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Results 251 - 300 of 1421
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Deakin Charles D - - 2004
BACKGROUND: Two mechanisms by which firm external paddle force decreases transthoracic impedance (TTI) have been proposed. Decreased impedance at the paddle-skin interface has been assumed to be the primary mechanism, but expulsion of air from the lungs, reducing lung volume is also likely to contribute. The relative contribution of each ...
Bianchi Roberto - - 2004
BACKGROUND: Pursed-lip breathing (PLB) is a strategy often spontaneously employed by patients with COPD during distress situations. Whether and to what extent PLB affects operational lung volume is not known. Also, conflicting reports deal with PLB capability of decreasing breathlessness. Participants and measurements: Twenty-two patients with mild-to-severe COPD were studied. ...
El-Dawlatly Abdelazeem Ali - - 2004
BACKGROUND:The effects of pneumoperitoneum (PPM) on respiratory mechanics during bariatric surgery were investigated. PATIENTS AND METHODS: 10 patients with BMI 50.5+/-8 kg/m(2) (range 40.9- 66.8) who underwent laparoscopic adjustable gastric banding with the Swedish band under general anesthesia were studied. Besides routine monitoring of vital signs and lung volumes, respiratory ...
Luecke Thomas - - 2003
BACKGROUND: Numerous studies suggest setting positive end-expiratory pressure during conventional ventilation according to the static pressure-volume (P-V) curve, whereas data on how to adjust mean airway pressure (P(aw)) during high-frequency oscillatory ventilation (HFOV) are still scarce. The aims of the current study were to (1) examine the respiratory and hemodynamic ...
Wohlgemuth M - - 2003
Spirometry and maximal respiratory pressures are pulmonary function parameters commonly used to evaluate respiratory function. Prediction values are available for conventional lung function devices using a standard tube or flanged type of mouthpiece connection. This equipment is not suitable for patients with facial or buccal muscle weakness, because of air ...
Weiner Paltiel - - 2003
BACKGROUND: It is well documented that the perception of dyspnea (POD), subjectively reported by patients, is an important index used to guide treatment. The severity of dyspnea following methacholine-induced bronchoconstriction and added mechanical loads is increasing in popular. No formal attention has been addressed to the reduction in dyspnea following ...
Albaiceta Guillermo M - - 2003
OBJECTIVE: To evaluate a new technique for pressure-volume curve tracing. DESIGN: Prospective experimental study. SETTING: Animal research laboratory. SUBJECTS: Six anesthetized rats. INTERVENTIONS: Two pressure-volume curves were obtained by means of the super-syringe method (gold standard) and the continuous positive airway pressure (CPAP) method. For the CPAP method, the ventilator ...
DePalo Vera A - - 2004
The diaphragm and abdominal muscles can be recruited during nonrespiratory maneuvers. With these maneuvers, transdiaphragmatic pressures are elevated to levels that could potentially provide a strength-training stimulus. To determine whether repeated forceful nonrespiratory maneuvers strengthen the diaphragm, four healthy subjects performed sit-ups and biceps curls 3-4 days/wk for 16 wk ...
Kallet Richard H - - 2003
The interpretation of P-V curves is uncertain for several reasons: the influence of chest wall compliance, differences in regional lung compliance and intrapulmonary gas distribution, lung volume history, lung recruitment beyond the LIP, peripheral airway fluid movement, expiratory-flow limitation, differences between inflation and deflation limb characteristics, and interobserver variability in ...
Albaiceta Guillermo M - - 2003
OBJECTIVE: To assess the differences in the deflation pressure-volume (PV) curves between acute respiratory distress syndrome from pulmonary (ARDSp) and extrapulmonary (ARDSe) origin. DESIGN:. Prospective study. SETTING: Twenty-bed intensive care unit in an university hospital. PATIENTS: Ten patients within the first 24 h from meeting ARDS criteria, classified as ARDSp ...
Contador Renata S - - 2003
To develop a reproducible model of atelectasis, 15 mechanically ventilated Wistar rats were wrapped around the thorax/abdomen with a sphygmomanometer. The cuff was inflated to transpulmonary pressures (PL) of -4 cmH2O (group A) and -8 cmH2O (group B) for 5 sec. Group C was not compressed. Airflow, volume, tracheal and ...
Maggiore S M - - 2003
Mechanical impairment of the respiratory system was recognised soon after the description of acute respiratory distress syndrome. The analysis of the pressure/volume (P/V) curve of the respiratory system contributed a lot to the understanding of the pathophysiology of acute lung injury and formed the basis for lung protection. The lower ...
Mehta Sangeeta - - 2003
OBJECTIVES: To assess the reproducibility of the static pressure-volume curve of the respiratory system by using a "mini-syringe" technique; to assess the temporal change in upper (UIP) and lower inflection points (LIP) measured from pressure-volume curves of the respiratory system; to assess the inter- and intraobserver variability in detection of ...
Unoki Takeshi - - 2003
INTRODUCTION: Expiratory rib cage compression is a chest physiotherapy technique known as "squeezing" technique in Japan. It has been claimed that rib cage compression effectively treats and/or prevents lung collapse, but no studies have been reported on rib cage compression focused on improving ventilation and/or oxygenation in subjects with collapsed ...
Pereira Cécile - - 2003
To assess incidence and magnitude of the "lower inflection point" of the chest wall, the sigmoidal equation was used in 36 consecutive patients intubated and mechanically ventilated with acute lung injury (ALI). They were 21 primary and 5 secondary ALI, 6 unilateral pneumonia, and 4 cardiogenic pulmonary edema. The lower ...
Man William D-C - - 2003
Maximal expiratory mouth pressure is a well established test that is used to assess expiratory muscle strength. However, low values are difficult to interpret, as they may result from technical difficulties in performing the test, particularly in patients with facial muscle weakness or bulbar dysfunction. We hypothesized that measuring the ...
Vassiliou M P - - 2003
BACKGROUND/AIMS: Laparoscopic cholecystectomy is accompanied by significant increase of the respiratory system elastic and resistive properties. These changes are completely abolished after peritoneal deflation. In the present study we examine the volume and flow dependence of respiratory mechanics during four operation phases. METHODOLOGY: Airway pressure and flow were recorded from ...
Rohdin M - - 2003
Both in normal subjects exposed to hypergravity and in patients with acute respiratory distress syndrome, there are increased hydrostatic pressure gradients down the lung. Also, both conditions show an impaired arterial oxygenation, which is less severe in the prone than in the supine posture. The aim of this study was ...
Iiyori Nao - - 2003
Short-term chest compression has been shown to decrease tidal volume and increase respiratory frequency. The present study was designed to assess and characterize the effect of long-term chest compression on breathing pattern and blood gases in awake rats. Chest compression was carried out by inflating a pneumatic cuff placed around ...
de Dios Escolar Juan - - 2003
The bronchus is an imperfect elastic structure because part of the energy transmitted in inspiration is not recovered in expiration. This phenomenon is known as bronchial hysteresis. The aim of this paper is to demonstrate bronchial hysteresis using morphometric techniques: differences in the wall and the bronchial lumen, between inspiration ...
Takayama Tetsuro - - 2003
BACKGROUND: Patients with severe pulmonary emphysema have a greatly increased oxygen cost of breathing (O(2) cost), and this is the cause of serious malnutrition, or respiratory cachexia, in such patients. STUDY OBJECTIVES: To clarify the effect of lung volume reduction surgery (LVRS) on respiratory function and the nutritional state of ...
Hantos Zoltán - - 2003
A tracking impedance estimation technique was developed to follow the changes in total respiratory impedance (Zrs) during slow total lung capacity maneuvers in six anesthetized and mechanically ventilated BALB/c mice. Zrs was measured with the wave-tube technique and pseudorandom forced oscillations at nine frequencies between 4 and 38 Hz during ...
Klein Wilfried - - 2003
The surgical removal of the post-hepatic septum (PHS) in the tegu lizard, Tupinambis merianae, significantly reduces resting lung volume (V(Lr)) and maximal lung volume (V(Lm)) when compared with tegus with intact PHS. Standardised for body mass (M(B)), static lung compliance was significantly less in tegus without PHS. Pleural and abdominal ...
Girgis Reda E - - 2003
A deficiency in airway nitric oxide (NO) could contribute to pulmonary vaso-occlusion in sickle cell disease (SCD). We measured the fractional expired concentration of NO (FE(NO)) by chemiluminescence during a slow vital capacity maneuver against a positive pressure of 16 cm H(2)O at an expiratory flow rate of 50 mL/sec ...
Lausberg Henning F - - 2003
BACKGROUND: The crippling effects of emphysema are due in part to dynamic hyperinflation, resulting in altered respiratory mechanics, an increased work of breathing, and a pervasive sense of dyspnea. Because of the extensive collateral ventilation present in emphysematous lungs, we hypothesize that placement of stents between pulmonary parenchyma and large ...
Sedeek Khaled A - - 2003
OBJECTIVE: High-frequency oscillation has been proposed for use in adult acute respiratory distress syndrome. However, limited data are available on the effect of pressure amplitude and rate (Hz) on tidal volumes delivered during high-frequency oscillation in adults. DESIGN: Prospective, animal model, lung injury study. SETTING: Large-animal laboratory of a university-affiliated ...
Escolar J D - - 2003
The resistance to airflow that develops in most obstructive processes takes place in the small airways. The aim of the present paper is to describe bronchial hysteresis morphometrically in a respiratory cycle model. As a working hypothesis, it is proposed that the changes that take place in the respiratory tract ...
Gronkvist Mikael - - 2003
This study assessed the effects of increased gravity in the head-to-foot direction (+G(z)) and anti-G suit (AGS) pressurization on functional residual capacity (FRC), the volume of trapped gas (V(TG)), and ventilation distribution by using inert- gas washout. Normalized phase III slope (Sn(III)) analysis was used to determine the effects on ...
Díaz O - - 2002
Two previous uncontrolled studies have suggested that noninvasive mechanical ventilation (NIMV) in patients with hypercapnic chronic obstructive pulmonary disease (COPD) improves arterial blood gas tensions by decreasing lung hyperinflation with the consequent reduction in inspiratory loads and changes in ventilatory pattern. The aim of this randomised placebo-controlled study was to ...
Loer S A - - 2002
During partial liquid ventilation perfluorocarbons are eliminated mainly by evaporation via the airways. The effects of intrapulmonary perfluorocarbon volume, respiratory rate, tidal volume, as well as the level of end-expiratory pressure on perfluorocarbon elimination from isolated lungs, were studied. Nonperfused rabbit lungs underwent partial liquid ventilation (2-15 mL x kg(-1) ...
Lum Sooky - - 2002
While the use of the raised volume rapid thoraco-abdominal compression (RVRTC) technique has been shown to provide new insights into airway and pulmonary pathophysiology in infants, and appears to resemble the spirometric techniques used in older subjects, there is as yet no consensus regarding measurement procedures, which are known to ...
Prisk G Kim - - 2003
The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (Va/Q) inequality in the lung. To further validate this estimate, we examined three measures of Va/Q inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions ...
Ingenito Edward P - - 2003
Bronchoscopic lung volume reduction (BLVR), a minimally invasive procedure based on tissue engineering principles, was performed in six sheep with papain-induced experimental emphysema (EMPH). Physiologic measurements, at baseline, after generation of EMPH, and at 3 and 9 weeks after BLVR, included lung volumes, diffusing capacity (DL(CO)), pressure-volume relationships for the ...
Aliverti A - - 2003
To estimate diaphragm fiber length from thoracoabdominal configuration, we measured axial motion of the right-sided area of apposition by ultrasonography and volumes displaced by chest wall compartments [pulmonary, abdominal rib cage, and abdomen (Vab)] by optoelectronic plethysmography in four normal men during quiet breathing and incremental exercise without and with ...
Villars Penelope S - - 2002
Like the windbag of a bagpipe, the functional residual capacity (FRC) is the lung volume that acts as a reservoir of air for physiologic use. This reserve volume is particularly important during the period of apnea that occurs during induction of general anesthesia. The balance of the inward elastic recoil ...
Lundblad Lennart K A - - 2002
Presently, unrestrained plethysmography is widely used to assess bronchial responsiveness in mice. An empirical quantity known as enhanced pause is derived from the plethysmographic box pressure [P(b)(t), where t is time] and assumed to be an index of bronchoconstriction. We show that P(b)(t) is determined largely by gas conditioning when ...
Ingenito Edward P - - 2003
This paper examines potential physiological mechanisms responsible for improvement after lung volume reduction surgery (LVRS). In 25 patients (63 +/- 9 yr; 11 men, 14 women), spirometry [forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC)], lung volumes [residual volume (RV) and total lung capacity (TLC)], small ...
Ganzert Steven - - 2002
We present a case study of machine learning and data mining in intensive care medicine. In the study, we compared different methods of measuring pressure-volume curves in artificially ventilated patients suffering from the adult respiratory distress syndrome (ARDS). Our aim was to show that inductive machine learning can be used ...
Man W D C - - 2002
Twitch transdiaphragmatic pressure (Pdi,tw), measured following magnetic stimulation of the phrenic nerves, is used to assess diaphragm strength, contractility and fatigue. Although the effects of posture, lung volume and potentiation on Pdi,tw are well described, it is not known whether the degree of gastric filling affects the measurement. Pdi,tw was ...
Topulos George P - - 2002
Increased surface tension is an important component of several respiratory diseases, but its effects on pulmonary capillary mechanics are incompletely understood. We measured capillary volume and specific compliance before and after increasing surface tension with nebulized siloxane in excised dog lungs. The change in surface tension was sufficient to increase ...
Bettinelli D - - 2002
The volume-pressure relationship of the lung was studied in six subjects on changing the gravity vector during parabolic flights and body posture. Lung recoil pressure decreased by approximately 2.7 cmH(2)O going from 1 to 0 vertical acceleration (G(z)), whereas it increased by approximately 3.5 cmH(2)O in 30 degrees tilted head-up ...
Sly Peter D - - 2003
We measured respiratory input impedance (1-25 Hz) in mice and obtained parameters for airway and tissue mechanics by model fitting. Lung volume was varied by inflating to airway opening pressure (Pao) between 0 and 20 cm H2O. The expected pattern of changes in respiratory mechanics with increasing lung volume was ...
Wood Brian - - 2002
OBJECTIVES: To evaluate the use of specific compliance (static compliance/functional residual capacity) to adjust mean airway pressure, resulting in optimal gas exchange during high-frequency oscillatory ventilation in a surfactant-deficient newborn piglet. DESIGN: Prospective controlled animal study. SETTING: Laboratory. SUBJECTS: Eight newborn piglets at 5 days of age. BACKGROUND: High-frequency oscillatory ...
Fine Gavin F - - 2002
The administration of rapacuronium increases the risk of severe bronchospasm. There have been no studies of pulmonary function directly demonstrating airway constriction with rapacuronium in children. In this study, 10 ASA physical status I or II patients (aged 2-6 yr) were randomly divided into 2 equal groups, receiving either rapacuronium ...
Kauczor Hans-Ulrich - - 2002
The purpose of this prospective study was to measure lung attenuation at paired HRCT obtained at full inspiratory/expiratory position, to correlate with pulmonary function tests (PFTs) and to characterize different types of ventilatory impairment. One hundred fifty-five patients with and without pulmonary disease underwent paired HRCT obtained at full inspiratory/expiratory ...
Bellemare François - - 2002
STUDY OBJECTIVES: To determine the effect of emphysema and lung volume reduction surgery (LVRS) on diaphragm length (Ldi) and its capacity to generate transdiaphragmatic pressure (Pdi). DESIGN: Prospective clinical trial with a parallel group design. SETTING: Laboratory investigations in normal volunteers recruited by advertisement and in emphysema outpatients being evaluated ...
Servillo Giuseppe - - 2002
OBJECTIVE: The pressure-volume (P/V) curve has been proposed as a tool to adjust the ventilatory settings in cases of acute respiratory distress syndrome (ARDS). The aim of this study was to test the influence of P/V tracing methodology on the presence and value of the upper inflection point (UIP). METHODS: ...
Lemaître F - - 2002
Long term effects on respiratory function have been found in adult professional divers and have indicated the development of small-airway disease. The aim of this report was to investigate pulmonary lung function and breathing pattern of recreational divers, especially in young subjects. Pulmonary function was measured in 84 air divers ...
Tantucci Claudio - - 2002
Recently, it has been suggested that peak expiratory flow (PEF) may be determined by the wave speed flow-limiting mechanism. In six normal male subjects (age = 33 +/- 8 years) performing expiratory forced vital capacity (FVC) maneuvers, a negative expiratory pressure (NEP) of -10 cm H2O was randomly applied at ...
Lee Warren L - - 2002
STUDY OBJECTIVES: To assess the safety of frequent pressure-volume (PV) curve measurement in patients with acute lung injury (ALI)/ARDS. DESIGN: Prospective observational study. SETTING: Academic medical-surgical critical care unit. PATIENTS: Consecutive patients with ALI or ARDS. INTERVENTIONS: Static inspiratory PV curves of the respiratory system were determined twice on day ...
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