Evidence of skeletal muscle metabolic reserve during whole body exercise in patients with chronic obstructive pulmonary disease.

When freed from central cardiorespiratory limitations, healthy human skeletal muscle has exhibited a significant metabolic reserve. We studied the existence of this reserve in 10 severely compromised (FEV1 = 0.97 +/- SE 0.01) patients with chronic obstructive pulmonary disease (COPD). To manipulate O2 supply and O2 demand in locomotor and respiratory muscles, subjects performed both maximal conventional two-legged cycle ergometry (large muscle mass) and single-leg knee extensor exercise (KE, small muscle mass) while breathing room air (RA), 100% O2, and 79% helium + 21% O2 (HeO2). With each gas mixture, peak ventilation, peak heart rate, and perceived breathlessness were lower in KE than cycle exercise (p < 0. 05). Arterial O2 saturation and maximal work capacity increased in both exercise modalities while subjects breathed 100% O2 (work: +10% bike, +25% KE, p < 0.05). HeO2 increased maximal work capacity on the cycle (+14%, p < 0.05) but had no effect on KE. HeO2 resulted in the greatest maximum minute ventilation in both bike and KE (p < 0. 05) but had no effect on arterial O2 saturation. Thus, a skeletal muscle metabolic reserve in these patients with COPD is evidenced by: (1) greater muscle mass specific work in KE; (2) greater work rates with higher fraction of inspired oxygen (FIO2); (3) an even greater effect of FIO2 during KE (i.e., when the lungs are less challenged); and (4) the positive effect of HeO2 on bicycle work rate. This skeletal muscle metabolic reserve suggests that reduced whole body exercise capacity in COPD is the result of central restraints rather than peripheral skeletal muscle dysfunction, while the beneficial effect of 100% O2 (with no change in maximum ventilation) suggests that the respiratory system is not the sole constraint to oxygen consumption.

Maximizing functional capacity. Pulmonary rehabilitation and adjunctive measures.

Pulmonary rehabilitation has become an important adjunct to standard medical therapy, with the primary goal of restoring patients to the highest possible functional state using a combination of exercise training, education, respiratory and chest physiotherapy techniques, and psychosocial support. Evidence supports the use of this combined modality therapy for motivated patients with disability from chronic lung disease. Although pulmonary function generally does not change, exercise tolerance can improve, together with decreased symptoms of breathlessness, improved quality of life, and less need for health care services. Patients are empowered with a better understanding of their disease and the proper usage of medications, oxygen therapy, and chest physiotherapy techniques. Thus, pulmonary rehabilitation enables patients to make the most of their lungs and their life.

Validation of a new dyspnea measure: the UCSD Shortness of Breath Questionnaire. University of California, San Diego.

OBJECTIVE: Evaluate the reliability and validity of a new version of the University of California, San Diego Shortness of Breath Questionnaire (SOBQ), a 24-item measure that assesses self-reported shortness of breath while performing a variety of activities of daily living. DESIGN: PATIENTS enrolled in a pulmonary rehabilitation program were asked to complete the SOBQ, the Quality of Well-Being Scale, the Center for Epidemiologic Studies Depression Scale, and a 6-min walk with modified Borg scale ratings of perceived breathlessness following the walk. SETTING: University medical center pulmonary rehabilitation program. PATIENTS: Thirty-two male subjects and 22 female subjects with a variety of pulmonary diagnoses: COPD (n=28), cystic fibrosis (n=9), and postlung transplant (n=17). MEASUREMENTS AND RESULTS: The current version of the SOBQ was compared with the previous version, the format of which often resulted in a significant number of "not applicable" answers. The results demonstrated that the SOBQ had excellent internal consistency (alpha=0.96). The SOBQ was also significantly correlated with all validity criteria. CONCLUSIONS: The SOBQ is a valuable assessment tool in both clinical practice and research in patients with moderate-to-severe lung disease.

Analysis of chronic obstructive pulmonary disease referrals for lung volume reduction surgery. The University of California San Diego Emphysema Treatment Group.

BACKGROUND: Preliminary results of lung volume reduction surgery (LVRS) for patients with severe emphysema are promising, although many issues regarding the selection process for LVRS are still unaddressed. For example, it is unclear which patients should be referred for pulmonary rehabilitation, lung transplantation, or LVRS, and whether health-care providers are optimizing conservative treatment options before referral for surgical intervention. The purpose of this analysis is to describe preliminary results of the evaluation process for LVRS implemented as part of an integrated, programmatic approach to the evaluation, treatment, and rehabilitation of patients with advanced emphysema. METHODS: The records of 105 consecutive patients with chronic obstructive pulmonary disease (COPD) referred for consideration for LVRS at the University of California San Diego Medical Center were reviewed. Results of prospective data collection pertaining to patient demographic, baseline dyspnea scores, and history of prior treatment, including pulmonary rehabilitation, were extracted. Patient disposition after the evaluation was noted. RESULTS: One hundred five patients (mean age 65 years, range 40 to 84 years) completed evaluation. Fifty-eight had never before participated in pulmonary rehabilitation, and 47 of these patients were eventually referred to a rehabilitation program. Fourteen patients were referred for consideration of lung transplantation, 25 were considered eligible for LVRS, 13 were still undergoing rehabilitation and surgical eligibility had not yet been determined, and 53 were ineligible for LVRS because patients had other illnesses (n = 34), did not meet radiological or physiologic criteria (n = 5), were considered too ill (n = 5), or were too healthy (n = 9) after rehabilitation to warrant surgical intervention. CONCLUSIONS: Lung volume reduction surgery is a surgical option to be considered within the framework of an integrated medical evaluation program that includes pulmonary rehabilitation. Pulmonary rehabilitation remains an often underused therapeutic alternative in patients with severe COPD. It has become the central component of our comprehensive management program for patients with severe dyspnea and deteriorating quality of life.

Asthma in a Vietnamese refugee population.

Asians and Pacific Islanders comprise a large and growing minority group in the United States, yet data on health status specific to these populations are scant. We conducted an epidemiologic study of asthma in a Vietnamese refugee population to estimate prevalence, evaluate risk factors, and better understand treatments of asthma among Vietnamese individuals. One hundred twenty-four asthma cases were identified from a population of 2,536 new Vietnamese refugees in San Diego (prevalence = 49 per 1,000; 4.9%). Two nonasthmatic control groups of Vietnamese refugees, matched for age and gender with the asthma cases, were recruited for a case-control study, using a questionnaire administered in Vietnamese. Vietnamese asthmatic individuals used both Western and non-Western therapies. Most subjects used traditional health practices, such as coining, cupping, and oil inhalation. As compared with current-refugee controls, the asthmatic subjects used significantly more bleeding (OR: 3.40; 95% CI: 1.06 to 10.80) and herbal ingestion (OR: 1.87; 95% CI: 1.08 to 3.19). As compared with former-refugee controls, the asthmatic subjects used significantly more oil inhalation (OR: 2.58; 95% CI: 1.45 to 4.85), bleeding (OR: 8.64, 95% CI: 1.02 to 73.70), and herbal ingestion (OR: 1.93; 95% CI: 1.02 to 3.67). The presentation and recognition of asthma among the Vietnamese subjects were similar to those in other populations. This information may be helpful in designing culture-specific health-education programs.

Patients' self-reports of dyspnea: An important and independent outcome in chronic obstructive pulmonary disease.

Patients'' self-reports of dyspnea are an important clinical outcome in evaluating treatments in chronic obstructive pulmonary disease (COPD). This study evaluated the dimensions underlying self-reported dyspnea ratings, lung function, and respiratory muscle pressures in 143 patients with COPD. The validity of dyspnea ratings and lung function parameters to predict the variance of a common functional measure, the six-minute walk test, was also assessed. Results of a factor analysis confirmed previous work demonstrating the independence of dyspnea ratings from pulmonary function parameters. Dyspnea ratings also explained a greater proportion of the variance in the six-minute walk test than did lung function. Results of this study provide further evidence for the importance and independence of self-reported dyspnea ratings in evaluating outcomes in COPD.

The impact of social support in pulmonary rehabilitation of patients with chronic obstructive pulmonary disease.

Social support has been shown to be an important mediator of health status and survival in chronic illness but little information is available in patients with lung diseases. We used the Social Support Questionnaire (SSQ) to examine the relationships of number of persons (SSQ-N) and satisfaction (SSQ-S) with other measures of health status, treatment changes, and survival in 110 patients with chronic obstructive pulmonary disease (COPD) participating in a randomized, controlled clinical trial of pulmonary rehabilitation (PR). Included in the analyses were measures of lung function (FEV1.0), exercise tolerance (maximum and endurance), symptoms ratings, age, self-efficacy, depression, and gender. At baseline, SSQ-N and SSQ-S were correlated positively with self-efficacy and negatively with depression and self-reported shortness of breath (SOB). SSQ-N was also correlated with disease severity and maximum exercise tolerance (FEV1.0 and VO2 max). Using the Cox Proportional Hazard Model, SSQ-S was significantly related to improved survival up to six years. However, in multivariate analysis, after adjusting for FEV1.0 and SOB which were better predictors of survival, SSQ-S was marginally significant. SSQ-S and survival were computed separately for males and females across treatment groups. SSQ-S was significantly related to mortality for women but not for men. We conclude that social support is related to measures of physical and psychological function in patients with COPD and may influence improvement and survival after pulmonary rehabilitation.

Quality of well-being predicts survival in lung transplantation candidates.

Predictors of survival were evaluated among 74 patients selected for a lung transplantation program. Each patient received the quality of well-being scale, a utility-based outcome measure that gives a score on a continuum ranging from 0 (for dead) to 1.0 (for optimum function), and a measure of depressive symptoms (Beck depression inventory). Over the course of follow-up, 24 patients died (ranging from listing date, 3 to 1, 110 d). Of the 49 patients who received lung transplantation, 13 died. In a multivariate analysis, the most significant predictor of survival was quality of well-being (relative risk = 0.454, p < 0.05). Lung transplant status, when entered as a time-dependent covariate (a function of how long the patient waited for surgery) was not a significant predictor of survival (relative risk = 0.942, p > 0.05). Depression was not a significant predictor of survival (relative risk = 0.961, p > 0.05). We conclude that health-related quality of life is a significant predictor of survival for patients with serious lung diseases.

Effects of pulmonary rehabilitation on physiologic and psychosocial outcomes in patients with chronic obstructive pulmonary disease.

OBJECTIVE: To compare the effects of comprehensive pulmonary rehabilitation with those of education alone on physiologic and psychosocial outcomes in patients with chronic obstructive pulmonary disease. DESIGN: Randomized clinical trial. SETTING: University medical center. PATIENTS: 119 outpatients with chronic obstructive pulmonary disease that was stable while patients received a standard medical regimen. INTERVENTION: Patients were randomly assigned to either an 8-week comprehensive pulmonary rehabilitation program or to an 8-week education program. Pulmonary rehabilitation consisted of twelve 4-hour sessions that included education, physical and respiratory care instruction, psychosocial support, and supervised exercise training. Monthly reinforcement sessions were held for 1 year. The education group attended four 2-hour sessions that included video-tapes, lectures, and discussions but not individual instruction or exercise training. MEASUREMENTS: Pulmonary function, maximum exercise tolerance and endurance, gas exchange, symptoms of perceived breathlessness and muscle fatigue with exercise, shortness of breath, self-efficacy for walking, depression, general quality of well-being, and hospitalizations associated with pulmonary diseases. Patients were followed for 6 years. RESULTS: Compared with education alone, comprehensive pulmonary rehabilitation produced a significantly greater increase in maximal exercise tolerance (+1.5 metabolic equivalents [METS] compared with +0.6 METS [P < 0.001]; maximal oxygen uptake, +0.11 L/min compared with +0.03 L/min [P = 0.06]), exercise endurance (+10.5 minutes compared with +1.3 minutes [P < 0.001]), symptoms of perceived breathlessness (score of -1.5 compared with +0.2 [P < 0.001]) and muscle fatigue (score of -1.4 compared with -0.2 [P < 0.01]), shortness of breath (score of -7.0 compared with +0.6 [P < 0.01]), and self-efficacy for walking (score of +1.4 compared with +0.1 [P < 0.05]). There were slight but nonsignificant differences in survival (67% compared with 56% [P = 0.32]) and duration of hospital stay (-2.4 days/patient per year compared with +1.3 days/patient per year [P = 0.20]). Measures of lung function, depression, and general quality of life did not differ between groups. Differences tended to diminish after 1 year of follow-up. CONCLUSIONS: Comprehensive pulmonary rehabilitation significantly improved exercise performance and symptoms for patients with moderate to severe chronic obstructive pulmonary disease. Benefits were partially maintained for at least 1 year and tended to diminish after that time.

Treatment of dyspnea in COPD. A controlled clinical trial of dyspnea management strategies.

We conducted a randomized clinical trial to evaluate a limited pulmonary rehabilitation program focused on coping strategies for shortness of breath but without exercise training. Eighty-nine patients with COPD were randomly assigned to either 6-week treatment or general health education control groups. Treatment consisted of instruction and practice in techniques of progressive muscle relaxation, breathing retraining, pacing, self-talk, and panic control. Tests of 6-min walk distance, quality of well-being, and psychological function as well as six dyspnea measures were administered at baseline, posttreatment, and 6 months after the intervention. Baseline pulmonary function tests also were obtained. At the end of the 6-week treatment, there were no significant differences between the treatment and control groups on any outcome measure. At the 6-month follow-up, a significant group difference was seen on only one variable, Mahler's transition dyspnea index. The results of this evaluation suggest that a treatment program of dyspnea management strategies, without structured exercise training or other components of a comprehensive pulmonary rehabilitation program, is not sufficient to produce significant improvement in dyspnea, exercise tolerance, health-related quality of well-being, anxiety, or depression.

Reliability and validity of dyspnea measures in patients with obstructive lung disease.

Dyspnea, the clinical term for shortness of breath, is the primary symptom and an important outcome measure in evaluations of patients with lung disease. It is a subjective symptom that has proved difficult to quantify. Many dyspnea measures are available, yet it is difficult, based on the existing literature, to determine the most reliable and valid. In this study, we evaluated 6 measures of dyspnea for reliability and validity: (a) Baseline Dyspnea Index (BDI) and Transition Dyspnea Index, (b) UCSD Shortness of Breath Questionnaire (SOBQ),(c) American Thoracic Society Dyspnea Scale, (d) Oxygen Cost Diagram, (e) Visual Analog Scale, and (f) Borg Scale. Subjects were 143 patients (74 women) and 69 men) with obstructive lung disease, ages 40 to 86, FEV(1.0) 0.36 to 3.53 L, FVC 1.07 to 5.74 L. Dyspnea measures were assessed for test-retest reliability internal consistency, interrater reliability, and construct validity (i.e., correlations among dyspnea measures and correlations of dyspnea measures with exercise tolerance, health-related quality of life, lung function, anxiety, and depression). Results suggest that the SOBQ and BDI demonstrated the highest levels of reliability and validity among the dyspnea measures examined.

The effects of exercise testing on the prescription of oxygen therapy.

This study reviews the effects of using oxygen saturation measurements during exercise and the effects of the method of exercise testing on the prescription of oxygen therapy. Using cutaneous oximetry (designated A and B models) and co-oximetry, 25 of 41 patients (model A), 30 of 39 patients (model B), and 28 of 42 patients (co-oximetry) had an oxygen saturation measurement greater than 85 percent at maximal incremental exercise despite an arterial oxygen tension less than 55 mm Hg. Also, in a group of patients who underwent incremental followed by constant work rate testing, 9 of 28 exhibited a fall in arterial oxygen tension to 55 mm Hg or below only during the constant work rate testing. Oxygen saturation measurements cannot reliably be used as a substitute for arterial oxygen tension measurements for the prescription of oxygen therapy. The type of exercise study performed may influence the outcome of such oxygen prescription.

Self-efficacy expectations predict survival for patients with chronic obstructive pulmonary disease.

The validity of self-efficacy expectations as predictors of mortality was evaluated for 119 patients with chronic obstructive pulmonary disease (COPD). Patients completed 4 physiological measures that represent common clinical indicators of disease severity: (a) forced expiratory volume in 1 s (FEV1.0), (b) arterial blood gas measurement of resting partial pressure of oxygen (PaO2), (c) single-breath diffusing capacity (DLCO), and (d) maximum oxygen uptake (VO2max) during exercise. In addition, self-reported self-efficacy expectation for walking on a treadmill was measured. Self-efficacy was a significant univariate predictor of 5-year survival. However, when controlling for FEV1.0 in multivariate survival analysis, self-efficacy had only a marginal effect. We concluded that simple self-report scales could provide significant information about health status.

The importance of exercise in pulmonary rehabilitation.

Exercise has been shown to be an important component of pulmonary rehabilitation and may be associated with both physiologic and psychological benefits for patients with chronic lung disease. In evaluating patients for pulmonary rehabilitation, exercise testing can be useful in measuring exercise tolerance, assessing causes of exercise limitation, developing a prescription for training, evaluating often unexpected changes in arterial blood gases, and screening for exercise-induced bronchospasm. A variety of testing procedures and measurements are available in pulmonary laboratories. The appropriate test depends on several variables, including patient and program goals, questions identified in the initial patient evaluation, the specific exercise training program, available laboratory expertise, and cost.

Measurement of dyspnoea in chronic obstructive pulmonary disease.

This paper reviews the assessment of shortness of breath in chronic obstructive pulmonary disease (COPD). The validity criteria for evaluating measures of dyspnoea are discussed and a description and critique of current measures of shortness of breath are offered. Across studies, dyspnoea measures are moderately correlated with pulmonary function (e.g. FEV1.0 and FVC), psychological function, and walking tests (6 min walk). In addition, dyspnoea measures tend to be correlated with one another. The need for standardisation of dyspnoea measures for research and clinical practice is identified as an important objective for future work.

Cardiovascular risk factor assessment of medical students as an educational tool.

For three consecutive years, beginning in 1986, we evaluated cardiovascular disease (CVD) risk factors of medical students as part of the teaching program in a Preventive Cardiology Academic Award. Entering students in three consecutive classes were screened on the first day of orientation to medical school. The first year, we evaluated 108 students (71 men and 37 women), the second year, 99 students (75 men, 24 women), and the third year 108 students (67 men and 41 women). During the single four-hour period, we obtained data on personal and family history of CVD risk factors, type A behavior, knowledge of CVD, attitudes toward CVD prevention, measures of depression and anger, blood pressure, blood pressure reactivity, physical activity, and diet. Blood was drawn for lipid analysis. Height and weight were measured, and a physical fitness step test was administered. Pulmonary function was measured during the third year. We used a four-tiered approach to preventive cardiology education. During the assessment session, abnormalities, such as elevated blood pressure or abnormal pulse, were discussed with the student. In the second tier, the data were analyzed and returned to all students during teaching sessions, enabling them to compare their levels with the class and the national averages. For the third tier, students with high-risk values, defined as low-density lipoprotein cholesterol level > or = 150 mg/dL, a total cholesterol or triglyceride level > or = 200 mg/dL, or blood pressure > or = 140/90 mmHg, were seen by faculty physicians who suggested remedial interventions in separate sessions.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of posture on arterial oxygenation in patients with chronic obstructive pulmonary disease.

We studied 117 patients with chronic obstructive pulmonary disease (COPD) to evaluate (1) the frequency and magnitude of postural changes in resting arterial oxygenation and (2) the relationship of these changes to other measures of pulmonary function and exercise arterial blood gases. Compared to the supine measurement, room air PaO2 measured while standing increased more than 3 mm Hg in 28 patients (group 1), did not change (+/- 3 mm Hg) in 57 patients (group 2), and decreased more than 3 mm Hg in 32 patients (group 3) (range = 31 mm Hg increase to 20 mm Hg decrease). Patients in group 1 had significantly less severe disease than patients in the other two groups. There were no significant pulmonary function differences between groups 2 and 3. Supine PaO2 was similar for all groups, suggesting that standing PaO2 accounted for the postural change in PaO2. Because of unpredictable postural changes in PaO2 in patients with COPD, we believe that body position should be noted for arterial blood gas measurements and should be kept constant for valid comparison of serial measurements. These findings may also be important for other diffuse lung diseases.

Laser resection of granulation tissue secondary to transtracheal oxygen catheter.

Oxygen therapy through a transtracheal catheter has been used increasingly for the long-term delivery of continuous oxygen. Compared to nasal cannula it results in significant reduction in oxygen flow requirements. This form of therapy has gained patient acceptance because of several advantages including improved convenience, aesthetics, compliance, and mobility. Reported complications generally have been minor, including subcutaneous emphysema, cough, "mucous ball" formation and mild hemoptysis. In this report, we describe a case of granulation tissue formation at the transtracheal catheter puncture site which was treated with Nd:YAG laser bronchoscopy to reestablish patency of the upper airway. No recurrence was noted after two years of follow-up.

Maximum intensity exercise training in patients with chronic obstructive pulmonary disease.

We studied high intensity, symptom-limited, endurance exercise training in 52 patients with COPD participating in a pulmonary rehabilitation program. The patients had moderate to severe airway obstruction and reduced exercise tolerance with ventilatory limitation. The target workload for endurance exercise testing was 95 percent of the baseline maximum treadmill work load. At training weeks 1, 4 and 8, they were training at 85, 84, and 86 percent respectively, of baseline maximum. After rehabilitation, there was an increase in maximal treadmill work load, VO2max, and endurance exercise time, and a decrease in perceived symptoms. Patients who did not reach anaerobic threshold (group 2) were able to train at a higher percentage of maximum exercise tolerance than patients who reached anaerobic threshold (group 1). The increase in exercise performance of both groups, however, was similar. We conclude that patients with moderate to severe COPD can perform exercise training successfully at intensity targets which represent higher percentages of maximum than typically recommended in normal individuals or other patients.