Abstract: Bone mineral density decreases with advancing chronic obstructive pulmonary disease (COPD) severity, but it is not known whether this is reflected in higher fracture rates. The present authors wanted to compare the prevalence of vertebral deformities in COPD patients with those in a population-based reference group to determine whether the number of deformities was related to the severity of COPD and how far the use of oral corticosteroids (OCS) influenced the prevalence of deformities. In the present cross-sectional study of 465 COPD patients and 462 controls, vertebral deformities were found in 31% of the COPD patients and 18% of the controls. In subjects who had never or sporadically used OCS, deformities were found in 29% of the COPD patients and 17% of the controls. In females, the average number of vertebral deformities was almost two-fold when COPD severity increased from Global Initiative of Chronic Obstructive Lung Disease stage II to III. In males, the use of OCS had a small but significant influence. Prevalence of vertebral deformities was significantly higher in chronic obstructive pulmonary disease patients than in the controls. In females, the average number of deformities was related to chronic obstructive pulmonary disease severity even after adjustment for other known risk factors. The difference between patients and controls remained significant even in those who never or sporadically used oral corticosteroids.
Abstract: INTRODUCTION: In a British Thoracic Society (BTS) statement on preflight evaluation of patients with respiratory disease, sea level pulse oximetry (Spo2sl) is recommended as an initial assessment. The present study aimed to evaluate if the BTS algorithm can be used to identify chronic obstructive pulmonary disease (COPD) patients in need of supplemental oxygen during air travel, i.e. patients with an in-flight PaO2 < 6.6 kPa (50 mmHg). METHODS: There were 100 COPD patients allocated to groups according to the BTS algorithm: Spo2sl > 95%, Spo2sl 92-95% without additional risk factors; Spo2sl 92-95% with additional risk factors; Spo2sl < 92%; and patients using domiciliary oxygen. Pulse oximetry, arterial blood gases, and an hypoxia-altitude simulation test (HAST) to simulate a cabin altitude of 2438 m (8000 ft), were performed. RESULTS: The percentage of patients in the various groups dropping below 6.6 kPa during HAST were: Spo2sl > 95%: 30%; Spo2sl 92-95% without additional risk factors: 67%; Spo2sl 92-95% with additional risk factors: 70%; Spo2sl < 92%: 83%; and patients using domiciliary oxygen: 81%. In patients dropping below P(a)o(2) 6.6 kPa, supplemental oxygen of median 1 L x min(-1) was needed to exceed this limit. DISCUSSION: If in-flight P(a)o(2) > or = 6.6 kPa is regarded as a strict requirement, the use of pulse oximetry as an initial assessment in the preflight evaluation of COPD patients, as suggested by the BTS, might not discriminate adequately between patients who fulfill the indications for supplemental oxygen during air travel, and patients who can travel without such treatment.
Abstract: We investigated the interaction between skeletal muscle exercise capacity and central restrictions using exercise modalities, which recruit differing levels of muscle mass in eight patients chronic obstructive lung disease (COPD) (FEV(1)% of predicted; 35 [SE 4%]) and eight healthy controls. Subjects performed conventional bicycling, two-leg knee extensor (2-KE) and single-leg knee extensor (1-KE) exercises. Maximal values for pulmonary VO(2) (VO(2max)), power output, blood lactate, heart rate, blood pressure, and arterial oxygen saturation of hemoglobin were registered. VO(2max) in controls was 2453 (210), 1468 (124), and 976 (76) mL/min during bicycling, 2-KE and 1-KE, respectively. The COPD patients achieved 48% (P<0.05), 62% (P<0.05), and 81% (P=0.10) of the control values. The mass-specific VO(2max) (VO(2max)/exercising muscle mass) during 1-KE was 345 (25) and 263 (30) mL/kg/min (P<0.05) in controls and COPD patients, respectively. During 2-KE the controls and COPD patients achieved 85% (4%) and 67% (5%) (P=0.06) of the mass-specific VO(2) during 1-KE, while during bicycling they achieved 31% (2%) and 17% (1%) (P<0.05), respectively. The COPD patients have central restrictions when exercising with a relatively small muscle mass (2-KE) and have a higher muscular metabolic reserve capacity than controls during whole body exercise.
Abstract: Changes in health according to World Health Organization's International Classification of Functioning, Disability and Health (ICF) after four weeks of pulmonary rehabilitation (PR) were investigated. Gender differences in the response to PR, and the correlation between improvements in the two components of ICF (Body functions and Activities and Participation) were examined. Twenty-two men and 18 women with chronic obstructive pulmonary disease in Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage II-IV attended in-patient, multidisciplinary PR consisting of endurance training four to five times/week at 70% of peak work rate (WRpeak), resistance training three to four times/week at 72% of 15 repetitions maximum, educational sessions and individual counselling. The results were compared to those of 20 Chronic Obstructive Pulmonary Disease (COPD) patients included after the same criteria and investigated while waiting for admission to PR. In the rehabilitation group, we found significant improvements in health related quality of life (HRQoL) (-7 units, St. George's Respiratory Questionnaire), arm (6%) and leg (15%) maximal voluntary contraction, peak oxygen uptake (6%), WRpeak (60%) and treadmill endurance time (93%). At iso-WR, ventilation and dyspnoea were significantly lower, but inspiratory capacity remained unchanged. Improvements in HRQoL correlated with increases in peak ventilation, but not in muscle strength or exercise capacity. Men improved their six-minute walking distance significantly in contrast to women. Clinically important improvements in HRQoL were found in two out of three of the men, and one out of three of the women. Four weeks of intensive PR generated significant health effects comparable to longer lasting programmes. Changes in exercise capacity and muscle strength were not related to improvements in HRQoL. The gender differences in the response to PR deserve attention in future studies.
Abstract: Chronic obstructive pulmonary disease (COPD) appears to be associated with low bone mineral density (BMD). BMD loss can be accelerated by a number of factors associated with COPD, but it is not known whether COPD itself has a direct effect. Our aim was to investigate in a cross-sectional study whether COPD patients have lower BMD than healthy individuals, and whether the severity of the disease affects BMD. Eighty-eight COPD patients attending a rehabilitation program were classified into stages II, III and IV using GOLD criteria. BMD was measured by dual X-ray absorptiometry in lumbar spine (L2-4), femoral neck (FN) and total body (TB). Values were converted to Z-scores (adjusted for age and sex). Associations between Z-scores and steroid use, body mass index, pack-years and six-min walking distance were analyzed. The Z-scores (mean and (CI)) for all patients were for L2-4: -0.6 (-0.9, -0.3), FN: -0.8 (-1.0, -0.5) and TB: -0.5 (-0.8, -0.2). All scores were significantly different from those of a control population (p<0.001). For all three variables (ZL2-4, ZFN, ZTB) there were significant differences between the stages. The difference for ZL2-4 was still significant after adjustment for risk factors. We conclude that BMD is low in COPD patients and decreases with increasing severity of the disease. Low BMD may to some extent be a disease-specific effect.
Abstract: Patients with chronic obstructive pulmonary disease (COPD) frequently experience activity restrictions and discomfort during activities of daily living (ADL). Functional status refers to the capacity to perform ADL. Available tests only partly measure this domain. Our aim was therefore to establish an assessment tool for functional status in COPD, the Glittre ADL-test. This field test includes a standardised set of ADL-like activities: Walking stairs, carrying, lifting objects, bending down and rising from a seated position. The primary variable was time to complete the test (ADL-time). Validity was investigated in 57 COPD patients by correlating ADL-time to pulmonary function, 6-min walking distance (6MWD) and questionnaires addressing health-related quality of life. Responsiveness was investigated in another 40 patients comparing ADL-time before and after rehabilitation. Median ADL-time was 4.16 min (range 2.57-14.47). Spearman rho=0.93 for test-retest reliability. ADL-time correlated with forced expiratory volume in 1s (rho=-0.61), St. George's Respiratory Questionnaire activity subscore (rho=0.43), dyspnoea during ADL (rho=0.35) and hospitalisation rate (rho=0.35). Despite a close overall correlation with 6MWD (rho=-0.82), variability was substantial, particularly for the more disabled patients. ADL-time improved significantly after rehabilitation. Glittre ADL-test yields information complementary to 6MWD. It is a valid and reliable measure of functional status, useful for assessment of individual patients and rehabilitation programs.
Abstract: Chronic obstructive pulmonary disease (COPD) limits the ability to perform activities of daily living (ADL). The Pulmonary Functional Status and Dyspnoea Questionnaire (PFSDQ) measures general dyspnoea, dyspnoea during ADL (dyspnoea score) and loss of functional performance (activity score) for a large number of activities commonly performed by adults. The questionnaire is only validated for male patients. The aim of our study was therefore to validate the PFSDQ for women with COPD. We then wanted to investigate possible gender differences in responses to the PFSDQ and whether associations between the PFSDQ and pulmonary function, exercise capacity, health related quality of life (HRQoL) and general quality of life (QoL) were influenced by gender. This cross-sectional, observational study included 110 COPD patients. Sixty-five men and 45 women, referred to pulmonary rehabilitation participated. Pulmonary function and six-minute walking distance (6MWD) were measured. Patients completed PFSDQ, St George's Respiratory Questionnaire (SGRQ, HRQoL) and Perceived Quality of Life Scale (PQoL, QoL). No gender differences were found in pulmonary function (% of predicted), 6MWD, SGRQ or PQoL. Most items in the PFSDQ were found relevant by both women and men. Activity Scores were only different for men and women for items concerning home management; women had changed their functional performance the most, particularly for the heaviest chores. No gender differences were found in dyspnoea scores. Moderate correlations were found between PFSDQ and 6MWD, SGRQ and PQoL. Multiple linear regression analyses showed that these relations were not influenced by gender. We consider PFSDQ as applicable to women as to men as a comprehensive measure of functional performance and dyspnoea. The questionnaire gives information complementary to measures of exercise capacity, HRQOL and QOL. The larger loss of functional performance in home management among women should be taken into account in the treatment of COPD patients.
Abstract: Patients with chronic obstructive pulmonary disease (COPD) are characterised by decreased exercise tolerance, and, more variably, exercise induced hypoxaemia (EIH). Evaluation of physical work capacity and physiological responses to exercise may be performed by various procedures, but there are diverging opinions as to which exercise test should be preferred. In the current study, oxygen uptake and arterial blood gases in COPD patients have been compared during submaximal and maximal exercise on treadmill and ergometer bicycle. Treadmill exercise resulted in higher peak oxygen uptake than bicycle exercise (1111+/-235 vs. 987+/-167 ml min(-1), P<0.02), while the plasma lactate levels were higher during cycling (1.8+/-0.8 vs. 3.8+/-1.7 mmol l(-1), P<0.001). Neither carbon dioxide output, ventilation, nor rate of perceived exertion (Borg RPE scale) showed significant differences between the two modes of exercise. The EIH during both maximal (delta Sa,O2 = -5.6+/-4.2 vs. -3.4+/-5.1%) and sub-maximal exercise was more pronounced during treadmill walking than during cycling. The present study indicates that the VO2peak in COPD patients is higher, the maximal lactate concentrations lower and the development of EIH more pronounced when exercise testing is performed on a treadmill than on a bicycle ergometer.
Abstract: Pulmonary hypertension (PH) in patients with chronic obstructive pulmonary disease (COPD) has traditionally been explained as an effect of hypoxaemia. Recently, other mechanisms, such as arterial remodelling caused by inflammation, have been suggested. The aim of this study was to investigate whether exercise-induced PH (EIPH) could occur without concurrent hypoxaemia, and whether exercise-induced hypoxaemia (EIH) was regularly accompanied by increased pulmonary artery pressure or pulmonary vascular resistance index (PVRI). Pulmonary haemodynamics in 17 patients with COPD of varying severity, but with no or mild hypoxaemia at rest, were examined during exercise equivalent to the activities of daily living (ADL) and exhaustion. EIPH occurred in 65% of the patients during ADL exercise. Pulmonary arterial pressure during exercise was negatively correlated with arterial oxygen tension, but EIPH was not invariably accompanied by hypoxaemia. Conversely, EIPH was not found in all patients with EIH. The resting PVRI was negatively correlated with arterial oxygen tension during ADL exercise, but an elevated PVRI without EIH occurred in 35% of the patients. In conclusion, exercise-induced pulmonary hypertension occurred during exercise equivalent to the activities of daily living in chronic obstructive pulmonary disease patients with no or mild hypoxaemia at rest. Although pulmonary artery pressure and arterial oxygen tension were negatively correlated during exercise, a consistent relationship between hypoxaemia and pulmonary hypertension could not be demonstrated. This may indicate that mechanisms other than hypoxaemia contribute significantly in the development of pulmonary hypertension in these patients.
Abstract: Several publications have reported effects of hypobaric conditions in patients with chronic obstructive pulmonary disease. To the current authors' knowledge, similar studies concerning patients with restrictive lung disease have not been published. The effect of simulated air travel in a hypobaric chamber on arterial blood gases, blood pressure, and cardiac frequency during rest and 20 W exercise, and the response to supplementary oxygen in 17 patients with chronic restrictive ventilatory impairment has been investigated. Resting oxygen tension in arterial blood (Pa,O2) decreased from 10.4+/-1.6 kPa at sea level to 6.5+/-1.1 kPa at 2,438 m simulated altitude, and decreased further during light exercise in all patients (5.1+/-0.9 kPa). Pa,O2 at this altitude correlated positively with sea-level Pa,O2 and transfer factor of the lung for carbon monoxide (TL,CO), and negatively with carbon dioxide tension in arterial blood (Pa,CO2). Pa,O2 increased to acceptable levels with an O2 supply of 2 L x min(-1) at rest and 4 L x min(-1) during 20 W exercise. In conclusion, most of the patients with restrictive ventilatory impairment developed hypoxaemia below the recommended levels of in-flight oxygen tension in arterial blood during simulated air travel. Light exercise aggravated the hypoxaemia. Acceptable levels of oxygen tension in arterial blood, with only a minor increase in carbon dioxide tension in arterial blood, were obtained by supplementary oxygen.
