Search results for "Gas exchange"
showing 10 items of 52 documents
A model of stepwise isovolaemic blood exchange in anaesthetised, spontaneously breathing rats to evaluate the oxygen transport efficiency of artifici…
2000
Our research pursues the production of hypo-oncotic artificial oxygen carriers, based on artificial covalently cross-linked hyperpolymeric mammalian haemoglobins. To evaluate their in vivo efficiency in oxygen delivery to the tissue we developed a small animal model of stepwise isovolaemic blood exchange in anaesthetised, spontaneously breathing rats. With the aid of a two-way respiratory micro valve for small animals the overall oxygen uptake by the tissue of the animal can be determined. Measurements of oxygen contents in arterial and mixed venous blood and of some further blood parameters together with known oxygen-binding characteristics of artificial and native oxygen carriers, permits…
Measurement of phase I volume breath by breath in spontaneously breathing guinea pigs.
1990
A new method to determine phase I volume in tracheotomized spontaneously breathing guinea pigs is presented. Measurements were performed in three animals weighing 567-896 g. In simultaneous tracings of tidal volume (VT) and expiratory profiles of endogenous gases (PO2 or PCO2), the phase I volume of each breath was determined graphically as the volume expired up to the end of phase I of the expirogram. The mean phase I volume of different animals ranged from 0.29 to 0.43 ml with an arithmetic dispersion between 0.014 and 0.021 ml. Spontaneous sighs sometimes with doubling of the VT caused a significant rise of phase I volume up to 50% of the normal values. The linear regression curve was c…
Bronchodilatory Effect of Deep Inspiration Is Absent in Subjects With Mild COPD
2004
Study objectives To investigate whether the bronchodilatory effect of deep inspiration is impaired in subjects with COPD. Methods We measured deep inspiration-induced bronchodilation in 19 patients with COPD and 17 healthy subjects (mean age, 67.8 ± 7.1 years vs 62.5 ± 9.3 years, respectively [± SEM]). Each subject underwent a series of single-dose methacholine provocations to induce at least a 15% reduction in inspiratory vital capacity (IVC). When this was achieved, subjects were asked to perform four consecutive deep inspirations, after which the IVC measurement was repeated and the percentage of bronchodilation by deep inspiration was calculated. Results The percentage of reduction in I…
Ultra-low tidal volume ventilation-A novel and effective ventilation strategy during experimental cardiopulmonary resuscitation.
2018
Abstract Background The effects of different ventilation strategies during CPR on patient outcomes and lung physiology are still poorly understood. This study compares positive pressure ventilation (IPPV) to passive oxygenation (CPAP) and a novel ultra-low tidal volume ventilation (ULTVV) regimen in an experimental ventricular fibrillation animal model. Study design Prospective randomized controlled trial. Animals 30 male German landrace pigs (16–20 weeks). Methods Ventricular fibrillation was induced in anesthetized and instrumented pigs and the animals were randomized into three groups. Mechanical CPR was initiated and ventilation was either provided by means of standard IPPV (RR: 10/min,…
Impact of the Prone Position in an Animal Model of Unilateral Bacterial Pneumonia Undergoing Mechanical Ventilation
2013
Abstract Background: The prone position (PP) has proven beneficial in patients with severe lung injury subjected to mechanical ventilation (MV), especially in those with lobar involvement. We assessed the impact of PP on unilateral pneumonia in rabbits subjected to MV. Methods: After endobronchial challenge with Enterobacter aerogenes, adult rabbits were subjected to either “adverse” (peak inspiratory pressure = 30 cm H2O, zero end-expiratory pressure; n = 10) or “protective” (tidal volume = 8 ml/kg, 5 cm H2O positive end-expiratory pressure; n = 10) MV and then randomly kept supine or turned to the PP. Pneumonia was assessed 8 h later. Data are presented as median (interquartile range). Re…
Effect of physical training on exercise capacity, gas exchange and N-terminal pro-brain natriuretic peptide levels in patients with chronic heart fai…
2006
BACKGROUND: Decreased exercise capacity is the main factor restricting the daily life of patients with chronic heart failure. N-terminal pro-brain natriuretic peptide (NT pro-BNP) is strongly related to the severity of and is an independent predictor of outcome in chronic heart failure. DESIGN: The study aimed to evaluate the effect of exercise training on functional capacity and on changes in NT pro-BNP levels and to assess the effect of exercise training on quality of life. MATERIALS AND METHODS: Sixty patients (45 men/15 women, mean age 52.7 years; +/-5.3 SD), with stable heart failure (45 ischaemic/hypertensive and 15 idiopathic patients), in New York Heart Association (NYHA) functional…
Airway cell composition at rest and after an all-out test in competitive rowers
2004
Med Sci Sports Exerc. 2004 Oct;36(10):1723-9. Airway cell composition at rest and after an all-out test in competitive rowers. Morici G, Bonsignore MR, Zangla D, Riccobono L, Profita M, Bonanno A, Paternò A, Di Giorgi R, Mirabella F, Chimenti L, Benigno A, Vignola AM, Bellia V, Amato G, Bonsignore G. SourceDepartment of Experimental Medicine Italian National Research Council (CNR), Palermo, Italy. Abstract PURPOSES: This study was designed to assess: a) whether rowing affects airway cell composition, and b) the possible relationship between the degree of ventilation during exercise and airway cells. SUBJECTS AND METHODS: In nine young, nonasthmatic competitive rowers (mean age +/- SD: 16.2 …
Pulmonary effects of expiratory-assisted small-lumen ventilation during upper airway obstruction in pigs
2015
Summary Novel devices for small-lumen ventilation may enable effective inspiration and expiratory ventilation assistance despite airway obstruction. In this study, we investigated a porcine model of complete upper airway obstruction. After ethical approval, we randomly assigned 13 anaesthetised pigs either to small-lumen ventilation following airway obstruction (n = 8) for 30 min, or to volume-controlled ventilation (sham setting, n = 5). Small-lumen ventilation enabled adequate gas exchange over 30 min. One animal died as a result of a tension pneumothorax in this setting. Redistribution of ventilation from dorsal to central compartments and significant impairment of the distribution of ve…
Ventilation and Heart Rate Response During Exercise in Normals: Relevance for Rate Variable Pacing
1993
The observation of a close relationship of heart rate to oxygen uptake (HR-VO2) and heart rate to minute ventilation (HR-VE) has been shown to be of particular value in rate variable pacing. However, the impact of anaerobic threshold (AT) for the HR-VO2 and HR-VE slope has been studied less. Twenty-three male and 16 female subjects, mean age 52 +/- 7 years, were selected in whom complete heart catherization and extensive noninvasive studies excluded major cardiopulmonary disease. Semisupine bicycle exercise testing with analysis of respiratory gas exchange was performed using a ramping work rate protocol with work increments of 20 watts/min. At the respiratory AT, determined by the V slope …
The effects of skin and core tissue cooling on oxygenation of the vastus lateralis muscle during walking and running
2016
Skin and core tissue cooling modulates skeletal muscle oxygenation at rest. Whether tissue cooling also influences the skeletal muscle deoxygenation response during exercise is unclear. We evaluated the effects of skin and core tissue cooling on skeletal muscle blood volume and deoxygenation during sustained walking and running. Eleven male participants walked or ran six times on a treadmill for 60 min in ambient temperatures of 22°C (Neutral), 0°C for skin cooling (Cold 1), and at 0°C following a core and skin cooling protocol (Cold 2). Difference between oxy/deoxygenated haemoglobin ([diffHb]: deoxygenation index) and total haemoglobin content ([tHb]: total blood volume) in the vastus lat…