonary disease during a six minute walk test and an incremental treadmill cardiorespiratory exercise test

The six minute walk test (6MWT) is a standardized test that provides information on exercise capacity in patients with COPD. It is considered a submaximal test in opposition to incremental cardiopulmonary exercise tests (CPET) that provide valuable information on all the systems involved in exercise.

OBJECTIVES

1. To compare the perceptive, physiological responses and degree of dynamic hyperinflation during two exercise tests: the 6MWT and the incremental CPET on a treadmill. 2. To evaluate how dyspnea is related to dynamic hyperinflation (DH) and other functional parameters in both tests.

METHODS

29 stable COPD male patients, age 68±5.8 years, mean post-bronchodilator FEV1 57±11%, were recruited. To evaluate dynamic hyperinflation, inspiratory capacity (IC) was measured at rest and upon completing each one of the tests. At the same time, perceived dyspnea and leg discomfort were rated on specific modified Borg scales.

RESULTS

The mean walk distance in 6MWT was 494±88m. The Borg scale rating for shortness of breath upon completing the test was 4.7±2, whilst 2.9±2 for leg discomfort. IC changed from 2.53±0.63l before to 2.34±0.60l after completion of the test. In the treadmill CPET, maximal oxygen consumption (V˙O₂max) was 21.8±5mL/kg/min with 6.6±2 dyspnea and 4.3±2 leg discomfort on Borg scales. IC changed from 2.17±0.53l to 1.20±0.43l.

CONCLUSIONS

Dynamic hyperinflation occurs in male COPD patients during submaximal exercise such as the 6MWT. This phenomenon is more pronounced after incremental CPET on a treadmill. Despite being dyspnea the dominant limiting symptom for both tests, we observed different physiological responses.

Sleep-disordered breathing in patients with COPD and mild hypoxemia: prevalence and predictive variables

OBJECTIVE:

To infer the prevalence and variables predictive of isolated nocturnal hypoxemia and obstructive sleep apnea (OSA) in patients with COPD and mild hypoxemia.

METHODS:

This was a cross-sectional study involving clinically stable COPD outpatients with mild hypoxemia (oxygen saturation = 90-94%) at a clinical center specializing in respiratory diseases, located in the city of Goiânia, Brazil. The patients underwent clinical evaluation, spirometry, polysomnography, echocardiography, arterial blood gas analysis, six-minute walk test assessment, and chest X-ray.

RESULTS:

The sample included 64 patients with COPD and mild hypoxemia; 39 (61%) were diagnosed with sleep-disordered breathing (OSA, in 14; and isolated nocturnal hypoxemia, in 25). Correlation analysis showed that PaO2 correlated moderately with mean sleep oxygen saturation (r = 0.45; p = 0.0002), mean rapid eye movement (REM) sleep oxygen saturation (r = 0.43; p = 0.001), and mean non-REM sleep oxygen saturation (r = 0.42; p = 0.001). A cut-off point of PaO2 ≤ 70 mmHg in the arterial blood gas analysis was significantly associated with sleep-disordered breathing (OR = 4.59; 95% CI: 1.54-13.67; p = 0.01). The model showed that, for identifying sleep-disordered breathing, the cut-off point had a specificity of 73.9% (95% CI: 51.6-89.8%), a sensitivity of 63.4% (95% CI: 46.9-77.9%), a positive predictive value of 81.3% (95% CI: 67.7-90.0%), and a negative predictive value of 53.1% (95% CI: 41.4-64.4%), with an area under the ROC curve of 0.69 (95% CI: 0.57-0.80), correctly classifying the observations in 67.2% of the cases.

CONCLUSIONS:

In our sample of patients with COPD and mild hypoxemia, the prevalence of sleep-disordered breathing was high (61%), suggesting that such patients would benefit from sleep studies.

OBJETIVO:

Inferir a prevalência e as variáveis preditivas de hipoxemia noturna e apneia obstrutiva do sono (AOS) em pacientes portadores de DPOC com hipoxemia leve.

MÉTODOS:

Estudo transversal realizado em pacientes ambulatoriais, clinicamente estáveis, portadores de DPOC e hipoxemia leve (saturação de oxigênio = 90-94%) em um centro clínico especializado no atendimento de doenças respiratórias em Goiânia (GO). Os pacientes foram submetidos à avaliação clínica, espirometria, polissonografia, ecocardiografia, gasometria arterial, teste de caminhada de seis minutos e radiografia de tórax.

RESULTADOS:

Foram avaliados 64 pacientes com DPOC e hipoxemia leve, e 39 (61%) apresentaram distúrbios respiratórios do sono (14 com AOS e 25 com hipoxemia noturna isolada). A análise de correlação mostrou moderada correlação da PaO2 com saturação média do sono (r = 0,45; p = 0,0002), saturação média do sono rapid eye movement (REM; r = 0,43; p = 0,001) e saturação média do sono não-REM (r = 0,42; p = 0,001). Um ponto de corte de PaO2 ≤ 70 mmHg (OR = 4,59; IC95%: 1,54-13,67; p = 0,01) na gasometria arterial foi significativamente associada com distúrbios respiratórios do sono. O modelo mostrou que, para identificar distúrbios respiratórios do sono, o ponto de corte teve uma especificidade de 73,9% (IC95%: 51,6-89,8%), uma sensibilidade de 63,4% (IC95%: 46,9-77,9%) e valores preditivos positivo e negativo de 81,3% (IC95%: 67,7-90,0%) e 53,1% (IC95%: 41,4-64,4%), respectivamente. A área sob a curva ROC foi de 0,69 (IC95%: 0,57-0,80), e a proporção de observações corretamente classificadas foi de 67,2% dos casos.

CONCLUSÕES:

A elevada prevalência de distúrbios respiratórios do sono em portadores de DPOC e hipoxemia leve nesta amostra (61%) sugere que esses pacientes podem se beneficiar da realização de estudos do sono.

Changes in Muscle Strength and Six-Minute Walk Distance Before and After Living Donor Liver Transplantation

BACKGROUND

Impaired exercise capacity and muscle weakness are important characteristics of liver transplantation recipients. Perioperative rehabilitation has been introduced to promote early mobilization of patients and to prevent postoperative pulmonary complications. However, it is unknown how physical status recovers during the hospital stay after a liver transplant. The purpose of this study was to evaluate the changes in clinical indicators that represent the functional exercise capacity and muscle strength before and after living donor liver transplantation (LDLT).

METHODS

We retrospectively reviewed 21 consecutive patients who underwent LDLT with perioperative rehabilitation from April 2014 to December 2015. Twelve patients who were tested for 6-minute walk distance, hand-grip strength, and isometric knee extensor muscle strength before and 4 weeks after LDLT were enrolled.

RESULTS

At the preoperative baseline, the 6-minute walk distance significantly correlated with the Model for End-stage Liver Disease score and pulmonary functions (vital capacity, forced vital capacity, and forced expiratory volume in 1 second of predictive values). Comparisons between the preoperative and postoperative values revealed significant decreases in weight, Barthel Index, hand-grip strength, and isometric knee extensor muscle strength. Changes in hand-grip strength and isometric knee extensor muscle strength after LDLT correlated with the preoperative Model for End-stage Liver Disease score.

CONCLUSIONS

Physical functional status had not been fully recovered 4 weeks after LDLT. Further investigation regarding developing a strategy for prevention of muscle atrophy before LDLT and recovery of physical fitness after LDLT would be helpful.

A multicentre validation of the 1-min sit-to-stand test in patients with COPD

Our aim was to comprehensively validate the 1-min sit-to-stand (STS) test in chronic obstructive pulmonary disease (COPD) patients and explore the physiological response to the test.We used data from two longitudinal studies of COPD patients who completed inpatient pulmonary rehabilitation programmes. We collected 1-min STS test, 6-min walk test (6MWT), health-related quality of life, dyspnoea and exercise cardiorespiratory data at admission and discharge. We assessed the learning effect, test-retest reliability, construct validity, responsiveness and minimal important difference of the 1-min STS test.In both studies (n=52 and n=203) the 1-min STS test was strongly correlated with the 6MWT at admission (r=0.59 and 0.64, respectively) and discharge (r=0.67 and 0.68, respectively). Intraclass correlation coefficients (95% CI) between 1-min STS tests were 0.93 (0.83-0.97) for learning effect and 0.99 (0.97-1.00) for reliability. Standardised response means (95% CI) were 0.87 (0.58-1.16) and 0.91 (0.78-1.07). The estimated minimal important difference was three repetitions. End-exercise oxygen consumption, carbon dioxide output, ventilation, breathing frequency and heart rate were similar in the 1-min STS test and 6MWT.The 1-min STS test is a reliable, valid and responsive test for measuring functional exercise capacity in COPD patients and elicited a physiological response comparable to that of the 6MWT.