Search Results
Results 1001 - 1050 of 2050
< 16 17 18 19 20 21 22 23 24 25 26 >
Hay H - - 2000
The delivery of an hypoxic gas mixture to a patient during general anaesthesia is a rare event due to contemporary standards of monitoring, equipment design and alarm features. An incident is described where a split occurred in a rubber seal round the top of a flowmeter control tube. This resulted ...
Virani N A - - 2000
Rates of oxygen consumption (M(O(2))) for Fundulus grandis, the gulf killifish, were measured in air-saturated water, at four progressively lower levels of oxygen and upon normoxic recovery. The pattern of M(O(2)) versus oxygen partial pressure (P(w)O(2)) was that of an oxygen regulator, with a critical oxygen pressure (P(c)) of 34 ...
Fewell J E - - 2000
Experiments were carried out on chronically instrumented newborn and older rabbits to characterize their core temperature (T(c)) responses to acute hypoxemia and to differentiate "forced" vs. "regulated" thermoregulatory responses. Three age ranges of kits were studied: 4-6, 9-11, and 28-30 days of age. During an experiment, T(c), selected ambient temperature ...
Whiteley J P - - 2000
The coupled conservation of mass equations for oxygen, carbon dioxide and nitrogen are written down for a lung model consisting of two homogeneous alveolar compartments (with different ventilation-perfusion ratios) and a shunt compartment. As inspired oxygen concentration and oxygen consumption are varied, the flux of oxygen, carbon dioxide and nitrogen ...
Nwaigwe C I - - 2000
Previous studies have shown that cortical tissue oxygenation is impaired during hyperventilation. However, it is important to quantify the effect of hyperventilation on brain tissue PO(2) and cerebrovenous PO(2) simultaneously especially since cerebral venous oxygenation is often used to assess brain tissue oxygenation. The present study was designed to measure ...
Puggaard L - - 2000
This study explores the effect of regular training on blood pressure, maximal oxygen uptake, maximal isometric muscle strength, and walking speed in the very old. A total of 55 community-dwelling women, 85-year-old, were enrolled in a training group (N = 22) or a control group (N = 33). These groups ...
Nishikawa K - - 2000
PURPOSE: The concept of the second gas effect is well known, however, there have been no studies that showed the relationship between alveolar oxygen concentration and arterial oxygen tension (PaO2) after the inhalation of nitrous oxide (N2O) in humans. The purpose of this study was to examine the changes in ...
Pinheiro R - - 2000
The use of air pressure as a way of improving oxygen transfer in aerobic bioreactors was investigated. To compare the air pressure effects with traditional air bubbled cultures, experiments using a pressure reactor and a stirred flask, with the same oxygen transfer rate, were made. Kluyveromyces marxianus is an important ...
Ramirez J - - 2000
OBJECTIVE: To test if a relatively long-term exogenous hypercapnia, equivalent to those maintained during permissive hypercapnia, can persistently increase oxygen-carrying capacity in ventilated dogs. DESIGN: Prospective study. SETTING: Research laboratory in a hospital. SUBJECTS: Six mongrel dogs (3 males; 3 females). INTERVENTIONS: The dogs were anesthetized (30 mg/kg pentobarbital, i.v.), ...
Reid G M - - 2000
The blood hemoglobin F (HbF) concentration increases in response to chronic arterial hypoxemia and is abnormally elevated in sudden infant death syndrome (SIDS) post-mortem indicating a need for greater oxygen affinity of hemoglobin (Hb) or diminished oxygen usage by tissues or both. Modifying Hb oxygen affinity in rats revealed that ...
Deninger A J - - 2000
We applied a recently developed method of following the time course of the intrapulmonary oxygen partial pressure p(O2)(t) during apnea by (3)He MRI to healthy volunteers. Using two imaging series with different interscan times during two breathholds (double acquisition technique), relaxation of (3)He due to paramagnetic oxygen and depolarization by ...
Nitzan M - - 2000
A method for the measurement of oxygen saturation in the venous blood, SvO2, based on optical measurements of light absorption in the infrared region is presented. The method consists of applying relatively low external pressure of 25 mm Hg on the forearm, thereby increasing the venous blood volume in the ...
Aleksic I - - 2000
We aimed to investigate the effects of high-dose esmolol on haemodynamics and oxygen extraction in minimally invasive direct coronary artery bypass (MIDCAB) surgery patients. METHODS: In 18 patients, heart rate (HR), mean arterial (MAP), central venous (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and mixed venous oxygen saturation ...
Stücker M - - 2000
It has been known since the nineteenth century that oxygen is taken up by the human skin. With a newly developed sensor it became possible to examine the influence of the vascular supply on the oxygen flux into the skin, tcJ(O2). tcJ(O2) was measured optically by determining the oxygen partial ...
Chien J W - - 2000
STUDY OBJECTIVES: To determine if 100% oxygen administration adversely influences gas exchange in acutely ill asthmatic subjects. DESIGN: Prospective preinterventional and postinterventional comparison. SETTING: University hospital emergency department. PATIENTS: Thirty-seven asthmatic subjects seeking care for symptomatic exacerbations. INTERVENTIONS: Twenty minutes of 100% oxygen administration by face mask. MEASUREMENTS AND RESULTS: ...
Corbo M G - - 2000
We investigated if nonnutritive sucking (NNS) during heelstick procedures alleviates behavioral distress in neonates. In our NICU, 26 neonates without severe complications (mean Minde score 0.8, range 0-3), undergoing heelstick procedures at least twice a day, in the first 2 weeks of life, were enrolled in the trial (mean gestational ...
Sleeman J M - - 2000
Ten desert tortoises (Gopherus agassizii) were given i.m. injections of 150 microg/kg of medetomidine. Sedation was achieved in all tortoises by 20 min postinjection and was accompanied by a significant decrease in mean heart and respiratory rates, systolic, diastolic, and mean ventricular pressures, and mean ventricular partial pressure of oxygen ...
Kragelj R - - 2000
The purpose of this study was to investigate postocclusive hyperemic response using near infrared spectroscopy (NIRS) and transcutaneous oximetry (TcpO2). Five minute arterial occlusion on the calf muscle was performed in six healthy volunteers (mean age 29, range 23-34 years, mean TcpO2 at rest 53 mm Hg, range 47-58 mmHg, ...
Fitch C L - - 2000
PURPOSE: To measure the partial pressure of oxygen in the anterior chamber of the rat eye under a variety of physiological conditions. METHODS: Polarographic oxygen electrode measurements were made in methoxyflurane-anesthetized Wistar or Sprague-Dawley rats. After ketamine-xylazine or pentobarbital induction, animals were artificially ventilated with a variety of gas mixtures; ...
Rose D M DM Institute of Occupational-, Social- and Environmental Medicine, Johannes Gutenberg-University of Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany. - - 2000
Patients with cystic fibrosis (CF) represent a special risk for commercial airlines. Even on ground conditions the oxygen partial pressure (paO subset2) of these patients is partially clearly reduced. The reduced air pressure on board of an airplane can cause a drop of the paO subset2 to a critical point ...
West J B - - 2000
Climbing Mt. Everest without supplementary oxygen presents a fascinating physiological challenge because, at the summit, humans are very near the limit of tolerance to hypoxia. It was not until 1978 that the feat was accomplished, and this was after many unsuccessful attempts over a period of more than 50 years, ...
Leder S B - - 2000
If an indirect bedside variable can reliably predict whether an objective instrumental dysphagia evaluation is needed, time and money can be saved without compromising patient care. To date, the search for a reliable indirect subjective marker of aspiration has not been successful. However, research on indirect objective markers of aspiration ...
Monge C C - - 2000
Gray gulls, Larus modestus, nest 1500 m above sea level in northern Chile's Atacama Desert, one of the driest in the world. Their eggshell gas permeability, one third of that found in other Larus species, is an adaptation that reduces water loss, but at the expense of oxygen diffusion into ...
Bäumer C - - 2000
The mayfly larvae Epeorus sylvicola and Ecdyonurus torrentis inhabit either fast-flowing or, for the latter species, calm zones of running water. We studied (1) mechanisms and limitations of oxygen transport in single individuals (oxygen consumption rate, occurrence and rate of gill movements, and heartbeats) in running water of different oxygen ...
Gu Y J - - 2000
The membrane oxygenator is known to be superior to the bubble oxygenator, but little information is available about the difference between the hollow fiber and flat sheet membrane oxygenators with regard to pressure drop, shear stress, and leukocyte activation. In this study, we compared these 2 types of membrane oxygenators ...
Thalhofer Stefan - - 2000
Cheyne-Stokes respiration is known to be associated with severe left heart failure. Because of severe desaturation, sleep fragmentation, arousals, and an increase in sympathetic activity, Cheyne-Stokes respiration may lead to a further impairment of cardiac function and to a worsening of quality of life. Although the pathology of Cheyne-Stokes respiration ...
Law R C - - 2000
Computerized tomography (CT) of the lungs and arterial oxygen tension studies were performed during general anaesthesia in an animal model to understand changes in pulmonary atelectasis associated with anaesthesia in children during a 2 min apnoeic period. Six anaesthetized lambs were subjected to three periods of apnoea lasting 2 min ...
Deninger A J - - 1999
We present a new method to determine in vivo the temporal evolution of intrapulmonary oxygen concentrations by functional lung imaging with hyperpolarized (3)Helium ((3)He-->). Single-breath, single-bolus visualization of (3)He--> administered to the airspaces is used to analyze nuclear spin relaxation caused by the local oxygen partial pressure p(O(2))(t). We model ...
Shoemaker W C - - 1999
Postoperative survivors' and nonsurvivors' hemodynamic and oxygen transport patterns have been extensively studied, and the early postoperative circulatory events leading to organ failures and death have been documented. Outcome was improved when potentially lethal circulatory patterns were treated during the early (the first 8-12 hours) postoperative period; but after the ...
Terry C C Department of Rehabilitation Medicine, Hospital of the University of Pennsylvania, Philadelphia 19104, - - 1999
Study physiologic changes occurring during "knockouts" produced by application of pressure point techniques during martial arts demonstrations. prospective analysis of physiologic variables during and immediately following an acute event. martial arts demonstration carried out at a medical center hospital. 12 normal volunteers participating in a martial arts demonstration. application of ...
Schaeffer E M - - 1999
OBJECTIVES: To determine the effect of breathing helium-oxygen (HELIOX) mixtures on pulmonary gas exchange during severe asthma. DESIGN: A retrospective case-match control design was used to compare the changes in alveolar to arterial gradient [(A-a)gradient] in the first 2 hrs of mechanical ventilation (MV) for status asthmaticus (SA) in patients ...
Papazian L - - 1999
The combination of inhaled nitric oxide with almitrine bismesylate has been proposed for the management of acute respiratory distress syndrome in order to divert pulmonary blood flow away from poorly ventilated toward well-ventilated areas. The aims of this prospective and comparative study were to: 1) confirm the beneficial effects on ...
Jensen B R - - 1999
STUDY DESIGN: Brief (30-second) isometric trunk extensions at 5%, 20%, 40%, 60%, and 80% of maximal voluntary contraction (MVC) and 3 minutes of prolonged trunk extension (20% MVC) in erect position were studied in nine healthy male subjects. OBJECTIVES: To investigate the intercorrelation between intramuscular pressure and tissue oxygenation of ...
Jolliet P - - 1999
OBJECTIVE: To test the hypothesis that, in decompensated chronic obstructive pulmonary disease (COPD), noninvasive pressure support ventilation using 70:30 helium:oxygen instead of 70:30 air:oxygen could reduce dyspnea and improve ventilatory variables, gas exchange, and hemodynamic tolerance. DESIGN: Prospective, randomized, crossover study. SETTING: Medical intensive care unit, university tertiary care center. ...
Trittenwein G - - 1999
While extracorporeal membrane oxygenation (ECMO) is being used increasingly after pediatric cardiac surgery, criteria are lacking for initiating ECMO after bypass weaning. To develop clinically useful ECMO entry criteria based on parameters readily available, children were examined at postoperative pediatric intensive care unit (PICU) admission. Using hospital mortality as the ...
Calzia E - - 1999
BACKGROUND: Because of its high density and viscosity, xenon (Xe) may influence respiratory mechanics when used as an inhaled anesthetic. Therefore the authors studied respiratory mechanics during xenon and nitrous oxide (N2O) anesthesia before and during methacholine-induced bronchoconstriction. METHODS: Sixteen pentobarbital-anesthetized pigs initially were ventilated with 70% nitrogen-oxygen. Then they ...
Ferrante E - - 1999
We studied 12 asymptomatic conscripts affected by bronchial asthma to evaluate the level of hypoxemia and its relationship with bronchial obstruction induced by methacholine (Mch) challenge. Arterial blood samples were obtained before and immediately after bronchial challenge. The range of decrease of forced expiratory volume/forced vital capacity x 100 in ...
Arbabi S - - 1999
BACKGROUND: Near-infrared spectroscopy (NIRS) noninvasively measures tissue O2 saturation (StO2), and has been proposed as a means of monitoring for compartmental syndrome (CS). However, its specificity in hypoxemic, hypotensive patients with severely reduced systemic oxygen delivery has not been tested. We hypothesized that NIRS can differentiate muscle ischemia caused by ...
Christensen V L - - 1999
The hypothesis was tested that increased oxygen tensions during the plateau stage of oxygen consumption (25 and 26 d of incubation) would cause different metabolic responses from embryos selected for increased egg production or growth. Embryos were exposed to 171 or 152 mm Hg partial pressure of oxygen from 25 ...
Lim H S - - 1999
The effect of oxygen partial pressure on viral replication was investigated with Vero/VSV system. At 10% oxygen partial pressure in spinner culture, VSV titer was significantly increased 130 fold compared to that obtained at 21%. A similar result was obtained for viral production in 1liter bioreactor. This implies that oxygen ...
Quinn J V - - 1999
OBJECTIVE: Platelet-activating factor (PAF) and eicosanoids are putative mediators of septic shock that are associated with release of tumor necrosis factor (TNF). The purpose of this investigation was to a) examine temporal patterns of TNF and arachidonic acid metabolite release in a porcine model of bacteremic shock and b) selectively ...
Zhi D S - - 1999
BACKGROUND: We studied the change of brain tissue oxygen pressure (PbrO2) value within 24 hours after trauma and during moderate hypothermia in patients with severe head injury. The PbrO2 value was used to differentiate patients at risk of brain ischemia and to predict outcome. METHODS: A flexible microcatheter to be ...
Ter Minassian A - - 1999
Near-infrared spectroscopy has been used to monitor cerebral oxygen saturation during cerebral circulatory arrest and carotid clamping. However, its utility has not been demonstrated in more complex situations, such as in patients with head injuries. The authors tested this method during conditions that may alter the arteriovenous partition of cerebral ...
Streatfeild K A - - 1999
Addis Ababa is situated at an altitude of approximately 8500 ft and has a barometric pressure of close to 570 mmHg. Arterial blood gas values during the administration of anaesthesia with spontaneous ventilation have not been extensively studied. During the period January to July 1993, oxygen saturation was determined in ...
Hoffman W E - - 1999
Two probes, using different technologies, are currently available to measure tissue oxygen pressure. One of these also measures oxygen pressure, carbon dioxide pressure, pH and temperature. Research has delineated normal brain tissue oxygen pressure as 25-45 mmHg and ischemic thresholds of less than 10 mmHg that are related to ischemic ...
Linnarsson D - - 1999
We sought to determine whether hydrostatic pressure contributed to bradycardia and hypoventilation in hyperbaria. Eight men were studied during exercise at 50, 150, and 250 W while breathing 1) air at 1 bar, 2) helium-oxygen (He-O(2)) at 5.5 bar, 3) sulfur hexafluoride-oxygen (SF(6)-O(2)) at 1.3 bar, and 4) nitrogen-oxygen (N(2)-O(2)) ...
Loke K E - - 1999
Background-Our objective for this study was to investigate whether nitric oxide (NO) modulates tissue respiration in the failing human myocardium. Methods and Results-Left ventricular free wall and right ventricular tissue samples were taken from 14 failing explanted human hearts at the time of transplantation. Tissue oxygen consumption was measured with ...
Schmidt P - - 1999
To study the effects of positional restraint on heart rate and oxygen saturation during recovery, a crossover experimental design with prospective control trials was used in a two-phase study. In phase 1, serial resting oxygen saturations (RO1) measured on 18 volunteers were compared with those measured in the seated unrestrained ...
Korhonen K - - 1999
OBJECTIVE: To investigate the response of subcutaneous tissue oxygen (O2) and carbon dioxide (CO2) tensions to hyperbaric oxygenation. DESIGN: Experimental study. SETTING: University hospital, Finland. SUBJECTS: 10 Wistar rats. INTERVENTION: Subcutaneous tissue PO2 and PCO2 were directly measured with an implanted Silastic tube tonometer and capillary sampling technique while breathing ...
Mildenberger E - - 1999
OBJECTIVE: We question the hypothesis that vascular tone of human umbilical vein is insensitive to oxygen pressure and minimal already at resting conditions. STUDY DESIGN: Isometric tension and intracellular membrane potential of native (n = 7) and endothelium-denuded (n = 7) human umbilical vein strips were recorded simultaneously at oxygen ...
< 16 17 18 19 20 21 22 23 24 25 26 >