| ventilation perfusion scanning | <investigation, radiology> A nuclear medicine test that involves the inhalation of a radioactive gas and the injection of a radioactive compound into the bloodstream. A special camera measures the radioactive compound and generates a image of the lungs. Comparisons are made between the images generated. Pulmonary embolism can be diagnosed using this procedure. (12 Jan 1998) |
|---|---|
| maximal voluntary ventilation | Measure of the maximum amount of air that can be breathed in and blown out over a sustained interval such as 15 or 20 seconds. Common abbreviations are mvv and mbc. (12 Dec 1998) |
| maximum voluntary ventilation | The volume of air breathed when an individual breathes as deeply and as quickly as possible for a given time (e.g., 15 sec.). Synonym: maximum breathing capacity. (05 Mar 2000) |
| mechanical ventilation | <anaesthetics> Mechanically assisted breathing using a electrically powered device that forces oxygenated air into the lungs and then allow time for passive exhalation of air. (27 Sep 1997) |
| middle ear ventilation | Ventilation of the middle ear in the treatment of secretory (serous) otitis media, usually by placement of tubes or grommets which pierce the tympanic membrane. (12 Dec 1998) |
| wasted ventilation | That part of the pulmonary ventilation which is ineffective in exchanging oxygen and carbon dioxide with pulmonary capillary blood; calculated as physiologic dead space multiplied by respiratory frequency. (05 Mar 2000) |
| controlled mechanical ventilation | Artificial ventilation in which all inspirations are provided by positive pressure applied to the airway. Synonym: continuous positive pressure breathing, continuous positive pressure ventilation, intermittent positive pressure breathing, intermittent positive pressure ventilation. (05 Mar 2000) |
| controlled ventilation | Intermittent application of mechanically or manually generated positive pressure to gas(es) in or about the airway as a means of forcing gases into the lungs in the absence of spontaneous ventilatory efforts. Synonym: controlled respiration. (05 Mar 2000) |
| pulmonary ventilation | The process of exchange of air between the lungs and the ambient air. Pulmonary ventilation is a measure of the rate of ventilation expressed usually in liters per minute. (12 Dec 1998) |
| spontaneous intermittent mandatory ventilation | Intermittent mandatory ventilation spontaneously initiated by the patient, to increase tidal volume, and subsequently synchronised with patient's respiratory cycle. Synonym: synchronised intermittent mandatory ventilation. (05 Mar 2000) |
| synchronised intermittent mandatory ventilation | Intermittent mandatory ventilation spontaneously initiated by the patient, to increase tidal volume, and subsequently synchronised with patient's respiratory cycle. Synonym: synchronised intermittent mandatory ventilation. (05 Mar 2000) |
| intermittent mandatory ventilation | Mechanical application of positive pressure at a predetermined frequency to the airway to increase tidal volume. (05 Mar 2000) |
| lung ventilation agents | <radiology> Xe-133, most commonly used, Xe-127, t = 36.4 days; photons @ 172, 203, 375 keV, can image V after Q, Kr-81m, very expensive, t = 13 sec; photon 190 keV, can repeat V in each projection, Tc-99m DTPA aerosol, can image V in mult. Projections, image Q after V, 1 mCi most likely to be 50-75 mrad to lung, V/Q imaging (12 Dec 1998) |
| CD4-positive T-lymphocytes | A critical subpopulation of regulatory T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the t4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes, which includes both the helper-inducer (T-lymphocytes, helper-inducer) and suppressor-inducer (T-lymphocytes, suppressor-inducer) T-cells. (12 Dec 1998) |
| CD8-positive T-lymphocytes | A critical subpopulation of regulatory T-lymphocytes involved in MHC class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-lymphocytes, cytotoxic) and suppressor T-lymphocytes (T-lymphocytes, suppressor-effector). (12 Dec 1998) |