Pruebas de ejercicio cardiopulmonar

Patient Profile of Drop-Outs From a Pulmonary Rehabilitation Program

INTRODUCTION

While the benefits of pulmonary rehabilitation programs (PR) in COPD have been demonstrated, poor adherence, related with worse clinical outcomes, is common.

OBJECTIVE

The purpose of this study was to examine causes for drop-out during a 12-week multidisciplinary pulmonary rehabilitation program and to investigate the characteristics of patients with poor adherence, with special emphasis on functional and clinical characteristics.

METHOD

A prospective study was performed between February and November 2015in 83 COPD patients enrolled in an outpatient program of 36 strength +resistance training sessions. Ambulances were provided to facilitate access to the clinic. Patients were divided into: adherent (A) (attended at least 70% of the program) or non-adherent (NA) (at least one session).

RESULTS

A total of 83 patients were evaluated and 26 excluded; 15.7% refused to participate. The drop-out rate was 38.5%. The main causes were low motivation and transport problems. Lower forced vital capacity (NA, 58.9% vs A, 67.8%; P=.03), worse results on submaximal exercise test (NA, 6.2minutes vs A, 9.2minutes; P=.02), in total distance walked (NA, 42.6 vs A, 56.5; P=.03) and VO₂ in ml/min/kg (NA, 11.4 vs A, 13.6; P=.03) and in ml/min (NA, 839 vs A, 1020; P=.04) were found in the non-adherent group. This group also showed higher use of oral steroids (NA, 23.8% vs A, 2.9%; P=.01).

CONCLUSIONS

More than 1/3 of patients leave programs. The main causes are related to motivation and transport. The patients who dropout are those with worse functional tests, more exacerbations, steroids and smoking habit.

Assessment of dyspnea and dynamic hyperinflation in male patients with chronic obstructive pulmonary disease during a six minute walk test and an incremental treadmill cardiorespiratory exercise test

The six minute walk test (6MWT) is a standardized test that provides information on exercise capacity in patients with COPD. It is considered a submaximal test in opposition to incremental cardiopulmonary exercise tests (CPET) that provide valuable information on all the systems involved in exercise.

OBJECTIVES

1. To compare the perceptive, physiological responses and degree of dynamic hyperinflation during two exercise tests: the 6MWT and the incremental CPET on a treadmill. 2. To evaluate how dyspnea is related to dynamic hyperinflation (DH) and other functional parameters in both tests.

METHODS

29 stable COPD male patients, age 68±5.8 years, mean post-bronchodilator FEV1 57±11%, were recruited. To evaluate dynamic hyperinflation, inspiratory capacity (IC) was measured at rest and upon completing each one of the tests. At the same time, perceived dyspnea and leg discomfort were rated on specific modified Borg scales.

RESULTS

The mean walk distance in 6MWT was 494±88m. The Borg scale rating for shortness of breath upon completing the test was 4.7±2, whilst 2.9±2 for leg discomfort. IC changed from 2.53±0.63l before to 2.34±0.60l after completion of the test. In the treadmill CPET, maximal oxygen consumption (V˙O₂max) was 21.8±5mL/kg/min with 6.6±2 dyspnea and 4.3±2 leg discomfort on Borg scales. IC changed from 2.17±0.53l to 1.20±0.43l.

CONCLUSIONS

Dynamic hyperinflation occurs in male COPD patients during submaximal exercise such as the 6MWT. This phenomenon is more pronounced after incremental CPET on a treadmill. Despite being dyspnea the dominant limiting symptom for both tests, we observed different physiological responses.

[Phenotypic characterization and course of chronic obstructive pulmonary disease in the PAC-COPD Study: design and methods]

BACKGROUND AND OBJECTIVES

The Phenotype and Course of Chronic Obstructive Pulmonary Disease (PAC-COPD) study aims to improve our understanding of the phenotypic heterogeneity of this disease and the extent to which this heterogeneity is related to clinical course. The main objectives are a) to characterize the phenotypic variability in first-time hospitalizations for exacerbation of COPD and to propose a classification into subtypes and b) to ascertain the association between the defined subtypes and the clinical and functional course of COPD.

PATIENTS AND METHODS

This is a cross-sectional and cohort study of 342 patients with COPD from 9 tertiary hospitals in 3 autonomous communities. The minimum follow-up period is 5 years. The main variables of interest are respiratory symptoms, smoking, alcohol use, physical activity, use of health care services, medical care, treatment received, activities of daily living, comorbid conditions, sleepiness, anxiety and depression, quality of life, forced spirometry and bronchodilation tests, lung volume and inspiratory capacity measured by body plethysmography, carbon monoxide diffusing capacity, baseline arterial blood gas values, respiratory and peripheral muscle function, electrocardiogram, body weight and composition measured by bioelectric impedance, chest radiograph, skin prick test, capacity for exercise measured in the 6-minute walk test and cardiopulmonary exercise test, induced sputum (for quantitative microbiological culture and determination of inflammatory markers), nighttime pulse oximetry, chest computed tomography scan, and echocardiography. Serum and plasma samples are also taken to measure levels of inflammatory markers and oxidative stress, for genetic analysis, and for other possible measurements that might be required in the future. The statistical analysis combines factor analysis and survival models such as Cox regression analysis. This project will enable us to reconsider the definition and classification of COPD and to better understand the factors associated with its natural history.

Actividades de la vida diaria en pacientes con enfermedad pulmonar obstructiva crónica: validación de la traducción española y análisis comparativo de 2 cuestionarios

BACKGROUND AND OBJECTIVE

Exercise limitation is a common finding in chronic obstructive pulmonary disease (COPD) patients and has an important role in disease prognosis and the use of health care services. There are no questionnaires in Spanish language that evaluate the impact of the disease in the activities of daily living in these patients. Our objective was to adapt and validate the Spanish versions of 2 standard questionnaires for assessment of physical activity: the London Chest Activity of Daily Living scale (LCADL) and the Modified Baecke Physical Activity Questionnaire (modified Baecke).

PATIENTS AND METHOD

After carrying out the translation and back-translation, the 2 questionnaires were administered to 55 patients with COPD (mean age [standard deviation]: 66 [8] years; forced expiratory volume in 1 s: 1.2 [0.5] l, 38 [15]%) in 2 occasions and a conventional exercise test was performed.

RESULTS

Cronbach's alpha coefficient was very high (0.98 and 0.97 for LCADL and modified Baecke, respectively; p < 0.0001 each). Intraclass correlation coefficients of the test re-test reliability was also very high (0.97 and 0.96, respectively). Mean values of the questionnaires in the 2 administrations were 20 (11) vs 19 (11) for LCADL (p = 0.26), and 15 (9) vs 14 (9) for modified Baecke (p = 0.51). The 2 questionnaires showed a significant correlation with quality of life (St. George's Respiratory Questionnaire), dyspnea score (Medical Research Council scale) and 6 min walk test.

CONCLUSIONS

The Spanish versions of these 2 questionnaires to assess physical activity are relibale and they display the expected association with health related quality of life, dyspnea score, and the 6 min walk test, confirming their validity. Therefore, we propose its use to complement the assessment of physical activity in those patients with COPD in whom direct measurements of this variable are not available.

[Variability in walk test conditions in pulmonary rehabilitation programs in Latin America and on the Iberian peninsula]

OBJECTIVE

1) To determine the frequency of use of the 6-minute walk test in pulmonary rehabilitation programs in Latin America and on the Iberian Peninsula; 2) to identify how the test is performed and possible variations from center to center.

MATERIALS AND METHODS

A questionnaire was sent to 55 pulmonary rehabilitation centers in Latin America, Portugal, and Spain.

RESULTS

Forty-nine (89.1%) centers answered the questionnaire. Forty-seven (95.9%) perform a walk test lasting 6 minutes; 22 (46.8%) take the longest distance of 2 tests as the real one; and 35 (74.5%) carry out the test in a corridor. The course distance ranged from 17 to 90 meters, but in 21 (44.7%) centers, the corridor was between 17 and 30 meters long. In 29 (61.7%) centers, the patients are routinely informed about the time that had elapsed during the test. Verbal encouragement is used in 44 (93.6%) centers. Thirty-eight (80.8%) use supplemental oxygen when a patient needs it. An increase in absolute values in the distance covered is used as a parameter indicating improvement at 21 (46.7%) sites while at 15 (33.3%) other centers the percentage increase is taken as a measure of improvement.

CONCLUSIONS

The 6-minute walk test is widely used for the evaluation of the exercise capacity at the pulmonary rehabilitation centers of Latin America and the Iberian Peninsula. However, there is great variability in the way the test is performed.

[Exercise limitation in patients with chronic obstructive pulmonary disease at the altitude of Bogota (2640 m). Breathing pattern and arterial gases at rest and peak exercise]

OBJECTIVE

To describe the response to exercise of normal subjects and patients with chronic obstructive pulmonary disease (COPD) in Bogota, Colombia (altitude: 2640 m; atmospheric pressure: 560 mm Hg) and compare it with data published on COPD patients at sea level. Healthy people increase their minute ventilation to attenuate hypoxemia (PaCO2: 30 mm Hg; PaO2: 63 mm Hg).

MATERIAL AND METHOD

A descriptive study was carried out on healthy subjects and COPD patients. Exercise limitation was determined by an incremental test on a cycle ergometer.

RESULTS

The study enrolled 16 healthy subjects and 25 COPD patients (forced expiratory volume in 1 second: 43.3% [SD 13%]). Minute ventilation at rest was greater in COPD patients compared with healthy subjects, it was not adequately sustained during exercise, and there was a reduction in peak oxygen uptake (53.0% [15%]). At peak exercise, inspiratory capacity decreased (-0.62 [0.34] L), the ratio of minute ventilation to maximal voluntary ventilation increased, and severe hypoxemia occurred (PaO2: 49.9 [9.9] mm Hg). There was significant correlation between hypoxemia and the percentage of predicted peak oxygen uptake (r=0.60), leg fatigue (r=-0.62), percentage of predicted peak inspiratory capacity (r=0.61), and the percentage of predicted peak tidal volume (r=0.49). Minute ventilation at rest was shown to be higher, there was a greater reduction in the inspiratory capacity during exercise, and hypoxemia was more severe at rest and during exercise for patients with COPD in Bogota, compared with those at sea level.

CONCLUSIONS

Patients with COPD living in Bogota were shown to have lower tolerance to exercise evidenced by ventilatory limitation and severe hypoxemia. Increased minute ventilation at rest, greater reduction in inspiratory capacity, and severity of hypoxemia during exercise were the main differences between COPD in Bogota and at sea level.

[Dyspnea in COPD: relation to the MRC scale with dyspnea induced by walking and cardiopulmonary stress testing]

OBJECTIVE

Exercise-related dyspnea is the main symptom of chronic obstructive pulmonary disease (COPD), yet its relation to lung function deterioration is weak. The aim of this study was to evaluate the relation between the patients' usual level of dyspnea and dyspnea caused by a maximum cardiopulmonary stress test or a 6-minute walking test.

METHODOLOGY

Thirty-six consecutive patients with stable COPD (age 66 7 years post-bronchodilator FEV1 47 14% of predicted) were studied. In addition to full baseline function testing, all patients underwent stress testing on a cycle ergometer and a 6-minute walking test in a corridor 50 m long. Exercise-induced dyspnea was assessed by the patient on a Borg scale before beginning and after completing each test. Chronic dyspnea during activities of daily living was quantified on the Medical Research Council (MRC) scale.

RESULTS

The MRC value was only weakly related to percent of predicted FEV1 (r = 0.34, p = 0.04). Parameters obtained during exercise tests that were associated with the MRC were SaO2 at the end of the 6-minute walking test (r = 0.49, p = 0.004) and change in dyspnea on the Borg scale during the 6-minute walking test (deltaBorg-6mWT, r = 0.54, p = 0.0008) and during the stress test (r = 0.35, p = 0.04). Multiple regression analysis, with the MRC result as the dependent variable, showed that deltaBorg-6mWT and SaO2 at the end of the walking test explained 29% of the variance.

CONCLUSION

Severity of chronic dyspnea in COPD patients assessed on the MRC scale is more related to dyspnea triggered by the walking test than with dyspnea induced by cycle ergometer stress testing.