Respiratory medicine
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Respiratory medicine · Mar 1999
Eosinophilic inflammation assessed by induced sputum in corticosteroid-dependent asthma.
Sputum induction can be used to study airway inflammation in asthmatics. However, it has not been used in patients with corticosteroid-dependent asthma requiring long-term oral corticosteroids. The aim of the study was to assess the number of eosinophils and the levels of eosinophil cationic protein (ECP) in sputum of 17 corticosteroid-dependent asthmatics by comparison with nine mild untreated asthmatics, 10 moderate asthmatics receiving inhaled steroids (ICS) and 11 healthy subjects. ⋯ During follow-up, corticosteroid-dependent asthmatics with a controlled disease had no significant change in eosinophil numbers or ECP levels. On the other hand, corticosteroid-dependent asthmatics with recent exacerbations had a non-significant increase in eosinophil numbers and a significant increase in ECP levels. This study shows that ECP levels may be more accurate than eosinophil numbers in assessing exacerbations in corticosteroid-dependent asthmatics.
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The aim of this study was to identify factors which might predict nocturnal desaturation (defined as a fall of > 4% from awake baseline level for > or = 5 min) in normoxic or mildly hypoxic patients with stable COPD [arterial O2 saturation (SaO2) > or = 91%]. The study was prospective in nature, had full ethical approval and was performed in the Respiratory Department of a city teaching hospital. Thirty-three patients [mean (SD) age 67.2 (9) years] with stable COPD [mean (SD) FEV1 36.8 (11.0)% pred.] were recruited via the respiratory outpatient clinics and through the respiratory wards. ⋯ We observed nocturnal desaturation in all patients with a daytime SaO2 < or = 93% but in no patient with SaO2 > or = 95%. We conclude that daytime SaO2 can be used to predict nocturnal desaturation in normoxic or mildly hypoxic patients with stable COPD. Nocturnal desaturation is likely in patients with COPD where daytime SaO2 < or = 93%, and unlikely where daytime SaO2 > or = 95%.
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Respiratory medicine · Feb 1999
Sleep quality, carbon dioxide responsiveness and hypoxaemic patterns in nocturnal hypoxaemia due to chronic obstructive pulmonary disease (COPD) without daytime hypoxaemia.
In order to clarify whether nocturnal hypoxaemia (arterial oxygen saturation, SaO2 < 90%) may exist in the long-term before daytime hypoxaemia (PaO2 < 8.0 kPa) occurs in chronic obstructive pulmonary disease (COPD), 21 patients with stable severe COPD without daytime hypoxaemia (PaO2 > or = 8.0 kPa) were studied prospectively. Subjects were monitored twice by polysomnography (PSG) 12 months apart. Spirometry was performed, and diffusion capacity (DLCO) and hypercapnic respiratory drive response delta PI0.1 delta PCO2(-1)) were measured during the daytime in conjunction with polysomnography. ⋯ Prolonged nocturnal hypoxaemia and reduced whole night oxygenation are associated with increased superficial sleep. Sleep fragmentation and high carbon dioxide sensitivity may be important defence mechanisms against sleep-related hypoxaemia. The appearance of daytime hypoxaemia is preceded by a substantial deterioration in lung function, but by only a minor deterioration of nocturnal hypoxaemia.
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Respiratory medicine · Feb 1999
Agreement between spirometry and tracheal auscultation in assessing bronchial responsiveness in asthmatic children.
We have recently found that changes in lung sounds correspond well with a 20% fall in the forced expiratory volume in 1 s (FEV1) after methacholine challenge in asthmatic children. Up to now, little was known about the agreement between a 20% fall in FEV1 and a change in lung sounds after repeated bronchial challenge. In this study we investigated the agreement between the total cumulative histamine dose causing a fall in FEV1 of 20% or more (PD20) and the detection of a change in lung sounds (PDlung sounds) after two bronchial challenges on different occasions in asthmatic children. ⋯ Good agreement between the logarithm of PD20 and the logarithm of PDlung sounds was found on both test days. The mean difference was 0.04 and the limits of agreement (d +/- 2 SD of the differences) were 0.04 +/- 0.41. A good agreement was found between the total cumulative histamine dose causing a fall in FEV1 of 20% or more and the detection of a change in lung sounds after two bronchial challenges on different occasions in asthmatic children.
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Respiratory medicine · Jan 1999
Randomized Controlled Trial Comparative Study Clinical TrialCough induced by low pH.
Citric acid has been used as a tussive agent in the investigation of the cough reflex. The mechanism of cough stimulation remains unclear. We conducted studies to compare the cough response of citric acid to an organic (acetic acid) and an inorganic acid (phosphoric acid). ⋯ These results show that an individual's cough response to acetic and phosphoric acid are similar to that caused by citric acid. Thus these acids may cause cough by a common mechanism such as disturbance of the pH of the airway surface liquid. Capsaicin does not appear to share this common pathway.