The Prevalence of Chronic Obstructive Pulmonary Disease (COPD) and the Heterogeneity of Risk Factors in the Canadian Population: Results from the Canadian Obstructive Lung Disease (COLD) Study.

PURPOSE: To determine the spirometric-based prevalence of COPD across different regions in Canada and to evaluate the site heterogeneity of risk factors. PATIENTS AND METHODS: In this cross-sectional, population-based study, random samples of non-institutionalized adults aged ≥40 years were generated by random digit dialling. Participants answered an interviewer-administered questionnaire and performed spirometry before and after bronchodilator administration. COPD was defined as post-bronchodilator FEV1/FVC <0.70 (fixed ratio, FR) and as FEV1/FVC <5th percentile (lower limits of normal, LLN). Separate logistic regression models were used to compute the risk (adjusted odds ratio, aOR) for COPD. I2 and Tau2 analyses were used to evaluate heterogeneity. RESULTS: Out of 5176 (95%) participants, 4893 (47% male with mean age 56.6 years (95% confidence interval, 56.0-57.2)) had spirometry that satisfied ATS criteria. The population prevalence of COPD was 16.2% (95% CI, 14.5-17.8) by FR and 11.2% (95% CI, 9.7-12.6) by LLN. Male predominance in prevalence was shown by FR but not by LLN criteria. Patient characteristics associated with an increased risk of COPD included: age (OR 1.56; 95% CI 1.33-1.84); history of physician-diagnosed asthma (OR 3.30; 95% CI 2.42-4.49); and childhood hospitalization for respiratory illness (OR 1.81; 95% CI 1.17-2.80). In terms of smoking-related risk factors, current smoking status had the highest odds ratio (OR 3.49; 95% CI 2.55-4.80). Variance in prevalence among sites was significantly reduced by adjusting for risk factors in Tau2 analyses. Higher odds of exposure for each risk factor was found in more severe COPD, suggesting that a higher risk could be linked to the development of severe disease. CONCLUSION: This study reports the population prevalence of COPD in nine urban cities which collectively represent the majority of the Canadian population and demonstrates that heterogeneity in prevalence among sites is substantially explained by variation in associated risk factors for COPD.

Evaluation of the Vibe Actigraph in Patients With Chronic Obstructive Pulmonary Disease: A Pilot Study.

STUDY OBJECTIVE: To validate the Vibe actigraph in assessing sleep-wake patterns compared to polysomnography (PSG) in patients with COPD. METHODS: Nine stable COPD patients wore actigraphs while undergoing PSG. The correlation between total sleep time (TST), total sleep period (TSP), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency was determined for corresponding measurements from the actigraph and PSG. Sensitivity, specificity, and positive and negative predictive values were calculated for the actigraph, considering PSG the gold standard. Levels of agreement between the variables of PSG and the actigraph were estimated using Bland-Altman plots. RESULTS: A strong and statistically significant correlation was noted between PSG and the actigraph in detecting movement during sleep [mean activity score (counts)], TST and TSP (all rs = 0.83; p = 0.005). The median agreement of sleep and wake counts between PSG and the actigraph was 73% and the Cohen's Kappa value was 0.66. The medians of sensitivity and specificity of the actigraph for detecting sleep versus PSG were 84 and 66%, respectively. The median positive and negative predictive values of the actigraph were 74 and 72%, respectively. CONCLUSIONS: This study demonstrated that, under controlled laboratory conditions, the Vibe actigraph in its default settings is a promising tool for the detection of sleep-wake parameters in a small number of ambulatory patients with COPD. Clinical Impact: The actigraph used in this pilot study suggests that these devices could provide clinically relevant information in COPD to better understand the relationship between sleep and health in this population.

Manipulation of mechanical ventilatory constraint during moderate intensity exercise does not influence dyspnoea in healthy older men and women.

KEY POINTS: The perceived intensity of exertional breathlessness (i.e. dyspnoea) is higher in older women than in older men, possibly as a result of sex-differences in respiratory system morphology. During exercise at a given absolute intensity or minute ventilation, older women have a greater degree of mechanical ventilatory constraint (i.e. work of breathing and expiratory flow limitation) than their male counterparts, which may lead to a greater perceived intensity of dyspnoea. Using a single-blind randomized study design, we experimentally manipulated the magnitude of mechanical ventilatory constraint during moderate-intensity exercise at ventilatory threshold in healthy older men and women. We found that changes in the magnitude of mechanical ventilatory constraint within the physiological range had no effect on dyspnoea in healthy older adults. When older men and women perform moderate intensity exercise, mechanical ventilatory constraint does not contribute significantly to the sensation of dyspnoea. ABSTRACT: We aimed to determine the effect of manipulating mechanical ventilatory constraint during submaximal exercise on dyspnoea in older men and women. Eighteen healthy subjects (aged 60-80 years; nine men and nine women) completed two days of testing. On day 1, subjects were assessed for pulmonary function and performed a maximal incremental cycle exercise test. On day 2, subjects performed three 6-min bouts of cycling at ventilatory threshold, in a single-blind randomized manner, while breathing: (i) normoxic helium-oxygen (HEL) to reduce the work of breathing (Wb ) and alleviate expiratory flow limitation (EFL); (ii) through an inspiratory resistance (RES) of ∼5 cmH2 O L-1  s-1 to increase Wb ; and (iii) ambient air as a control (CON). Oesophageal pressure, diaphragm electromyography, and sensory responses (category-ratio 10 Borg scale) were monitored throughout exercise. During the HEL condition, there was a significant decrease in Wb (men: -21 ± 6%, women: -17 ± 10%) relative to CON (both P < 0.01). Moreover, if EFL was present during CON (four men and five women), it was alleviated during HEL. Conversely, during the RES condition, Wb (men: 42 ± 19%, women: 50 ± 16%) significantly increased relative to CON (both P < 0.01). There was no main effect of sex on Wb (P = 0.59). Across conditions, women reported significantly higher dyspnoea intensity than men (2.9 ± 0.9 vs. 1.9 ± 0.8 Borg scale units, P < 0.05). Despite significant differences in the degree of mechanical ventilatory constraint between conditions, the intensity of dyspnoea was unaffected, independent of sex (P = 0.46). When older men and women perform moderate intensity exercise, mechanical ventilatory constraint does not contribute significantly to the sensation of dyspnoea.

Effects of Age and Sex on Inspiratory Muscle Activation Patterns during Exercise.

PURPOSE: To characterize the effects of age, sex, and their interaction on inspiratory muscle activation patterns during exercise. METHODS: Twenty younger (20-30 yr, n = 10 women) and 20 older (60-80 yr, n = 10 women) subjects performed an incremental cycle exercise test. Electromyography (EMG) of the scalene (EMGsca) and EMG of the sternocleidomastoid (EMGscm) muscles were measured using skin surface electrodes, whereas diaphragm EMG (EMGdi) and esophageal and transdiaphragmatic pressures were measured using an esophageal catheter. Electromyography data were transformed into root mean square with a 100-ms time constant. Esophageal and diaphragmatic pressure-time products were used as indices of total inspiratory muscle pressure production and diaphragmatic pressure production, respectively. RESULTS: At absolute minute ventilations (V˙E), women and older subjects had greater EMGdi than men and younger subjects, respectively (all P < 0.05), but no differences were noted when V˙E was expressed in relative terms (all P > 0.05). Women had greater EMGsca activity than men at absolute and relative levels of V˙E (all P < 0.05). Older subjects had greater EMGsca than younger subjects when V˙E was expressed in relative (all P < 0.05) but not absolute terms (all P > 0.05). At absolute and relative levels of V˙E, women and older subjects had greater EMGscm than men and younger subjects, respectively (all P < 0.05). Women and older subjects had a greater esophageal and diaphragmatic pressure-time products at a V˙E of 70 L·min than men and younger subjects, respectively (both P < 0.05), but no differences were noted when V˙E was expressed in relative terms (all P > 0.05). No significant interactions between age and sex were noted (all P > 0.05). CONCLUSIONS: Age and sex significantly affect inspiratory muscle activation patterns during exercise; however, the extent of the effects depends on whether comparisons are made at absolute or relative V˙E.

The effects of age and sex on mechanical ventilatory constraint and dyspnea during exercise in healthy humans.

We examined the effects of age, sex, and their interaction on mechanical ventilatory constraint and dyspnea during exercise in 22 older (age = 68 ± 1 yr; n = 12 women) and 22 younger (age = 25 ± 1 y, n = 11 women) subjects. During submaximal exercise, older subjects had higher end-inspiratory (EILV) and end-expiratory (EELV) lung volumes than younger subjects (both P < 0.05). During maximal exercise, older subjects had similar EILV ( P > 0.05) but higher EELV than younger subjects ( P < 0.05). No sex differences in EILV or EELV were observed. We noted that women had a higher work of breathing (Wb) for a given minute ventilation (V̇e) ≥65 l/min than men ( P < 0.05) and older subjects had a higher Wb for a given V̇e ≥60 l/min ( P < 0.05). No sex or age differences in Wb were present at any submaximal relative V̇e. At absolute exercise intensities, older women experienced expiratory flow limitation (EFL) more frequently than older men ( P < 0.05), and older subjects were more likely to experience EFL than younger subjects ( P < 0.05). At relative exercise intensities, women and older individuals experienced EFL more frequently than men and younger individuals, respectively (both P < 0.05). There were significant effects of age, sex, and their interaction on dyspnea intensity during exercise at absolute, but not relative, intensities (all P < 0.05). Across subjects, dyspnea at 80 W was significantly correlated with indexes of mechanical ventilatory constraint (all P < 0.05). Collectively, our findings suggest age and sex have significant impacts on Wb, operating lung volumes, EFL, and dyspnea during exercise. Moreover, it appears that mechanical ventilatory constraint may partially explain sex differences in exertional dyspnea in older individuals. NEW & NOTEWORTHY We found that age and sex have a significant effect on mechanical ventilatory constraint and the perception of dyspnea during exercise. We also observed that the perception of exertional dyspnea is associated with indexes of mechanical ventilatory constraint. Collectively, our results suggest that the combined influences of age and biological sex on mechanical ventilatory constraint during exercise contributes, in part, to the increased perception of dyspnea during exercise in older women.

A Comparison of Pain, Fatigue, Dyspnea and their Impact on Quality of Life in Pulmonary Rehabilitation Participants with Chronic Obstructive Pulmonary Disease.

In addition to dyspnea and fatigue, pain is a prevalent symptom in chronic obstructive pulmonary disease (COPD). Understanding the relative prevalence, magnitude, and interference with aspects of daily living of these symptoms can improve COPD management. Therefore, the purposes of this study were to: (1) compare the prevalence and magnitude of dyspnea, fatigue, and pain and how each limits aspects of daily living; (2) determine the association between pain and the other two symptoms; and (3) assess the impact of these symptoms on quality of life in COPD. Participants were recruited from pulmonary rehabilitation programs. Pain, dyspnea, and fatigue were measured using the Brief Pain Inventory (BPI), Brief Fatigue Inventory (BFI), and Dyspnea Inventory (DI), respectively. Quality of life was measured using the Clinical COPD Questionnaire (CCQ). The prevalence of dyspnea, fatigue, and pain were 93%, 77%, and 74%, respectively. Individuals with COPD reported similar severity scores of the three symptoms. Dyspnea interfered with general activity more than pain (F1.7,79.9 = 3.1, p < 0.05), whilst pain interfered with mood (F1.8, 82.7 = 3.6, p < 0.05) and sleep (F1,46 = 7.4, p < 0.01) more than dyspnea and fatigue. These three symptoms were moderately-to-highly correlated with each other (ρ = 0.49-0.78, p < 0.01) and all individually impacted quality of life. In summary, pain is a common symptom in addition to dyspnea and fatigue in COPD; all three interfere similarly among aspects of daily living with some exceptions. Accordingly, management of COPD should include a multifaceted approach that addresses pain as well as dyspnea and fatigue.

Framing of mobility items: a source of poor agreement between preference-based health-related quality of life instruments in a population of individuals receiving assisted ventilation.

PURPOSE: To explore the influence of descriptive differences in items evaluating mobility on index scores generated from two generic preference-based health-related quality of life (HRQoL) instruments. METHODS: The study examined cross-sectional data from a postal survey of individuals receiving assisted ventilation in two state/province-wide home mechanical ventilation services, one in British Columbia, Canada and the other in Victoria, Australia. The Assessment of Quality of Life 8-dimension (AQoL-8D) and the EQ-5D-5L were included in the data collection. Graphical illustrations, descriptive statistics, and measures of agreement [intraclass correlation coefficients (ICCs) and Bland-Altman plots] were examined using index scores derived from both instruments. Analyses were performed on the full sample as well as subgroups defined according to respondents' self-reported ability to walk. RESULTS: Of 868 individuals receiving assisted ventilation, 481 (55.4%) completed the questionnaire. Mean index scores were 0.581 (AQoL-8D) and 0.566 (EQ-5D-5L) with 'moderate' agreement demonstrated between the two instruments (ICC = 0.642). One hundred fifty-nine (33.1%) reported level 5 ('I am unable to walk about') on the EQ-5D-5L Mobility item. The walking status of respondents had a marked influence on the comparability of index scores, with a larger mean difference (0.206) and 'slight' agreement (ICC = 0.386) observed when the non-ambulant subgroup was evaluated separately. CONCLUSIONS: This study provides further evidence that between-measure discrepancies between preference-based HRQoL instruments are related in part to the framing of mobility-related items. Longitudinal studies are necessary to determine the responsiveness of preference-based HRQoL instruments in cohorts that include non-ambulant individuals.

Lung volume recruitment acutely increases respiratory system compliance in individuals with severe respiratory muscle weakness.

The aim of the present study was to determine whether lung volume recruitment (LVR) acutely increases respiratory system compliance (Crs) in individuals with severe respiratory muscle weakness (RMW). Individuals with RMW resulting from neuromuscular disease or quadriplegia (n=12) and healthy controls (n=12) underwent pulmonary function testing and the measurement of Crs at baseline, immediately after, 1 h after and 2 h after a single standardised session of LVR. The LVR session involved 10 consecutive supramaximal lung inflations with a manual resuscitation bag to the highest tolerable mouth pressure or a maximum of 50 cmH2O. Each LVR inflation was followed by brief breath-hold and a maximal expiration to residual volume. At baseline, individuals with RMW had lower Crs than controls (37±5 cmH2O versus 109±10 mL·cmH2O-1, p<0.001). Immediately after LVR, Crs increased by 39.5±9.8% to 50±7 mL·cmH2O-1 in individuals with RMW (p<0.05), while no significant change occurred in controls (p=0.23). At 1 h and 2 h post-treatment, there were no within-group differences in Crs compared to baseline (all p>0.05). LVR had no significant effect on measures of pulmonary function at any time point in either group (all p>0.05). During inflations, mean arterial pressure decreased significantly relative to baseline by 10.4±2.8 mmHg and 17.3±3.0 mmHg in individuals with RMW and controls, respectively (both p<0.05). LVR acutely increases Crs in individuals with RMW. However, the high airway pressures during inflations cause reductions in mean arterial pressure that should be considered when applying this technique.

Comorbidities That Cause Pain and the Contributors to Pain in Individuals With Chronic Obstructive Pulmonary Disease.

OBJECTIVE: To determine comorbidities that cause pain and the potential contributors to pain in individuals with chronic obstructive pulmonary disease (COPD). DESIGN: Prospective cross-sectional survey study. SETTING: Pulmonary rehabilitation programs of 6 centers. PARTICIPANTS: A convenience sample of individuals with COPD (N=137) who attended pulmonary rehabilitation programs. In total, 100 (73%) returned the survey packages. Of those responders, 96 participants (70%) were included in the analyses. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Pain was measured using the Brief Pain Inventory. The questionnaire used to obtain information about health conditions that might contribute to pain and a medication record asked, in lay terms, about comorbidities that cause pain. The health conditions that cause pain were then validated by health professionals. Demographics, fatigue, dyspnea, quality of life, and self-efficacy were also measured using questionnaires. RESULTS: Pain was reported in 71% (68/96) of participants. Low back pain was the most common location (41%). Arthritis (75%), back problems (47%), and muscle cramps (46%) were the most common comorbidities that caused pain. Lower self-efficacy, and renting rather than home ownership increased the likelihood of pain (P<.05). Pain severity and Brief Fatigue Inventory scores contributed to pain interference scores (P<.05). CONCLUSIONS: Pain was highly prevalent in pulmonary rehabilitation program participants with COPD. The most common causes of pain were musculoskeletal conditions. Pain severity and higher levels of fatigue contributed to how pain interfered with daily aspects of living. The assessment and management of pain need to be addressed within the overall care of individuals with COPD.

Recruitment and Deoxygenation of Selected Respiratory and Skeletal Muscles During Incremental Loading in Stable COPD Patients.

PURPOSE: To evaluate changes in oxygenated (O2Hb), deoxygenated (HHb), and total hemoglobin (tHb) of the sternocleidomastoid (SCM), parasternal (PS), biceps (BC), and tibialis anterior (TA) using near-infrared spectroscopy during incremental loading of the inspiratory muscles and the elbow flexors in people with stable chronic obstructive pulmonary disease. METHODS: Fifteen participants with obstructive pulmonary disease were recruited in a repeated-measures crossover design. Near-infrared spectroscopy optodes were applied over the SCM, PS, BC, and TA to measure O2Hb, HHb, and tHb. Participants were randomly assigned to perform incremental inspiratory threshold loading or elbow flexor loading that imposed higher loads every 2 minutes until task failure. At least 1 week later, participants performed the other test. Arterial oxygen saturation (SpO2) was monitored continuously. RESULTS: O2Hb of the main agonist muscles, SCM and BC, decreased compared with the other muscles during inspiratory threshold loading and elbow flexor loading, respectively. SCM O2Hb and BC O2Hb decreased at higher loads compared with baseline. SCM tHb and HHb increased, whereas TA tHb decreased during inspiratory threshold loading. tHb did not change among any muscles during elbow flexor loading. SpO2 did not change from baseline to task failure. CONCLUSIONS: Our data suggest that the SCM was recruited progressively during incremental inspiratory threshold loading; however, O2Hb was not maintained in this muscle. Similarly, O2Hb was not maintained in the biceps during elbow flexor loading. This regional deoxygenation in SCM and BC during incremental loading protocols was not reflected by a decrease in SpO2.

Care Practices and Health-related Quality of Life for Individuals Receiving Assisted Ventilation. A Cross-National Study.

RATIONALE: Comparisons of home mechanical ventilation services have demonstrated considerable regional variation in patient populations managed with this therapy. The respiratory care practices used to support individuals receiving assisted ventilation also appear to vary, but they are not well described. It is uncertain whether differences in the approach to care could influence health outcomes for individuals receiving assisted ventilation. OBJECTIVES: We sought to identify and describe the respiratory care practices of home ventilation providers in two different regions and determine whether care practice differences influence health-related quality of life. METHODS: We conducted a cross-national survey of individuals receiving assisted ventilation managed by two statewide home mechanical ventilation providers, one in Victoria, Australia, and the other in British Columbia, Canada. The survey was used to evaluate care practices, functional and physical measures, socioeconomic attributes, and health-related quality of life. MEASUREMENTS AND MAIN RESULTS: Overall, 495 individuals receiving assisted ventilation (57.2%) responded to the survey. Responders had clinical attributes similar to those of nonresponders. The Canadian population had a greater proportion of individuals with neuromuscular disorders and lesser percentages with obesity hypoventilation syndrome and chronic obstructive pulmonary disease. We also found marked differences in the reported care practices in Canada that were not fully explained by population differences. Subjects in the Canadian sample were more likely than their Australian counterparts to use invasive mechanical ventilation (24.2% vs. 2.5%; P < 0.001), to use routine airway clearance techniques (28.9% vs. 14.8%; P < 0.001), and to have had home implementation of noninvasive ventilation (39.9% vs. 3.6%; P < 0.001). Subjects in the Australian population were more likely than those in Canada to have undergone polysomnography to evaluate their ventilatory support (93.9% vs. 37.4%; P < 0.001). There was no difference in summary measures of health-related quality of life between the two sites. In a multivariable regression model, age, ability to perform activities of daily living, physical function, employment, and household income were all independently associated with health-related quality of life, but neither geographic location (Canada vs. Australia) nor underlying diagnosis were significant factors in the model. CONCLUSIONS: In two cohorts of individuals receiving assisted ventilation, one in Australia and the other in Canada, we found marked differences in both the care practices employed and the populations served. Despite these regional differences, measures of health-related quality of life were not different. Further research is required to examine costly or burdensome interventions that are currently used routinely in the management of individuals receiving assisted ventilation.

Dysanapsis and the resistive work of breathing during exercise in healthy men and women.

We asked if the higher work of breathing (Wb) during exercise in women compared with men is explained by biological sex. We created a statistical model that accounts for both the viscoelastic and the resistive components of the total Wb and independently compares the effects of biological sex. We applied the model to esophageal pressure-derived Wb values obtained during an incremental cycle test to exhaustion. Subjects were healthy men (n = 17) and women (n = 18) with a range of maximal aerobic capacities (V̇o2 max range: men = 40-68 and women = 39-60 ml·kg(-1)·min(-1)). We also calculated the dysanapsis ratio using measures of lung recoil and forced expiratory flow as index of airway caliber. By applying the model we found that the differences in the total Wb during exercise in women are due to a higher resistive Wb rather than viscoelastic Wb. We also found that the higher resistive Wb is independently explained by biological sex. To account for the known effect of lung volumes on the dysanapsis ratio we compared the sexes with an analysis of covariance procedures and found that when vital capacity was accounted for the adjusted mean dysanapsis ratio is statistically lower in women (0.17 vs. 0.25 arbitrary units; P < 0.05). Our collective findings suggest that innate sex-based differences may exist in human airways, which result in significant male-female differences in the Wb during exercise in healthy subjects.

Pulmonary rehabilitation in Canada: A report from the Canadian Thoracic Society COPD Clinical Assembly.

BACKGROUND: Pulmonary rehabilitation (PR) is a recommended intervention in the management of individuals with chronic lung disease. It is important to study the characteristics and capacity of programs in Canada to confirm best practices and identify future areas of program improvement and research. OBJECTIVE: To identify all Canadian PR programs, regardless of setting, and to comprehensively describe all aspects of PR program delivery. The present article reports the results of the survey related to type of program, capacity and program characteristics. METHODS: All hospitals in Canada were contacted to identify PR programs. A representative from each program completed a 175-item online survey encompassing 16 domains, 10 of which are reported in the present article. RESULTS: A total of 155 facilities in Canada offered PR, of which 129 returned surveys (83% response rate). PR programs were located in all provinces, but none in the three territories. Most (60%) programs were located in hospital settings, 24% were in public health units and 8% in recreation centres. The national capacity of programs was estimated to be 10,280 patients per year, resulting in 0.4% of all Canadians with chronic obstructive pulmonary disease (COPD) and 0.8% of Canadians with moderate to severe COPD having access to PR. COPD, interstitial lung disease, and asthma were the most common diagnoses of patients. The majority of programs had at least four health care professionals involved; 9% had only one health care professional involved. CONCLUSION: The present comprehensive survey of PR in Canada reports an increase in the number of programs and the total number of patients enrolled since the previous survey in 2005. However, PR capacity has not kept pace with demand, with only 0.4% of Canadians with COPD having access.

Home mechanical ventilation in Canada: a national survey.

BACKGROUND: No comprehensive Canadian national data describe the prevalence of and service provision for ventilator-assisted individuals living at home, data critical to health-care system planning for appropriate resourcing. Our objective was to generate national data profiling service providers, users, types of services, criteria for initiation and monitoring, ventilator servicing arrangements, education, and barriers to home transition. METHODS: Eligible providers delivering services to ventilator-assisted individuals (adult and pediatric) living at home were identified by our national provider inventory and referrals from other providers. The survey was administered via a web link from August 2012 to April 2013. RESULTS: The survey response rate was 152/171 (89%). We identified 4,334 ventilator-assisted individuals: an estimated prevalence of 12.9/100,000 population, with 73% receiving noninvasive ventilation (NIV) and 18% receiving intermittent mandatory ventilation (9% not reported). Services were delivered by 39 institutional providers and 113 community providers. We identified variation in initiation criteria for NIV, with polysomnography demonstrating nocturnal hypoventilation (57%), daytime hypercapnia (38%), and nocturnal hypercapnia (32%) as the most common criteria. Various models of ventilator servicing were reported. Most providers (64%) stated that caregiver competency was a prerequisite for home discharge; however, repeated competency assessment and retraining were offered by only 45%. Important barriers to home transition were: insufficient funding for paid caregivers, equipment, and supplies; a shortage of paid caregivers; and negotiating public funding arrangements. CONCLUSIONS: Ventilatory support in the community appears well-established, with most individuals managed with NIV. Although caregiver competency is a prerequisite to discharge, ongoing assessment and retraining were infrequent. Funding and caregiver availability were important barriers to home transition.

Prevention of acute exacerbations of COPD: American College of Chest Physicians and Canadian Thoracic Society Guideline.

BACKGROUND: COPD is a major cause of morbidity and mortality in the United States as well as throughout the rest of the world. An exacerbation of COPD (periodic escalations of symptoms of cough, dyspnea, and sputum production) is a major contributor to worsening lung function, impairment in quality of life, need for urgent care or hospitalization, and cost of care in COPD. Research conducted over the past decade has contributed much to our current understanding of the pathogenesis and treatment of COPD. Additionally, an evolving literature has accumulated about the prevention of acute exacerbations. METHODS: In recognition of the importance of preventing exacerbations in patients with COPD, the American College of Chest Physicians (CHEST) and Canadian Thoracic Society (CTS) joint evidence-based guideline (AECOPD Guideline) was developed to provide a practical, clinically useful document to describe the current state of knowledge regarding the prevention of acute exacerbations according to major categories of prevention therapies. Three key clinical questions developed using the PICO (population, intervention, comparator, and outcome) format addressed the prevention of acute exacerbations of COPD: nonpharmacologic therapies, inhaled therapies, and oral therapies. We used recognized document evaluation tools to assess and choose the most appropriate studies and to extract meaningful data and grade the level of evidence to support the recommendations in each PICO question in a balanced and unbiased fashion. RESULTS: The AECOPD Guideline is unique not only for its topic, the prevention of acute exacerbations of COPD, but also for the first-in-kind partnership between two of the largest thoracic societies in North America. The CHEST Guidelines Oversight Committee in partnership with the CTS COPD Clinical Assembly launched this project with the objective that a systematic review and critical evaluation of the published literature by clinical experts and researchers in the field of COPD would lead to a series of recommendations to assist clinicians in their management of the patient with COPD. CONCLUSIONS: This guideline is unique because it provides an up-to-date, rigorous, evidence-based analysis of current randomized controlled trial data regarding the prevention of COPD exacerbations.

In vivo dopaminergic and serotonergic dysfunction in DCTN1 gene mutation carriers.

INTRODUCTION: We used positron emission tomography (PET) to assess dopaminergic and serotonergic terminal density in three subjects carrying a mutation in the DCT1 gene, two clinically affected with Perry syndrome. METHODS: All subjects had brain imaging using 18F-6-fluoro-l-dopa (FDOPA, dopamine synthesis and storage), (+)-11C-dihydrotetrabenazine (DTBZ, vesicular monoamine transporter type 2), and 11C-raclopride (RAC, dopamine D2/D3 receptors). One subject also underwent PET with 11C-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile (DASB, serotonin transporter). RESULTS: FDOPA-PET and DTBZ-PET in the affected individuals showed a reduction of striatal tracer uptake. Also, RAC-PET showed higher uptake in these area. DASB-PET showed significant uptake changes in left orbitofrontal cortex, bilateral anterior insula, left dorsolateral prefrontal cortex, left orbitofrontal cortex, left posterior cingulate cortex, left caudate, and left ventral striatum. CONCLUSIONS: Our data showed evidence of both striatal dopaminergic and widespread cortical/subcortical serotonergic dysfunctions in individuals carrying a mutation in the DCTN1 gene.

Do isolated leg exercises improve dyspnea during exercise in chronic obstructive pulmonary disease?

Dyspnea, the subjective feeling of shortness of breath, is a hallmark feature of chronic obstructive pulmonary disease (COPD). Pulmonary rehabilitation (PR) programs aim to improve dyspnea, thereby increasing exercise tolerance and health-related quality of life in patients with COPD. Exercise training is proven to be an essential component of PR; however, there is no consensus regarding which training modality confers the greatest therapeutic benefit. Secondary to pulmonary impairment, many COPD patients develop limb muscle dysfunction (LMD), particularly in the leg muscles. Mounting evidence suggests that peripheral limitation to exercise as a result of LMD is frequent in patients with COPD. LMD of the legs, or lower limb muscle dysfunction, has been shown to markedly influence ventilatory and dyspnea responses to exercise. Accordingly, isolated training of leg muscles may contribute to reducing dyspnea and increase exercise tolerance in patients with COPD. Indeed, relative to the largely irreversible impairment of the pulmonary system, the leg muscles are an important site by which to improve patients' level of function and quality of life. Isolated leg exercises have been shown to improve LMD and may constitute an effective training modality to improve dyspnea and exercise tolerance in COPD within the context of PR.

Pain and physical performance in people with COPD.

INTRODUCTION: Patients with Chronic Obstructive Pulmonary Disease (COPD) have been shown to experience significant pain that interferes with their daily activities and quality of life. The purpose of this study was to examine if pain is associated with functional exercise capacity (assessed with the six-minute walk test, 6MWT), physical activity (assessed by accelerometry), and muscle performance (maximal knee extensor torque) in people with COPD. METHODS: Twenty-six people with moderate to severe COPD completed the McGill Pain Questionnaire (MPQ), the Brief Pain Inventory (BPI), the Short Form-36 (SF-36), and a form to list medications and comorbidities. After spirometric testing, participants performed the 6MWT. Physical activity was monitored for two days using a tri-axial accelerometer (DynaPort MiniMod). At least 3 days after the 6MWT, maximal and fatiguing concentric contractions of knee extensors were assessed. RESULTS: Pain severity was negatively correlated with the 6MWT (p < 0.05), and quality of life (p < 0.05), whereas it was positively correlated with body mass index (BMI) (p < 0.001), and the number of comorbidities (p < 0.001). Subjects with severe pain showed lower standing and activity times (p < 0.01), lower 6MWT (p < 0.05), higher BMI (p < 0.001), a higher number of comorbidities (p < 0.001) and lower quality of life (p < 0.01) compared to subjects with minimal or no pain. CONCLUSION: Pain in patients with COPD is associated with low functional exercise capacity, reduced physical activity, and high BMI. Pain can adversely affect physical activity and quality of life in patients with COPD. Early evaluation of pain needs to be considered in the assessment and treatment plan for people with COPD.

Pain in people with chronic obstructive pulmonary disease (COPD).

INTRODUCTION: The prevalence and characteristics of pain are not known in COPD patients. The purposes of this study were to determine if pain is more common in COPD patients than in healthy people and if it was related to self-reported physical activity, health related quality of life (HRQoL) and comorbidities. METHODS: Participants returned a mailed survey package that contained: 1) McGill Pain Questionnaire (MPQ) and Brief Pain Inventory (BPI) to evaluate pain severity and how pain interferes with activities; 2) Tampa Scale for Kinesiophobia (TSK) to evaluate fear of movement related to pain; 3) Short Form-36 (SF-36), to measure HRQoL; 4) Community Health Activities Model Program for Seniors (CHAMPS) to evaluate physical activity; 5) a form to list medications and comorbidities. RESULTS: Forty-seven COPD patients and 47 age- and gender-matched healthy people responded. People with COPD demonstrated more pain (MPQ and BPI, p = 0.000), a greater pain-related interference in their lives (BPI, p = 0.000), a higher pain-related fear of movement, and lower frequency and energy expenditure of physical activities (CHAMPS, p = 0.000) than healthy people (TSK, p < 0.001). Pain severity (MPQ and BPI) was indirectly correlated to the Physical Component Score of the SF-36. COPD patients identified pain in the neck and trunk 3.1 times more often than healthy people. The number of comorbidities was the most consistent independent correlate of pain in COPD patients. CONCLUSIONS: COPD patients demonstrate more pain which interferes with activities more so than healthy people of similar age. Pain is also negatively associated with HRQoL in COPD.