| blood gas analysis | <investigation> A test which analyses arterial blood for oxygen, carbon dioxide and bicarbonate content in addition to blood pH. Used to test the effectiveness of respiration. (27 Sep 1997) |
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| blood gas monitoring, transcutaneous | The noninvasive measurement or determination of the partial pressure (tension) of oxygen and/or carbon dioxide locally in the capillaries of a tissue by the application to the skin of a special set of electrodes. These electrodes contain photoelectric sensors capable of picking up the specific wavelengths of radiation emitted by oxygenated versus reduced haemoglobin. (12 Dec 1998) |
| carbonic acid gas | <biochemistry, physiology> A metabolic byproduct of carbohydrate metabolism. Carbon Dioxide collects in the tissues, is cleared by the blood (via the veins) and removed from the body via the lungs when we exhale air. Abbreviation: CO2 (13 Nov 1997) |
| gas | Origin: Invented by the chemist Van Helmont of Brussels, who died in 1644. 1. An aeriform fluid; a term used at first by chemists as synonymous with air, but since restricted to fluids supposed to be permanently elastic, as oxygen, hydrogen, etc, in distinction from vapors, as steam, which become liquid on a reduction of temperature. In present usage, since all of the supposed permanent gases have been liquified by cold and pressure, the term has resumed nearly its original signification, and is applied to any substance in the elastic or aeriform state. 2. A complex mixture of gases, of which the most important constituents are marsh gas, olefiant gas, and hydrogen, artificially produced by the destructive distillation of gas coal, or sometimes of peat, wood, oil, resin, etc. It gives a brilliant light when burned, and is the common gas used for illuminating purposes. Laughing gas. Any irrespirable aeriform fluid. Gas is often used adjectively or in combination; as, gas fitter or gasfitter; gas meter or gas-meter, etc. <chemistry> Air gas, a kind of gas made by forcing air through some volatile hydrocarbon, as the lighter petroleums. The air is so saturated with combustible vapor as to be a convenient illuminating and heating agent. <physics> Gas battery, a kind of gas made by forcing steam over glowing coals, whereby there results a mixture of hydrogen and carbon monoxide. This gives a gas of intense heating power, but destitute of light-giving properties, and which is charged by passing through some volatile hydrocarbon, as gasoline. Source: Websters Dictionary (01 Mar 1998) |
| gas abscess | An abscess containing gas caused by Enterobacter aerogenes, Escherichia coli, or other gas-forming microorganisms. (05 Mar 2000) |
| gas bacillus | The most common aetiologic agent of gas gangrene. It is differentiable into several distinct types based on the distribution of twelve different toxins. (12 Dec 1998) |
| gas blanket | <radiobiology> A cold, dense volume of gas surrounding a hot plasma and used to protect a material wall from bombardment by hot ions (and its resultant sputtering and impurity production). (09 Oct 1997) |
| gas cautery | Cautery by means of a measured amount of a lighted gas jet. (05 Mar 2000) |
| gas chromatography | <technique> A chromatographic technique (a type of column chromatography) in which the stationary phase is solid while the mobile phase is gaseous samples. The gaseous samples are separated based on their different adsorption ability to the solid phase. (09 Oct 1997) |
| gas constant | R (symbol for the constant) = 8.314 × 107 ergs per degree Celsius per mole = 8.314 J K-1 mol-1 (joules per kelvin mole). (05 Mar 2000) |
| gas cyst | A cyst with gaseous instead of the ordinary liquid or pultaceous contents. (05 Mar 2000) |
| gas engine | A piston engine that uses gaseous fuel rather than gasoline. Fuel and air are mixed before they enter cylinders; ignition occurs with a spark. (05 Dec 1998) |
| gas gangrene | <microbiology> A severe form of gangrene (tissue necrosis) caused by Clostridium infection. Also referred to as necrotising subcutaneous infection. Results in death of the subcutaneous tissues and muscle layers. See: necrotising fascitis. (27 Sep 1997) |
| gas gangrene antitoxin | Antitoxin specific for the toxin of one or more species of Clostridium that cause gaseous gangrene and associated toxaemia, especially C. Perfringens C. Novyi, C. Histolyticum, and commercially available preparations are usually polyvalent, i.e., contain antitoxin for two or more species. Synonym: pentavalent gas gangrene antitoxin. (05 Mar 2000) |
| gas, intestinal | The complaint referred to as intestinal gas is a common one and the discomfort can be quite significant. Everyone has gas and eliminates it by burping or passing it through the rectum. In many instances people think they have too much gas when in reality they have normal amounts. most people produce 1 to 3 pints of intestinal gas in 24 hours and pass gas an average of 14 times a day. It is made up primarily of odourless vapors such as carbon dioxide, oxygen, nitrogen, hydrogen, and in some families, methane. The unpleasant odour is due to bacteria in the large intestine that release small amounts of gases containing sulfur. (12 Dec 1998) |