Three-minute constant rate step test for detecting exertional dyspnea relief after bronchodilation in COPD

Fixed-intensity exercise tests to measure exertional dyspnoea in chronic heart and lung populations: a systematic review

INTRODUCTION

Exertional dyspnoea is the primary diagnostic symptom for chronic cardiopulmonary disease populations. Whilst a number of exercise tests are used, there remains no gold standard clinical measure of exertional dyspnoea. The aim of this review was to comprehensively describe and evaluate all types of fixed-intensity exercise tests used to assess exertional dyspnoea in chronic cardiopulmonary populations and, where possible, report the reliability and responsiveness of the tests.

METHODS

A systematic search of five electronic databases identified papers that examined 1) fixed-intensity exercise tests and measured exertional dyspnoea, 2) chronic cardiopulmonary populations, 3) exertional dyspnoea reported at isotime or upon completion of fixed-duration exercise tests, and 4) published in English.

RESULTS

Searches identified 8785 papers. 123 papers were included, covering exercise tests using a variety of fixed-intensity protocols. Three modes were identified, as follows: 1) cycling (n=87), 2) walking (n=31) and 3) other (step test (n=8) and arm exercise (n=2)). Most studies (98%) were performed on chronic respiratory disease patients. Nearly all studies (88%) used an incremental exercise test. 34% of studies used a fixed duration for the exercise test, with the remaining 66% using an exhaustion protocol recording exertional dyspnoea at isotime. Exertional dyspnoea was measured using the Borg scale (89%). 7% of studies reported reliability. Most studies (72%) examined the change in exertional dyspnoea in response to different interventions.

CONCLUSION

Considerable methodological variety of fixed-intensity exercise tests exists to assess exertional dyspnoea and most test protocols require incremental exercise tests. There does not appear to be a simple, universal test for measuring exertional dyspnoea in the clinical setting.

Tele-Rehabilitation Interventions for Motor Symptoms in COVID-19 Patients: A Narrative Review

The COVID-19 pandemic brought new challenges to global healthcare systems regarding the care of acute patients and the delivery of rehabilitation programs to post-acute or chronic patients. Patients who survive severe forms of COVID-19 often report incomplete healing and long-term symptoms. The need of these patients for rehabilitation has been recognized as a public health problem. In this context, the application of tele-rehabilitation has been explored to reduce the burden on healthcare systems. The purpose of this narrative review is to present an overview of the state of the art regarding the application of remote motor rehabilitation programs for paucisymptomatic acute and post-acute COVID-19 patients, with a focus on the motor aspects of tele-rehabilitation. Following an extensive search on PubMed, the Web of Science, and Scopus, specific studies have been reviewed and compared in terms of study objectives and participants, experimental protocols and methods for home-based interventions, functional assessment, and rehabilitation outcomes. Overall, this review suggests the feasibility and the effectiveness of tele-rehabilitation as a promising tool to complement face-to-face rehabilitation interventions. However, further improvements are needed to overcome the limitations and the current lack of knowledge in the field.

Tests to uncover and assess breathlessness: a proposed framework

PURPOSE OF REVIEW

Breathlessness is a common, distressing, and limiting symptom that many people avoid by reducing their activity. This review discusses exertional tests that can be used for uncovering and assessing breathlessness depending on the person's severity of illness, function, the setting, and aim of the assessment.

RECENT FINDINGS

Standardized exertional tests are useful to uncover 'hidden' breathlessness earlier in people who may have adapted their physical activity to limit their breathing discomfort. In 'more fit' ambulatory people and outpatients, cardiopulmonary exercise testing is the gold standard for assessing symptom severity, underlying conditions, and mechanisms and treatment effects. Among field tests, the 6-min walk test is not useful for assessing breathlessness. Instead, the 3-min step test and walk test are validated for measuring breathlessness change in chronic obstructive pulmonary disease. In people with more severe illness (who are most often not breathless at rest), reported tests include upper limb exercise or counting numbers aloud, but a valid and useful test for this population is lacking.

SUMMARY

A framework for selecting the most appropriate test to assess breathlessness validly is proposed, and research needs are identified.

Optimising the Dyspnoea Challenge: exertional dyspnoea responses to changing treadmill gradients

BACKGROUND

The Dyspnoea Challenge is a two-minute treadmill walk designed to measure exertional dyspnoea(ED). To efficiently individualise workload, we aimed to assess; 1) whether the Dyspnoea Challenge is responsive to 1% changes in treadmill gradient and 2) the minimum gradient variation necessary to generate a clinically meaningful change in ED (≥1 modified Borg scale).

METHODS

Thirty individuals with COPD(GOLD II-IV) (age: 69.2 ± 9.2 years; FEV₁: 49.3 ± 19.1%) completed six Dyspnoea Challenges at a fixed treadmill speed of 3 km·h^-1 and at a gradient of between 3% and 8%, performed in random order. ED intensity and leg fatigue were measured using the 0-10 modified Borg scale. Heart rate(HR) and oxygen saturation(S_pO₂) were monitored continuously. A multidimensional dyspnoea profile(MDP) was used to quantify the discomfort, physical, e.g., work/effort and breathing frequency, and emotional components of ED.

RESULTS

Higher treadmill gradients generated stronger intensities of ED (3%:2.6 ± 1.8; 4%:2.8 ± 2.2; 5%:3.2 ± 2.2; 6%:3.4 ± 2.2; 7%:3.7 ± 1.8; 8%:4.0 ± 2.1units). Statistical changes were observed in ED(e.g.,3 vs. 5%: P = .03) and the MDP discomfort data(e.g.,4 vs. 6%: P = .04) at ≥ a 2% variation in treadmill gradient. Linear regression found a 4% variation in treadmill gradient corresponded to a rise in ED ≥ 1unit. Increases in ED intensity corresponded to heightened sensations of work/effort(P < .01) and breathing frequency(P < .01). There were no changes in emotional constructs(P = .27). While there was an increase in HR with increasing gradient(P < .01), no differences were observed in end-exercise S_pO₂(P = .79) or leg fatigue(P = .06).

CONCLUSION

To significantly change ED, the treadmill gradient must be manipulated by ≥ 2%, with a ≥ 4% change in gradient required to induce a clinically meaningful change in ED.

Linguistic Validation of the Japanese Version of the Multidimensional Dyspnea Profile and Relation to Physical Activity in Patients with COPD

Purpose

This study aimed to develop a linguistically validated Japanese translation of the multidimensional dyspnea profile (MDP) and assess whether worsening of dyspnea’s sensory and affective domains during exercise had detrimental effects on physical activity in stable outpatients with chronic obstructive pulmonary disease (COPD).

Materials and Methods

The Japanese version of the MDP was prepared in collaboration with Mapi Research Trust (Lyon, France) after the approval of the developer. Physical activity was assessed using a 3-axis accelerometer. Dyspnea upon exertion was investigated using a 3-minute step test.

Results

The Japanese version of the MDP was obtained and validated linguistically. Air-hunger was significantly associated with total calories from walking (r = − 0.47, p < 0.05), while anxiety and depression were significantly correlated with both the amount and intensity of physical activity (r = − 0.49, p < 0.05, and r = − 0.46, p < 0.05, respectively).

Conclusion

The Japanese version of the MDP was suggested to reflect both pulmonary functions, ventilatory response during exercise, and intensity and amount of physical activity in patients with COPD.

Examining the repeatability of a novel test to measure exertional dyspnoea in chronic obstructive pulmonary disease

BACKGROUND

Exertional dyspnoea(ED) is a hallmark of chronic obstructive pulmonary disease(COPD). We examined the repeatability and face validity of the end-exercise ED(ED_end) response during the Dyspnoea Challenge and compared those to the six-minute walk test (6MWT) in COPD.

METHODS

Twenty-six individuals with COPD(13 Females, age:69 ± 5.5yrs, FEV₁:63.4 ± 11.9 %) completed 2 × 6MWTs and 4 x Dyspnoea Challenges on three occasions. The challenge consisted of a two-minute treadmill walk at 80 % of 6MWT speed(3.9 ± 0.5 km·hr^-1) at either a low(LI_DC:5.3 ± 2%) or high angle of incline(HI_DC:9.5 ± 3%). Dyspnoea(0-10 scale), heart rate(HR) and oxygen saturation(S_pO₂) were monitored continuously.

RESULTS

Mean 6MWT distance was 488 ± 58 m. End-exercise ED and HR were higher in the HI_DC(ED_end 6.2 ± 2.0; HR: 123 ± 17beats·min^-1) compared to the LI_DC(ED_end 4.2 ± 2.0; HR: 119 ± 15beats·min^-1) and the 6MWT(ED_end 4.3 ± 2.0; HR: 115 ± 16beats·min^-1)(P < 0.01). SpO₂ was not different between 6MWT, LI_DC or HI_DC(P = 0.34). The intraclass correlation coefficient(ICC) for each intensity was excellent (HI_DC, ICC = 0.88, LI_DC, ICC = 0.93, P < 0.001) with neither reporting bias(HI_DC, P = 0.63; LI_DC, P = 0.94).

CONCLUSIONS

The Dyspnoea Challenge is a simple measure of ED that appears to have both repeatability and face validity. With further optimisation, this test may enhance the field-based clinical assessment of ED.

Exertional multidimensional dyspnoea predicts exacerbation in stable outpatients with COPD

Dyspnoea is a risk factor for mortality in patients with chronic obstructive pulmonary disease (COPD) [1]. Awareness of the magnitude of respiratory drive to the respiratory muscles contributes to dyspnoea [2]. In line with this mechanism, elevated respiratory neural drive during hospitalisation and at hospital discharge, predicts readmission and mortality in patients with acute exacerbation of COPD [3, 4]. Furthermore, patients with COPD who experienced frequent exacerbations had heightened dyspnoea due to hypercapnia, compared with those with infrequent exacerbations [5]. Therefore, changes in the afferent and efferent loops involved in dyspnoea contribute to COPD exacerbations.

This study assessed the sensory and emotional aspects of breathlessness under the same exercise load in patients with COPD. Breathing discomfort with constant exercise predicted exacerbations within 1 year.https://bit.ly/3l2oA4A

[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.

Determination of the minimal important difference for Dyspnoea-12 questionnaire in patients with COPD, after pulmonary rehabilitation

INTRODUCTION

The authors of the international task force about the management of Dyspnoea recommend assessing sensory and affective components of dyspnoea. The Dyspnoea-12 questionnaire (D-12) allows to assess both components of dyspnoea. D-12 is valid and reliable but its sensitivity to pulmonary rehabilitation was not studied. The aim of this study was to estimate the minimal important difference (MID) for D-12 in COPD patients undergoing a pulmonary rehabilitation programme (PRP).

METHODS

Severe or very severe COPD patients undergoing a PRP were included. Dyspnoea was assessed using D-12, MMRC dyspnoea scale, London chest of Activity of Daily Living questionnaire (LCADL). Quality of life was assessed using Saint-George respiratory questionnaire (SGRQ) and COPD assessment Test (CAT); exercise capacity using 6-Minute walk Test (6MWT) and 1-minute sit to-stand test (1STST). The MID was evaluated using distribution and anchor-based methods.

RESULTS

Sixty patients (age: 64.4 ± 8.2; FEV1 (%): 28.6 ± 8.1) were included. At the end of the PRP, patients had significantly decreased their dyspnoea measured with D-12, MMRC, LCADL (D-12:23.9 ± 8.9 to 17.6 ± 9.4; MMRC: 3 ± 0.7 to 2.2 ± 1.1, LCADL: 38 ± 13.9 to 31.6 ± 11; p < 0.0001). Using the distribution-based analysis, MID of -2.67 (standard error of measurement) or -4.45 (standard deviation) was found. According to methodology, we could only use SGRQ as anchor. With SGRQ as anchor, the receiver operating characteristic curve identified MID for the change in D-12 at -6.1 (sensibility: 58%, specificity: 79%). The correlation with SGRQ was modest (r = 0.33), so the calculated MID should be interpreted with caution.

CONCLUSION

D-12 is a good tool to assess the decrease of dyspnoea after PR. We propose MID of -6 points. However, Future estimates of MID for the D-12 should use anchors that are more strongly correlated with it.

Effects of Sarcopenia on Ventilatory Behavior and the Multidimensional Nature of Dyspnea in Patients With Chronic Obstructive Pulmonary Disease

OBJECTIVES

This study tested the hypothesis that sarcopenia, a common extrapulmonary feature of chronic obstructive pulmonary disease (COPD), can affect ventilatory behavior, and worsen the multidimensional nature of dyspnea in patients with COPD.

DESIGN

Cross-sectional survey study.

SETTING

and Participants: Stable outpatients with COPD encountered in general practice and respiratory clinic.

METHOD

Sarcopenia was diagnosed according to an appendicular skeletal muscle mass index based on measurements of electrical impedance and handgrip strength. Exertional dyspnea was tested using a 3-minute Step Test and a 6-minute Walk Test. The dimensions of dyspnea were assessed by a multidimensional dyspnea profile.

RESULTS

Of 60 stable patients with COPD, 16 met the criteria for sarcopenia. During the 3-minute Step Test, minute ventilation as a proportion of exercise time, tidal volume as a proportion of inspiratory capacity, the change in inspiratory capacity, and ventilation as a proportion of maximal voluntary ventilation did not differ between patients with and without sarcopenia. Patients with sarcopenia exhibited lower evolution of tidal volume, higher evolution of respiratory frequency versus ventilation and breathing discomfort on the 3-minute Step Test, as well as increased physical breathing effort on the 6-minute Walk Test, compared with those without sarcopenia. In a multivariable model adjusted using inverse probability weighting, sarcopenia was independently associated with breathing discomfort during the 3-minute Step Test and physical breathing effort during the 6-minute Walk Test.

CONCLUSIONS AND IMPLICATIONS

Sarcopenia may be associated with shallow breathing and diverse sensory and affective components of exertional dyspnea in patients with COPD. The study indicates that improvement of the rapid breathing pattern may offer unique ways to alleviate dyspnea in older patients with COPD and sarcopenia.

Measurement properties of step tests for exercise capacity in COPD: A systematic review

Objective:

To determine the level of evidence of the measurement properties (validity, reliability, and responsiveness) and interpretability of the step tests available for assessing the exercise capacity in patients with chronic obstructive pulmonary disease.

Data sources:

The data sources Web of Science, MEDLINE, PubMed, PEDro, CENTRAL of Cochrane Library, and Scopus were searched up to June 26, 2020.

Review methods:

Studies of any design that reported results for any measurement property of the step tests for assessing the exercise capacity in COPD patients were selected. One reviewer extracted the data, and two reviewers independently rated the level of evidence by using the Consensus-Based Standards for the Selection of Health Measurements Instruments recommendations.

Results:

Thirty-one studies were included in the data synthesis. Chester Step Test, Modified Incremental Step Test, two-, three-, four-, and six-Minute Step Test, Paced Step Test, and six-Minute Stepper Test were identified. A step test protocol was also found. The level of evidence of their results for the measurement properties was mostly determined as “low” to “very low.” The best level of evidence found was for the six-minute stepper test: “high” on construct validity (r = 0.56–0.71); and “moderate” on criterion validity (r = 0.36–0.69), and responsiveness (r = 0.26–0.34).

Conclusion:

The general level of evidence of the measurement properties of the step tests is “low” to “very low” for assessing exercise capacity in patients with chronic obstructive pulmonary disease, which can limit their application in clinical practice. The six-minute Stepper Test is currently the most appropriate step test available.

Home-based or remote exercise testing in chronic respiratory disease, during the COVID-19 pandemic and beyond: A rapid review

Objectives:

To identify exercise tests that are suitable for home-based or remote administration in people with chronic lung disease.

Methods:

Rapid review of studies that reported home-based or remote administration of an exercise test in people with chronic lung disease, and studies reporting their clinimetric (measurement) properties.

Results:

84 studies were included. Tests used at home were the 6-minute walk test (6MWT, two studies), sit-to-stand tests (STS, five studies), Timed Up and Go (TUG, 4 studies) and step tests (two studies). Exercise tests administered remotely were the 6MWT (two studies) and step test (one study). Compared to centre-based testing the 6MWT distance was similar when performed outdoors but shorter when performed at home (two studies). The STS, TUG and step tests were feasible, reliable (intra-class correlation coefficients >0.80), valid (concurrent and known groups validity) and moderately responsive to pulmonary rehabilitation (medium effect sizes). These tests elicited less desaturation than the 6MWT, and validated methods to prescribe exercise were not reported.

Discussion:

The STS, step and TUG tests can be performed at home, but do not accurately document desaturation with walking or allow exercise prescription. Patients at risk of desaturation should be prioritised for centre-based exercise testing when this is available.

Standardized measurement of breathlessness during exercise

PURPOSE OF REVIEW

Exertional breathlessness is common and pervasive across various chronic disease populations. To accurately assess response to intervention and optimize clinical (symptom) management, detailed assessment of exertional breathlessness is imperative. This review provides an update on current approaches to assess exertional breathlessness and presents the need for individualized assessment of breathlessness standardized for the level of exertion.

RECENT FINDINGS

Breathlessness assessment tools commonly invite people to recall their breathlessness while at rest with reference to activities of daily living. To directly quantify breathlessness, however, requires assessment of the dimensions of breathlessness (e.g., sensory intensity, quality, and unpleasantness) in response to a standardized exercise stimulus. Different exercise stimuli (e.g., self-paced, incremental, and constant work rate exercise tests) have been used to elicit a breathlessness response. Self-paced (e.g., 6-min walk test) and incremental exercise tests assess exercise tolerance or endurance, and are not recommended for assessment of exertional breathlessness. Constant work rate tests, however, including recently validated 3-min constant-rate stair stepping and walking tests, standardize the exercise stimulus to enable the breathlessness response to be directly quantified and monitored over time.

SUMMARY

To adequately guide symptom management and assess intervention efficacy, clinicians and researchers should assess breathlessness with multidimensional assessment tools in response to a standardized and individualized exercise stimulus.

Why treatment efficacy on breathlessness in laboratory but not daily life trials? The importance of standardized exertion

PURPOSE OF REVIEW

Treatments for chronic breathlessness, including opioids and oxygen, have shown efficacy in the controlled laboratory setting, whereas effects have been inconsistent or absent in trials in daily life. This review discusses the lack of standardized exertion as a potential cause of false negative findings for breathlessness in daily life.

RECENT FINDINGS

The level of breathlessness can be modified by patients by changing their level of physical activity. Effects of opioids and oxygen have been shown at standardized level of exertion (iso-time) but not at the end of symptom-limited (peak) exertion. Trials in daily life reporting no effects on breathlessness did not standardize the exertion or employed insensitive methods, such as the 6-min walk test that should not be used for measuring breathlessness. Novel tests - the 3-min walk and stepping tests have been validated in chronic obstructive pulmonary disease and are responsive for measuring change in breathlessness.

SUMMARY

Breathlessness should be measured at standardized exertion, otherwise treatment effects may be biased or overlooked. Tests for valid measurement of breathlessness in clinical practice and daily life are available and emerging.

Predicting the rate of oxygen consumption during the 3-minute constant-rate stair stepping and shuttle tests in people with chronic obstructive pulmonary disease

Background

The 3-minute constant-rate stair stepping (3-min CRSST) and constant-speed shuttle tests (3-min CSST) were developed to assess breathlessness in response to a standardized exercise stimulus. Estimating the rate of oxygen consumption (V’O₂) during these tests would assist clinicians to relate the stepping/shuttle speeds that elicit breathlessness to daily physical activities with a similar metabolic demand. This study: (I) developed equations to estimate the V’O₂ of these tests in people with chronic obstructive pulmonary disease (COPD); and (II) compared the newly developed and American College of Sports Medicine (ACSM) metabolic equations for estimating the V’O₂ of these tests.

Methods

This study was a retrospective analysis of people with COPD who completed a 3-min CRSST (n=98) or 3-min CSST (n=69). Multivariate linear regression estimated predictors (alpha <0.05) of V’O₂ to construct COPD-specific metabolic equations. The mean squared error (MSE) of the COPD-specific and ACSM equations was calculated and compared. Bland-Altman analyses evaluated level of agreement between measured and predicted V’O₂ using each equation; limits of agreement (LoA) and patterns of bias were compared.

Results

Stepping rate/shuttle speed and body mass were identified as significant predictors of V’O₂. The MSE of the COPD-specific equations was 0.05 L·min⁻¹ for both tests. Mean difference between measured and predicted V’O₂ was 0.00 L·min⁻¹ (95% LoA −0.46, 0.46) and 0.00 L·min⁻¹ (95% LoA −0.44, 0.44) for the 3-min CRSST and 3-min CSST, respectively. For the ACSM metabolic equations, the MSE was 0.10 L·min⁻¹ and 0.18 L·min⁻¹ for the 3-min CRSST and 3-min CSST, respectively. The ACSM metabolic equations underestimated V’O₂ of the 3-min CRSST by −0.18 L·min⁻¹ (95% LoA −0.68, 0.32), and overestimated V’O₂ of the 3-min CSST by 0.35 L·min⁻¹ (95% LoA −0.14, 0.84).

Conclusions

This study presents metabolic equations to predict V’O2 of the 3-min CRSST and 3-min CSST for people with COPD that are more accurate than the ACSM metabolic equations.

Physiological and perceptual responses to exercise according to locus of symptom limitation in COPD

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease, with pulmonary and extra-pulmonary factors contributing to exercise intolerance. The primary self-reported exercise-limiting symptom may reflect the primary pathophysiological factor contributing to exercise intolerance. We compared physiological and perceptual responses at the symptom-limited peak of incremental cardiopulmonary cycle exercise testing between people with COPD reporting breathlessness (B, n = 34), leg discomfort (LD, n = 16), or a combination of B and LD (BOTH, n = 42) as their main exercise-limiting symptom(s). Despite similarly impaired health status, symptomology and peak exercise capacity, the B group had greater restrictive constraints on tidal volume expansion at end-exercise and was more likely to report unpleasant qualities of exertional breathlessness than LD and BOTH groups. In conclusion, reporting breathlessness as the primary exercise-limiting symptom indicated the presence of distinct lung pathophysiology and symptom perception during exercise in people with COPD.

Faster oxygen uptake, heart rate, and ventilatory kinetics in stepping compared with cycle ergometry in patients with COPD during moderate-intensity exercise

Step tests are a stressful and feasible cost-effective modality to evaluate aerobic performance. However, the eccentric in addition to concentric muscle contractions of the legs on stepping emerge as a potential speeding factor for cardioventilatory and metabolic adjustments towards a steady-state, since eccentric contractions would prompt an earlier and stronger mechanoreceptor activation, as well as higher heart rate/cardiac output adjustments to the same metabolic demand. Moreover, shorter tests are ideal for exercise-limited subjects. Nine subjects with chronic obstructive pulmonary disease were invited to participate in comprehensive lung function tests and constant work tests performed on different days at a 90% gas exchange threshold for 6 min, in single-step tests or cycle ergometry. After careful monoexponential regression modelling, statistically relevant faster phase II time constants for oxygen uptake (45 ± 18 s vs 53 ± 17 s, p = 0.017) and minute ventilation (61 ± 13 s vs 74 ± 17 s, p = 0.027) were observed in the 6-min step tests compared with cycle ergometry, respectively. Despite an absence of heart rate time constant difference (43 ± 20 s vs 69 ± 46 s, p = 0.167), there was a significantly faster rate constant toward a steady state for heart rate (p = 0.02). In addition, 4-min compared with 6-min analysis presented similar results (p > 0.05), providing an appropriate steady-state. We conclude that step tests might elicit faster time constants compared with cycle ergometry, at the same average metabolic level, and 4-min analysis has similar mean errors compared with 6-min analysis within an acceptable range. New studies, comprising mechanisms and detailed physiological backgrounds, are necessary.