Search results for " Gas exchange"
showing 10 items of 42 documents
Initiation of high-frequency oscillatory ventilation and its effects upon cerebral circulation in pigs: an experimental study
2006
BACKGROUND: Current practice at high-frequency oscillatory ventilation (HFOV) initiation is a stepwise increase of the constant applied airway pressure to achieve lung recruitment. We hypothesized that HFOV would lead to more adverse cerebral haemodynamics than does pressure controlled ventilation (PCV) in the presence of experimental intracranial hypertension (IH) and acute lung injury (ALI) in pigs with similar mean airway pressure settings. METHODS: In 12 anesthetized pigs (24-27 kg) with IH and ALI, mean airway pressure (P(mean)) was increased (to 20, 25, 30 cm H(2)O every 30 min), either with HFOV or with PCV. The order of the two ventilatory modes (cross-over) was randomized. Mean art…
Successful treatment of a patient with ARDS after pneumonectomy using high-frequency oscillatory ventilation.
1999
High frequency oscillatory ventilation (HFOV) was used in a patient who developed the acute respiratory distress syndrome 5 days following a right pneumonectomy for bronchogenic carcinoma. When conventional pressure-controlled ventilation failed to maintain adequate oxygenation, HFOV dramatically improved oxygenation within the first few hours of therapy. Pulmonary function and gas exchange recovered during a 10-day period of HFOV. No negative side effects were observed. Early use of HFOV may be a beneficial ventilation strategy for adults with acute pulmonary failure, even in the postoperative period after lung resection.
Deliberate Arterial Hypotension Does Not Reduce Intraocular Pressure in Pigs
1992
Among the accepted advantages of general anesthesia in ophthalmic surgery is improved control of intraocular pressure (IOP). Although standard textbooks advocate deliberate arterial hypotension to facilitate intraocular surgery by reducing IOP, scientific proof of such an effect is lacking. The authors investigated effects of induced arterial hypotension on IOP in an anesthetized porcine model. Forty-two piglets were anesthetized with piritramide, were placed in the prone position, and had the anterior chamber of one eye punctured with a small Teflon cannula to measure IOP. Six pigs were used in a pilot study to establish dose-response relationships for the hypotensive agents; 36 pigs were …
Cardiorespiratory Fitness and Physical Activity following Lung Transplantation: A National Cohort Study
2020
<b><i>Background:</i></b> Low cardiorespiratory fitness and inactivity are common after lung transplantation (LTx). The causes of exercise intolerance are incompletely understood. <b><i>Objectives:</i></b> The aim of this study was to objectively assess cardiorespiratory fitness and physical activity, evaluate causes of exercise intolerance, and explore clinical factors associated with cardiorespiratory fitness after bilateral LTx (BLTx). <b><i>Materials and Methods:</i></b> Peak oxygen uptake (V<b>∙</b>O<sub>2peak</sub>) and exercise-limiting factors were evaluated by a treadmill cardiopulmonary…
Quantification of atelectatic lung volumes in two different porcine models of ARDS.
2006
BACKGROUND: Cyclic recruitment during mechanical ventilation contributes to ventilator associated lung injury. Two different pathomechanisms in acute respiratory distress syndrome (ARDS) are currently discussed: alveolar collapse vs persistent flooding of small airways and alveoli. We compare two different ARDS animal models by computed tomography (CT) to describe different recruitment and derecruitment mechanisms at different airway pressures: (i) lavage-ARDS, favouring alveolar collapse by surfactant depletion; and (ii) oleic acid ARDS, favouring alveolar flooding by capillary leakage. METHODS: In 12 pigs [25 (1) kg], ARDS was randomly induced, either by saline lung lavage or oleic acid (…
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 …
Bronchoalveolar Lavage and Oleic Acid-Injection in Pigs as a Double-Hit Model for Acute Respiratory Distress Syndrome (ARDS).
2020
The treatment of ARDS continues to pose major challenges for intensive care physicians in the 21st century with mortality rates still reaching up to 50% in severe cases. Further research efforts are needed to better understand the complex pathophysiology of this disease. There are different well-established animal models to induce acute lung injury but none has been able to adequately mimic the complex pathomechanisms of ARDS. The most crucial factor for the development of this condition is the damage to the alveolar capillary unit. The combination of two well-established lung injury models allow us to mimic in more detail the underlying pathomechanism. Bronchoalveolar lavage (BAL) leads to…
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…
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,…