Search Results
Results 501 - 550 of 1429
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Mercat A - - 2001
OBJECTIVE: To assess the short-term effects of extending inspiratory time by lengthening end-inspiratory pause (EIP) without inducing a clinically significant increase in intrinsic positive end-expiratory pressure (PEEPi) in patients with acute respiratory distress syndrome (ARDS). DESIGN: Controlled, randomized, crossover study. SETTING: Two medical intensive care units of university hospitals. PATIENTS: ...
Khirani S - - 2001
Patients suffering from chronic obstructive pulmonary diseases, frequently exhibit expiratory airflow limitation. We propose a mathematical model describing the mechanical behavior of the ventilated respiratory system. This model has to simulate applied positive end-expiratory pressure (PEEP) effects during expiration, a process used by clinicians to improve airflow. The proposed model ...
Hickling K G - - 2001
A mathematical model of the acute respiratory distress syndrome (ARDS) lung, incorporating simulated gravitational superimposed pressure and alveolar opening and closing pressures, was used to study the mean tidal pressure-volume (PV) slope ("effective compliance") during incremental and decremental positive end-expiratory pressure (PEEP) trials with constant tidal volume (VT) "ventilation." During ...
Mols G - - 2001
OBJECTIVE: Volume-dependent alterations of lung compliance are usually studied over a very large volume range. However, the course of compliance within the comparably small tidal volume (intratidal compliance-volume curve) may also provide relevant information about the impact of mechanical ventilation on pulmonary gas exchange. Consequently, we determined the association of ...
Lichtwarck-Aschoff M - - 2000
Between the lower and the upper inflection point of a quasistatic pressure-volume (PV) curve, a segment usually appears in which the PV relationship is steep and linear (i.e., compliance is high, with maximal volume change per pressure change, and is constant). Traditionally it is assumed that when positive end-expiratory pressure ...
Rafferty G F - - 2000
A nonvolitional test to assess diaphragm strength in neonates has not been previously described. Our aim was to assess the feasibility of cervical (CMS) and anterior (AMS) magnetic stimulation of the phrenic nerves in neonates. Double circular stimulating coils (90-mm) were used. For CMS, one coil was placed over the ...
Vitacca M - - 2000
STUDY OBJECTIVE: To evaluate the short-term physiologic effects of two settings of nasal pressure-support ventilation (NPSV) in stable COPD patients with chronic hypercapnia. DESIGN: Randomized controlled physiologic study. SETTING: Lung function units and outpatient clinic of two affiliated pulmonary rehabilitation centers. PATIENTS: Twenty-three patients receiving domiciliary nocturnal NPSV for a ...
Hartog A - - 2000
The use of a ventilation strategy with high positive end-expiratory pressure (PEEP) that is intended to recruit collapsed alveoli and to prevent recurrent collapse can reduce alveolar protein influx in experimental acute lung injury (ALI). This could affect the pulmonary response to treatment with surfactant, since plasma proteins inhibit surfactant ...
Lu Q - - 2000
This study was directed at assessing changes in bronchial cross-sectional surface areas (BCSA) and in respiratory resistance induced by endotracheal suctioning in nine anesthetized sheep. Cardiorespiratory parameters (Swan-Ganz catheter), respiratory resistance (inspiratory occlusion technique), BCSA, and lung aeration (computed tomography) were studied at baseline, during endotracheal suctioning, and after 20 ...
Teboul J L - - 2000
OBJECTIVE: When positive end-expiratory pressure (PEEP) is applied, the intracavitary left ventricular end-diastolic pressure (LVEDP) exceeds the LV filling pressure because pericardial pressure exceeds 0 at end-expiration. Under those conditions, the LV filling pressure is itself better reflected by the transmural LVEDP (tLVEDP) (LVEDP minus pericardial pressure). By extension, end-expiratory ...
Chaney M A - - 2000
OBJECTIVE: To ascertain if protective ventilation can attenuate the damaging postoperative pulmonary effects of cardiopulmonary bypass (increases in airway pressure, decreases in lung compliance, and increases in shunt). DESIGN: Prospective, randomized clinical trial. SETTING: Single university hospital. PARTICIPANTS: Twenty-five patients undergoing elective coronary artery bypass graft procedure and early extubation. ...
Haitsma J J - - 2000
OBJECTIVES: To determine the effect on compartmentalization of the tumor necrosis factor (TNF)-alpha response in the lung and systemically after ventilation with high peak inspiratory pressure with and without positive end-expiratory pressure (PEEP). DESIGN AND SETTING: Prospective, randomized, animal study in an experimental laboratory of a university. SUBJECTS AND INTERVENTIONS: ...
Lichtwarck-Aschoff M - - 2000
The lower inflection point (LIP) of the inspiratory limb of a static pressure-volume (PV) loop is assumed to indicate the pressure at which most lung units are recruited. The LIP is determined by a static manoeuvre with a PV-history that is different from the PV-history of the actual ventilation. In ...
Nakajima Y - - 2000
Mild hypothermia is a major concomitant of surgery under general anesthesia. We examined the hypothesis that baroreceptor loading/unloading modifies thermoregulatory peripheral vasoconstriction and, consequently, body core temperature in subjects undergoing lower abdominal surgery with general anesthesia. Thirty-six patients were divided into four groups: control group (C), applied positive end-expiratory pressure ...
Dinger J - - 2000
BACKGROUND/PURPOSE: Congenital diaphragmatic hernia (CDH) is associated with pulmonary hypoplasia that limits survival. The authors' knowledge on lung mechanics and lung volumes in these patients with hypoplastic lungs is still limited. Therefore, the authors performed measurements of functional residual capacity (FRC), compliance of the respiratory system (CRS), and tidal volume ...
Fessler H E - - 2000
Patients undergoing partial liquid ventilation (PLV) are often monitored with pulmonary artery catheters and receive positive end-expiratory pressure (PEEP). PEEP can dissociate wedge pressure (Pcw) from transmural left atrial pressure (Platm) by elevating pleural pressure and can dissociate Pcw from Pla by elevating alveolar pressure, PLV, like PEEP, also elevates ...
Miro A M - - 2000
OBJECTIVE: The major benefit of tracheal gas insufflation (TGI) is an increase in CO2 elimination efficiency by removal of CO2 from the anatomical deadspace. In conjunction with mechanical ventilation, TGI may also alter variables that affect CO2 elimination, such as minute ventilation and peak airway pressure (peak Paw) and cause ...
Sigurdsson S - - 2000
BACKGROUND: In acute respiratory distress syndrome, lung volume is lost immediately after positive end-expiratory pressure (PEEP) is removed and is not immediately regained when PEEP is restored to its original value. The aim of this study was to investigate whether the same phenomenon also occurs in cardiopulmonary healthy individuals during ...
Lawson R W RW Department of Respiratory Care, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA. - - 2000
To evaluate the effects of fiberoptic bronchoscopy (FOB) on delivered volumes and pressures during mechanical ventilation, utilizing a lung model. Bench study. Laboratory. Using varying-sized endotracheal tubes (ETTs), we ventilated a lung model at two levels of compliance utilizing different modes and parameters of ventilation. After establishing baseline measurements, the ...
Kallet R H - - 2000
BACKGROUND: Positive end-expiratory pressure (PEEP) may interfere with accurate assessment of cardiac function. PEEP may decrease left ventricular volume by lowering the transmural gradient between ventricular and pleural surface pressure (P(PL)) around the heart while raising the absolute pulmonary arterial occlusion pressure (PAOP). Clinical formulas used to predict the transmural ...
Suh G Y - - 2000
PURPOSE: The purpose of this article is to evaluate the effect of positive end-expiratory pressure (PEEP) during partial liquid ventilation (PLV) and to investigate if lung damage associated with mechanical ventilation can be reduced by PLV. MATERIALS AND METHODS: Twenty-two New-Zealand white rabbits were ventilated in pressure-controlled mode maintaining constant ...
Guerin C - - 2000
OBJECTIVE: To study the effects of PEEP on the inspiratory work done per breath on the respiratory system (W(I,rs)) in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Physiological study. SETTING: Fourteen-bed Medical ICU of a 1,000-bed teaching tertiary hospital. PATIENTS AND PARTICIPANTS: Ten patients with COPD intubated and mechanically ...
Girardis M M Cattedra di Anestesiologia e Rianimazione and Cattedra di Fisiologia Umana, Università degli Studi di Udine, Italy. - - 2000
We evaluated the effects of tourniquet application on the cardiovascular system and metabolism in 10 young men undergoing knee surgery with general anesthesia. The duration of inflation was from 75 to 108 min. Heart rate, mean arterial pressure, cardiac index (CI) by pulse contour method, and systemic vascular resistance were ...
Williams E M - - 2000
Tidal ventilation causes within-breath oscillations in alveolar oxygen concentration, with an amplitude which depends on the prevailing ventilator settings. These alveolar oxygen oscillations are transmitted to arterial oxygen tension, PaO2, but with an amplitude which now depends upon the magnitude of venous admixture or true shunt, QS/QT. We investigated the ...
Gomes R F - - 2000
Because of the wide utilization of rodents as animal models in respiratory research and the limited data on measurements of respiratory input impedance (Zrs) in small animals, we measured Zrs between 0.25 and 9.125 Hz at different levels (0-7 hPa) of positive end-expiratory pressure (PEEP) in mice, rats, guinea pigs, ...
Vassiliou M P - - 2000
OBJECTIVE: Linear modeling as a method of exploring respiratory mechanics during mechanical ventilation, was compared to nonlinear modeling for flow dependence of resistance in three distinct groups of patients, those with: (a) normal respiratory function (NRF), (b) chronic obstructive pulmonary disease (COPD), or (c) adult respiratory distress syndrome (ARDS). DESIGN ...
Antonaglia V - - 2000
Viscoelasticity represents an important component of respiratory mechanics, being responsible, in some cases, for most of the pressure dissipated during breathing. Hitherto the methods available for determining the viscoelastic properties have been simplified, but are still time-demanding and depend on a great deal of calculation. In this study, a simple ...
Hoffman L A - - 2000
In mechanically ventilated adults with acute respiratory distress syndrome (ARDS), peak airway pressures (Paw(peak)) above 35 cm H(2)O may increase the risk of barotrauma or volutrauma. Tracheal gas insufflation (TGI), an adjunctive ventilatory technique, may facilitate a reduction in set inspiratory pressure in these patients, and thereby in the tidal ...
Fujino Y - - 2000
Partial liquid ventilation (PLV) improves oxygenation in several models of lung injury. However, PLV has only been compared with conventional gas ventilation (GV) with low PEEP. Both PLV and GV can markedly improve oxygenation when PEEP is set above the lower corner pressure (Plc) on the inspiratory pressure-volume (P-V) curve ...
Tassaux D - - 2000
OBJECTIVE: To test the hypothesis that replacing 70:30 nitrogen: oxygen (Air-O2) with 70:30 helium:oxygen (He-O2) can decrease dynamic hyperinflation ("intrinsic" positive end-expiratory pressure) in mechanically ventilated patients with chronic obstructive pulmonary disease (COPD), and to document the consequences of such an effect on arterial blood gases and hemodynamics. DESIGN: Prospective, ...
Mancebo J - - 2000
BACKGROUND: Although the use of external positive end-expiratory pressure (PEEP) is recommended for patients with intrinsic PEEP, no simple method exists for bedside titration. We hypothesized that the occlusion pressure, measured from airway pressure during the phase of ventilator triggering (P0.1t), could help to indicate the effects of PEEP on ...
Murphy D B - - 2000
Accumulating evidence strongly suggests that ventilatory strategy has an important impact on development of lung injury and patient outcome. Adverse ventilatory strategies have been shown to cause release of pulmonary-derived cytokines and may permit bacterial translocation from the lung to the systemic circulation. Because endotoxin is a potent and clinically ...
Chelucci G L - - 2000
OBJECTIVE: To assess the effects of the association of positive end-expiratory pressure (PEEP) with different inflation volumes (V(T)'s) on passive lung deflation and alveolar recruitment in ARDS patients. DESIGN: Clinical study using PEEP with two different V(T)'s and analyzing whether passive lung deflation and alveolar recruitment (Vrec) depend on end-inspired ...
Mutch W A - - 2000
OBJECTIVES: We compared biologically variable ventilation (BVV) (as previously described) (1) with conventional control mode ventilation (CV) in a model of acute respiratory distress syndrome (ARDS) both at 10 cm H2O positive end-expiratory pressure. DESIGN: Randomized, controlled, prospective study. SETTING: University research laboratory. SUBJECTS: Farm-raised 3- to 4-month-old swine. INTERVENTIONS: ...
Cakar N - - 2000
Prone position and recruitment maneuvers (RM) are proposed as adjuncts to mechanical ventilation to open up the lung and keep it open. We studied the oxygenation response to a RM (composed of a 30-s sustained inflation at 60 cm H(2)O airway pressure) performed in prone and supine positions in dogs ...
Krenn C G - - 2000
OBJECTIVE: To determine the impact of positive end-expiratory pressure (PEEP) ventilation on hemodynamics and a clinical test for assessment of dynamic liver performance in patients undergoing orthotopic liver transplantation (OLT). DESIGN: Prospective, descriptive patient study. SETTING: University hospital intensive care unit. PATIENTS: A total of 25 patients after OLT. INTERVENTIONS: ...
Malbouisson L M - - 2000
In the acute respiratory distress syndrome (ARDS), lower lobes appear essentially non-aerated in contrast to upper lobes whose aeration can be preserved in some patients. The aim of this study was to assess the mechanical compression exerted by the heart on lower lobes in patients with ARDS. Fourteen healthy volunteers ...
Iwama H - - 2000
PURPOSE: The aim of this study was to examine whether the epidural pressure (EPIP) can be monitored for a long period of time using the continuous epidural infusion via the lower thorax. MATERIALS AND METHODS: Twenty-one adult patients undergoing gastrointestinal surgery had an epidural catheter inserted via the lower thoracic ...
Okamoto K - - 2000
We studied the combined effects of inhaled nitric oxide (INO) and positive end expiratory pressure (PEEP) during mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). Eleven patients received 0 and 4 parts per million of INO in random order for 30 min at PEEP levels of 0, 5, ...
Koutsoukou A - - 2000
It has been suggested that in patients with adult respiratory distress syndrome (ARDS), intrinsic positive end-expiratory pressure (PEEPi) is generated by a disproportionate increase in expiratory flow resistance. Using the negative expiratory pressure (NEP) technique, we assessed whether expiratory flow limitation (EFL) and PEEPi were present at zero PEEP in ...
Neumann P - - 2000
Continuous as well as cyclic (with each expiration) lung collapse in acute respiratory failure can be reduced by positive end-expiratory pressure (PEEP) or short expiration times, as in inverse ratio ventilation (IRV). In 20 pigs with oleic acid-induced lung edema, we compared the effects of a PEEP of 20 cm ...
Janssens J P - - 2000
Progression of chronic obstructive pulmonary disease (COPD) is frequently associated with increasing dyspnea; indeed, patients with severe COPD constitute the largest group of patients with chronic respiratory insufficiency. The sensation of dyspnea in these patients is mostly related to increased work of breathing, a consequence of an increased resistive load, ...
Yamaguchi N - - 2000
OBJECTIVE: To assess whether the delivered nitric oxide (NO) concentration is affected by a change in the ventilatory setting during neonatal mechanical ventilatory support. DESIGN: Prospective, experimental study. SETTING: Laboratory at Nagoya City University Medical School. INTERVENTIONS: This study was performed by using a pressure-limited, time-cycled, ventilatory support with a ...
Kloot T E - - 2000
Recruitment maneuvers (RM), consisting of sustained inflations at high airway pressures, have been advocated as an adjunct to mechanical ventilation in acute respiratory distress syndrome (ARDS). We studied the effect of baseline ventilatory strategy and RM on end-expiratory lung volume (EELV) and oxygenation in 18 dogs, using three models of ...
Chin C - - 2000
To evaluate surfactant and positive end-expiratory pressure (PEEP) as potential therapies for the acute lung injury after tracheal instillation of 0.8 ml kg-1 human breast milk (HBM) acidified to pH 1.8, adult white rabbits were anaesthetized, tracheostomized, ventilated and randomized to (six rabbits per treatment): (i) no treatment after HBM ...
Foti G - - 2000
OBJECTIVE: We wished to investigate whether volume recruitment maneuvers (VRMs) could improve alveolar recruitment and oxygenation in acute respiratory distress syndrome (ARDS) patients, ventilated at relatively low positive end-expiratory pressure (PEEP). SETTING: General intensive care unit (ICU) located in a teaching hospital. PATIENTS: 15 PEEP responder ARDS patients undergoing continuous ...
Aliverti A - - 2000
We used optoelectronic plethysmography to study 11 normal subjects during quiet and deep breathing, six sedated and paralyzed patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS) receiving continuous positive pressure ventilation (CPPV) (positive end-expiratory pressure [PEEP] = 10 cm H(2)O, tidal volume [VT] = 300, 600, 900 ...
Johannigman J A - - 2000
BACKGROUND: Inhaled nitric oxide (INO) has been shown to improve oxygenation in two thirds of patients with acute respiratory distress syndrome (ARDS). Failure to respond to INO is multifactorial. We hypothesized that the addition of positive end expiratory pressure (PEEP) might modify the response to INO in patients who had ...
Medoff B D - - 2000
OBJECTIVE: To present the use of a novel high-pressure recruitment maneuver followed by high levels of positive end-expiratory pressure in a patient with the acute respiratory distress syndrome (ARDS). DESIGN: Observations in one patient. SETTING: The medical intensive care unit at a tertiary care university teaching hospital. PATIENT: A 32-yr-old ...
Max M - - 2000
BACKGROUND: Partial liquid ventilation, positive end-expiratory pressure (PEEP) and inhaled nitric oxide (NO) can improve ventilation/perfusion mismatch in acute lung injury (ALI). The aim of the present study was to compare gas exchange and hemodynamics in experimental ALI during gaseous and partial liquid ventilation at two different levels of PEEP, ...
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