European Respiratory Journal
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Effects of proportional assist ventilation on exercise tolerance in COPD patients with chronic hypercapnia This study investigates the impact of proportional assist ventilation (PAV), a new mode of partial ventilatory support, on exercise tolerance and breathlessness in severe hypercapnic chronic obstructive pulmonary disease (COPD) patients. We also examined the effects of continuous positive airway pressure (CPAP) and pressure support ventilation (PSV). On two consecutive days, 15 stable hypercapnic COPD patients underwent four endurance tests on a cycle ergometer at 80% of their maximal workrate, receiving, via a nasal mask in random order, either: 1) sham ventilation (CPAP: 1 cmH2O); 2) CPAP (6 cmH2O); 3) PSV (inspiratory pressure support: 12-16 cmH2O; expiratory positive airway pressure (EPAP): 1 cmH2O); or 4) PAV (8.6+/-3.6 cmH2O x L(-1) and 3+/-1.3 cmH2O x L(-1)x s(-1) of volume and flow assistance, respectively plus EPAP: 1 cmH2O). Oxygen supply was standardized to maintain an arterial oxygen saturation (Sa,O2) of 92-93%. Breathing pattern and minute ventilation (by respiratory inductive plethysmography), pulse oximetry, end tidal partial pressure of CO2, cardiac frequency and sensations of dyspnoea and leg discomfort (by Borg scale) were monitored. In comparison to sham ventilation, PAV, PSV and CPAP were able to increase the endurance time (from 7.2+/-4.4 to 12+/-5.6, 10+/-5.2 and 9.6+/-4.6 min, respectively) and to reduce dyspnoea and oxygen flow to the nasal mask. However, the greatest improvement was observed with PAV. We conclude that PAV delivered by nasal mask can im-prove exercise tolerance and dyspnoea in stable hypercapnic COPD patients and hence this mode of ventilatory support may be useful in respiratory rehabilitation programmes.
European Respiratory Journal - Tập 11 Số 2 - Trang 422-427 - 1998
Short-term effects of nitrogen dioxide on mortality: an analysis within the APHEA project The short-term effects of nitrogen dioxide (NO2 ) on total, cardiovascular and respiratory mortality in 30 European cities participating in the Air Pollution on Health: a European Approach (APHEA)-2 project were investigated. The association was examined using hierarchical models implemented in two stages. In the first stage, data from each city were analysed separately, whereas in the second stage, the city-specific air pollution estimates were regressed on city-specific covariates to obtain overall estimates and to explore sources of possible heterogeneity. A significant association of NO2 with total, cardiovascular and respiratory mortality was found, with stronger effects on cause-specific mortality. There was evidence of confounding in respiratory mortality with black smoke and sulphur dioxide. The effect of NO2 on total and cardiovascular mortality was observed mainly in western and southern European cities, and was larger when smoking prevalence was lower and household gas consumption was higher. The effect of NO2 on respiratory mortality was higher in cities with a larger proportion of elderly persons in the population and higher levels of particulate matter with a 50% cut-off aerodynamic diameter of 10 μm. The results of this large study are consistent with an independent effect of nitrogen dioxide on mortality, but the role of nitrogen dioxide as a surrogate of other unmeasured pollutants cannot be completely ruled out.
European Respiratory Journal - Tập 27 Số 6 - Trang 1129-1138 - 2006
Air pollution and multiple acute respiratory outcomes Short-term effects of air pollutants on respiratory mortality and morbidity have been consistently reported but usually studied separately. To more completely assess air pollution effects, we studied hospitalisations for respiratory diseases together with out-of-hospital respiratory deaths. A time-stratified case-crossover study was carried out in six Italian cities from 2001 to 2005. Daily particulate matter (particles with a 50% cut-off aerodynamic diameter of 10 μm (PM10 )) and nitrogen dioxide (NO2 ) associations with hospitalisations for respiratory diseases (n = 100 690), chronic obstructive pulmonary disease (COPD) (n = 38 577), lower respiratory tract infections (LRTI) among COPD patients (n = 9886) and out-of-hospital respiratory deaths (n = 5490) were estimated for residents aged ≥35 years. For an increase of 10 μg·m−3 in PM10 , we found an immediate 0.59% (lag 0–1 days) increase in hospitalisations for respiratory diseases and a 0.67% increase for COPD; the 1.91% increase in LRTI hospitalisations lasted longer (lag 0–3 days) and the 3.95% increase in respiratory mortality lasted 6 days. Effects of NO2 were stronger and lasted longer (lag 0–5 days). Age, sex and previous ischaemic heart disease acted as effect modifiers for different outcomes. Analysing multiple rather than single respiratory events shows stronger air pollution effects. The temporal relationship between the pollutant increases and hospitalisations or mortality for respiratory diseases differs.
European Respiratory Journal - Tập 42 Số 2 - Trang 304-313 - 2013
Air pollution and mortality in the Netherlands: are the elderly more at risk? The association between daily mortality and short-term variations in the ambient levels of ozone (O3 ), black smoke (BS), sulphur dioxide (SO2 ), nitrogen dioxide (NO2 ), carbon monoxide (CO) and particulate matter was studied in the Netherlands. Daily total and cause-specific mortality counts (cardiovascular, chronic obstructive pulmonary disease (COPD) and pneumonia), air quality, temperature, relative humidity and influenza data were obtained from 1986–1994. The relationship between daily mortality and air pollution was modelled using Poisson regression analysis. All pollution mortality associations were adjusted for potential confounding due to long-term trends, seasonal trends, influenza epidemics, ambient temperature, ambient relative humidity, day of the week and holidays, using generalised additive models. Statistically significant associations were mostly found in the elderly, that is the age categories of 65–74 and ≥75 yrs for the pollutants PM10 (particles with a 50% cut-off aerodynamic diameter of 10 µm), BS, SO2 , NO2 and CO. This may partly be due to a better precision of relative risk (RR) estimates for the larger numbers of deaths in these age groups. Significant associations for those <65 yrs were found for O3 (total and COPD mortality), PM10 (pneumonia), NO2 (pneumonia) and CO (pneumonia). RR estimates for deaths between 45–65 yrs tended to be smaller than those in >65 yrs, with the exception of ozone; for cardiovascular mortality the RR for PM10 , O3 and CO were similar in these age groups. In conclusion, larger relative risks for air pollution were mostly found in the elderly except for ozone and for death-cause pneumonia which showed larger relative risk in younger age groups.
European Respiratory Journal - Tập 21 Số 40 suppl - Trang 34s-38s - 2003
Diet and asthma, allergic rhinoconjunctivitis and atopic eczema symptom prevalence: an ecological analysis of the International Study of Asthma and Allergies in Childhood (ISAAC) data Several studies have suggested that the increasing prevalence of symptoms of asthma, rhinitis and eczema, could be associated with dietary factors. In the present paper, a global analysis of prevalence rates of wheeze, allergic rhinoconjunctivitis and atopic eczema was performed in relation to diet, as defined by national food intake data. Analyses were based on the International Study of Asthma and Allergies in Childhood (ISAAC) data for 6–7 and 13–14 yr old children. Symptoms of wheeze, allergic rhinoconjunctivitis and atopic eczema symptom prevalence were regressed against per capita food intake, and adjusted for gross national product to account for economic development. Dietary data were based on 1995 Food and Agriculture Organisation of the United Nations data for 53 of the 56 countries that took part in ISAAC phase I (1994/1995). The 13–14 year age group showed a consistent pattern of decreases in symptoms of wheeze (current and severe), allergic rhinoconjunctivitis and atopic eczema, associated with increased per capita consumption of calories from cereal and rice, protein from cereals and nuts, starch, as well as vegetables and vegetable nutrients. The video questionnaire data for 13–14 yr olds and the ISAAC data for 6–7 yr olds showed similar patterns for these foods. A consistent inverse relationship was seen between prevalence rates of the three conditions and the intake of starch, cereals, and vegetables. If these findings could be generalised, and if the average daily consumption of these foods increased, it is speculated that an important decrease in symptom prevalence may be achieved.
European Respiratory Journal - Tập 17 Số 3 - Trang 436-443 - 2001
Smoking cessation improves both direct and indirect airway hyperresponsiveness in COPD Smoking induces chronic obstructive pulmonary disease (COPD) and is associated with airway inflammation and airway hyperresponsiveness (AHR). It has not been studied in COPD whether direct (methacholine) and indirect (adenosine-5'-monophosphate (AMP)) stimuli are associated with airway inflammation and neither whether smoking cessation improves these features. The current authors cross-sectionally investigated the relationship of AHR to methacholine and AMP with lung function and inflammatory cells in the sputum of 33 smokers with COPD. In addition, changes in these parameters were prospectively assessed in 14 smokers who successfully quit smoking for 1 yr. The presence of AHR to both methacholine and AMP was associated with lower lung function, but not with sputum inflammation. AHR to methacholine and AMP improved significantly after a 1-yr smoking cessation, yet this was unrelated to changes in sputum cell counts. The numbers of neutrophils and epithelial cells significantly increased with smoking cessation. Both direct and indirect airway hyperresponsiveness are associated with lower lung function, but not with sputum inflammation in chronic obstructive pulmonary disease. Interestingly, 1-yr smoking cessation improved both direct and indirect airway hyperresponsiveness, yet without a significant association with changes in lung function or sputum inflammation. Thus, other factors are likely to induce these improvements,e.g. a reduction in stimulation of irritant receptors, airway wall changes or mucus hypersecretion.
European Respiratory Journal - Tập 24 Số 3 - Trang 391-396 - 2004
Bronchial mucosal manifestations of atopy: a comparison of markers of inflammation between atopic asthmatics, atopic nonasthmatics and healthy controls We studied the role of atopy, as defined by positive skin tests to common inhalant allergens, in allergic bronchial inflammation. Endobronchial biopsies were taken via the fibreoptic bronchoscope in 13 symptomatic atopic asthmatics, 10 atopic nonasthmatics, and 7 normals. The numbers of mast cells, identified in the submucosa by immunohistochemistry using the AA1 monoclonal antibody against tryptase, were no different between the three groups, but electron microscopy showed that mast cell degranulation, although less marked in atopic nonasthmatics, was a feature of atopy in general. The numbers of eosinophils, identified by immunohistochemical staining using the monoclonal anti-eosinophil cationic protein antibody, EG2, were greatest in the asthmatics, low or absent in the normals and intermediate in the atopic nonasthmatics. In both atopic groups eosinophils showed ultrastructural features of degranulation. Measurements of subepithelial basement membrane thickness on electron micrographs showed that the collagen layer was thickest in the asthmatics, intermediate in the atopic nonasthmatics and thinnest in the normals. The results suggest that airways eosinophilia and degranulation of eosinophils and mast cells, as well as increased subepithelial collagen deposition, are a feature of atopy in general and suggest that the degree of change may determine the clinical expression of this immune disorder.
European Respiratory Journal - Tập 5 Số 5 - Trang 538-544 - 1992
Indirect airway challenges Indirect challenges act by causing the release of endogenous mediators that cause the airway smooth muscle to contract. This is in contrast to the direct challenges where agonists such as methacholine or histamine cause airflow limitation predominantlyvia a direct effect on airway smooth muscle. Direct airway challenges have been used widely and are well standardised. They are highly sensitive, but not specific to asthma and can be used to exclude current asthma in a clinic population. Indirect bronchial stimuli, in particular exercise, hyperventilation, hypertonic aerosols, as well as adenosine, may reflect more directly the ongoing airway inflammation and are therefore more specific to identify active asthma. They are increasingly used to evaluate the prevalence of bronchial hyperresponsiveness and to assess specific problems in patients with known asthma,e.g. exercise-induced bronchoconstriction, evaluation before scuba diving. Direct bronchial responsiveness is only slowly and to a modest extent, influenced by repeated administration of inhaled steroids. Indirect challenges may reflect more closely acute changes in airway inflammation and a change in responsiveness to an indirect stimulus may be a clinically relevant marker to assess the clinical course of asthma. Moreover, some of the indirect challenges,e.g. hypertonic saline and mannitol, can be combined with the assessment of inflammatory cells by induction of sputum.
European Respiratory Journal - Tập 21 Số 6 - Trang 1050-1068 - 2003
Inhibition of adenosine 5'-monophosphate- and methacholine-induced bronchoconstriction in asthma by inhaled frusemide Recent studies have shown that inhaled frusemide exerts a protective effect against various bronchoconstrictor stimuli in asthma including exercise, fog and allergen. Since mast cell activation seems to be a component of bronchoconstriction by these stimuli it is possible that inhibition of mediator release accounts for some or all of the inhibitory effects of frusemide in asthma. Since inhaled adenosine 5'-monophosphate (AMP) is another stimulus that produces bronchoconstriction by augmenting mast cell mediator release, we have investigated the ability of this drug to antagonise the airway effects of inhaled AMP and methacholine in a randomized, placebo-controlled, double-blind study of 12 asthmatic subjects. Inhaled frusemide (approximately 28 mg) administered 5 min prior to challenge increased the provocation concentration of inhaled AMP and methacholine required to reduce forced expiratory volume in one second (FEV) by 20% from baseline from 30 to 96 mg.ml-1 (p less than 0.01) and from 1.1 to 1.8 mg.ml-1 (p less than 0.01), respectively. The protection that frusemide afforded against AMP was significantly greater than that against methacholine (p less than 0.05). These data suggest that inhaled frusemide may serve as a functional antagonist against a smooth muscle spasmogen, such as methacholine, possibly by augmenting prostanoid generation. Its more potent activity against AMP and other bronchoconstrictor stimuli, that are considered to involve mast cell mediators, suggests an additional action on mast cell functions possibly at the level of the Ca++/Mg(++)-ATPase.
European Respiratory Journal - Tập 3 Số 6 - Trang 665-672 - 1990
Bronchial hyperresponsiveness and airway inflammation markers in nonasthmatics with allergic rhinitis Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma which is often associated with airways inflammation. However, some patients with allergic rhinitis and no clinical evidence of asthma also exhibit BHR. This study therefore investigated whether inflammatory cell infiltrate is present in the induced sputum of nonasthmatic subjects with allergic rhinitis during the pollen season and examined its relationship with airway hyperresponsiveness to inhaled methacholine and adenosine 5'-monophosphate (AMP). Twenty subjects (12 allergic rhinitis, eight nonallergic controls) underwent methacholine and AMP challenge and sputum induction with hypertonic saline on separate days. Cell differentials were calculated from whole sputum samples. A significantly greater number of eosinophils was found in the sputum of nonasthmatic subjects with allergic rhinitis compared to that of nonallergic controls, their median (range) percentages being 17.5 (4-47) and 1.5 (0-5) (p<0.001) respectively. Although sputum eosinophilia failed to be significantly associated with methacholine responsiveness (r(s)=-0.50; p=0.095), the provocative concentration of AMP causing a 20% fall in forced expiratory volume in one second correlated strongly and significantly with the absolute number of eosinophils (r(s)= -0.73; p=0.007). Eosinophil cationic protein levels in the sputum of rhinitic subjects were significantly elevated compared to controls and correlated with eosinophil number (r(s)=0.67; p=0.017). These findings support the view that bronchial eosinophilia alone is insufficient to cause asthmatic symptoms. Diverse agonists for assessing bronchial hyperresponsiveness are selectively associated with airway inflammation in allergic rhinitis.
European Respiratory Journal - Tập 15 Số 1 - Trang 30-35 - 2000
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