Exposure to nitrogen dioxide and the occurrence of bronchial obstruction in children below 2 years.
BACKGROUND: The objective of the investigation was to test the hypothesis that exposure to nitrogen dioxide (NO2) has a causal influence on the occurrence of bronchial obstruction in children below 2 years of age. METHODS: A nested case-control study with 153 one-to-one matched pairs was conducted within a cohort of 3754 children born in Oslo in 1992/93. Cases were children who developed > or = 2 episodes of bronchial obstruction or one episode lasting >4 weeks. Controls were matched for date of birth. Exposure measurements were performed in the same 14-day period within matched pairs. The NO2 exposure was measured with personal samplers carried close to each child and by stationary samplers outdoors and indoors. RESULTS: Few children (4.6%) were exposed to levels of NO2 > or = 30 microg/m3 (average concentration during a 14-day period). In the 153 matched pairs, the mean level of NO2 was 15.65 microg/m3 (+/-0.60, SE) among cases and 15.37 (+/-0.54) among controls (paired t = 0.38, P = 0.71). CONCLUSIONS: The results suggest that NO2 exposure at levels observed in this study has no detectable effect on the risk of developing bronchial obstruction in children below 2 years of age. (+info)
Comparison of two new methods for the measurement of lung volumes with two standard methods.
BACKGROUND: The two most commonly used methods for the measurement of lung volumes are helium dilution and body plethysmography. Two methods have been developed which are both easier and less time consuming to perform. Mathematical modelling uses complex calculations from the flow-volume loop to derive total lung capacity (TLC), and the nitrogen balance technique uses nitrogen from the atmosphere to calculate lung volume in a similar way to helium dilution. This study was designed to compare the two new methods with the two standard methods. METHODS: Sixty one subjects were studied, 23 with normal lung function, 17 with restrictive airway disease, and 21 with obstructive ventilatory defects. Each subject underwent repeated measurements of TLC by each of the four methods in random order. Reproducible values were obtained for each method according to BTS/ARTP guidelines. Bland-Altman plots were constructed for comparisons between the methods and paired t tests were used to assess differences in means. RESULTS: Bland-Altman plots showed that the differences between body plethysmography and helium dilution fell into clinically acceptable ranges (agreement limits +/-0.9 l). The agreement between mathematical modelling or the nitrogen balance technique and helium dilution or body plethysmography was poor (+/-1.8-3.4 l), especially for subjects with airflow obstruction. CONCLUSIONS: Neither of the new methods agrees sufficiently with standard methods to be useful in a clinical setting. (+info)
Respiratory mechanics in airways obstruction associated with inspiratory dyspnoea.
Inspiratory muscle strength and the flow and elastic pressure opposing inspiration were measured in seven patients with severe airways obstruction who found inspiration difficult at rest. A comparison was made of measurements obtained from seven normal subjects and five patients with airways obstruction not experiencing inspiratory dyspnoea at rest. Measurements were also obtained when inspiratory dyspnoea was induced in the normal subjects by adding an inspiratory resistance or by voluntarily increasing lung volume. Compared with the controls the inspiratory muscle strength of the patients was reduced but was not significantly less than that of the patients without inspiratory dyspnoea. The pressure required to produce inspiratory flow was significantly greater when inspiratory dyspnoea was present (P = 0-01). However, there was considerable overlap in the pressures of those with and without inspiratory dyspnoea. A better relationship was obtained when muscle strength was considered. The ratio of inspiratory muscle strength to the pressure required to produce flow was 0-24 +/- 0-07 (mean +/- SD) in patient with inspiratory dyspnoea, 0-10 +/- 0-03 in patients without inspiratory dyspnoea, and 0-033 +/- 0-019 in normal subjects. There was no overlap between the two patient groups. The ratios of the normal subjects were increased when inspiratory dyspnoea was induced and, with the exception of two cases, were all above those obtained when inspiratory dyspnoea was absent. Inspiratory dyspnoea was experienced with lower ratios in the normals than in the patients with airways obstruction. (+info)
Aspects of serum and sputum antibody in chronic airways obstruction.
Immunoglobulin levels and precipitating antibody against a range of microbial antigens were measured in simultaneously collected serum and sputum samples from patients with chronic bronchitis (11), cystic fibrosis (9), bronchiectasis (9), and asthma (4). Sputum was prepared by dialysis and high-speed centrifugation methods. Results showed that it was possible to detect precipitating antibody in the sputum, and the rate was increased when both methods were used. A discrepancy was noted between the detection rate in the sputum and serum. This, combined with the lack of correlation between sputum and serum immunoglobulins, lack of relationship between bronchial inflammation and sputum immunoglobulins, and the lack of IgM in the sputum suggested that the antibody and immunoglobulin were locally produced. Sputum IgA (7S) in patients with chronic bronchitis was significantly lower (P less than 0-05) than that found in patients with cystic fibrosis and bronchiectasis. Significant differences (P less than 0-05) were also noted in serum IgG levels between patients with chronic bronchitis, bronchiectasis, and cystic fibrosis while serum IgM levels in patients with chronic bronchitis were significantly lower (P less than 0-05) when compared to serum levels in patients with cystic fibrosis. The presence of precipitating antibody in the sputum raises the possibility that type III reactions may be important in the pathogenesis of these conditions. (+info)
Localised upper airway obstruction in a patient with acquired immunodeficiency syndrome.
We describe a case of rapidly progressive upper airway obstruction due to tracheal Pseudomonas abscesses in a patient with acquired immunodeficiency syndrome. The case highlights the aggressive nature of Pseudomonas infections and the difficulty of eradicating this organism in patients infected with the human immunodeficiency virus. (+info)
Gastric rupture secondary to successful Heimlich manoeuvre.
A fatal case of gastric rupture following the Heimlich manoeuvre is reported. This life-threatening complication has only been reported previously in seven patients with a high mortality rate. All patients should be assessed immediately following this manoeuvre for any potentially life-threatening complications. (+info)
A resuscitated case from asphyxia by large bronchial cast.
A 62-year-old woman with bronchiectasis suffered from asphyxia due to a large bronchial cast that obstructed the bronchial tree. Immediate bronchoscopic suction of a bronchial cast of 17 cm in length through the intubated tube relieved the patients without any complications. Large bronchial casts appear to be rare in this century but it should be considered in patients with acute exacerbation of excessive sputa not only in patients with asthma or allergy but also in patients with respiratory tract infection. (+info)
Clinical studies of styrene workers: initial findings.
Styrene monomer is a high volume chemical used chiefly in production of polystyrene. A clinical survey of 493 production workers was undertaken at the oldest and largest monomer production, polymerization, and extrusion facility in the U.S. Relative exposure durations and levels were obtained from occupational histories. Significant differences between the high and low exposure groups were found with regard to history of acute prenarcotic symptoms, acute lower respiratory symptoms, prevalence of FEV 1/FV less than 75 per cent, and elevated GCTP. Other liver function tests, chest x-ray, FVC less than 80 per cent, and hematological parameters showed no distinct pattern. A concomitant mortality study has been mounted and is in progress. (+info)