Brian Tiep

Criterion validity of the Duke Activity Status Index for assessing functional capacity in patients with chronic obstructive pulmonary disease

PURPOSE This study evaluated the concurrent criterion validity of the Duke Activity Status Index (DASI) with respect to standard physiologic work capacity indices in patients with chronic obstructive pulmonary disease (COPD) and compared its performance with similar surrogates. METHODS 119 patients with moderate to severe COPD (86 men, 33 women) completed medical and smoking histories, physical examination, pulmonary function testing (PFT), cycle ergometry (CE), arm ergometry (AE), and 6-minute walk distance (6MWD), DASI, the Sickness Impact Profile-68 (SIP-68) and the Chronic Respiratory Disease Questionnaire (CRDQ). Correlation methods were used to assess the validity of the potential surrogates DASI and the domain scores for SIP-68 and CRDQ, with the standards CE, AE, PFT, and 6MWD (as a standard). RESULTS The mean DASI score was 33.4 +/- 13.0. Significant Pearson correlations (P <.01) were observed between the DASI and PFT outcomes maximum voluntary ventilation (r =.28); peak expiratory flow (r =.21); diffusion capacity of lung for carbon monoxide (r =.30). For CE, the correlations with DASI were oxygen consumption (VO(2))(r =.34); minute ventilation (r =.25); watts (r =.37). For AE, the correlations with DASI were VO(2) (r=.38); watts (r =.47). For 6MWD, the correlation was r =.53. Higher correlations were obtained for the distance completed during the first minute of the 6MWD and ergometric indices as well as DASI scores: watts(AE) (r =.39); VO(2AE) (r =.45); watts(CE) (r =.50); VO(2CE) (r =.44). Correlation coefficients for all SIP-68 and CRDQ domain and total scores were lower than corresponding correlations obtained for the DASI. Regression analysis demonstrated that the DASI and 6MWD were important (P <.05) for predicting VO(2) or work for CE while DASI and SIP range or CRDQ dyspnea entered for AE, when gender, age, BMI, and the FEV1 were forced into the model. In forward stepwise analyses, DASI entered first for AE, and 6MWD entered first for CE. The DASI was selected in 3 of 4 models with R(2) values ranging from.47 to.70. SIP-68 and CRDQ subscores were significant as additional predictors. CONCLUSIONS DASI has high criterion validity for predicting CE and/or AE outcomes in the COPD population. It is warranted in addition to the 6MWD, and its predictive significance and simplicity recommends it over several other self-administered instruments for evaluating functional capacity.

Predicting oxygen uptake for men and women with moderate to severe chronic obstructive pulmonary disease.

OBJECTIVE To develop regression equations for estimating peak oxygen consumption (Vo(2)) for men and women with moderate to severe chronic obstructive pulmonary disease (COPD) from the 6-minute walk test (6MWT). DESIGN Multivariate analysis of patient pulmonary function and exercise gas exchange indices to 2 outcomes for the 6MWT (distance ambulated, calculated work [6M(WORK)]). SETTING A university hospital and clinics. PARTICIPANTS A total of 124 patients (90 men 34 women; age range, 45\N81y), from the community, with moderate to very severe COPD. Forced expiratory volume in 1 second (FEV(1)) ranged from.70 to 2.79L/min, forced vital capacity (FVC) ranged from 1.73 to 5.77L, and FEV(1)/FVC ranged from 24% to 69%. All patients were in stable condition at the time of testing and were on a stable drug regimen. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Pulmonary function testing was completed according to American Thoracic Society criteria. Cycle ergometry with gas exchange, by using a ramp protocol, was completed. The 6MWT was done in the hospital corridor, with distances recorded after each minute. Work capacity by each method was reduced from the normal predicted. RESULTS Peak oxygen uptake (Vo(2)) averaged 1184+/-302mL/min for men and 860+/-256mL/min for women (58%, 68% of predicted, respectively). Ventilatory reserve was limited at an achieved peak ventilation (Ve) of 79.9%+/-19.1% of predicted. Borg scores for dyspnea and leg fatigue were equivalent for each test modality, with leg fatigue being slightly higher for each gender. 6M(WORK) for the 6MWT was the strongest independent predictor of peak Vo(2) (r=.81, P<.0001), whereas that for distance ambulated was correlated at r equal to.54 (P<.0001). This is a 36% improvement in the variance accounted for by the application of 6M(WORK) as the outcome for the 6MWT. Generalized regression modeling was then used to develop equations for the estimation of peak Vo(2) for the 6MWT. Additional variables included in the model were diffusing capacity of lung for carbon dioxide, FVC, maximal inspiratory pressure, weight (in kilograms), and age, with their appropriate interactions. This derived regression model accounted for 79% on the variance for estimation of peak Vo(2) in the patients studied. CONCLUSION Peak Vo(2) can be estimated for men and for women by using the generalized equations presented. The calculation of 6M(WORK) is an improvement over distance ambulated as the 6MWT outcome. These data build on the existing body of knowledge for the 6MWT and extend its application for patients with COPD. Knowledge of the peak Vo(2) can be used for patient assessment, serial monitoring, evaluating disability, and as a common index of function across modalities. The calculation of 6M(WORK) outperformed distance ambulated and is easily converted to other indices of caloric expenditure that are commonly used in the laboratory and clinical settings.

Influence of Lightweight Ambulatory Oxygen on Oxygen Use and Activity Patterns of COPD Patients Receiving Long-Term Oxygen Therapy

Abstract Lightweight ambulatory oxygen devices are provided on the assumptions that they enhance compliance and increase activity, but data to support these assumptions are lacking. We studied 22 patients with severe chronic obstructive pulmonary disease receiving long-term oxygen therapy (14 men, average age = 66.9 y, FEV1 = 33.6%pred, PaO2 at rest = 51.7 torr) who were using E-cylinders as their portable oxygen. Subjects were recruited at 5 sites and studied over a 2-week baseline period and for 6 months after randomizing them to either continuing to use 22-lb E-cylinders towed on a cart or to carrying 3.6-lb aluminum cylinders. Utilizing novel electronic devices, ambulatory and stationary oxygen use was monitored continuously over the 2 weeks prior to and the 6 months following randomization. Subjects wore tri-axial accelerometers to monitor physical activity during waking hours for 2–3 weeks prior to, and at 3 and 6 months after, randomization. Seventeen subjects completed the study. At baseline, subjects used 17.2 hours of stationary and 2.5 hours of ambulatory oxygen daily. At 6 months, ambulatory oxygen use was 1.4 ± 1.0 hrs in those randomized to E-cylinders and 1.9 ± 2.4 hrs in those using lightweight oxygen (P = NS). Activity monitoring revealed low activity levels prior to randomization and no significant increase over time in either group. In this group of severe chronic obstructive pulmonary disease patients, providing lightweight ambulatory oxygen did not increase either oxygen use or activity. Future efforts might focus on strategies to encourage oxygen use and enhance activity in this patient group. This trial is registered at ClinicalTrials.gov (NCT003257540).

Peak Physiologic Responses to Arm and Leg Ergometry in Male and Female Patients With Airflow Obstruction

STUDY OBJECTIVE To investigate differences in work capacity for the arms and legs in patients with moderate-to-severe COPD. DESIGN Cross-sectional investigation. PATIENTS One hundred twenty-four patients (90 men and 34 women) aged 45 to 81 years with moderate-to-very severe COPD. FEV(1) ranged from 0.70 to 2.79 L/min (FVC, 1.73 to 5.77 L; FEV(1)/FVC, 24 to 69%). All patients were in stable condition at the time of testing and receiving a stable drug regime. MEASUREMENTS Each patient completed a demographic and medical history questionnaire, pulmonary function studies (spirometry, lung volumes, and diffusion capacity), peak exercise ergometry with gas exchange for the arms and legs; they also rated their subjective assessment of perceived dyspnea and extremity fatigue using Borg scores during exercise. RESULTS Patients were of comparable age, with men taller and heavier than women. Smoking history was significantly less for women (47.9 pack-years vs 66.6 pack-years for men) even though each group presented with equivalent age (p > 0.05). Women were less obstructed than men, with FEV(1)/FVC (mean +/- SD) of 46.5 +/- 10.9% vs 40.2 +/- 9.3%, respectively. Ventilatory limitation during exercise was noted for all patients studied. Peak work capacity was greater for men, and leg peak responses were greater than arm values for each gender. As airway obstruction increased, work capacity became more limited. Peak arm work achieved was 38.9 +/- 19.6 W, oxygen uptake (VO(2)) was 903.9 +/- 263.5 mL/min, and minute ventilation (VE) was 33.7 +/- 9.5 L. Peak leg work value was 62.9 +/- 24.8 W, VO(2) was 1,091.4 +/- 321.5 mL/min, and VE was 39.3 +/- 12.0 L. Hence, arm values were 62%, 83%, and 85% of the measured leg values, respectively. Dyspnea and extremity effort scores were similar for men and women, and for arms and legs. Regression analysis was used to derive prediction equations for arm work from measured leg ergometry testing. For watts of work, a three-variable model emerged explaining 66% of the variance; VO(2) yielded a four-variable model with 80% of the variance explained; and VE yielded a three-variable model explaining 72% of the variance. CONCLUSION Arm work is reduced by 38% that of the legs, while more modest reductions are noted for VO(2) and VE, suggesting greater mechanical efficiency for leg work as compared to arm work. These data also suggest greater metabolic demand for respiratory muscles and arm ergometry. Dyspnea and extremity Borg scores were equivalent for each modality and level of airway obstruction studied, suggesting that perception plays an important role in limiting exercise, and that a threshold for termination of exercise may exist. Further, peak leg ergometry results can be used with pulmonary function indexes to predict peak arm workload in watts, VO(2), and VE. These data may be used to assist the clinician in prescribing rehabilitation or estimating arm exercise ability when arm testing is unavailable.

Oxygen for end-of-life lung cancer care: managing dyspnea and hypoxemia.

Oxygen is commonly prescribed for lung cancer patients with advancing disease. Indications include hypoxemia and dyspnea. Reversal of hypoxemia in some cases will alleviate dyspnea. Oxygen is sometimes prescribed for non-hypoxemic patients to relieve dyspnea. While some patients may derive symptomatic benefit, recent studies demonstrate that compressed room air is just as effective. This raises the question as to whether to continue their oxygen. The most efficacious treatment for dyspnea is pharmacotherapy–particularly opioids. Adjunctive therapies include pursed lips breathing and a fan blowing toward the patient. Some patients may come to require high-flow oxygen. High-flow delivery devices include masks, high-flow nasal oxygen and reservoir cannulas. Each device has advantages and drawbacks. Eventually, it may be impossible or impractical to maintain a SpO2 > 90%. The overall goal in these patients is comfort rather than a target SpO2. It may eventually be advisable to remove continuous oximetry and transition focus to pharmacological management to achieve patient comfort.

Severe Exercise-Induced Hypoxemia

Exercise training is an essential component of pulmonary rehabilitation and is associated with improved function and other important outcomes in persons with chronic lung disease. A subset of pulmonary rehabilitation patients experience hypoxemia that may occur or worsen with exercise. For the purpose of this review, severe exercise-induced hypoxemia is defined as an SpO2 of < 89% during exercise, despite use of supplemental oxygen delivered at up to 6 L/min. There is a paucity of evidence and clinical guidelines that address assessment and management of this important manifestation of chronic lung disease. This review presents background of this topic and suggests strategies for assessment, management, and safety measures for patients with severe exercise-induced hypoxemia.

The Emerging Chronic Obstructive Pulmonary Disease Epidemic: Clinical Impact, Economic Burden, and Opportunities for Disease Management

The incidence and economic impact of chronic obstructive pulmonary disease (COPD) is escalating worldwide and is projected to remain on a positive trajectory for many years to come. At some point in this escalation, COPD may be regarded as a true epidemic. Unfortunately, the incidence among women is escalating more rapidly than in men, reflecting the social anthropology of changing smoking habits. This knowledge, coupled with the fact that the true disease prevalence is under-reported, suggests that we are facing a significant medical and economic crisis. The most preventable risks for COPD continue to be cigarette smoking and exposure to second-hand smoke. This is a particular problem for youth in their formative and critical growth years. Amalgamated with these alarming trends are the decline in air quality, occupational exposure to inhaled pollutants and pro-inflammatory materials, poor nutrition, lack of exercise, and increasing body mass index.There is a lack of patient and family understanding regarding this chronic disease process and its co-morbid conditions. First and foremost, smoking-cessation efforts must be increased, and protection from second-hand smoke needs to be emphasized. Spirometric testing to identify populations at risk and in the early stages of disease should be implemented on a large scale and should trigger implementation of appropriate preventive steps. Disease management processes and strategies used in alliance with educational-, nutritional-, and physical exercise-related interventions may hold the key to altering behavioral patterns of patients and their families. We need to provide patients with simple and definitive interventions that can be self-initiated at the earliest possible time. This may help us to integrate best medical practices early in the disease process. Thus, we can improve bodily function from a systemic perspective, while implementing coordinated disease surveillance and treatment plans for each affected individual. From an economic perspective, financial incentives can be provided by way of shifting costs from disease treatment to disease prevention and health enhancement. When the correct incentives and disease management strategies are embraced, a disease-oriented intervention can ameliorate the devastating impact of COPD on patients and their families while relieving the economic impact of the disease.In summary, numerous stakeholders will need to come together in order to identify and remove barriers for implementation of preventive measures, provide early intervention, modify the disease course, and minimize the economic impact of COPD. Strategies should be developed for populations, as well as individual patients, if we are to adequately address this emerging epidemic.

Preparing Cancer Patients and Family Caregivers for Lung Surgery: Development of a Multimedia Self-Management Intervention.

The surgical treatment of lung malignancies often results in persistent symptoms, psychosocial distress, and decrements in quality of life (QOL) for cancer patients and their family caregivers (FCGs). The potential benefits of providing patients and FCGs with preparatory education that begins in the preoperative setting have been explored in multiple medical conditions, with positive impact observed on postoperative recovery, psychological distress, and QOL. However, few studies have explored the benefits of preparatory educational interventions to promote self-management in cancer surgery, including lung surgery. This paper describes the systematic approach used in the development of a multimedia self-management intervention to prepare cancer patients and their FCGs for lung surgery. Intervention development was informed by (1) contemporary published evidence on the impact of lung surgery on patients and FCG, (2) our previous research that explored QOL, symptoms, and caregiver burden after lung surgery, (3) the use of the chronic care self-management model (CCM) to guide intervention design, and (4) written comments and feedback from patients and FCGs that informed intervention development and refinement. Pilot-testing of the intervention is in process, and a future randomized trial will determine the efficacy of the intervention to improve patient, FCG, and system outcomes.

Objective physical and mental markers of self‐reported fatigue in women undergoing (neo)adjuvant chemotherapy for early‐stage breast cancer

Objective, treatment‐independent markers of cancer‐related fatigue are needed to advance clinical trials. In the current study, the authors evaluated physical, neurocognitive, and serologic markers for correlation with self‐reported fatigue before and after (neo)adjuvant chemotherapy for patients with early‐stage breast cancer.

Pulmonary Rehabilitation and Palliative Care for the Lung Cancer Patient

Pulmonary rehabilitation, as a quality-of-life intervention, has a role to play in palliative care for lung cancer patients. Combining the art and skills of clinical care, physiological, and behavioral tools, pulmonary rehabilitation can serve to rebuild the functional capacity of patients limited by breathlessness and deconditioning. Exercise programs are the primary tool used to restore and rebuild the patient’s endurance by challenging the entire pathway of oxygen transport and improving gas exchange. Other tools of pulmonary rehabilitation include breathing retraining, self-management skills, airway clearance techniques, bronchodilation, smoking cessation, and oxygen therapy. Pulmonary rehabilitation is now becoming a part of supportive care for patients undergoing chemotherapy and radiation therapy. The ability to be more active without suffering the consequences of dyspnea on exertion boosts the patient’s self-efficacy and allows for an improved quality of life, so that lung cancer patients can participate in their family lives during this therapeutic challenge.