Search Results
Results 851 - 900 of 2050
< 13 14 15 16 17 18 19 20 21 22 23 >
Jones Stephanie B - - 2004
STUDY OBJECTIVE: To determine whether, in maintaining normovolemia during acute normovolemic hemodilution, replacement fluid choice influences intraoperative hemodynamic variables. DESIGN: Prospective, randomized, single-blinded study. SETTING: Operating room of a tertiary-care university hospital. PATIENTS: 40 adult, ASA physical status I, II, and III patients scheduled for acute normovolemic hemodilution during radical ...
Henze Dirk - - 2004
OBJECTIVE: The goal of this study was to investigate the reliability of the multi-parameter sensor NeuroTrend in a hyperbaric environment for up to 3bar absolute pressure. Measurement of brain tissue oxygenation (ptiO2) under hyperbaric conditions is supposed to elucidate whether hyperbaric oxygenation therapy has the potential to improve ptiO2 to ...
Vespa Paul M - - 2004
INTRODUCTION: Aneurysmal subarachnoid hemorrhage (SAH) affects 30,000 patients per year, causing neurologic morbidity and mortality. The etiology of hypoxemia and its role in comorbidity are controversial and unknown. PURPOSE: To identify the incidence and etiologies of oxygenation abnormalities following SAH and to determine its impact on length of hospital stay ...
Zeis Bettina - - 2004
Daphnia magna responds to changing environmental conditions impeding aerobic metabolism by synthesizing hemoglobin of adequate quantity and quality to maintain oxygen supply of the tissues. Hemoglobin subunit composition and its oxygen affinity were analyzed as a function of temperature as well as depending on the oxygen partial pressure of the ...
Patzer John F JF - - 2004
Oxygen consumption dynamics in a hollow fiber, hepatocyte-loaded bioartificial liver are investigated both theoretically and experimentally. The theoretical model is based upon the Krogh cylinder, which approximates the bioreactor as a collection of cylindrical elements comprised of an inner fiber lumen for media perfusion, the fiber wall through which oxygen ...
Greenlee Kendra J - - 2004
We tested the hypothesis that oxygen delivery from the atmosphere to the tissues becomes more difficult as grasshoppers increase in body size throughout development due to increases in tracheal length. If this is true, then older, larger grasshoppers should have smaller safety margins [higher critical oxygen partial pressures (P(O2)s)] for ...
Compañ V - - 2004
The instrument oxygen transmissibility (IOT) of organosilicon hydrogels, measured by electrochemical procedures, is 5-10 times larger than that of conventional hydrogels. A method is described that allows the estimation of the oxygen tension at the lens-cornea interface for closed- and open-eyelids situations by combining the IOT of the hydrogels and ...
Renner Markus - - 2004
Breathing 100% oxygen at the end of general anesthesia has been shown to worsen postoperative pulmonary gas exchange when an endotracheal tube is used. Counter measures, such as high positive end-expiratory pressure or the vital-capacity maneuver, may limit this effect. Such strategies, however, may be impracticable, or even contraindicated, when ...
Pypendop Bruno H - - 2004
OBJECTIVE: To determine hemodynamic effects of 3 concentrations of sevoflurane in cats. ANIMALS: 6 cats. PROCEDURE: Cats were anesthetized with sevoflurane in oxygen. After instruments were inserted, end-tidal sevoflurane concentration was set at 1.25, 1.5, or 1.75 times the individual minimum alveolar concentration (MAC), which was determined in another study. ...
Horowitz Michal - - 2003
Heat acclimation enhances cardiac efficiency by increasing stroke volume and decreasing heart rate. These adaptations involve biochemical changes in the contractile apparatus, switched on by altered expression of genes coding contractile and calcium-regulatory proteins and partially mediated by persistent low thyroxine. Heat acclimation also produces cross-tolerance to oxygen deprivation, thus ...
Coggrave M J - - 2003
Description of a clinical service, evaluation of pressure relief practices. To describe a specialist seating assessment clinic and a change in clinical practice arising from its work. National Spinal Injuries Centre, Stoke Mandeville Hospital, UK. Retrospective review of the ischial transcutaneous oxygen measurements of 50 newly injured and chronic spinal ...
Sasaki Hideaki - - 2003
PURPOSE: The aim of this investigation was to compare the efficiency of four oxygen delivery systems in healthy volunteers. METHODS: The subjects received oxygen at flow rates of 3.0 and 5.0 L*min(-1) via a face mask, nasal cannulae, and two kinds of new open- and microphone-type oxygen delivery systems (OxyArm(TM) ...
Morelli Andrea - - 2003
Critically-ill patients are at risk of developing renal disorders as a consequence of systemic hypoperfusion. Ischemic acute tubular necrosis and resulting acute renal failure are caused by hypotension or therapeutic management. In this study, we tested the change of O(2) availability induced by fenoldopam mesylate using the continuous measurement of ...
Hodges A N H - - 2003
OBJECTIVE: To examine venous partial pressure of oxygen (PvO(2)), transcutaneous oxygen tension (tcPO(2)), and VO(2)MAX in a normobaric environment after a single hyperbaric oxygen (HBO(2)) treatment. METHODS: This was a prospective study of conditions after the intervention compared with baseline. The participants were 10 moderately trained (VO(2)MAX = 57.6 ml/kg/min) ...
Kabon Barbara - - 2003
Intraoperative surgical stress may markedly increase adrenergic nerve activity and plasma catecholamine concentrations, which causes peripheral vasoconstriction and decreased tissue oxygen partial pressure possibly leading to tissue hypoxia. Tissue hypoxia is associated with an increased incidence of surgical wound infections. Thoracic epidural anesthesia blocks afferent neural stimuli and inhibits efferent ...
Sahoo Susmita - - 2003
Responses of bacterial (Bacillus subtilis) cells under different shear levels, from both the macro and genetic viewpoints, have been presented. The responses were studied using a novel, couette flow bioreactor (CFB), in which the entire cultivation can be performed under defined shear conditions. Oxygen supply, the normal limiting factor for ...
Wladis Andreas - - 2004
BACKGROUND: Hypothermia is occasionally employed to reduce the metabolic rate and to protect the brain in patients undergoing surgery, but it is controversial whether hypothermia (HT) is beneficial or harmful in trauma victims with soft-tissue injuries. For this purpose, we studied the acute effects of hypothermia induced after infliction of ...
Perez-de-Sá Valéria - - 2003
To assess the hemodynamic and metabolic effects of shivering during extreme normovolemic hemodilution, we anesthetized 16 pigs with fentanyl-midazolam-pancuronium. Mild hypothermia (36.5 degrees +/- 0.1 degrees C) was induced by surface cooling, and the animals were randomized to either a control group (hemoglobin 118 +/- 3 g/L) or a hemodilution ...
Goto Eiji - - 2003
In the present study, we examined carbohydrate contents of Arabidopsis thaliana seeds during seed development under hypobaric conditions in order to characterize the mechanism of low pressure-induced seed damage, and to determine critical pressures for seed development under low total and/or low oxygen partial pressures. We analyzed contents of starch, ...
Kohara Hiroyuki - - 2003
We evaluated the effect of ultrasonically nebulized furosemide (20 mg) on dyspnea uncontrollable by standard therapy in patients with terminal cancer. Dyspnea was evaluated using the Cancer Dyspnea Scale (CDS) before and 60 min after inhalation. Changes in arterial blood gases, hemoglobin oxygen saturation (SpO2), heart rate (HR), and respiratory ...
Létienne Robert - - 2003
The effects of naratriptan, rizatriptan, and sumatriptan on arteriovenous oxygen saturation difference and carotid hemodynamics were compared in the anesthetized pig. Oxygen and carbon dioxide partial pressures in systemic arterial and jugular venous blood as well as hemoglobin oxygen saturation were determined by conventional blood gas analysis. Vehicle (n = ...
Altshuler Douglas L - - 2003
Hovering flight is one of the most energetically demanding forms of animal locomotion. Despite the cost, hummingbirds regularly hover at high elevations, where flight is doubly challenging because of reduced air density and oxygen availability. We performed three laboratory experiments to examine how air density and oxygen partial pressure influence ...
Charles Nichola - - 2003
Enhanced oxygen delignification of softwood pulp samples (taken upstream and downstream of a commercial oxygen delignification unit) improved the initial rate of enzymatic saccharification and overall yield of monomeric sugars by 62-82% and 76-80%, respectively. Laboratory-scale experiments were used to examine the effect of a broad range of operating parameters ...
Buyse B - - 2003
Patients with kyposcoliosis and chronic respiratory insufficiency are treated either with home oxygen therapy or ventilation. Kyphoscoliotic patients demonstrate impaired ventilatory mechanics, consequently ventilation seems to be the treatment of choice. Yet, no randomised controlled trials (CRT) exist to prove it. Most investigators find it difficult to ethically justify a ...
Schaal Shlomit - - 2003
PURPOSE: To investigate the possible toxic effect of oxygen on lenses in an organ culture. METHODS: Bovine lenses were exposed to four different combinations of ambient pressure and oxygen concentration in an organ culture throughout a 7-day period. Lens transparency, histology, enzymatic activities, and photomicrographs were compared in study and ...
Miyachi Kenji - - 2003
The authors investigated the effects of felypressin (Fely), a non-adrenergic vasoconstrictor, used together with prilocaine on myocardial oxygen balance. Six open-chest dogs were studied under urethane and alpha-chloralose anesthesia. Systolic arterial pressure, diastolic arterial pressure, mean pulmonary arterial pressure and pulmonary capillary wedge pressure, heart rate, coronary blood flow (CBF), ...
Waring W Stephen - - 2003
Supplementary oxygen is commonly administered in current medical practice. However, attention has recently been drawn to the potentially disadvantageous hemodynamic consequences in certain patients. Possible mechanisms underlying the cardiovascular responses to acute hyperoxia are unclear. The effects of acute oxygen administration on heart rate, blood pressure, cardiac output, systemic vascular ...
Gainnier Marc - - 2003
OBJECTIVE: To evaluate whether helium-oxygen mixture reduces inspiratory work of breathing (WOB) in sedated, paralyzed, and mechanically ventilated patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). DESIGN AND SETTING: Open, prospective, randomized, crossover study in the medical intensive care unit in a university hospital. PATIENTS AND PARTICIPANTS: 23 ...
Jiang Shudong - - 2003
A diffuse near-infrared tomography system was used to measure dynamic changes in the absolute optical properties of the human breast that were induced through pressure applied to the tissue surface. Results from five subjects show that absorption and scattering coefficients changed measurably when pressure was increased and that these relative ...
Sprung Juraj - - 2003
Morbidly obese (MO) patients undergoing laparoscopy have lower PaO(2) compared with normal-weight (NW) patients. We hypothesized that increases in tidal volume (V(T)) or respiratory rate (RR) would improve oxygenation. All measurements were performed at: 1) baseline: V(T) 600-700 mL and 10 breaths/min, 2) double V(T): V(T) 1200-1400 mL and 10 ...
Abd-Allah Shamel A - - 2003
OBJECTIVE: To illustrate the use of helium-oxygen gas mixtures as therapy for pediatric patients with acute severe asthma requiring conventional mechanical ventilation. DESIGN: Retrospective review. SETTING: Tertiary care children's teaching hospital. PATIENTS: All mechanically ventilated patients with severe asthma admitted to the pediatric intensive care unit from August 1994 to ...
Arieli Ran - - 2003
Clinical hyperbaric oxygen (HBO) therapy and the use of pure oxygen or gases having a high partial pressure of oxygen in diving carry a risk of central nervous system (CNS) oxygen toxicity. Previously, we solved the power equation K = t2(PO2/101.3)C for humans, where t is the exposure time, PO2 ...
Whiteley J P - - 2003
The Grodins model of respiratory control (Grodins et al., 1967) describes cardio-respiratory control for a lung with homogeneous gas concentrations. In this study we modify the Grodins model to take account of the inhomogeneities in gas concentration within the lung that are seen in many subjects with respiratory illnesses. This ...
Treschan Tanja A - - 2003
The risk of wound infections is inversely related to subcutaneous tissue oxygen tension. General anesthesia increases local blood flow by direct vasodilation and central inhibition of thermoregulatory vasoconstriction. Epidural anesthesia can increase perfusion in blocked regions by decreasing sympathetic tone. We therefore tested the hypothesis that epidural anesthesia increases tissue ...
Akça O - - 2003
Postsurgical infection risk is correlated with subcutaneous tissue oxygenation. Mild hypercapnia augments cutaneous perfusion. We tested the hypothesis that peripheral tissue oxygenation increases as a function of arterial PCO2 in surgical patients. Twenty patients were randomly assigned to intra-operative end tidal PCO2 of 3.99 (control) or 5.99 kPa (hypercapnia). All ...
Wittenberg Jonathan B - - 2003
The heart and those striated muscles that contract for long periods, having available almost limitless oxygen, operate in sustained steady states of low sarcoplasmic oxygen pressure that resist change in response to changing muscle work or oxygen supply. Most of the oxygen pressure drop from the erythrocyte to the mitochondrion ...
Driessen Bernd - - 2003
OBJECTIVE: To compare effects of 6% hetastarch (Hextend) and hemoglobin-based oxygen carrier hemoglobin glutamer-200 (Hb-200) (bovine; Oxyglobin) on hemodynamics, arterial oxygen content, and systemic oxygen delivery in a canine hemorrhagic shock model. DESIGN: Randomized laboratory investigation. SETTING: University surgical research facility. SUBJECTS: Twenty-four anesthetized healthy, adult, mongrel dogs (28 +/- ...
Kottenberg-Assenmacher Eva - - 2003
BACKGROUND: To prevent neurologic damage, monitoring cerebral function by somatosensory evoked potentials is used in selected settings. Excision of intraocular melanoma provides a unique opportunity to assess independently during anesthesia the effects on median nerve somatosensory evoked potentials (MN-SSEPs) and cerebral oxygen extraction of sodium nitroprusside-evoked arterial hypotension with and ...
van Hulst Robert A - - 2003
OBJECTIVE: To investigate the effect of hyperbaric conditions on brain oxygenation, intracranial pressure and brain glucose/lactate levels in healthy non-brain-traumatized animals. DESIGN AND SETTING: Prospective animal study in a hyperbaric chamber. SUBJECTS: Twelve adult Landrace/Yorkshire pigs. INTERVENTIONS: The animals were normoventilated in a pressure-controlled mode according to the open lung ...
Westphal Martin - - 2003
OBJECTIVE: To determine the effects of titrated arginine vasopressin (AVP) alone or in combination with norepinephrine (NE) on hemodynamics and oxygen transport in healthy and endotoxemic sheep. DESIGN: Prospective controlled trial. SETTING: University research laboratory. SUBJECTS: Six adult ewes. INTERVENTIONS: Healthy sheep received AVP as a titrated infusion, initiated with ...
Wu Swei-Pi - - 2003
This study used the psychophysical approach to evaluate the effects of asymmetric lifting on the maximum acceptable weight of lift (MAWL) and the resulting heart rate, oxygen uptake and rating of perceived exertion (RPE). A randomized complete block factorial design was employed. Twelve female college students lifted weights at three ...
Vandegriff Kim D - - 2003
BACKGROUND: Vasoconstriction has been an obstacle to clinical development of Hb-based O2 carriers. It is proposed that this limitation can be overcome by increasing molecular size and oxygen affinity. STUDY DESIGN AND METHODS: Surface-modified Hb (MP4) was designed, whose properties are consistent with the theory that cell-free Hb engages autoregulatory ...
Hansell Douglas R - - 2003
Extracorporeal membrane oxygenation (ECMO) is a technique developed to ensure adequate tissue oxygen delivery in patients suffering cardiac and/or respiratory failure. ECMO can provide this delivery without causing the iatrogenic damage associated with high mechanical ventilation pressures, high fraction of inspired oxygen, or high doses of inotropic medications. Though practitioners ...
Belo I - - 2003
Fed-batch is the dominating mode of operation in high-cell-density cultures of Saccharomyces cerevisae in processes such as the production of baker's yeast and recombinant proteins, where the high oxygen demand of these cultures makes its supply an important and difficult task. The aim of this work was to study the ...
Pypendop Bruno H - - 2003
OBJECTIVE: To determine the hemodynamic effects of nitrous oxide in isoflurane-anesthetized cats. ANIMALS: 12 healthy adult domestic shorthair cats. PROCEDURE: Cats were anesthetized by administration of isoflurane in oxygen. After instruments were inserted, end-tidal isoflurane concentration was set at 1.25 times the individual minimum alveolar concentration, and nitrous oxide was ...
Franz Michele - - 2003
Song production in birds is driven by temporally complex respiratory patterns. In zebra finches (Taeniopygia guttata), song consists of repetitions of a stereotyped sequence of distinct syllables (motif). Syllables correspond to distinct expiratory pulses, which alternate with short deep inspirations. We investigated the effect of the song motor pattern on ...
Fisher Anthony Richard - - 2003
A prospective study was conducted with the aims of 1) determining the normal trans-oxygenator pressure gradient characteristics for a range of oxygenators and 2) determining the characteristics, incidence and outcome of abnormally raised gradients. The trans-oxygenator pressure gradient was monitored in 3684 patients undergoing open-heart surgery in eight different hospitals. ...
Letienne Robert - - 2003
The effects of donitriptan on systemic arterial-jugular venous oxygen saturation difference were evaluated in pentobarbitone-anesthetized pigs. Oxygen and carbon dioxide partial pressures in systemic arterial and jugular venous blood as well as hemoglobin oxygen saturation were determined by conventional blood gas analysis. Vehicle (40% polyethyleneglycol in saline, n = 9) ...
Jolliet Philippe - - 2003
The density of helium is markedly lower than that of air or any of its components, leading to a substantial decrease in airway resistance to flow when it is inhaled. In mechanically ventilated patients with obstructive airway disease, replacing the usual air-oxygen mixture with helium-oxygen has been shown to reduce ...
Lukyanetz E A - - 2003
Anoxia/hypoxia induces dramatic changes in brain activity leading to the damages in brain structure. Several minutes of decrease in environmental oxygen partial pressure (P(O2)) can irreversibly destroy nerve cells. Therefore, investigations of intracellular mechanisms responsible for hypoxia-induced changes of mammalian nerve system are very important. On-line adjustment and measurements of ...
< 13 14 15 16 17 18 19 20 21 22 23 >