We have evaluated the performance of the Intersurgical 40% Oxygen Recovery T-Kit in ten healthy volunteers. Inspired oxygen and end-tidal carbon dioxide concentrations were measured during normal respiration and with variations in respiratory rate and depth. The performance of the device was then studied after modifications to the inspiratory limb, ...

Ambulatory oxygen therapy in patients with COPD and exercise hypoxaemia may improve exercise capacity and breathlessness. The improvement in exercise tolerance is related to the degree of exercise hypoxaemia. As effects from ambulatory oxygen therapy are prone to placebo effects, careful patient selection is required, with formal assessment. For effective ...

The local oxygen supply to the skin immediately before and after withdrawal of blood was appraised in 18 healthy test subjects by measuring the intracapillary hemoglobin oxygenation (HbO2). The investigation was carried out with the Erlanger Microlightguide Photometer (EMPHO). EMPHO measurements are based on the registration of tissue remission spectra ...

METHODS: Radiosensitisation with oxygen, carbogen or nicotinamide alone and oxygen or carbogen combined with nicotinamide was compared in early and late responding normal tissues in rodents. X-ray treatments were delivered as single doses or fractionated schedules of 2 fractions in 1 day, 2, 12 and 36 fractions in an overall ...

The effects of vasopressin plus oxygen and vasopressin alone on gastric mucosal perfusion and oxygenation were studied using reflectance spectrophotometry and laser Doppler velocimetry in 23 cirrhotic patients with portal-hypertensive gastropathy. The measurements were performed under basal conditions and after double-blinded administration of placebo (n = 7), vasopressin (0.3 U/min; ...

BACKGROUND: The aim of this study was to simulate an in flight environment at sea level with a fractional inspired concentration of oxygen (FiO2) of 0.15 to determine how much supplemental oxygen was needed to restore a subject's oxygen saturation (SaO2) to 90% or to the level previously attained when ...

In a previous study an apparent discrepancy was found between the radiobiological hypoxic fraction of tumours and the tumour oxygenation: the lowest percentage of low pO2 values was observed in the most hypoxic tumour, a heavily pigmented melanoma Na11+. This report describes a similar study with two other less pigmented ...

Key questions on how intertidal animals adapt to hypoxic stress center on the high energy phosphate response to decreasing oxygenation. With recent 1H/31P-NMR techniques to monitor mammalian tissue metabolism, a novel approach has emerged to observe potentially the intracellular oxygen interaction in invertebrates. The present study indicates that Arenicola marina, ...

The body does not always achieve a steady state and is more often kept in a nonsteady state. It is important not only in terms of physiological anthropology but also in its application to rehabilitation and training to clarify whether oxygen transport or utilization is the limiting factor in oxygen ...

Control and regulation of mitochondrial and cellular respiration by oxygen is discussed with three aims: (1) A review of intracellular oxygen levels and gradients, particularly in heart, emphasizes the dominance of extracellular oxygen gradients. Intracellular oxygen pressure, pO2, is low, typically one to two orders of magnitude below incubation conditions ...

Sixteen female games players completed 15 min of intermittent exercise on a treadmill. The speed and incline of the treadmill were varied to elicit a similar heart rate response to that found during women's hockey match-play. The mean heart rate response was 169 +/- 8 beats min-1 and the mean ...

STUDY OBJECTIVE: To compare oxygen administration by means of an inflatable portable hyperbaric chamber with that through a nonrebreather mask for the elimination of carboxyhemoglobin (COHb). DESIGN: Double-crossover prospective analysis. SETTING: University emergency department, Level I trauma center. PARTICIPANTS: Twelve healthy paid adult volunteers, all smokers. INTERVENTIONS: Each subject smoked ...

It is unclear whether short-term benefits from supplemental oxygen translate into improved quality of life in patients with severe COPD. In a 12 wk double-blind randomized crossover study, we assessed the effects of supplemental air and oxygen on exercise performance (step tests and 6 min walking distance [6MWD]) initially and ...

The formation and accumulation of reactive oxygen species within liver macrophages and their release into the medium were determined by lucigenin-enhanced chemiluminescence, the reduction of cytochrome c, the formation of formazan from nitroblue tetrazolium and the fluorescence of 5- (and 6)-carboxy-2',7'-dichlorodihydrofluorescein. Zymosan, phorbol ester and fluoride induced the formation and ...

A wide range of organismic, physiological and biochemical adjustments to improve oxygen transfer is observed in fish exposed to environmental hypoxia and during anemia. Many fish species of the Amazon obtain oxygen directly from air when water oxygen is low. The accessory air-breathing organs include modifications of the gills, mouth, ...

The purpose of this study was to determine the accuracy of equations developed by the American College of Sports Medicine and by Latin et al. (Med. Sci. Sports Exerc. 25:970-974, 1993) for estimating the oxygen cost of cycle ergometry in obese women. Fifty-six deconditioned subjects, aged 23-60 yr, performed a ...

The ability to monitor the match between systemic oxygen delivery and consumption using mixed venous oxygen saturation is an important component of management of critically ill patients. Mixed venous oxygen saturation is a particularly useful parameter in circumstances where systemic oxygen delivery is significantly compromised, such as the acute respiratory ...

While arterial oxygen desaturation during apnea is a common occurrence in adults and infants, the factors determining the rate of desaturation are poorly understood. We describe a theoretical model which suggests that arterial desaturation during an apneic episode occurs in two stages. In the initial stage (stage 1) the oxygen ...

In order to compare the cardiovascular and perceived exertion responses to 6 modes of exercise, 10 male recreational exercisers were habituated to treadmill jogging, stationary skiing, shuffle skiing, stepping, stationary cycling, and stationary rowing. After following a specific dietary preparation, each participant performed a 20-min exercise bout at a constant ...

The adequacy of tissue oxygenation depends on the interaction of many factors. Assuming the presence of sufficient tissue perfusion, oxygenation failure must be caused by depressed respiratory efficiency (shunt or other ventilation/perfusion mismatch), inadequate FIO2/PaO2 relationships (alveolar-capillary diffusion deficits, for example), or oxygen transport difficulties (hemoglobin loading/unloading dysfunction). When presented ...

Perfusion of capillaries was investigated in the tenuissimus muscle of young anesthetized New Zealand White rabbits during control conditions, complete aorta occlusion, and reactive hyperemia at various local oxygen tensions. Capillaries were visualized with bright-field microscopy. The number of capillaries perfused under experimental conditions was compared with that during control ...

BACKGROUND: Peak exercise oxygen consumption provides valuable short-term prognostic information in patients with heart failure. However, peak exercise oxygen consumption is determined not only by the cardiac output response to exercise but also by age, gender, and muscle mass. We investigated whether percentage of predicted maximal exercise oxygen consumption rather ...

BACKGROUND: Intravascular perfluorochemical emulsions together with a high oxygen tension may increase the delivery of dissolved oxygen to useful levels. The hypothesis of this study is that increasing the dissolved oxygen content of blood with incremental doses of a perfluorochemical emulsion improves tissue oxygenation during cardiopulmonary bypass in a dose-related ...

Historically, the achievement of maximal oxygen uptake (VO2max) has been based on objective criteria such as a leveling off of oxygen uptake with an increase in work rate, high levels of lactic acid in the blood in the minutes following the exercise test, elevated respiratory exchange ratio, and achievement of ...

BACKGROUND: Oxygen depletion of the superior and central cornea in response to standard conditions is of clinical interest because of pathological conditions, usually resulting from the hypoxia of contact lens wear, that affect these areas. A study was designed to determine if there are differences in oxygen depletion at these ...

Atelectasis is an important cause of impaired gas exchange during general anaesthesia; it causes pulmonary shunting. We studied the effects of gas composition on the formation of atelectasis and on gas exchange during the induction of general anaesthesia. In 12 adult patients, the lungs were ventilated with 30% oxygen in ...

The present paper describes theoretical and experimental bases for quantitation of the oxygen level inside a single isolated ventricular rat myocyte. We applied three-wavelength microspectrophotometry to a single cardiomyocyte, where the sensitivity of the spectrophotometry was augmented by a digital image processing technique known as video-enhanced microscopy. Oxygen-dependent changes in ...

A new electron paramagnetic resonance (EPR)-based method was developed to obtain selective information on pO2 in a specific intracellular compartment (phagosomes). This method did not require the use of a broadening agent thereby eliminating one of the potential sources of experimental error with EPR oximetry. An oxygen-sensitive probe (4-(Trimethylammonium) 2,2,6,6-tetramethylpiperidine-d17-1-oxyl ...

Patients with chronic obstructive pulmonary disease (COPD) may benefit from ambulatory oxygen; however, the effect of exercise on arterial oxygen saturation (Sa,O2) in patients with kyphoscoliosis and of correction with ambulatory oxygen have not been previously reported. Twelve patients with stable kyphoscoliosis (mean (SD) Cobb angle 79 (26) degrees) were ...

Modern anaesthetic machines are equipped with several safety components to prevent delivery of hypoxic mixtures. However, such a technical development has increased the complexity of the equipment. We report a reconstructed anaesthetic machine in which a paramagnetic oxygen analyzer has provided the means to simplify the apparatus. The new machine ...

The use of local anesthesia and intravenous sedation has made same-day outpatient surgery a viable option for many aesthetic and reconstructive procedures. These procedures often include the use of supplemental oxygen. Oxygen-enriched environments increase the combustibility of most materials, and "oxygen pooling" has been suspected to play an integral role ...

Mixed venous oxygen saturation (SvO2) is a physiologic parameter reflecting cardiac output (CO) and tissue oxygen utilization. An implantable oxygen sensor incorporated in a right ventricular pacing lead has been developed to assess the feasibility of ambulatory monitoring of SvO2 to predict cardiorespiratory parameters. Eight patients with a mean age ...

Measurements of oxygen deficit during submaximal exercise were correlated with the anaerobic threshold (as measured by gas exchange analysis), peak work rate on a ramp protocol, and the ability to perform constant work rate exercise in 10 male patients with New York Heart Association class 2 congestive heart failure and ...

Exercise influences blood flow distribution and may thereby influence tissue oxygen. Given that experimental evidence suggests exercise improves wound healing, this study was undertaken to determine the effect of exercise on subcutaneous tissue oxygen tension (PscO2). Subjects performed a treadmill test to maximum oxygen consumption (VO2) while PscO2 and subcutaneous ...

The goal of cardiorespiratory monitoring is to evaluate the components of oxygen delivery and consumption. Parameters obtained from the physiologic profile are used to assess and optimize oxygen transport to meet the tissue needs of the critically ill patient. Threats to the process of tissue oxygen balance can lead to ...

A highly sensitive galvanic cell oxygen sensor was successfully developed for determining parts per billion of oxygen in high purity gases such as nitrogen, argon, etc. The response of this improved sensor was proportional in the range of oxygen concentrations from 10.0 ppm to the detection limit. The response speed ...

We report experimental data of mass transfer of oxygen into yeast resuspension in a pulsed baffled bioreactor. The bioreactor consists of a 50-mm-diameter column with the presence of a series of either wall (orifice) or central (disc) baffles or a mixture of both where fluid oscillation can also be supermposed ...

One source of muscle fatigue may be the failure to provide the required oxygen by any step in the oxygen transport cascade or a lack of the necessary machinery to utilize that oxygen. We favor abandoning the concept of a single rate-limiting step for the concept of tuned resistors, each ...

Whether maximal oxygen uptake (VO2max) during exercise in healthy subjects reflects limitation of the supply of oxygen to muscle mitochondria or an inability to use oxygen beyond some biochemical limit remains debated. This paper summarizes evidence for the hypothesis that VO2max is limited by O2 supply. How the many steps ...

Hypoxia during haemodialysis, mainly acetate, has been reported several times. In our study we have monitored oxygen status during 258 bicarbonate haemodialyses. A significant drop below 80 mmHg in mean oxygen tension occurred. Mean oxygen saturation reflected this drop but did not reach levels below 90%. The mean oxygen concentration ...

To determine the change in muscle oxygenation in response to progressively increasing work rate exercise, muscle oxyhemoglobin + oxymyoglobin saturation was measured transcutaneously with near infrared spectroscopy in the vastus lateralis muscle during cycle ergometry. Studies were done in 11 subjects while gas exchange was measured breath-by-breath. As work rate ...

Hyperbaric oxygen therapy is used in ophthalmology in ischemic pathologies of the anterior and posterior segments. Our experiment was done on a healthy group of volunteers aged between 10 and 50 yr. We examined the subject's vision before and after acute HBO exposure (60 min at 2.5 atm abs with ...

Metabolic myopathies due to a variety of enzymatic deficiencies are well recognized. The dynamics of oxygen delivery and utilization during exercise have not been observed previously in these disorders. We used a noninvasive optical technique to measure oxygen consumption in the exercising limb in normal subjects and patients with metabolic ...

Oxygen tolerance of the microaerophile Campylobacter jejuni subsp. jejuni varied with different brands of complex media which were used for plating the dilute cell suspensions. The tryptone component was one factor. With some tryptones growth occurred at 21% oxygen whereas with others there was no growth at oxygen levels of ...

To determine oxygen tension (pO2) in gingival tissue, an oxygen micro-electrode with a membrane-coated Pt needle was inserted into the gingiva of 12 dogs. Teeth were brushed using a modified Bass technique for 10 s under 200 g pressure. pO2 increased and reached a maximum 15 min after brushing, then ...

We describe the haemodynamic and oxygen transport response in a patient undergoing exchange transfusion for severe falciparum malaria. We found that exchange transfusion produced a significant increase in left ventricular stroke work index, systemic oxygen delivery and oxygen consumption. This potentially beneficial effect of exchange transfusion has not been reported ...

BACKGROUND: Baseline data are needed to provide a foundation for future studies investigating the effects of various nursing interventions on the oxygen requirements of critically ill patients. OBJECTIVES: To establish reference values for the oxygen requirements of adults in response to three common patient events: a nurse-administered bed bath, passive ...

Due to the high flexibility of the micro-light guides used with the Erlangen micro-light guide spectrophotometer (EMPHO) the instrument can be coupled to the lung surface without interfering with the local lung mechanics. The local pressure exerted on the lung varies between 45 and 47 mg/cm2. This enables the continuous ...

Pulse delivery (PD) of oxygen was compared with continuous flow (CF) utilizing transtracheal oxygen catheter (TTO) and nasal cannula (NC) in 20 stable patients with chronic hypoxemia. Oxygen saturation, respiratory rate, and accuracy of pulsed oxygen delivery were measured during sleep studies and these parameters, as well as arterial blood ...

Because of potential for mathematical coupling of measurement errors in shared variables used to calculate oxygen consumption (FickVO2) and oxygen delivery (DO2), we asked whether determination of the FickVO2-DO2 relationship in individual patients with ARDS was statistically valid. We studied 17 clinically resuscitated patients with severe ARDS, measuring FickVO2, CalorimetricVO2 ...