The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
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Fourteen consecutive ARDS patients were examined within 24 h from the onset of mechanical ventilation to determine respiratory resistance (Rrs) and compliance (Cstrs), and to assess the influence of "intrinsic" positive end-expiratory pressure (PEEPi) on the measurement of Cstrs. Flow, pressure, and changes in lung volume were measured with the transducers of the Servo 900C Siemens ventilator. Airway occlusion was performed with the end-inspiratory and end-expiratory buttons of the ventilator. ⋯ Maximum and minimum respiratory resistance (Rrsmax and Rrsmin), and frequency-dependence of Rrs were also measured. On average, there was a marked frequency-dependence of resistance, as manifested by the difference between Rrsmax and Rrsmin, with an increase of both Rrsmin (7.7 +/- 4.2 cm H2O.l-1.s) and Rrsmax (14.3 +/- 5.0 cm H2O.l-1.s). The added resistance of the endotracheal tubes and ventilator tubings was flow dependent, and averaged 13.2 +/- 2.9 cm H2O.l-1.s.(ABSTRACT TRUNCATED AT 250 WORDS)
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Levels of serum immunoglobulins and immunoglobulin G subclasses were measured in 32 cystic fibrosis (CF) patients, 30 asthmatics and 27 controls. When compared with the asthmatic patients and controls, the CF patients had raised levels of all IgG subclasses as well as total IgG, IgM and IgA, but there was not a statistically significant increase in IgE. The levels of immunoglobulins in the CF patients were examined in relation to the clinical features of the disease. ⋯ IgG1 was significantly correlated with IgG2 and IgG4; IgG2 with IgG4; and IgG4 with IgE. Total IgG was the immunoglobulin most closely correlated with poor lung function. Serum IgA was higher in patients with positive immediate skin prick reactions to pollens (p less than 0.005) and death within two years of the study was related to high levels of total IgG (p less than 0.01), IgG3 (p less than 0.001), IgA (p less than 0.001), and IgE (p less than 0.005).
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A tuberculous pseudo-aneurysm of the thoracic descending aorta was found in a 57 year-old female with haemoptysis three months after successful chemotherapy for a miliary tuberculosis. After aortic angiography, the aneurysm was resected and the aorta was repaired with a Dacron prosthetic graft. The patient is doing well one year after the operation.
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Both respiratory centres and the preganglionic vagal motoneurones, which control respiratory (striated) and airway (smooth) muscles respectively, receive information on the lungs, the circulation and the skeletal and respiratory muscles. Each of these nervous pathways has two components: one is phasic, i.e. in phase with biological rhythms, and comes from mechanoreceptors connected to large myelinated fibres; the second has a tonic low frequency firing rate and corresponds to the spontaneous activity of polymodal receptors connected to thin sensory fibres, which act mostly as sensors of changes in extracellular fluid composition (O2 and/or CO2 partial pressure, pH, release of algesic agents etc...). Some of them also detect large mechanical disturbances or local temperature changes. ⋯ Moreover, the stimulation of thin sensory fibres in particular circumstances is responsible for hyperventilation (arterial chemoreceptors and muscle afferents), increased airway tone (arterial chemoreceptors and mostly thin vagal afferent fibres) or bronchodilation (muscle afferents). These peripheral inputs project centrally on different structures and also on brain stem neurones, which integrate simultaneously chemosensory, vagal and muscle information. This results in complex interactions between the different sensory pathways.
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Comparative Study
Comparison of central venous, oesophageal and mouth occlusion pressure with water-filled catheters for estimating pleural pressure changes in healthy adults.
The validity of the central venous and water-filled oesophageal catheter technique as a measure of pleural pressure changes was tested in ten healthy subjects in different body positions during inspiratory efforts with occluded airways, by comparing the simultaneous changes in mouth pressure (delta Pm) taken to represent pleural pressure changes, in central venous pressure (delta Pcv) and in oesophageal pressure (delta Poes). delta Pcv/delta Pm values were close to unity in the sitting and left lateral positions, whereas in the supine and right lateral position, substantial deviations from unity were found in some instances. delta Poes/delta Pm values were close to unity in all positions, except some rare instances. No appreciable phase difference between delta Pm/delta Poes and delta Pm/delta Pcv was found when the amplitude ratios were close to unity. We conclude that valid measurements of pleural pressure changes can be obtained in most instances with the central venous and the water-filled oesophageal catheter system according to the occlusion test procedure.