| ETCO2 | end-tidal carbon dioxide [concentration] |
|---|---|
| ETPCO2 | end-tidal partial carbon dioxide [concentration] |
| FECO2 | fractional concentration of carbon dioxide in expired gas |
| FiCO2, | FICO2 fractional concentration of carbon dioxide in inspired gas |
| PACO2 | partial pressure of carbon dioxide in alveolar gas |
| positive electrode | <microscopy> The electrode to which a major flow of electrons takes place internally (as in a cathode-ray tube) or to which an external positive voltage supply is connected. (05 Aug 1998) |
|---|---|
| Severinghaus electrode | A glass electrode in a film of bicarbonate solution covered by a thin plastic membrane permeable to carbon dioxide but impermeable to water and electrolytes; the carbon dioxide pressure of a gas or liquid sample quickly equilibrates through the membrane and is measured in terms of the resulting pH of the bicarbonate solution, as sensed by the glass electrode; commonly used to analyze arterial blood samples. Synonym: Severinghaus electrode. (05 Mar 2000) |
| hydrogen electrode | The ultimate standard of reference in all pH determinations, limited and technically difficult to use, consisting of a piece of spongy platinum black partly immersed in a solution in a small glass tube; the tube above the solution is filled with hydrogen gas that is bubbled through the solution and absorbed by the platinum; the electrode thus measures the potential between H2 and H+, the "standard" potential of which (1 atmosphere, 1 molar) is taken as zero; hence, the hydrogen electrode potential measures [H+] or pH. (05 Mar 2000) |
| silent electrode | In unipolar electrocardiography, a remote electrode placed either upon a single limb or connected with the central terminal and paired with an exploring electrode; the indifferent electrode is supposed to contribute little or nothing to the resulting record. Synonym: dispersing electrode, silent electrode. (05 Mar 2000) |
| negative electrode | <chemistry, physics> The electrode in an electrochemical cell toward which cations are drawn and where reduction occurs. The negatively charged electrode in a vacuum tube. (16 Mar 1998) |
| dispersing electrode | In unipolar electrocardiography, a remote electrode placed either upon a single limb or connected with the central terminal and paired with an exploring electrode; the indifferent electrode is supposed to contribute little or nothing to the resulting record. Synonym: dispersing electrode, silent electrode. (05 Mar 2000) |
| indifferent electrode | In unipolar electrocardiography, a remote electrode placed either upon a single limb or connected with the central terminal and paired with an exploring electrode; the indifferent electrode is supposed to contribute little or nothing to the resulting record. Synonym: dispersing electrode, silent electrode. (05 Mar 2000) |
| quinhydrone electrode | One of several oxidation-reduction electrode's in which the ratio of the two forms (quinone-quinhydrone), determined by the hydrogen ion concentration, sets up a potential that can be measured and converted to a pH value (fails above pH 8). (05 Mar 2000) |
| ion selective electrode | An electrode half cell, with a semi permeable membrane that is permeable only to a single ion. The electrical potential measured between this and a reference half cell (e.g. A calomel electrode) is thus the Nernst potential for the ion. Given that the solution filling the ion selective electrode is known, the activity (rather than concentration) of the ion in the unknown solution can be measured. Commercial ion selective electrodes frequently use a hydrophobic membrane containing an ionophore, such as valinomycin (for potassium) or monensin (for sodium). A pH electrode is made with a thin membrane of pH sensitive (i.e. Proton permeable) glass. (18 Nov 1997) |
| oxidation-reduction electrode | An electrode capable of measuring oxidation-reduction potential. See: quinhydrone electrode. Synonym: redox electrode. (05 Mar 2000) |
| oxygen electrode | A sensitive method to detect oxygen consumption, involves a PTFE (Teflon) membrane. (18 Nov 1997) |
| therapeutic electrode | A small electrode whose exciting effect is used to stimulate or record potentials from a localised area. Synonym: exciting electrode, localizing electrode, therapeutic electrode. (05 Mar 2000) |
| electrode | <chemistry> Any terminal that conducts an electric current into or away from various conducting substances in a circuit (such as the anode or cathode of a battery). (09 Jan 1998) |
| electrode catheter ablation | A method of ablating the site of origin of arrhythmias whereby high energy electric shocks are delivered by intravascular catheters. (05 Mar 2000) |
| electrode knife | A blade-shaped electrical instrument used to cut tissues by means of a high-frequency electrical current. (05 Mar 2000) |