The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
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Comparative Study Clinical Trial
Respiratory resistance by the forced oscillation technique in asthmatic children and cystic fibrosis patients.
Measurement of the total resistance of the respiratory system (Rrs) is an attractive alternative to measurement of forced expiratory volume in one second (FEV1) in young children because it requires minimal co-operation. The purpose of this study was to assess the ability of the forced oscillation technique (FOT) to detect airway obstruction in asthmatic children and in patients with cystic fibrosis (CF). Spirometry and Rrs were recorded in 45 asthmatic children (32 males and 13 females) and in 45 patients with CF (28 males and 17 females). ⋯ In CF, Rrs failed to detect even severe airways obstruction. These findings might be accounted for by the inability of Rrs to reflect peripheral obstruction. We conclude that total respiratory resistance is suitable to assess airways obstruction in asthmatic children but not in cystic fibrosis patients.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of four different methods of sampling arterial blood and storage time on gas tensions and shunt calculation in the 100% oxygen test.
At the present time, plastic syringes are most commonly used for collecting arterial blood. The oxygen tension of the arterial blood (Pa,O2) in these syringes may fall. We studied the effect of the type of syringe, metabolism, and storage time on the arterial oxygen pressures measured and on the pulmonary shunt calculated. ⋯ The pulmonary shunt was significantly overestimated when the "gold standard" blood gas results were not used (range 0.8-9.9%). Glass (not plastic) syringes should be used in the 100% oxygen test. The syringe should be cooled immediately, even when the sample is analysed as soon as possible.
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Comparative Study Clinical Trial Controlled Clinical Trial
Altered accessory cell function of alveolar macrophages: a possible mechanism for induction of Th2 secretory profile in idiopathic pulmonary fibrosis.
Alveolar macrophages (AMs) are considered to play a central role in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Recent studies have revealed a predominance of the type-2 T-helper (Th2) cytokine pattern of inflammatory response in the pulmonary interstitium in IPF. The aim of the present study was to determine whether or not the altered accessory cell function of AMs could account for the Th2 pattern of chronic inflammation in IPF. ⋯ IL-10 suppressed T-cell proliferation in co-cultures with AMs from healthy volunteers (smokers and nonsmokers), but not with AMs from patients with IPF. Expression of CD80 and CD86 on AMs from these groups did not differ. Thus, the altered accessory cell function of alveolar macrophages from patients with idiopathic pulmonary fibrosis may possibly relate to the pattern of type-2 T-helper cytokine production in response to inflammation.
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Comparative Study Clinical Trial
Comparison of jet and ultrasonic nebulizer pulmonary aerosol deposition during mechanical ventilation.
Increased delivery of aerosol to a model lung (attached to a mechanical ventilator) has been demonstrated with an ultrasonic nebulizer as compared to a jet nebulizer. This study examined whether the increased aerosol deposition with an ultrasonic nebulizer could also be demonstrated in vivo. Seven patients (6 male and 1 female) were studied during mechanical ventilalion (Siemens Servo 900C, Middlesex, UK) after open heart surgery. ⋯ The ultrasonic nebulizer was also associated with a reduction in the time required to complete nebulization (9 vs 21 min, respectively) (p<0.0001). Use of the DP100 ultrasonic nebulizer more than doubled lung deposition compared with the System 22 jet nebulizers in mechanically-ventilated patients. Their efficiency, speed of drug delivery, and compatibility with mechanical ventilator circuits make ultrasonic nebulizers potentially attractive for use during mechanical ventilation.
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Short-term effects of air pollution (consisting primarily of sulphur dioxide and particulate matter but with low acidity) on respiratory morbidity were studied in asthmatic children from Sokolov, Czech Republic. Eighty nine children with asthma, who recorded daily peak expiratory flow measurements, symptoms and medication use in a diary, were analysed for 7 months during the winter of 1991-1992. Air pollution measurements included: SO2, total suspended particulates (TSPs), inhalable particles, ie. particulate matter of aerodynamic diameter < or = 10 microm, particle strong acidity (PSA) and fine particle sulphate concentration (SO4). ⋯ The association between respiratory symptoms and particulate SO4 was highly dependent on this episode, whilst the associations between lung function and SO4 as well as between fever and SO4 were still observed when this air pollution episode was excluded. Some evidence was found that exposure to air pollution might have enhanced the respiratory symptoms while children were experiencing respiratory infections. In this study, a panel of children with mild asthma experienced small decreases in peak expiratory flow and increased dyspnoea in association with fine particles formed during air pollution episodes.