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1.  Changes in Arterial Oxygenation and Self-Reported Oxygen Use after Lung Volume Reduction Surgery 
Rationale: Lung volume reduction surgery (LVRS) is inconsistently reported to improve arterial oxygenation in patients with chronic obstructive pulmonary disease.
Objectives: We studied the effects of surgery on oxygenation in a large cohort and identified predictors of postoperative oxygenation improvement.
Methods: We evaluated oxygenation in 1,078 subjects with chronic obstructive pulmonary disease enrolled in the National Emphysema Treatment Trial after LVRS compared with medical control subjects, including arterial blood gases, use of supplemental oxygen during treadmill walking, and self-reported use of oxygen during rest, exertion, and sleep.
Measurements and Main Results: PaO2 breathing room air was equal in medical and surgical subjects at baseline (64.8 vs. 65.0 mm Hg, P = not significant), but lower in medical subjects at 6 months (63.6 vs. 70.0 mm Hg, P < 0.001), 12 months (63.9 vs. 68.7 mm Hg, P < 0.001), and 24 months (62.4 vs. 68.0 mm Hg, P < 0.001). Fewer medical subjects required oxygen for treadmill walking at baseline compared with surgical subjects (46 vs. 53%, P = 0.02). However, more medical subjects required oxygen for this activity at 6 months (49 vs. 33%, P < 0.001), 12 months (50 vs. 36%, P < 0.001), and 24 months (52 vs. 42%, P = 0.02). Self-reported oxygen use was greater in medical than in surgical subjects at 6, 12, and 24 months. Multivariate modeling of preoperative characteristics showed baseline oxygenation status was the best predictor of postoperative oxygenation.
Conclusions: LVRS increases PaO2, and decreases treadmill and self-reported use of oxygen for up to 24 months post-procedure.
Clinical trial registered with (NCT 00000606).
PMCID: PMC2542439  PMID: 18535254
oxygen inhalation therapy; emphysema; lung diseases, obstructive
2.  Randomized Controlled Trial of an Internet-Based Versus Face-to-Face Dyspnea Self-Management Program for Patients With Chronic Obstructive Pulmonary Disease: Pilot Study 
People with chronic obstructive pulmonary disease (COPD) continue to experience dyspnea with activities of daily living (ADL) despite optimal medical management. Information and communication technologies may facilitate collaborative symptom management and could potentially increase the reach of such interventions to those who are unable to attend face-to-face pulmonary rehabilitation or self-management programs.
The purpose of this randomized study was to test the efficacy of two 6-month dyspnea self-management programs, Internet-based (eDSMP) and face-to-face (fDSMP), on dyspnea with ADL in people living with COPD.
We randomly assigned 50 participants with moderate to severe COPD who were current Internet users to either the eDSMP (n = 26) or fDSMP (n = 24) group. The content of the two programs was similar, focusing on education, skills training, and ongoing support for dyspnea self-management, including independent exercise. The only difference was the mode (Internet/personal digital assistant [PDA] or face-to-face) in which the education sessions, reinforcement contacts, and peer interactions took place. Participants returned to one of two academic clinical sites for evaluation at 3 and 6 months. The primary outcome of dyspnea with ADL was measured with the Chronic Respiratory Questionnaire. Secondary outcomes of exercise behavior, exercise performance, COPD exacerbations, and mediators, such as self-efficacy and social support, were also measured. A satisfaction survey was administered and a semistructured exit interview was conducted at the final visit.
The study was stopped early due to multiple technical challenges with the eDSMP, but follow-up was completed on all enrolled participants. Data were available for 39 participants who completed the study (female: 44%; age: 69.5 ± 8.5 years; percent predicted forced expiratory volume in 1 s: 49.6 ± 17.0%). The fDSMP and eDSMP showed similar clinically meaningful changes in dyspnea with ADL from baseline to 3 months (fDSMP: + 3.3 points; eDSMP: + 3.5 points) and sustained these improvements at 6 months (fDSMP: + 4.0 points; eDSMP: + 2.5 points; time effects P < .001; group by time P = .51). Self-reported endurance exercise time (P = .001), physical functioning (P = .04), and self-efficacy for managing dyspnea (P = .02) also showed positive improvements over time in both groups with no significant differences with respect to program modality. Participants who completed the study reported favorable satisfaction with the programs.
Although there were numerous technical challenges with the eDSMP, both dyspnea self-management programs were effective in reducing dyspnea with ADL in the short term. Our findings will need to be confirmed in a larger randomized trial with more mature Web and personal digital assistant tools, use of a control group, and longer follow-up.
Trial registration NCT00102401,
PMCID: PMC2483918  PMID: 18417444
Dyspnea; pulmonary disease; chronic disease; self-care; self-efficacy; health behavior; health education; exercise; monitoring; Internet; cellular phone; telemedicine; randomized controlled trial; Personal Digital Assistant (PDA)
3.  Anxiety is associated with diminished exercise performance and quality of life in severe emphysema: a cross-sectional study 
Respiratory Research  2010;11(1):29.
Anxiety in patients with chronic obstructive pulmonary disease (COPD) is associated with self-reported disability. The purpose of this study is to determine whether there is an association between anxiety and functional measures, quality of life and dyspnea.
Data from 1828 patients with moderate to severe emphysema enrolled in the National Emphysema Treatment Trial (NETT), collected prior to rehabilitation and randomization, were used in linear regression models to test the association between anxiety symptoms, measured by the Spielberger State Trait Anxiety Inventory (STAI) and: (a) six-minute walk distance test (6 MWD), (b) cycle ergometry peak workload, (c) St. Georges Respiratory Questionnaire (SRGQ), and (d) UCSD Shortness of Breath Questionnaire (SOBQ), after controlling for potential confounders including age, gender, FEV1 (% predicted), DLCO (% predicted), and the Beck Depression Inventory (BDI).
Anxiety was significantly associated with worse functional capacity [6 MWD (B = -0.944, p < .001), ergometry peak workload (B = -.087, p = .04)], quality of life (B = .172, p < .001) and shortness of breath (B = .180, p < .001). Regression coefficients show that a 10 point increase in anxiety score is associated with a mean decrease in 6 MWD of 9 meters, a 1 Watt decrease in peak exercise workload, and an increase of almost 2 points on both the SGRQ and SOBQ.
In clinically stable patients with moderate to severe emphysema, anxiety is associated with worse exercise performance, quality of life and shortness of breath, after accounting for the influence of demographic and physiologic factors known to affect these outcomes.
Trail Registration NCT00000606
PMCID: PMC2848143  PMID: 20214820
4.  Pilot study of a cell phone-based exercise persistence intervention post-rehabilitation for COPD 
To determine the feasibility and efficacy of a six-month, cell phone-based exercise persistence intervention for patients with chronic obstructive pulmonary disease (COPD) following pulmonary rehabilitation.
Participants who completed a two-week run-in were randomly assigned to either MOBILE-Coached (n = 9) or MOBILE-Self-Monitored (n = 8). All participants met with a nurse to develop an individualized exercise plan, were issued a pedometer and exercise booklet, and instructed to continue to log their daily exercise and symptoms. MOBILE-Coached also received weekly reinforcement text messages on their cell phones; reports of worsening symptoms were automatically flagged for follow-up. Usability and satisfaction were assessed. Participants completed incremental cycle and six minute walk (6MW) tests, wore an activity monitor for 14 days, and reported their health-related quality of life (HRQL) at baseline, three, and six months.
The sample had a mean age of 68 ±11 and forced expiratory volume in one second 18% predicted. Participants reported that logging their exercise and symptoms (FEV1) of 40 ± was easy and that keeping track of their exercise helped them remain active. There were no differences between groups over time in maximal workload, 6MW distance, or HRQL (p > 0.05); however, MOBILE-Self-Monitored increased total steps/day whereas MOBILE-Coached logged fewer steps over six months (p =0.04).
We showed that it is feasible to deliver a cell phone-based exercise persistence intervention to patients with COPD post-rehabilitation and that the addition of coaching appeared to be no better than self-monitoring. The latter finding needs to be interpreted with caution since this was a purely exploratory study.
Trial registration (NCT00373932).
PMCID: PMC2740952  PMID: 19750190
chronic obstructive pulmonary disease; physical activity; exercise persistence; pulmonary rehabilitation; cell phones
5.  Oxygen Therapy in Chronic Obstructive Pulmonary Disease 
Since the introduction of oxygen as a therapeutic agent 70 years ago, much has been learned regarding the detrimental effects of hypoxemia and the beneficial impact of oxygen therapy. It is projected that there are close to 800,000 patients receiving long-term oxygen therapy (LTOT) in the United States, at a cost of approximately $1.8 billion annually. The large numbers of patients receiving supplemental oxygen as treatment and the high costs incurred in providing oxygen therapy necessitate the practitioner to know the indications for LTOT as well its effects on survival, pulmonary hemodynamics, sleep, and exercise capacity. It is now recognized that the basis for LTOT prescription for all patients is founded on data that are over 25 years old and that only involve a very select cohort of patients. It is clear that further studies are required to assess the effects of oxygen on patients with chronic obstructive pulmonary disease with only mild hypoxemia, not only survival but also on neurocognitive function, quality of life, exercise physiology, and sleep quality. In addition, although proven to be safe when prescribed long term to individuals with lung disease, there are some concerns about worsening carbon dioxide retention and increased oxidant injury. The goals of this article are to briefly describe the indications for chronic oxygen administration, the physiologic effects of treatment, and potential toxicities, as well as its effect on morbidity and mortality.
PMCID: PMC2645328  PMID: 18453364
chronic obstructive pulmonary disease; oxygen therapy; long-term oxygen therapy; nocturnal oxygen desaturation; hypoxemia
6.  Genetic Determinants of Emphysema Distribution in the National Emphysema Treatment Trial 
Rationale: Computed tomography (CT) scanning of the lung may reduce phenotypic heterogeneity in defining subjects with chronic obstructive pulmonary disease (COPD), and allow identification of genetic determinants of emphysema severity and distribution.
Objectives: We sought to identify genes associated with CT scan distribution of emphysema in individuals without α1-antitrypsin deficiency but with severe COPD.
Methods: We evaluated baseline CT densitometry phenotypes in 282 individuals with emphysema enrolled in the Genetics Ancillary Study of the National Emphysema Treatment Trial, and used regression models to identify genetic variants associated with emphysema distribution.
Measurements and Main Results: Emphysema distribution was assessed by two methods—assessment by radiologists and by computerized density mask quantitation, using a threshold of −950 Hounsfield units. A total of 77 polymorphisms in 20 candidate genes were analyzed for association with distribution of emphysema. GSTP1, EPHX1, and MMP1 polymorphisms were associated with the densitometric, apical-predominant distribution of emphysema (p value range = 0.001–0.050). When an apical-predominant phenotype was defined by the radiologist scoring method, GSTP1 and EPHX1 single-nucleotide polymorphisms were found to be significantly associated. In a case–control analysis of COPD susceptibility limited to cases with densitometric upper-lobe–predominant cases, the EPHX1 His139Arg single-nucleotide polymorphism was associated with COPD (p = 0.005).
Conclusions: Apical and basal emphysematous destruction appears to be influenced by different genes. Polymorphisms in the xenobiotic enzymes, GSTP1 and EPHX1, are associated with apical-predominant emphysema. Altered detoxification of cigarette smoke metabolites may contribute to emphysema distribution, and these findings may lead to further insight into genetic determinants of emphysema.
PMCID: PMC2049064  PMID: 17363767
COPD; genetics; association analysis; computed tomography; emphysema
7.  Genetic Association Analysis of Functional Impairment in Chronic Obstructive Pulmonary Disease 
Rationale: Patients with severe chronic obstructive pulmonary disease (COPD) may have varying levels of disability despite similar levels of lung function. This variation may reflect different COPD subtypes, which may have different genetic predispositions.
Objectives: To identify genetic associations for COPD-related phenotypes, including measures of exercise capacity, pulmonary function, and respiratory symptoms.
Methods: In 304 subjects from the National Emphysema Treatment Trial, we genotyped 80 markers in 22 positional and/or biologically plausible candidate genes. Regression models were used to test for association, using a test–replication approach to guard against false-positive results. For significant associations, effect estimates were recalculated using the entire cohort. Positive associations with dyspnea were confirmed in families from the Boston Early-Onset COPD Study.
Results: The test–replication approach identified four genes—microsomal epoxide hydrolase (EPHX1), latent transforming growth factor-β binding protein-4 (LTBP4), surfactant protein B (SFTPB), and transforming growth factor-β1 (TGFB1)—that were associated with COPD-related phenotypes. In all subjects, single-nucleotide polymorphisms (SNPs) in EPHX1 (p ⩽ 0.03) and in LTBP4 (p ⩽ 0.03) were associated with maximal output on cardiopulmonary exercise testing. Markers in LTBP4 (p ⩽ 0.05) and SFTPB (p = 0.005) were associated with 6-min walk test distance. SNPs in EPHX1 were associated with carbon monoxide diffusing capacity (p ⩽ 0.04). Three SNPs in TGFB1 were associated with dyspnea (p ⩽ 0.002), one of which replicated in the family study (p = 0.02).
Conclusions: Polymorphisms in several genes seem to be associated with COPD-related traits other than FEV1. These associations may identify genes in pathways important for COPD pathogenesis.
PMCID: PMC2662917  PMID: 16456143
dyspnea; emphysema; exercise tolerance; genetic association; pulmonary function tests
8.  Use of accelerometers to characterize physical activity patterns with COPD exacerbations 
To determine the feasibility of using an accelerometer to characterize physical activity patterns (PA) surrounding chronic obstructive pulmonary disease (COPD) exacerbations (AECOPD) in patients with COPD for 16 weeks.
Patients with COPD (n = 8) wore the RT3®, a triaxial accelerometer (Stayhealthy, Monrovia, CA) during waking hours and kept daily symptom diaries. The mean vector magnitude unit (VMU) per minute was calculated by dividing the total VMU for the day by the number of minutes the device was worn. Descriptive statistics were used and plots were made showing PA for each subject with AECOPD markers based on symptom diaries and health resource utilization.
Sample characteristics were: age 71 ± 4; 5 Females; forced expiratory volume in one second (FEV1)% predicted: 40% ± 16%; FEV1/forced vital capacity: 45 ± 7; and Medical Research Council dyspnea scale: 2.3 ± 0.9. Overall adherence to the monitoring protocol was 97.6% (Range 92%–100%) while adherence to wearing the device for at least 10 hours per day was 91.5% (Range 75%–99%). Mean vector magnitude units per minute was 117.8 ± 47 (Range 61.4–184.1). Seven exacerbations were captured over a total of 896 person-days of monitoring. There were substantial intra-individual fluctuations in daily PA during both the stable state and with outpatient treated exacerbations.
Patients with COPD were able to adhere to a 16-week activity monitoring protocol and reported a willingness to wear such a device for an extended period of time if the data yield important and useful information for themselves and their health provider. Future work will need to focus first, on validating other promising devices that produce higher quality PA data and second, replicate this monitoring protocol with a larger sample of COPD patients over a longer period.
PMCID: PMC2707803  PMID: 18044101
physical activity; accelerometry; COPD; exacerbations

Results 1-8 (8)