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Physical activity, nutritional status and systemic inflammation in COPD
No full text[No abstract available
Clinical use of Heliox in Asthma and COPD
Full text linkHeliox is a low density gas mixture of helium and oxygen commonly used in deep diving (> 6 ATM). This mixture has been also used for clinical purposes, particularly in the critical care setting. Due to of its physical proprieties, Heliox breathing reduces air flow resistances within the bronchial tree; in patients with obstructive lung diseases Heliox may also reduce the work of breathing and improve pulmonary gas exchange efficiency. Beneficial effects have been documented in severe asthma attacks and in patients with chronic obstructive pulmonary disease. A reduction in WOB during mechanical ventilation and an increase in exercise endurance capacity have also been described in COPD. Heliox has been also used in the treatment of upper airways obstruction, bronchiolitis and bronchopulmonary dysplasia. Despite the encouraging results, Heliox use in routine practice remains controversial because of technical implications and high costs
Changes in operating lung volume and symptoms during daily activity in COPD
No full textPatients with moderate-severe COPD perform low levels of daily physical activity and both breathlessness and leg fatigue are important symptoms limiting exercise. It is now possible to accurately measure daily physical activity using accelerometers. Less is known about symptoms and hyperinflation measured during laboratory exercise testing relate to daily activity.
We studied 20 stable COPD patients (15 male, mean (SD) age 67 (7) yrs, FEV1 0,96 (0,4) l, 36 (12) % predicted, IC 1,7 (0,4) l, 62 (14) % predicted during a time-limited endurance cycle exercise test at 70 % VO2 max. IC, dyspnoea intensity and leg fatigue on a Borg scale were recorded every 2 minutes. We calculated the individual slope of the change in these variables expressed as IC absolute. We assessed daily physical activity using both AW (Actiwatch) and SW (SenseWear) that subjects wore for 3-4 consecutive days from waking until going to bed.
There was a good relationship between AW mean activity score and AW mean activity moving (r2=0,7; p<0,01) and a close relationship between SW step count and AW mean activity score (r2=0,8; p<0,001). We found a good relationship between the AW mean activity score and the rate of increase of dyspnoea (r2=0,5; p<0,05) but no correlation between AW mean activity score and the rate of rise of leg discomfort (r2=0,2; p=NS). There was no relationship between the baseline IC expressed as absolute and the AW mean activity score (r2=0,03; p=NS) and the SW number of steps (r2=0,1; p=NS).
Activity levels measured by these different devices worn on the lower and upper limb are similar and data registered with the same uniaxial leg accelerometer give similar level of the typical daily activity. Baseline level of hyperinflation did not predict daily activity and the individual’s perception of breathlessness as lung volume rises is the important factor limiting daily activity. Changes in symptoms related to peripheral muscle dysfunction did not limit the daily activity in our COPD patients
Individual variation in the time course of symptoms during exercise in COPD
No full textBreathlessness and leg fatigue are important symptoms during exercise in COPD patients. Breathlessness relates to increase in end-expiratory volume. Less is known about individual differences in the rate of change of symptoms with hyperinflation and whether this is influenced by the way data are presented and they relate to the severity of pre-exercise hyperinflation. We studied 15 stable COPD patients (11 male, mean (sd) age 65 (8) yrs, FEV1 0.91 (0.2) l, 32 (9)% predicted, IC 1.8 (0.4)l, 63 (13) % predicted) during constant load cycle ergometry at 70% VO2 max. We recorded intensity of breathlessness and leg fatigue on a Borg scale and IC every 2 minutes. We calculated the individual slopes of the change in these variables expressed as IC absolute and % predicted. There was a good relationship between symptoms and IC however expressed (r2 =0.25 p< 0.05). The individual slope of the dyspnoea/IC differed when %predicted changes were reported and values expressed in this way were not closely related to each other. There was a better relationship between the rate of change of dyspnoea and fatigue when expressed as absolute rather then % predicted (r2=0.74 p<0.01). Duration of exercise was not related to the IC% predicted before exercise the rate of change of breathlessness was greatest in patients with the highest baseline IC (r2 =0.5 p < 0.01). COPD patients show considerable variation in the rate at which symptoms develop during exercise, breathlessness relates to the degree of resting hyperinflation. Although fatigue scores show similar mean rates of change relative to IC the individual slopes are different to those for dyspnoea suggesting that different physiological processes underline these symptoms
Assessment of two physical activity monitors in COPD patients
No full textWe can objectively asses physical activity in COPD patients using accelerometers but we do not known whether different devices give equivalent results. We studied the Actiwatch (AW) worn on the ankle and Sensewear (SW) worn on the R arm.
12 stable COPD patients (2 female, mean(sd) age 68(5)yrs, FEV1 1.0(0.4), 37(14%) predicted) wore both devices for 3-4 days. We applied a threshold (derived from 13 different COPD patients) to AW readings to exclude background vibration.
There was no difference between the 29 weekday and 16 weekend recordings in any activity variable. There was no correlation of 6min walk, FEV1 or quadriceps strength and any measure of physical activity. SW step count correlated with AW mean activity score and AW % time moving and this relationship improved when threshold was applied. In general physical activity measured by AW was unrelated to overall energy expenditure derived from the SW.
COPD patients have similar levels of activity throughout the week. Activity levels measured by the different devices worn on the lower and upper limb are closely related; this is improved when a threshold is applied to the AW. AW data does not correlate as well with SW derived data such as estimates of energy expenditure or METs; caution should be exercised when interpreting such data
The effect of bronchodilation on symptom time course during exercise in COPD
No full textInhaled bronchodilator drugs improve exercise performance in COPD by reducing operating lung volumes. Whether this treatment modifies the rate at which symptoms intensify relative to increasing lung volume is less clear. Such a change is plausible given the improvement in frequency dependence of respiratory system resistance recently reported with nebulised beta-agonists (Dellacà et al ERJ 2009). We studied 16 patients (11 men, mean FEV1 1.21 L, mean inspiratory capacity (IC) 77% pred) who omitted their usual inhaled bronchodilators for 12-24 hours as appropriate. Patients performed a constant workload cycle ergometry test at 70% VO2 max during which symptoms of dyspnoea, leg fatigue and IC were recorded every 1 minute. Tests were done 15 minutes after 5 mg nebulised salbutamol or placebo in a double blind randomized fashion, the alternative therapy being given at a standardized time on another day with a further exercise test subsequently. Salbutamol increased FEV1 (mean change 214 ml), IC (mean change 278 ml) and exercise time (mean change 1.7 minutes).
The rate of change of symptoms per minute during the test was unchanged mean (sd) IC Vs time saline = -0.06 (0.1) and bronchodilator = -0.08 (0.1); leg fatigue Vs time saline = 0.8(0.49 and bronchodilator = 0.7 (0.3), dyspnoea Vs time = 0.6 (0.2) and bronchodilator = 0.7 (0.7) p=NS. The rate of rise of dyspnoea per unit fall in IC was unaffected (pre -10 (15) vs post -4.4 (5) dys/IC slope r2 0.56 and 0.46 respectively p=NS). Plotting the slope of dyspnoea Vs IC relationship is closely related and post is dependent on pre. These data support the view that the primary beneficial effect of bronchodilator dugs on exercise performance is to reduce operating volume and create more volume into which dynamic hyperinflation can occur
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
THE RELATIONSHIPS BETWEEN HYPERINFLATION DURING EXERCISE AND SYMPTOMS IN ADULTS WITH CYSTIC FIBROSIS
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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