Lisa Wickerson

The 6-min walk test: responses in healthy Canadians aged 45 to 85 years

We sought to describe responses to the 6-min walk test (6MWT) in healthy Canadian adults in order to facilitate interpretation of its results in patient populations. Seventy-seven healthy Canadians aged 45 to 85 years (65 ± 11 years, 40 females) completed this study. During a single visit, three 6MWTs were undertaken. The main outcome measure was 6-min walk distance (6MWD). Age, gender, height, and weight were recorded. In 61 (79%) participants, cardiorespiratory variables were collected during the third 6MWT using a calibrated portable gas analysis system. The 6MWD increased between the first and second test (615 ± 96 to 639 ± 98 m; p < 0.001) with no further improvement on the third test (638 ± 99 m; p = 0.945). The best 6MWD from the first 2 tests was 640 ± 99 m (range 416 to 880 m). A greater 6MWD was achieved by males compared with females (672 ± 94 vs. 611 ± 93 m; p = 0.005). The following equation accounted for 49% of the variance in 6MWD: 6MWD = 970.7 + (-5.5 × age) + (56.3 × gender), where females = 0, males = 1. The 6MWT elicited large cardiorespiratory responses with minimal symptoms. The rate of oxygen uptake measured at test-end was associated with the 6MWD (r = 0.802; p < 0.001). These data allow the 6MWD achieved in Canadian adults to be expressed as a percentage of the predicted value and provide researchers and clinicians with values for the expected cardiorespiratory responses in a healthy adult population for the purpose of comparison with patient populations.

Physical Activity Profile of Lung Transplant Candidates With Interstitial Lung Disease

PURPOSE: Little is known about physical activity in individuals with interstitial lung disease (ILD). The objectives of this study were (1) to objectively measure physical activity in lung transplant candidates with ILD, (2) to compare levels of physical activity on rehabilitation and nonrehabilitation days, and (3) to explore the relationships between physical activity and functional measures. METHODS: Twenty-four (14 men) lung transplant candidates with ILD on long-term oxygen therapy, who were enrolled in an exercise-based rehabilitation program, underwent measurements of physical activity using accelerometry (daily steps and time spent in moderate-intensity physical activity per day), functional exercise capacity (6-minute walk distance), and muscle strength (isometric quadriceps torque). RESULTS: Lung transplant candidates with ILD had reduced levels of physical activity compared to the general population but were more active on rehabilitation versus nonrehabilitation days (M ± SD) (daily steps, 3780 ± 2196 vs 2138 ± 1353; P < .001; and time spent in moderate-intensity activity per day, 4.5 [interquartile range, 1.5–17] minutes vs 2 [interquartile range, 1–3.5] minutes). The 6-minute walk distance showed the strongest correlation to daily steps (r = 0.59, P < .01) and time spent in moderate-intensity physical activity per day (r = 0.56, P < .01). CONCLUSIONS: Individuals with advanced ILD are markedly inactive; however, physical activity levels were significantly higher on rehabilitation days. The importance of physical activity as a rehabilitation outcome in ILD warrants further investigation.

Meeting Report: Consensus Recommendations for a Research Agenda in Exercise in Solid Organ Transplantation

With improved survival rates in solid organ transplantation there has been an increased focus on long‐term outcomes following transplant, including physical function, health‐related quality‐of‐life and cardiovascular mortality. Exercise training has the potential to affect these outcomes, however, research on the optimal timing, type, dose of exercise, mode of delivery and relevant outcomes is limited. This article provides a summary of a 2‐day meeting held in April 2013 (Toronto, Canada) in which a multi‐disciplinary group of clinicians, researchers, administrators and patient representatives engaged in knowledge exchange and discussion of key issues in exercise in solid organ transplant (SOT). The outcomes from the meeting were the development of top research priorities and a research agenda for exercise in SOT, which included the need for larger scale, multi‐center intervention studies, development of standardized outcomes for physical function and surrogate measures for clinical trials, examining novel modes of exercise delivery and novel outcomes from exercise training studies such as immunity, infection, cognition and economic outcomes. The development and dissemination of “expert consensus guidelines,” synthesizing both the best available evidence and expert opinion was prioritized as a key step toward improving program delivery.

Skeletal muscle atrophy in advanced interstitial lung disease

A limited number of studies examine skeletal muscle dysfunction in individuals with interstitial lung disease (ILD). We compared upper and lower limb muscle size and strength in individuals with advanced ILD with healthy controls. Second, the relationships of muscle size to muscle strength and function were explored.

Sarcopenia in lung transplantation: A systematic review

Lung transplant candidates and recipients have significant impairments in skeletal muscle mass, strength and function--individual measures of sarcopenia. Skeletal muscle dysfunction has been observed in the pre-transplant and post-transplant period and could have an important effect on transplant outcomes. A systematic review was performed to characterize the techniques used to study sarcopenia and assess the level of impairment throughout the transplant process. Electronic databases were searched (inception to July 2013) for prospective studies measuring at least 1 element of sarcopenia (muscle mass, strength, or function) in lung transplant patients. Eighteen studies were included, and study quality was assessed using the Downs and Black scale. A variety of measurements were used to evaluate sarcopenia in 694 lung transplant patients. Muscle mass in 7 studies was assessed using bioelectrical impedance (n = 4), computed tomography or magnetic resonance imaging (n = 2), or skin folds (n = 1), and was significantly reduced. Quadriceps strength was examined in 14 studies with computerized dynamometer (n = 10) and hand-held dynamometer (n = 4). Quadriceps strength was reduced in the pre-transplant period (mean range, 49%-86% predicted; n = 455 patients), further reduced immediately after transplant (51%-72%, n = 126), and improved beyond 3 months after transplant (58%-101%, n = 164). Only 2 studies measured lower extremity function (sit-to-stand test). A multitude of measurement techniques have been used to assess individual measures of sarcopenia, with reduced muscle mass and quadriceps strength observed in the pre-transplant and post-transplant period. Further standardization of measurement techniques is needed to assess the clinical effect of sarcopenia in lung transplantation.

Availability, characteristics, and barriers of rehabilitation programs in organ transplant populations across Canada.

Trojetto T, Elliott RJ, Rashid S, Wong S, Dlugosz K, Helm D, Wickerson L, Brooks D. Availability, characteristics, and barriers of rehabilitation programs in organ transplant populations across Canada. 
Clin Transplant 2011: 25: E571–E578.

Physical rehabilitation for lung transplant candidates and recipients: An evidence-informed clinical approach.

Physical rehabilitation of lung transplant candidates and recipients plays an important in optimizing physical function prior to transplant and facilitating recovery of function post-transplant. As medical and surgical interventions in lung transplantation have evolved over time, there has been a demographic shift of individuals undergoing lung transplantation including older individuals, those with multiple co-morbidites, and candidates with respiratory failure requiring bridging to transplantation. These changes have an impact on the rehabilitation needs of lung transplant candidates and recipients. This review provides a practical approach to rehabilitation based on research and clinical practice at our transplant centre. It focuses on functional assessment and exercise prescription during an uncomplicated and complicated clinical course in the pre-transplant, early and late post-transplant periods. The target audience includes clinicians involved in pre- and post-transplant patient care and rehabilitation researchers.

Factors affecting discharge destination following lung transplantation

Lung transplant (LT) recipients requiring additional care may be referred to inpatient rehabilitation prior to discharge home. This study seeks to describe discharge destinations following LT, compare the characteristics of patients discharged to different destinations, and identify the predictors of discharge destination.

Evaluation of Skeletal Muscle Function in Lung Transplant Candidates

Background Lung transplantation (LTx) is offered to older and more complex patients who may be at higher risk of skeletal muscle dysfunction, but the clinical implications of this remain uncertain. The study aims were to characterize deficits in skeletal muscle mass, strength and physical performance, and examine the associations of these deficits with clinical outcomes. Methods Fifty LTx candidates (58% men; age, 59 ± 9 years) were prospectively evaluated for skeletal muscle deficits: muscle mass using bioelectrical impedance, quadriceps, respiratory muscle and handgrip strength, and physical performance with the Short Physical Performance Battery. Comparisons between number of muscle deficits (low muscle mass, quadriceps strength and physical performance) and 6-minute walk distance (6MWD), London Chest Activity of Daily Living Questionnaire, and quality of life were assessed using one-way analysis of variance. Associations with pretransplant and posttransplant delisting/mortality, hospital duration, and 3-month posttransplant 6MWD were evaluated using Fisher exact test and Spearman correlation. Results Deficits in quadriceps strength (n = 27) and physical performance (n = 24) were more common than muscle mass (n = 8). LTx candidates with 2 or 3 muscle deficits (42%) compared with those without any deficits (26%) had worse 6MWD = −109 m (95% confidence interval [CI], −175 to −43), London Chest Activity of Daily Living Questionnaire = 18 (95% CI, 7-30), and St. Georges Activity Domain = 12 (95% CI, 2-21). Number of muscle deficits was associated with posttransplant hospital stay (r = 0.34, P = 0.04), but not with delisting/mortality or posttransplant 6MWD. Conclusions Deficits in quadriceps muscle strength and physical performance are common in LTx candidates and further research is needed to assess whether modifying muscle function pretransplant can lead to improved clinical outcomes.

Peripheral Muscle Dysfunction in Interstitial Lung Disease: A Scoping Study

Purpose: To characterize the state of the evidence for peripheral muscle dysfunction in individuals with interstitial lung disease (ILD). Method: A scoping study was performed by searching multiple electronic databases for published papers and conference abstracts of any study design that included a measure of peripheral muscle dysfunction and/or structural and metabolic characteristics of muscle. All sub-types of ILD were eligible. Result: Forty-five studies representing 2522 individuals with 34 sub-types of ILD were included in this study. Data were charted using descriptive numerical analysis of study characteristics. Peripheral muscle dysfunction was predominantly reflected by reduced volitional isometric strength (17 studies), whereas the evaluation of muscle endurance was rare (2 studies). Volitional muscle force or torque was measured in the quadriceps (14 studies) and handgrip (8 studies), with strength preferentially reduced in the lower limbs. Eight studies measured structural or metabolic characteristics and found evidence of reduced muscle size and oxidative stress. Findings of muscle injury and muscle inflammation (e.g. serum markers, electromyography and muscle biopsies) were reported primarily in individuals with idiopathic inflammatory myopathies and connective tissue diseases. Conclusions: Reduced volitional muscle strength was the most common finding of peripheral muscle dysfunction in ILD. Further quantification of peripheral muscle dysfunction and identification of structural and metabolic characteristics are needed to target specific interventions and optimize muscle function.