Preferential reduction of quadriceps over respiratory muscle strength and bulk after lung transplantation for cystic fibrosis

Physical Activity and Quality of Life among Patients with Cystic Fibrosis

BACKGROUND

Physical activity (PA) improves exercise capacity, slows the decline in lung function, and enhances Quality of Life (QoL) in patients with cystic fibrosis (pwCF).

OBJECTIVES

The study aimed to evaluate PA and QoL among children with CF compared to healthy controls; the secondary aim was to assess the correlation between PA, QoL, and lung function (FEV1).

METHODS

Forty-five children and adolescents with CF and 45 age-matched controls completed two self-administered validated questionnaires: The Godin Leisure-Time Exercise Questionnaire (GLTEQ) and the DISABKIDS for QoL. Moreover, pwCF performed spirometry and multiple breath washout tests (MBW). In addition, weight, height, and BMI were recorded. The Godin Leisure-Time Exercise Questionnaire was used to evaluate physical activity; QOL was assessed using the DISABKIDS Questionnaire. The correlation of PA with QOL was assessed as well.

RESULTS

Mean age of the CF population was 13.22 (±4.6) years, mean BMI 19.58 (±4.1) kg/m2, mean FEV1% 91.15 ± 20.46%, and mean LCI 10.68 ± 4.08. 68% of the CF group were active, 27% were medium active, 5% were sedentary, while 83% of the control group were active and 17% were medium active. PwCF with higher PA scores showed significantly higher emotional health (r2: 0.414, p: 0.006) and total QOL score (r2: 0.372; p: 0.014). The PA score showed no significant correlation with FEV1% or LCI.

CONCLUSIONS

The children with CF showed satisfactory PA levels, which positively correlated to their QoL. More research is needed on the effect of increased levels of habitual physical activity to establish the decline in pulmonary function among pwCF.

Body Function and Structure, Activity, and Participation Limitations of Lung Transplant Recipients Within the Scope of the International Classification of Functioning, Disability, and Health

OBJECTIVES

There is no study in the literature that specifically evaluates lung transplant recipients in the long-term under the framework of the International Classification of Functioning, Disability, and Health. The aim of this study was to evaluate the relationships between lung transplant recipient age, age at transplant, and comorbidity levels and the body structure and functions and the activity and participation levels of patients within the scope of the International Classification of Functioning, Disability, and Health.

MATERIALS AND METHODS

We evaluated 27 lung transplant recipients according to the International Classification of Functioning, Disability, and Health items in domain b (body functions), domain s (body structures), and domain d (activities and participation). For domain b, sleep functions, psychosocial status, respiratory functions, and upper and lower extremity exercise capacity were evaluated. Posture was evaluated for the s domain. Balance, arm functional capacity, health-related quality of life, and physical activity were evaluated for domain d.

RESULTS

As the age of lung transplant recipients and the age at transplant increase, their sleep quality and respiratory functions decreased, and postural impairment increased. There was a negative correlation between age at transplant and functional exercise capacity (P < .05). As the comorbidity level of the recipient increases, the upper and lower extremity exercise capacity, physical activity level, and quality of life declined. There was a moderately positive correlation between the level of comorbidity and balance disorder (P < .05).

CONCLUSIONS

We found the International Classification of Functioning, Disability, and Health framework to be useful for the evaluation and for planning pulmonary rehabilitation for lung transplant recipients; it can bring a new perspective to physiotherapists specialized in cardiopulmonary rehabilitation.

The effect of steroid administration on fetal diaphragm function

Background

Antenatal steroid administrations lead to not only accelerated lung maturation, improved blood gas measurements but also lung dynamics and lung compliance. This study aimed to investigate structural and functional changes in diaphragm after antenatal steroid administration.

Methods

The 79 volunteers were divided into 2 groups according to presence of preterm delivery. Betamethasone (Celestone^R) 12 mg intramuscularly was routinely administered to pregnancies complicated with preterm delivery between 28th -34th weeks of gestation. Same dose was repeated 24 h later. In all patients, diaphragm thickness, diaphragmatic excursion and costophrenic angle were measured in both the inspirium and expirium stage of respiration. This is an observational cross-sectional study.

Results

Diaphragm thickness, diaphragmatic excursion and diaphragm thickening fraction parameters were improved but costophrenic angle was not different 7 days after steroid administration. Diaphragm thickness, diaphragmatic excursion and costophrenic angle changes during inspiration and expiration stage after 7 days of betamethasone treatment reflects the effect of steroid administration on diaphragm muscle. Comparisons of the differences that occur after steroid rescue protocol were done by subtracting the diaphragm thickness, diaphragmatic excursion and costophrenic angle parameters before the treatment from the diaphragm thickness, diaphragmatic excursion and costophrenic angle parameters 7 days after steroid treatment respectively.

Conclusion

Diaphragm became more mobile in patients with preterm labor, 7 days after steroid administration. This situation reflects positive effect of steroid administration on diaphragm function.

Early postoperative complications in lung transplant recipients

Lung transplantation has become an established therapy for end-stage lung diseases. Early postoperative complications can impact immediate, mid-term, and long-term outcomes. Appropriate management, prevention, and early detection of these early postoperative complications can improve the overall transplant course. In this review, we highlight the incidence, detection, and management of these early postoperative complications in lung transplant recipients.

Glucocorticoid-induced myopathy in people with asthma: a systematic review

OBJECTIVES

To review the current literature on the evidence and the underlying characteristics of glucocorticoids (type, dosage, and duration) associated with myopathy in asthma.

DATA SOURCES

Four electronic databases were searched to October 19, 2020.

STUDY SELECTION

Inclusion criteria: adults or adolescents with asthma, taking systemic glucocorticoids, and measures of muscle impairments.

RESULTS

Nine studies met the eligibility criteria. The methodologic quality of most studies was fair or good. Two studies reported significantly lower inspiratory muscle function in outpatients taking daily oral glucocorticoids (≥10 mg), but one study reported no such difference. No differences was found in limb muscle strength in one study. Only 11-36% patients with acute exacerbation taking glucocorticoids intravenously suffered from limb muscle weakness during/after critical care admissions. Two studies reported significant associations between dosage of oral glucocorticoid use and inspiratory and limb muscle function, whereas seven studies did not find any significant correlations among the characteristics of systemic glucocorticoids and myopathy. Two studies comparing people with non-glucocorticoid dependent asthma taking inhaled glucocorticoid and healthy people did not find any significant differences in their inspiratory muscle strength and endurance.

CONCLUSIONS

There were limited studies and inconsistent results on glucocorticoid-induced myopathy in people with asthma, and its association with the characteristics of glucocorticoids use. We recommended future studies should use a commonly accepted operational definition of myopathy, utilize a cohort study design, measure the cumulative dosage of glucocorticoids, and integrate possible confounding factors in the analysis.

The Utility of the Sit-to-Stand Test for Inpatients in the Acute Hospital Setting After Lung Transplantation

OBJECTIVE

Measurement of physical function is important to guide physical therapy for patients post-lung transplantation (LTx). The Sit-to-Stand (STS) test has proven utility in chronic disease, but psychometric properties post-LTx are unknown. The study aimed to assess reliability, validity, responsiveness, and feasibility of the 60-second STS post-LTx.

METHODS

This was a measurement study in 62 inpatients post-LTx (31 acute postoperative; 31 medical readmissions). Interrater reliability was assessed with 2 STS tests undertaken by different assessors at baseline. Known group validity was assessed by comparing STS repetitions in postoperative and medical groups. Content validity was assessed using comparisons to knee extensor and grip strength, measured with hand-held dynamometry. Criterion validity was assessed by comparison of STS repetitions and 6-minute walk distance postoperatively. Responsiveness was assessed using effect sizes over inpatient admission.

RESULTS

Median (interquartile range) age was 62 (56-67) years; time post-LTx was 5 (5-7) days postoperative and 696 (244-1849) days for medical readmissions. Interrater reliability was excellent (intraclass correlation coefficient type 2,1 = 0.96), with a mean learning effect of 2 repetitions. Repetitions were greater for medical at baseline (mean 18 vs 8). More STS repetitions were associated with greater knee extensor strength (postoperative r = 0.57; medical r = 0.47) and 6-minute walk distance (postoperative r = 0.68). Effect sizes were 0.94 and 0.09, with a floor effect of 23% and 3% at baseline (postoperative/medical) improving to 10% at discharge. Patients incapable of attempting a STS test were excluded, reducing generalizability to critical care. Physical rehabilitation was not standardized, possibly reducing responsiveness.

CONCLUSIONS

The 60-second STS demonstrated excellent interrater reliability and moderate validity and was responsive to change postoperatively.

IMPACT

The 60-second STS represents a safe, feasible functional performance tool for inpatients post-LTx. Two tests should be completed at each time point.

Sarcopenia of thoracic muscle mass is not a risk factor for survival in lung transplant recipients

BACKGROUND

In lung transplantation (LTx), patients with thoracic muscle sarcopenia may have to require longer to recovery. We measured thoracic muscle volume by using the cross sectional area (CSA) and assessed its effect on early outcomes after LTx.

METHODS

A retrospective analysis was conducted to evaluate the effect of thoracic sarcopenia in patients undergoing LTx between January 2010 and July 2015. The lowest CSA quartile (Q1) was defined as sarcopenia.

RESULTS

In total, 109 patients were enrolled. The mean CSA was 58.24±15.82 cm(2). Patients in the highest CSA quartile were more likely to be male (92.6% vs. 17.9%, P<0.001), older (55.2±10.1 vs. 43.2±14.9 years, P=0.001), to have a higher body mass index (BMI) (22.3±4.0 vs. 19.4±3.7 kg/m(2), P=0.007), and to have pulmonary fibrosis (85.2% vs. 35.7%, P=0.003) compared with the lowest CSA quartile. Early outcomes including ventilator support duration [32.9±49.2 vs. 24.5±39.9 days, P= not significant (ns)], intensive care unit (ICU) stay duration (28.4±43.7 vs. 24.4±35.9 days, P= ns) and hospital stay duration (61.4±48.2 vs. 50.8±37.2 days, P= ns) tended to be longer in Q1 than Q4, but the difference was not significant. However, the 1-year survival rate was better in Q1 compared with Q4 (66.6% vs. 46.0%, P=0.04).

CONCLUSIONS

Although patients with thoracic sarcopenia seem to require a longer post-operative recovery time after LTx, this does not compromise their early outcomes. By contrast, patients with larger thoracic muscle volume (Q4) showed poorer survival times.

Pre-transplant wasting (as measured by muscle index) is a novel prognostic indicator in lung transplantation

BACKGROUND

Frailty in non-transplant populations increases morbidity and mortality. Muscle wasting is an important frailty characteristic. Low body mass index is used to measure wasting, but can over- or underestimate muscle mass. Computed tomography (CT) software can directly measure muscle mass. It is unknown if muscle wasting is important in lung transplantation.

AIM AND METHODS

The aim of this single-center, retrospective cohort study was to determine whether pre-transplant low muscle mass (as measured by CT using Slice-O-matic software at L2-L3 interspace) was associated with post-transplantation mortality, hospital and intensive care unit length of stay (LOS), duration of mechanical ventilation, or primary graft dysfunction. Lung transplant recipients from 2000 to 2012 with a CT scan less than six months prior to transplant were included. Univariate, multivariate, and Kaplan-Meier analyses were conducted.

RESULTS

Thirty-six patients were included. Those with low muscle index (lower 25th percentile) had a worse survival (hazard ratio = 3.83; 95% confidence interval 1.42-10.3; p = 0.007) and longer hospital LOS by an estimated 7.2 d (p = 0.01) when adjusted for age and sex as compared to those with higher muscle index.

CONCLUSION

Low muscle index at lung transplantation is associated with worse survival and increased hospital LOS.

Determinants of respiratory pump function in patients with cystic fibrosis

Respiratory failure constitutes the major cause of morbidity and mortality in patients with Cystic Fibrosis (CF). Respiratory failure could either be due to lung parenchyma damage or to insufficiency of the respiratory pump which consists of the respiratory muscles, the rib cage and the neuromuscular transmission pathways. Airway obstruction, hyperinflation and malnutrition have been historically recognised as the major determinants of respiratory pump dysfunction in CF. Recent research has identified chronic infection, genetic predisposition, dietary and pharmaceutical interventions as possible additional determinants of this impairment. Furthermore, new methodological approaches in assessing respiratory pump function have led to a better understanding of the pathogenesis of respiratory pump failure in CF. Finally, respiratory muscle function could be partially preserved in CF patients with structured interventions such as aerobic exercise, inspiratory muscle training and non-invasive ventilation and CF patients could consequently be relatively protected from respiratory fatigue and respiratory failure.

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.

Exercise limitation following transplantation

Organ transplantation is one of the medical miracles or the 20th century. It has the capacity to substantially improve exercise performance and quality of life in patients who are severely limited with chronic organ failure. We focus on the most commonly performed solid-organ transplants and describe peak exercise performance following recovery from transplantation. Across all of the common transplants, evaluated significant reduction in VO2peak is seen (typically renal and liver 65%-80% with heart and/or lung 50%-60% of predicted). Those with the lowest VO2peak pretransplant have the lowest VO2peak posttransplant. Overall very few patients have a VO2peak in the normal range. Investigation of the cause of the reduction of VO2peak has identified many factors pre- and posttransplant that may contribute. These include organ-specific factors in the otherwise well-functioning allograft (e.g., chronotropic incompetence in heart transplantation) as well as allograft dysfunction itself (e.g., chronic lung allograft dysfunction). However, looking across all transplants, a pattern emerges. A low muscle mass with qualitative change in large exercising skeletal muscle groups is seen pretransplant. Many factor posttransplant aggravate these changes or prevent them recovering, especially calcineurin antagonist drugs which are key immunosuppressing agents. This results in the reduction of VO2peak despite restoration of near normal function of the initially failing organ system. As such organ transplantation has provided an experiment of nature that has focused our attention on an important confounder of chronic organ failure-skeletal muscle dysfunction.

An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation

BACKGROUND

Pulmonary rehabilitation is recognized as a core component of the management of individuals with chronic respiratory disease. Since the 2006 American Thoracic Society (ATS)/European Respiratory Society (ERS) Statement on Pulmonary Rehabilitation, there has been considerable growth in our knowledge of its efficacy and scope.

PURPOSE

The purpose of this Statement is to update the 2006 document, including a new definition of pulmonary rehabilitation and highlighting key concepts and major advances in the field.

METHODS

A multidisciplinary committee of experts representing the ATS Pulmonary Rehabilitation Assembly and the ERS Scientific Group 01.02, "Rehabilitation and Chronic Care," determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant clinical and scientific expertise. The final content of this Statement was agreed on by all members.

RESULTS

An updated definition of pulmonary rehabilitation is proposed. New data are presented on the science and application of pulmonary rehabilitation, including its effectiveness in acutely ill individuals with chronic obstructive pulmonary disease, and in individuals with other chronic respiratory diseases. The important role of pulmonary rehabilitation in chronic disease management is highlighted. In addition, the role of health behavior change in optimizing and maintaining benefits is discussed.

CONCLUSIONS

The considerable growth in the science and application of pulmonary rehabilitation since 2006 adds further support for its efficacy in a wide range of individuals with chronic respiratory disease.

Impaired exercise capacity after lung transplantation is related to delayed recovery of muscle strength

Lung transplant recipients report reduced exercise capacity despite satisfactory graft function. We analysed changes in lung function, six-min walk distance (6MWD), and quadriceps strength in the first 26-wk post-transplant and examined what factors predict 6MWD recovery. All lung transplant recipients at a single institution between June 2007 and January 2011 were considered for inclusion. Lung function, 6MWD, and quadriceps strength corrected for body weight (QS%) were recorded pre- and two-, six-, 13-, and 26-wk post-transplant. Fifty recipients, of mean (± SD) age 42 (± 13) yr, were studied. Mean FEV1 % and 6MWD improved from 26.4% to 88.9% and from 397 to 549 m at 26 wk, respectively (both p < 0.001). QS% declined in the first two wk but had improved to above pre-transplant levels by 26 wk (p = 0.027). On multivariate analysis (n = 35), lower pre-transplant exercise capacity and greater recovery in muscle strength explained most of the improvement in exercise capacity. Delayed recovery of exercise capacity after lung transplantation is unrelated to delay in improvement in graft function, but occurs secondary to the slow recovery of muscle strength. Our findings show that additional controlled trials are needed to better understand the influence of exercise rehabilitation on improvement in exercise capacity post-transplantation.

The evolution of exercise capacity and its limiting factors in cystic fibrosis

The ability to perform exercise is an important determinant of both longevity and quality of life for patients with Cystic Fibrosis. There are a variety of physical and behavioural factors that contribute to exercise limitation. These, such as lung function or habitual physical activity, change over time. However, these factors can also be modified by treatments and interventions. This review discusses the various factors that contribute to exercise limitation in Cystic Fibrosis, and how these change with age.

Exercise training after lung transplantation improves participation in daily activity: a randomized controlled trial

The effects of exercise training after lung transplantation have not been studied in a randomized controlled trial so far. We investigated whether 3 months of supervised training, initiated immediately after hospital discharge, improve functional recovery and cardiovascular morbidity of patients up to 1 year after lung transplantation. Patients older than 40 years, who experienced an uncomplicated postoperative period, were eligible for this single blind, parallel group study. Sealed envelopes were used to randomly allocate patients to 3 months of exercise training (n = 21) or a control intervention (n = 19). Minutes of daily walking time (primary outcome), physical fitness, quality of life and cardiovascular morbidity were compared between groups adjusting for baseline assessments in a mixed models analysis. After 1 year daily walking time in the treated patients (n = 18) was 85 ± 27 min and in the control group (n = 16) 54 ± 30 min (adjusted difference 26 min [95%CI 8-45 min, p = 0.006]). Quadriceps force (p = 0.001), 6-minute walking distance (p = 0.002) and self-reported physical functioning (p = 0.039) were significantly higher in the intervention group. Average 24 h ambulatory blood pressures were significantly lower in the treated patients (p ≤ 0.01). Based on these results patients should be strongly encouraged to participate in an exercise training intervention after lung transplantation.

Effect of acute exacerbations on skeletal muscle strength and physical activity in cystic fibrosis

BACKGROUND

Skeletal muscle weakness is an important complication of chronic respiratory disease. The effect of acute exacerbations on strength in patients with cystic fibrosis is not known.

METHODS

Quadriceps (QMVC) and respiratory muscle strength were measured in patients at the time of acute admission, at discharge and one month later. Patients wore an activity monitor during admission and at one month. Convalescent values were compared to the stable clinic population.

RESULTS

Data were available for 13 acute admissions and 25 stable CF outpatients. Strength and other parameters including daily step count did not differ significantly between the stable and one month post-admission groups. At admission, QMVC was 16.7 (8.3)% lower than at convalescence, whereas inspiratory muscle strength did not change significantly. Reduction in QMVC did not correlate with activity levels or with markers of systemic inflammation.

CONCLUSION

Further research is needed to identify the mechanisms responsible for the reduction in QMVC.

Lung transplantation and lung volume reduction surgery

Since the publication of the last edition of the Handbook of Physiology, lung transplantation has become widely available, via specialized centers, for a variety of end-stage lung diseases. Lung volume reduction surgery, a procedure for emphysema first conceptualized in the 1950s, electrified the pulmonary medicine community when it was rediscovered in the 1990s. In parallel with their technical and clinical refinement, extensive investigation has explored the unique physiology of these procedures. In the case of lung transplantation, relevant issues include the discrepant mechanical function of the donor lungs and recipient thorax, the effects of surgical denervation, acute and chronic rejection, respiratory, chest wall, and limb muscle function, and response to exercise. For lung volume reduction surgery, there have been new insights into the counterintuitive observation that lung function in severe emphysema can be improved by resecting the most diseased portions of the lungs. For both procedures, insights from physiology have fed back to clinicians to refine patient selection and to scientists to design clinical trials. This section will first provide an overview of the clinical aspects of these procedures, including patient selection, surgical techniques, complications, and outcomes. It then reviews the extensive data on lung and muscle function following transplantation and its complications. Finally, it reviews the insights from the last 15 years on the mechanisms whereby removal of lung from an emphysema patient can improve the function of the lung left behind.

Benefits of home-based endurance training in lung transplant recipients

BACKGROUND

To investigate the effect of home-based exercise training on exercise tolerance, muscle function and quality of life in lung transplant recipients (LTR).

METHODS

Twelve LTR and 7 age-matched healthy subjects underwent exercise training (ET, 12-wk, 3×/wk, 40 min). Peak aerobic capacity VO2peak, endurance time (T(end)), minute ventilation (VE) quadriceps strength, percentage of type I fiber (%Ifb), fiber diameters and chronic respiratory questionnaire were assessed before and after ET. A positive response to ET was defined as an improvement in T(end) at least comparable to the mean change observed in healthy subjects.

RESULTS

Training significantly improved T(end) (+12 ± 11 min), isowatt during exercise (-5.5 ± 2.6L/min), muscle strength (+4.6 ± 2.6 kg) and dyspnea score (+0.6 ± 0.9) in LTR (p < 0.05), leading to recovery of T(end) and muscle strength up to healthy subjects' values. In responders (n = 6), VO2peak, %Ifb and fatigue score were improved after training (p < 0.05). Non-responders had lower %Ifb and greater delay between surgery and the beginning of the study than responders (56 [21-106] vs. 8 [2-59] months respectively, p = 0.03).

CONCLUSIONS

Home-based ET was effective to improve exercise tolerance, muscle strength and quality of life in LTR but more successful in patients with moderate muscle dysfunction and in the first years after transplantation. Multicenter and controlled-studies are needed to confirm the benefits and optimal modalities of home training in LTR.

Exercise training before and after lung transplantation

The benefits of exercise training in individuals with chronic lung diseases such as chronic obstructive pulmonary disease, cystic fibrosis, and interstitial lung disease have been well documented. Although there is limited research available, it appears that exercise is safe and beneficial for people with severe end-stage chronic lung disease who are awaiting lung transplantation in addition to recipients of lung transplants. Evidence-based guidelines for exercise training in the pre- and post-lung transplantation phases have not yet been developed. However, by considering exercise guidelines for people with chronic lung disease and in older adults in light of the physiological changes that can occur either pre- or post-lung transplantation, a safe and appropriate exercise training program can be developed. Depending on the individual's exercise capacity and goals, the training program may include aerobic and resistance exercise, and flexibility and balance training. In the pre-transplant and acute post-transplant phases, the intensity of exercise is dictated primarily by symptom limitation and adequate rest, which is required between exercise bouts to allow for recovery. In the post-transplant phase, it is possible for lung transplant recipients to increase their exercise capacity and even participate in sports. Further research needs to be conducted to determine the optimal training guidelines and the long-term benefits of exercise, both in lung transplant candidates and recipients.

Physical activity in daily life 1 year after lung transplantation

BACKGROUND

Reduced physical fitness has been reported to occur after lung transplantation. Pre- and post-transplant factors, including an inactive lifestyle, have been proposed as possible causes. However, daily physical activity has not been objectively assessed so far in lung recipients. The purpose of this study was to objectively measure daily physical activity in lung recipients.

METHODS

Twenty-two clinically stable patients with single (n = 7) and bilateral lung grafts (n = 15) underwent measurements of physical activity with activity monitors at least 12 months after surgery. Results were compared with findings from 22 healthy, age- and gender-matched control subjects.

RESULTS

Substantial and statistically significant differences in daily activity were observed. Steps, standing time and moderate-intensity activity of lung recipients were reduced by 42%, 29% and 66%, respectively, relative to controls. Daily sedentary time was increased by 30%. Daily steps correlated with self-reported physical functioning (r = 0.81), 6-minute walk distance (r = 0.68), quadriceps force (r = 0.66) and maximum workload (r = 0.63).

CONCLUSIONS

This study has shown for the first time that daily activity is substantially reduced after lung transplantation and related to measures of physical fitness and health-related quality of life. Future studies need to examine whether physical activity can be modified to improve functional recovery after lung transplantation.

Effect of lung transplant and volume reduction surgery on respiratory muscle function

Lung transplantation and lung volume reduction surgery have opened a new therapeutic era for patients with advanced emphysema. In addition to providing impressive clinical benefits, they have helped us better understand how the chest wall and respiratory muscles adapt to chronic hyperinflation. This article reviews the effects of these procedures on respiratory muscle and chest wall function. Inspiratory (including diaphragm) and expiratory muscle strength are often close to normal after unilateral and bilateral transplantation, although some patients have marked weakness. After bilateral transplantation for emphysema, graft volume is normal at full inflation but remains greater than normal at end expiration, which results from structural changes in the chest wall. In contrast, patients with unilateral transplantation have a reduction in graft volume at full inflation. The mediastinum is displaced toward the graft at end expiration, which reduces the surface area of the diaphragm on the transplanted side, and it moves toward the native lung during tidal and full inspiration and toward the graft during tidal and forced expiration. Lung volume reduction produces an increase in contractility, length and surface area of the diaphragm, and increases its contribution to tidal volume; at the same time, neural drive to the muscle and respiratory load are reduced, such that diaphragm neuromechanical coupling is improved. Diaphragm configuration and rib cage dimensions are only minimally affected by the procedure. Single-lung transplantation and lung volume reduction favorably impact on the disadvantageous size interaction by which the lungs are functionally restricted by the chest wall in emphysema.

The evidence regarding exercise training in the management of cystic fibrosis: a systematic review

PURPOSE

To conduct a systematic review of the evidence regarding the efficacy of exercise training in the management of cystic fibrosis (CF).

METHODS

Articles were found by searching PEDRO, MEDLINE, and CINAHL databases. Included articles involved exercise-related interventions for long-term adaptations (ie, not acute effects of exercise). Articles were excluded if the language was other than English or if other non-exercise interventions were used. Date of publication was not a factor for exclusion. Two independent reviewers evaluated the included articles using Sackett's levels of evidence and select scoring criteria.

RESULTS

Twelve articles were eligible for inclusion. Interventions studied included various aspects of exercise training: anaerobic, aerobic, or resistance training. Study end-points included pulmonary function, aerobic capacity, strength, and health-related quality of life (HRQL).

CONCLUSIONS

Exercise training in individuals with CF is beneficial, with aerobic and resistance training having the greatest support in the literature for improved aerobic capacity and strength, respectively. Exercise training does not appear to have an effect of improving pulmonary function, but may have a preservation effect. Strong conclusions about improvement in HQRL from exercise training cannot be made. However, greater consistency in measuring this outcome is needed in future trials. There is a paucity of evidence regarding the role of exercise training in reducing hospitalization and health care utilization, and questions raised by this review should be considered in the design of future trials.

Skeletal muscle strength and endurance in recipients of lung transplants

PURPOSE

Exercise limitation in recipients of lung transplant may be a result of abnormalities in the skeletal muscle. However, it is not clear whether these abnormalities are merely a reflection of the changes observed in the pretransplant condition. The purpose of this paper was to compare thigh muscle volume and composition, strength, and endurance in lung transplant recipients to people with chronic obstructive pulmonary disease (COPD).

METHODS

Single lung transplant recipients (n=6) and people with COPD (n=6), matched for age, sex, and BMI participated in the study. Subjects underwent MRI to determine muscle size and composition, lower extremity strength testing and an isometric endurance test of the quadriceps.

RESULTS

Lung transplant recipients had similar muscle volumes and intramuscular fat infiltration of their thigh muscles and similar strength of the quadriceps and hamstrings to people with COPD who had not undergone transplant. However, quadriceps endurance tended to be lower in transplant recipients compared to people with COPD (15 +/- 7 seconds in transplant versus 31 +/- 12 seconds in COPD, p = 0.08).

CONCLUSIONS

Recipients of lung transplant showed similar changes in muscle size and strength as people with COPD, however muscle endurance tended to be lower in people with lung transplants. Impairments in muscle endurance may reflect the effects of immunosuppressant medications on skeletal muscle in people with lung transplant.

The influence of body composition on respiratory muscle, lung function and diaphragm thickness in adults with cystic fibrosis

BACKGROUND

Weight loss and loss of fat-free mass (FFM) are associated with peripheral muscle wasting in cystic fibrosis (CF) although whether this co-exists with loss of diaphragm mass remains unclear.

METHODS

FFM was determined by dual-energy X-ray absorptiometry and bioelectrical impedance in 40 adults with CF and 30 age-matched healthy subjects (HS). Diaphragm thickness at functional residual capacity (FRC) [TDIrel] and total lung capacity (TLC) [TDIcont] and thickening ratio (TR) were assessed by ultrasonography. Inspiratory muscle strength and work capacity were determined by maximal inspiratory pressure (PImax), and sustained PImax (SPImax); pulmonary function (RV, VC and TLC) and physical activity status (PAS) were also determined.

RESULTS

When the CF patients were assessed as a group (low and normal FFM) they had similar age, weight, height and PAS compared to the HS, although patients had lower FFM (p<0.05), VC and TLC than the HS (p<0.01). In addition, although PImax, TDIrel, TDIcont and TR were similar between the patients and the HS, SPImax was lower in the patients (p<0.01). When analyses were made between patients with low versus normal FFM and between patients with low FFM and HS no significant differences were found between overall weight although TDIrel, TDIcont, TR and PAS were all reduced in patients with low FFM (p<0.01).

CONCLUSIONS

PImax is relatively well preserved in adults with CF although there is a relationship between the loss of inspiratory muscle work capacity, FFM, PAS and pulmonary function. Furthermore loss of FFM is associated with loss of diaphragm muscle mass.

Update on the role of exercise in cystic fibrosis

PURPOSE OF REVIEW

The role of exercise in patients with cystic fibrosis has been recognized for as long as cystic fibrosis has been identified as a clinical syndrome, as exercise intolerance has always been a hallmark of disease progression.

RECENT FINDINGS

Work published in the past year has shed new light on several aspects of this field, including physiologic responses to exercise, responses to exercise programs, and the epidemiologic and prognostic implications of activity and exercise testing.

SUMMARY

Barker's work is perhaps the most compelling, as it highlights the overwhelming interest and belief in the utility of exercise testing and prescription among cystic fibrosis physicians and the contrasting paucity of programs that test their patients and prescribe exercise for them. More studies are needed to identify the form of exercise programs and tests that are most likely to be effective and to be used by cystic fibrosis centers and patients.