Search results for "Airway Resistance"
showing 10 items of 30 documents
Use of an inspiratory impedance threshold valve during chest compressions without assisted ventilation may result in hypoxaemia
2007
Although the concept of intermittent airway occlusion with the inspiratory impedance threshold valve (ITV) is a well-recognised strategy for improving efficiency of cardiopulmonary resuscitation (CPR), little is known about possible pulmonary side effects.After a baseline chest CT-scan, 24 pigs with beating hearts undergoing apnoeic oxygenation received an injection of a contrast medium and were then assigned randomly to either active compression-decompression CPR with ITV (ACD ITV CPR), ACD CPR alone, or standard-CPR with ITV (standard-ITV CPR), or standard-CPR alone. After a maximum of 5 min of chest compressions or if oxygen saturation dropped below 70%, the experiment was stopped, haemo…
Pharmacological analysis of the responsiveness of guinea-pig lung parenchymal strip to dopamine
1984
Abstract Responses to dopamine were examined in the guinea-pig isolated lung parenchymal strip. Complete cumulative concentration-response curves to dopamine exhibited a biphasic pattern with a small initial contraction at concentrations below 10(-5) M followed by a dose-dependent relaxation at higher concentrations. Phentolamine (10(-5) M) completely abolished the contractile component and enhanced sensitivity and maximal relaxation to dopamine. In the presence of phentolamine, propranolol antagonized the dopamine-induced relaxation (pA2 = 8.54 +/- 0.07). In the presence of propranolol (10(-6) M), dopamine produced a dose-related contraction displaced to the right by phentolamine. Incubati…
New insights in respiratory impedance in young children after repair of congenital diaphragmatic hernia: a cross-sectional study
2019
Abstract Lung function impairment is common in Congenital Diaphragmatic Hernia (CDH) survivors. The aim of this study was to evaluate, in children who underwent CDH surgical repair, mid and long-term consequences on respiratory impedance, investigating the impact of CDH on both resistance and reactance parameters, as well as bronchodilator response. Forced Oscillation Technique (FOT) parameters were collected from 12 patients (2–11 years). Resistance and reactance values at 8 Hz (Rrs8, Xrs8) and the area under the reactance curve (AX) were measured pre and post-salbutamol. Quantitative variables were compared using Mann-Whitney U test. Differences of categorical variables were evaluated usi…
Relationship between rhinitis duration and worsening of nasal function
2008
BackgroundWhile it is well known that asthma is characterized by airway remodeling, few studies instead have investigated this issue in patients with allergic rhinitis (AR).ObjectiveThe aim of the study was to evaluate nasal function, ie, nasal airflow, in a cohort of patients with persistent AR (PER).MethodsOne hundred patients, 50 with short-term and 50 with long-term PER, were prospectively and consecutively evaluated, clinically evaluated by visit, skin prick test, and rhinomanometry.ResultsNasal airflow values were significantly lower (median flow: 348 mL/sec) in patients with long-term rhinitis (median duration nine years) as compared to patients with short-term (median duration one y…
Oral N-acetylcysteine attenuates the rat pulmonary inflammatory response to antigen.
2003
Oxidative stress is involved in the pathophysiology of inflammatory airway diseases including asthma; therefore, antioxidants might be of clinical benefit in asthma treatment. In the present study, the effects of N-acetylcysteine on sensitised brown Norway rats were examined. N-Acetylcysteine (3 mmol kg body weight(-1) administered orally) was given daily for 1 week before challenge and various antigen-induced pulmonary responses were studied. Antigen exposure increased lipid peroxidation in bronchoalveolar lavage fluid (BALF) and oxidised glutathione levels in lung tissue 2 h after challenge. Lung nuclear transcription factor-KB-binding activity was increased 2 h after challenge, and BALF …
Structural and functional evidence for the scaffolding effect of alveolar blood vessels
2017
A contribution of pulmonary blood distension to alveolar opening was first proposed more than 100 years ago. To investigate the contribution of blood distension to lung mechanics, we studied control mice (normal perfusion), mice after exsanguination (absent perfusion) and mice after varying degrees of parenchymal resection (supra-normal perfusion). On inflation, mean tracheal pressures were higher in the bloodless mouse (4.0α2.5 cmH2O); however, there was minimal difference between conditions on deflation (0.7α0.9 cmH2O). To separate the peripheral and central mechanical effects of blood volume, multi-frequency lung impedance data was fitted to the constant-phase model. The presence or abse…
Deep inspiration-induced bronchoprotection is stronger than bronchodilation
2000
We have previously shown that in healthy subjects, deep inspiration (DI) has not only a bronchodilatory but also a bronchoprotective effect that is absent in asthmatic subjects. We conducted the study reported here to test the hypothesis that the bronchoprotective effect is stronger than the bronchodilatory effect, and to determine the extent to which these two effects are related. Ten healthy subjects underwent provocations in which single doses of methacholine, previously shown to reduce FEV(1) by 10% to 20% (Dose 1) and by 20% to 40% (Dose 2) were administered after a 20-min period devoid of DI. To measure the bronchodilator effect, DIs were performed immediately after the first spiromet…
Bodyplethysmographischer Wirkeintritt von Formoterol bei Patienten mit mittel- bis schwergradiger partiell reversibler Atemwegsobstruktion
2002
BACKGROUND Formoterol is a long acting beta2-agonist used for the treatment of obstructive airway diseases. Compared with Salmeterol, Formoterol has a rapid onset of bronchodilation. There are only scant data regarding the comparative onset of action using bodyplethysmography in moderate to severely obstructive patients. METHODS In a mono-center, single-blinded parallel group study 60 patients (age: 61.9 +/- 12.8 years, 65 % male) with moderate to severe (mean FEV(1) 40.6 +/- 15.3 % of predicted), partially reversible (FEV(1) post bronchodilator > 15 % from baseline) airway obstruction were treated with either formoterol 12 microg bid or salmeterol 50 microg bid over a period of two weeks. …
The new agreement of the international RIGA consensus conference on nasal airway function tests.
2018
The report reflects an agreement based on the consensus conference of the International Standardization Committee on the Objective Assessment of the Nasal Airway in Riga, 2nd Nov. 2016. The aim of the conference was to address the existing nasal airway function tests and to take into account physical, mathematical and technical correctness as a base of international standardization as well as the requirements of the Council Directive 93/42/EEC of 14 June 1993 concerning medical devices. Rhinomanometry, acoustic rhinometry, peak nasal inspiratory flow, Odiosoft-Rhino, optical rhinometry, 24-h measurements, computational fluid dynamics, nasometry and the mirrow test were evaluated for importa…
Sleep Apnea: New Insights
2004
Sleep apnea is the most common disorder of breathing during sleep. It is defined as repeated episodes of obstructive apnea and hypopnea during sleep, together with daytime sleepiness or altered cardiopulmonary function [1]. There are three syndromes of upper airway closure during sleep: obstructive sleep apnea (OSA), obstructive sleep hypopnea, and upper airway resistance. These three syndromes share two features: excessive daytime sleepiness and arousal associated with increased ventilatory effort in response to upper airway closure. The specific sites of narrowing or closure and upper airway dysfunction are influenced by the underlying neuromuscular tone, upper airway muscle synchrony, an…