Search Results
Results 451 - 500 of 1441
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Beaumont M - - 1998
We measured upper airway caliber and lung volumes in six normal subjects in the sitting and supine positions during 20-s periods in normogravity, hypergravity [1.8 + head-to-foot acceleration (Gz)], and microgravity ( approximately 0 Gz) induced by parabolic flights. Airway caliber and lung volumes were inferred by the acoustic reflection ...
Murphy D J - - 1998
Pleural pressures are used to evaluate lung function and are generally measured acutely in anesthetized animals. Previous attempts to measure pleural pressure chronically in conscious animals have involved surgical implantation of pressure-sensitive catheters directly into the pleural cavity. The success of these techniques has been limited by lung damage and/or ...
Norman M - - 1998
Lung volume reduction surgery for severe emphysema with removal of 20-30% of the most destroyed parts of the lung parenchyma has been reported to improve lung function substantially. Increased elastic recoil has been suggested as one underlying mechanism for the improvement. Fourteen patients, seven men and seven women with a ...
Fahy B G - - 1998
STUDY OBJECTIVE: To test whether split torso positioning, abdominal insufflation, and other procedures performed during laparoscopic nephrectomy would affect mechanical impedances to inflation [i.e., elastance (E) and resistance (R) of the total respiratory system (Ers, and Rrs), lungs (EL and RL), and chest wall (Ecw and Rcw)] differently from previously ...
Romero P V - - 1998
To investigate whether changes of tissue resistance (Rti) during methacholine (MCh)-induced constriction correspond to an intrinsic mechanism or are an artifact of increased airways inhomogeneity, rabbits were studied after exposure to air (n = 7) or 1.5 parts/million O3 (n = 6). Animals were anesthetized and mechanically ventilated. Tracheal flow ...
Huh J - - 1998
OBJECTIVE: The purpose of this study is to investigate the effects of lung volume reduction surgery on pulmonary compliance, airway flow, and helium lung volumes in an elastase-induced emphysema animal model. METHODS: A 15,000-unit bolus of elastase was aerosolized through an endotracheal tube in 14 New Zealand White rabbits to ...
Laghi F - - 1998
The mechanisms for symptomatic improvement following lung volume reduction surgery for emphysema are poorly understood. We hypothesized that enhanced neuromechanical coupling of the diaphragm is an important factor in this improvement. We studied seven patients with diffuse emphysema before and 3 mo after surgery. Patients showed improvements in 6-min walking ...
Adler A - - 1998
We assessed in eight dogs the accuracy with which electrical impedance tomography (EIT) can monitor changes in lung volume by comparing the changes in mean lung conductivity obtained with EIT to changes in esophageal pressure (Pes) and to airway opening pressure (Pao) measured after airway occlusion. The average volume measurement ...
Venturoli D - - 1998
The present study reports data on respiratory function of lung and chest wall following the 180 days long European - Russian EuroMir '95 space mission. Data reported refer to two subjects studied before the mission, on day 9 and 175 in flight and on days 1, 10, 12, 27 and ...
Estenne M - - 1998
Patients with traumatic transection of the lower segments of the cervical cord contract the clavicular portion of the pectoralis major during forced expiration and cough, and the rise in intrathoracic pressure resulting from this contraction produces dynamic airway compression in many patients. Because the abdominal muscles are paralyzed, however, there ...
Valente S - - 1998
Static and dynamic lung volumes, arterial blood gases, alveolar ventilation and ventilation-perfusion (VA/Q) relationships were studied in 14 mild asthmatic patients and in 7 normal subjects (as controls) before and after fenoterol inhalation. Multiple nitrogen washout curves were analyzed by a bicompartmental distribution model, in order to assess the distribution ...
Prisk G K - - 1998
We performed multiple-breath washouts of N2 and simultaneous washins of He and SF6 with fixed tidal volume (approximately 1,250 ml) and preinspiratory lung volume (approximately the subject's functional residual capacity in the standing position) in four normal subjects (mean age 40 yr) standing and supine in normal gravity (1 G) ...
Venegas J G - - 1998
Quantification of pulmonary pressure-volume (P-V) curves is often limited to calculation of specific compliance at a given pressure or the recoil pressure (P) at a given volume (V). These parameters can be substantially different depending on the arbitrary pressure or volume used in the comparison and may lead to erroneous ...
Hayden M J - - 1997
The raised-volume forced-expiration technique measures infant lung function over an extended volume range. To improve comparisons between individuals and populations, we investigated the influence of jacket pressure on outcome variables in 21 infants. To quantify pressure transmitted from the jacket to the pleural space at a given lung volume, the ...
Williams E M - - 1997
Forced sinusoidal oscillations in the inspired concentration of a low-solubility inert gas can be used to measure airways dead space and alveolar volume. When inspired oxygen is oscillated about its mean value in the same way, the ratio between the amplitudes of the resulting end-expired and inspired oxygen oscillations is ...
Johan A - - 1997
Maximal static inspiratory and expiratory mouth pressures (PI,max and PE,max, respectively) enable the noninvasive measurement of global respiratory muscle strength. The aim of this study was primarily to obtain normal values of PI,max and PE,max for adult Chinese, Malays and Indians and, secondarily, to study their effect on lung volumes ...
Lemos M - - 1997
Fibers of the collagenous and elastic systems are most relevant in the double mechanical action of visceral pleura (VP), i.e. volume limitation and the generation of elastic recoil pressure. In this work we studied the organization of these fibrous components of VP in two situations: normal lungs and bullous disease. ...
Peták F - - 1997
We previously studied low-frequency respiratory impedance (Zrs) data at an elevated lung volume to separate airway and tissue mechanical properties in normal infants (Am. I. Respir. Crit. Care Med. 1996; 154:161-166). The aim of the present study was to determine the volume dependence of the airway and tissue mechanics by ...
Denny E - - 1997
A finite element model, comprising an assemblage of tetrakaidecahedra or truncated octahedra, is used to represent an alveolar duct unit. The dimensions of the elastin and collagen fibre bundles, and the surface tension properties of the air-liquid interfaces, are based on available published data. Changes to the computed static pressure-volume ...
Bloch K E - - 1997
Surgical lung volume reduction may improve pulmonary function and dyspnea in advanced pulmonary emphysema. To investigate mechanisms of these beneficial effects we studied breathing patterns before and after surgery. Nineteen patients with diffuse pulmonary emphysema (FEV1 < 35% of predicted, total lung capacity > 130% predicted) were studied within 1 ...
van der Schans C P - - 1997
Mucus hypersecretion and impaired mucus clearance are well-known symptoms in patients with chronic obstructive pulmonary disease and cystic fibrosis. These symptoms should not be considered as innocent but they deserve treatment. A well known therapy to improve mucus transport is chest physiotherapy. Forced expiratory manoeuvres are probably the most effective ...
Roth E J - - 1997
Weakness and spasticity of chest wall muscles are known to adversely affect pulmonary function in spinal cord-injured patients. To test the assertion that impaired strength and increased tone contribute to ventilation deficits, 52 patients with recent acute traumatic cervical and high thoracic spinal cord injury underwent complete pulmonary function testing. ...
Duranti R - - 1997
Lung volumes are decreased by tense ascites and increase after large volume paracentesis (LVP). The overall effect of ascites and LVP on the respiratory function is poorly understood. We studied eight cirrhotic patients with tense ascites before and after LVP. Inspiratory muscle force (maximal transdiaphragmatic pressure (Pdi,max), and the lowest ...
Barnas G M - - 1997
We examined how the changes in the acini caused by emphysema affected gas transfer out of the acinus (Taci) and lung and chest wall mechanical properties. Measurements were taken from five dogs before and 3 mo after induction of severe bilateral emphysema by exposure to papain aerosol (170-350 mg/dose) for ...
West J B JB Department of Medicine, University of California San Diego, La Jolla 92093-0623, USA. - - 1997
The lung is exquisitely sensitive to gravity, and so it is of interest to know how its function is altered in the weightlessness of space. Studies on National Aeronautics and Space Administration (NASA) Spacelabs during the last 4 years have provided the first comprehensive data on the extensive changes in ...
Moreira L F - - 1997
Pneumoperitoneum may give rise to several respiratory changes; nevertheless, no comprehensive analysis of respiratory mechanics has been performed under this condition. Respiratory mechanics and thoracoabdominal morphometry were evaluated in six sedated, anaesthetized, paralysed, and mechanically-ventilated rats before (control) and during pneumoperitoneum. After airway occlusion at end-inspiration, respiratory system, pulmonary, and ...
Korman B - - 1997
During induction with high inspired concentrations of nitrous oxide, net uptake of gas produces a contraction in volume and a concentrating effect. In turn, this results in concentration and second gas effects. Most explanations of these effects are based on the common "rectangle" diagram devised by Stoelting and Eger and ...
te Nijenhuis F C - - 1997
We studied the effect of increasing alveolar volume on pulmonary carbon monoxide transfer (DLCO) and its components, i.e. membrane diffusing capacity (DM) and capillary blood volume (Qc), during mechanical ventilation in eight anaesthetized and paralysed healthy pigs (mean weight 11.2 kg). We used an inspiratory pause procedure for simulation of ...
Conti G - - 1997
OBJECTIVE: To evaluate respiratory mechanics in the early phase of decompensation in a group of seven patients with severe kyphoscoliosis (KS) (Cobb angle > 90 degrees) requiring mechanical ventilatory support. DESIGN: Prospective clinical study with a control group. SETTING: General intensive care unit at University of Rome "La Sapienza". PATIENTS: ...
Servillo G - - 1997
Pressure-volume (P-V) curves of the respiratory system allow determination of compliance and lower and upper inflection points (LIP and UIP, respectively). To minimize lung trauma in mechanical ventilation the tidal volume should be limited to the P-V range between LIP and UIP. An automated low flow inflation (ALFI) technique, using ...
Russi E W - - 1997
Lung volume reduction surgery (LVRS) is performed to alleviate dyspnoea of selected patients with severe pulmonary emphysema, and to improve their pulmonary function, performance in daily activity and quality of life. By resection of targeted emphysematous lung tissue, the achievable changes in pulmonary function consist of: 1) an increase in ...
Aires S T - - 1997
This study was performed to evaluate the role of diethylcarbamazine (DEC), the drug of choice for treating Lymphatic Filariasis and Tropical Pulmonary Eosinophilia, on respiratory mechanics of higid rats. Thus, during 30 days two groups of six rats each received intraperitoneally either isotonic saline solution, or 12 mg/kg per day ...
Kaminsky D A - - 1997
The effects of hyperpnea on parenchymal lung mechanics are unknown, but they may contribute to the resultant airflow limitation commonly seen in asthma. To investigate these effects, we measured the following parameters in seven asthmatic and six normal subjects before and after 5 min of hyperpnea: specific conductance, upstream resistance, ...
Tomalak W - - 1997
Assuming homogeneity of alveolar pressure, the relationship between airway flow and flow at the chest during forced oscillation at the airway opening [flow transfer function (FTF)] is related to lung and chest wall tissue impedance (Zti): FTF = 1 + Zti/Zg, where Zg is alveolar gas impedance, which is inversely ...
Reiterer F - - 1997
We report our experience with pulmonary function testing in 11 out of 22 full-term neonates with severe respiratory failure, treated at the ECMO center Graz (Austria) during the period from 1990 to 1995. Altogether 17 out of 22 patients survived ECMO and all of them were successfully weaned from ECMO. ...
Laghi F - - 1997
The clinical application of transdiaphragmatic twitch pressure (Pdi,tw) response to phrenic nerve stimulation has been hindered by the requirement for placement of oesophageal and gastric balloons. Investigators have reported that mouth twitch pressure (Pmo,tw) estimates Pdi,tw accurately at lung volumes above and below functional residual capacity (FRC). However, it is ...
Pelosi P - - 1997
The effects of inspiratory flow and inflation volume on the mechanical properties of the respiratory system in eight sedated and paralyzed postoperative morbidly obese patients (aged 37.6 +/- 11.8 yr who had never smoked and had normal preoperative seated spirometry) were investigated by using the technique of rapid airway occlusion ...
Poole D C - - 1997
In emphysema, the diaphragm shortens by losing sarcomeres. We hypothesized that unless capillaries undergo a similar shortening, capillary geometry must be altered. Without quantifying this geometry, capillary length and surface area per fiber volume, which are critical measurements of the structural potential for blood-tissue exchange, cannot be resolved. Five months ...
Mink S N - - 1997
A canine model of unilobar papain-induced emphysema was used to examine the extent to which differences in alveolar pressures (PA) would develop between an emphysematous right lower lobe (RLL) and normal left lower lobe (LLL) during forced vital capacity (FVC) deflation. RLL and LLL PA (PARLL and PALLL, respectively) were ...
Kossmann S - - 1997
Workers of a chemical plant department producing dust and liquid pesticides (37 males and 17 females) exposed to dust containing free silica, organic solvents and active substances, among others: organophosphate compounds, pyrethroids, triazines, carbamates and dithiocarbamates, 2,4-D, captan, carboxine, carbendazim and dodine were studied. Spirometric investigations, including evaluation of vital ...
Laurikainen K - - 1997
In an open, randomized crossover study two different types of dry powder inhalers (DPIs) were compared. Twenty-five adult asthmatic patients inhaled a single dose of 200 micrograms of salbutamol (CAS 18559-94-9) on two separate days. Salbutamol was administered either from a novel multidose DPI (Easyhaler, test DPI) or from another ...
Cheung D - - 1997
Airway hyperresponsiveness is characterized by an increase in sensitivity and excessive airway narrowing to inhaled bronchoconstrictor stimuli. There is experimental evidence that maximal airway narrowing is related to lung elasticity in normal and asthmatic subjects. We hypothesized that reduced lung elasticity by parenchymal destruction increases the level of maximal airway ...
Hahn A - - 1997
OBJECTIVE: To analyze the relationship between disease progression, pulmonary volumes, respiratory muscle strength (maximum inspiratory [MIP] and expiratory [MEP] pressure), and arterial blood gases for patients with Duchenne muscular dystrophy (DMD). DESIGN: An inception cohort study of pulmonary volumes, MIPs, and MEPs, correlated with age and PaCO2 levels and with ...
Gounden P - - 1997
The purpose of this study was to examine ventilatory muscle strength as represented by static respiratory pressures in 30 tetraplegic patients with a complete lesion between the fifth and the eighth cervical vertebrae. The Inspiratory/Expiratory Pressure Meter was used to obtain maximum static expiratory mouth pressure (PEmax) and maximum static ...
Buyse B - - 1997
This study aimed to determine the relationship between pulmonary function, respiratory muscle function and neurological function in multiple sclerosis (MS). Sixty patients (27 males and 33 females) aged 27-75 yrs (mean +/- SD 48 +/- 12 yrs) were prospectively studied. The Kurtzke Expanded Disability Status Scale (EDSS; range 0-10) score ...
McFawn P K - - 1997
Maturational changes in the specific compliance could potentially contribute to the development or clinical presentation of respiratory diseases in infants and children. Changes in the specific compliance during development and its structural basis have been well characterized, but changes in bronchial compliance and the mechanisms involved have received little attention. ...
Beckett W S - - 1996
In a 3-year survey, respiratory symptoms, spirometry, and methacholine reactivity were measured annually in welders (n = 51) and non-welder controls subjects (n = 54) to determine whether welding-related symptoms are associated with accelerated decline in lung function or changes in airway reactivity. In the cross-workshift study, maximal midexpiratory flow ...
Sahebjami H - - 1996
STUDY OBJECTIVE: To determine pulmonary function test (PFT) profile and respiratory muscle strength (RMS) of a group of obese individuals who did not have evidence of obstructive airway disease or other underlying diseases affecting their respiratory system. DESIGN: Prospective, open. SETTING: PFT laboratory, VA Medical Center. PARTICIPANTS: Sixty-three consecutive obese ...
Svantesson C - - 1996
Respiratory mechanics was studied in 11 rabbits at tidal volumes (VT) of 6.7, 10, and 20 ml/kg. Flow interruptions were performed during the full respiratory cycle. The viscoelastic pressure (Pve) was measured as the dynamic elastic pressure (Pel(dyn)) after flow cessation minus the static elastic pressure (Pel(st)). Static elastic and ...
Gelb A F - - 1996
OBJECTIVE: To investigate the mechanism of airflow limitation before and 6 and 12 months after targeted emphysematous resection in 10 male patients aged 67 +/- 8 years (mean +/- SD) with very severe COPD undergoing bilateral thoracoscopic stapling techniques. DESIGN: Lung function, including static lung elastic recoil, was measured 2 ...
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