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At least 19 recordsLinked to original sources
PubMed1978

Chromatographic analysis of multiple tracer inert gases in the presence of anesthetic gases.

A gas chromatographic method for simultaneous analysis of multiple tracer inert gases in blood and expired gas samples is described. The method enables determination of the distribution of ventilation-perfusion ratios in the lungs during anesthesia with nitrous oxide and halothane. In addition, simultaneous analysis of anesthetic gas concentration in blood permits calculation of the amount of uptake or elimination of anesthetic gases from the Fick principle.

Anesthesia, Inhalation↗
PubMed1977

The opposing physiological effects of high pressures and inert gases.

The physiological effects on mammals of elevated pressures (approximately 100 atmospheres) must be considered in the context of the inert gases breathed. The most striking effect of pressure per se is a central hyperexcitability manifest at first by trembling of the entremities and finally by convulsions. Paralysis and death occur at higher pressures. The primary effects of the inert gases breathed are inert gas narcosis and general anesthesia. The exciting effects of pressure per se and the depressive effects of the inert gases tend to oppose each other. Thus consciousness may be restored to anesthetized mice by raising the pressure, and conversely the threshold pressure that causes convulsions is elevated in the presence of anesthetics. These mutually antagonistic effects can be rationalized in terms of model which proposes that both anesthetics and pressure non-specifically perturb thelipid bilayer regions of neutral membranes. This model is termed the critical volume hypothesis. Anthesthetics dissolve in and expand these lipid bilayer regions, while pressure causes mechanical compression. Expansion leads to anesthesia and compression to convulsions if a critical degree of change is achieved. At elevated partial pressures of inert gas the gas-induced expansion is opposed by the compression of pressure per se. With very insoluble gases, such as helium, this expansion is so small that net compression results and the effects of helium differ little from those of pressure per se. With more soluble gases, such as nitrogen, net expansion results in inert gas narcosis and anesthesia. The critical volume hypothesis enables "safe" mixtures of "expanding" and "compressing" gases to be defined. These enable higher pressures to be better tolerated by mammals.

Anesthesia↗
PubMed1978

Technique for measurement of inert gases in liquids by gas chromatography.

A method for quantitative analysis of inert gases in liquids by gas chromatography is described. The technique comprises an equilibration system for partial extraction of dissolved gases from liquids and a gas chromatograph equipped with helium ionization detector. The method is particularly devised for determination of solubility coefficients of gases in liquid materials, e.g. water, aqueous solutions, blood, tissue homogenates, and for simultaneous measurement of several inert gases dissolved in liquids. Coefficients of variation for serial analyses of individual samples were less than or equal to 3%. The method is applicable to studies of blood-tissue transfer of respiratory and inert gases.

Chromatography, Gas↗
PubMed1977

Hydrocarbon gases produced during in vitro peroxidation of polyunsaturated fatty acids and decomposition of preformed hydroperoxides.

Hydrocarbon gases have been used previously as an index of lipid peroxidation in vivo and in vitro. In vitro experiments are reported on the formation of hydrocarbon gases from peroxidizing omega-3 and omega-6 fatty acids. Hydrocarbon gases were not released during a 20-hr peroxidation phase but were released following the decomposition of hydroperoxides by addition of excess ascorbic acid. The major hydrocarbon gas products in iron, copper, or hematin catalyzed peroxidation systems were ethane or ethylene from linolenic acid, and pentane from linoleic acid and arachidonic acid. Calculations of the ratios of hydrocarbon gases formed were based on fatty acid decrease and/or change in diene conjugation and peroxide values. Depending on the fatty acid, catalyst, and calculation basis used, pentane formation was as high as 1.3 mol %, ethane 4.3 mol %, and ethylene 10.6 mol %.

Chemical Phenomena↗
PubMed1979

[On the problem of optimal warming and moistening of the inspired gases in controlled and assisted artificial ventilation (author's transl)].

The physiological significance of adequate temperature and humidity of respiratory gases and the problems of technical realization are demonstrated. Humidifying and warming of gases by the principle of bubbling through a heated waterbath are believed to be best. The problems with these techniques e.g. dependence of temperature and relative humidity of the gases delivered to the patient on respiratory minute volume, material of the tubing and room temperature are shown. A simple solution to these problems without the need of electrical heated tubing is offered. A new electronically controlled humidifier (H.R.P.-Humidifier 2000) with special developed tubing is presented. Optimal temperature and relative humidity of the respiratory gases is guaranteed by the high efficiency humidifier, and additional measurement and regulation of temperature close to the patients tracheal tube. The problem of increased amounts of condensed water in the tubing is solved by the H.R.P. special tracheal tube adapter with an automatic water exhaust. In addition the hygienic problems of artificial respiration can be solved optimally in combination with the complete H.R.P.-System 2000.

Electronics, Medical↗
PubMed1975

Diffusivity of various inert gases in rat skeletal muscle.

Krogh's diffusion constant (K) was determined for various inert gases in isolated rat abdominal muscle at 37 degrees C by measuring the amount of gas diffusing per unit time and partial pressure difference through a portion of the muscle of known surface area and thickness. The following mean values for K, in 10(-9) mmol-min-1-cm-1-torr-1, were obtained: C2H2, 42.2; N2O, 20.0; CHClF2, 18.8; H2, 1.67; He, 1.42; CH4, 1.27; SF6, 0.081. From Krogh's diffusion constant, the diffusion coefficient (D) was calculated using the solubility coefficient determined previously in the same preparation. The D values thus obtained were found to be about half the D values in water at 37 degrees C. Model calculations show that for gases with high lipid/water partition coefficient, D in tissues containing lipid is underestimated by this method. Graham's law (inverse proportionality between D and square root of molecular mass) was found to represent a useful approximation for these gases. A better correlation, however, was obtained between D and the molecular diameter.

Abdominal Muscles↗
PubMed1977

Gases released from tissue and analyzed by infrared and gas chromatography/mass spectroscopy techniques.

Two techniques for analyzing contaminants released as gases from postmortem tissues were described and compared. One technique used gas chromatography/mass spectrometry (GC/MS); the other, infrared spectroscopy (IR). Brain, lung, liver, blood and urine specimens were obtained from suspected drug-overdose victims whose deaths were contributed to or caused by inhalation of unknown gases or vapors during the period immediately preceding death. Gases from the postmortem tissues and liquid samples were separately admitted into an evacuated IR gas cell, the IR spectra recorded, and gas samples then removed for GC/MS analysis. Nitrous oxide, glue, and paint solvent constituents were identified and measured. Only the brain and lung tissues contained measurable amounts of inhalants. Both IR and GC/MS methods were adequate for normal confirmatory analyses; the GC/MS system was judged superior for fast routine efforts normally hampered by incomplete sample history.

Brain Chemistry↗
PubMed1976

Respiratory failure: correlation between encephalopathy, blood gases and blood ammonia.

In 59 patients with respiratory insufficiency due to chronic obstructive pulmonary disease (COPD) the relationship between the state of consciousness, the blood gases and blood ammonia were studied. Interindividually, a significant correlation was found between the encephalopathy and SaO2, PaCO2 or ammonia, and also between the blood gases and ammonia. On the other hand, an intraindividual study, performed on patients with minor cerebral dysfunction, showed that only PaCO2 was significantly correlated with the stage of consciousness. Ammonia did not appear to have a neurotoxic influence. The ammonia level seemed to be influenced primarily by other factors than the blood gases, although there was a borderline influence of SaO2 on aterial ammonia and a significant influence of PaCO2-HCO3 and pH on venous ammonia.

Adult↗
PubMedDate not supplied

Arterial blood gases in the coronary care unit. Part I.

Blood gas analyses are frequently helpful and at times vital in the management of patients who develop complications during an acute myocardial infarction. This vignette discusses the arterial blood gases when congestive heart failure complicates an acute myocardial infarction. Blood gas measurements are generally obtained for two principle reasons: (1) to determine if the patient is well oxygenated--Po2 and O2 arterial gas measurements, and (2) to determine the patient's acid base status (a) using respiratory component of acid base status--PCO2 measurement, (b) using metabolic component of acid base status--HCO-3 measurement, and (c) using both a and b. Arterial blood gases are preferred over venous blood gases. Venous blood gives information relative to the extremity it drains and may be misleading if the extremity is cold, clammy, or underperfused.

Arteries↗
PubMed1976

[Study of the composition of the exhaust gases from the manufacture of feed antibiotics and of fungal and bacterial entomopathogenic preparations].

The main composition of exhaust gases in production of various preparation, such as bacitracin, chlortetracycline, hygromycin, entobacterin, dendrobacillin, boverin and kormogrisin was determined by the method of group chemical analysis and gas chromatography. The exhaust gases contaned fatty acids c2--c6, aldehydes and ketones c2--c6, alcohols c2-c5, amines (diethylamine, triethylamine, etc) and some phenols. The level of the substances was insignificant. However, they were toxic for living beings. The exhaust gases had disagreeable odour.

Animal Feed↗
PubMedDate not supplied

Lipid peroxidation: detection in vivo and in vitro through the formation of saturated hydrocarbon gases.

Saturated, short-chain hydrocarbon gases (ethane, propane, etc.--but not methane) are evolved during the spontaneous lipid peroxidation of mouse tissue slices or homogenates. A relatively-selective increase in either ethane or pentane was observed when either linolenic acid or linoleic acid, respectively, was added to tissue homogenates. When mice were challenged by injection of carbon tetrachloride or cumene hydroperoxide (two agents that induce a lipid peroxidative attack on liver), they exhaled ethane. The gas chromatographic detection and monitoring of hydrocarbon gases can serve as an index of lipid peroxidation in vivo.

Animals↗
PubMed1979

Solubility of inert gases in homogenates of canine lung tissue.

The solubility of sulfur hexafluoride (SF6), ethane, cyclopropane, halothane, diethyl ether, and acetone in homogenates of dog lung tissue were measured and compared with values obtained in dog blood. The measurements were made to provide data for a method for determining distribution of ventilation, blood flow, and tissue volume (Physiologist 20: 95, 1977) and for reasons discussed, the blood was not washed from the tissue prior to homogenization. All gases except SF6 were significantly more soluble in blood than lung tissue, whereas SF6 was 3.7 times more soluble in tissue than blood. It was further found that SF6 is 5 times more soluble, and ethane is twice as soluble in tissue obtained from lungs containing blood than in tissue obtained from rinsed lungs, suggesting that measurements of parenchymal solubility made on tissue from sinsed lungs may be considerably in error for some lipid-soluble gases.

Animals↗
PubMed1976

[Viscosity and density fluctuations of natural respiratory gases and of mixtures of helium, oxygen and nitrogen due to temperature and composition of the gas mixture (author's transl)].

For the estimation and correction of errors in the measurement of the respiratory flow with viscosity-affected respiratory flow receptors the viscosity of natural respiratory gases (N2, O2, CO2, H2O) and of the ternary system helium-oxygen-nitrogen, which is of importance in pulmonary function diagnosis, was determined. Corresponding density values were calculated. Allowance was made for such special features of spirometry as exchange of O2 for CO2 and water vapour saturation at 37 degrees C. The viscosity of the ternary system is shown in a graph. The formulae indicated have been simplified as far as this was compatible with the demands of accuracy. The fluctuations in density and viscosity of natural respiratory gases can be read directly from a table.

Carbon Dioxide↗
PubMed1977

Investigations of some aspects of atmospheric pollution by anaesthetic gases. I: Diffusion of halothane across plastic and rubber tubes.

Plastic and rubber tubing, of the types used frequently to convey anaesthetic gases to and from the patient, or anaesthetic waste gases out of the operating theatre, were assessed for their capacity to allow diffusion of halothane through the tube wall. The magnitude of this effect has been calculated in relation to pollution of the operating theatre atmosphere under different circumstances.

Air Pollution↗
PubMed1978

Bacterial contamination of anaesthetic gases.

The bacterial content of oxygen and nitrous oxide immediately before and after passing through clean and used breathing systems (circuits) was measured using a specially constructed agar chamber (Bourdillon's slit sampler). The content per litre of oxygen from the outlet of the anaesthetic machine was 4.0 X 10-2, and 2.9 X 10-2 for nitrous oxide, corresponding to 3.5 X 10-2 for a 50% mixture of the gases. After passing through cleaned circuits, the bacterial pollution of the gas mixture had increased by 30%, but more than elevenfold after passing through used circuits. The content from cleaned circuits was less than that measured previously in the air of hospital wards and operating theatres, whereas gases from used circuits were polluted to approximately the same extent. It is concluded that used circuits may increase the risk of cross-infection. The cleaning method employed by us (dish-washer--hot airy drying) appeared to be acceptable.

Anesthesia, Inhalation↗
PubMed1978

Arterial blood gases in Pranayama practice.

Pranayama is a Yogic breathing practice which is known experientially to produce a profound calming effect on the mind. In an experiment designed to determine whether the mental effects of this practice were accompanied by changes in the arterial blood gases, arterial blood was drawn from 10 trained individuals prior to and immediately after Pranayama practice. No significance changes in arterial blood gases were noted after Pranayama. A neural mechanism for the mental effects of this practice is proposed.

Adult↗