| fixed pupil | A stationary pupil unresponsive to all stimuli. (05 Mar 2000) |
|---|---|
| fixed-rate pacemaker | An artificial pacemaker that emits electrical stimuli at a constant frequency. (05 Mar 2000) |
| fixed rate pulse generator | A generator in which the rate of discharge is independent of the natural activity of the heart. Synonym: fixed rate pulse generator. (05 Mar 2000) |
| fixed torticollis | Persistent contracture of cervical muscles on one side. (05 Mar 2000) |
| fixed virus | Rabies virus whose virulence for rabbits has been stabilised by numerous passages through this experimental host. See: street virus. (05 Mar 2000) |
| absolute filter | <apparatus> A fine-pored, steam-sterilisable filter that is used to trap airborne microorganisms. The filter's pores are about 2 micrometres in diameter, smaller than the particles it is designed to remove. (06 May 1997) |
| bandpass filter | A device that allows a limited range of frequencies to pass. (05 Mar 2000) |
| Berkefeld filter | A bacterial filter used in 1891, made of earth known as Kieselguhr taken from the name of the mine in Hanover, Germany, from which the earth was found. Ground water at this mine had a clear blue colour suggesting the use of the earth as a filter. Origin: Berkefield, name of owner of the mine from which the material to make the filter was taken (05 Mar 2000) |
| bird's nest filter | A wire mesh vena cava filter. (05 Mar 2000) |
| bird's nest ivc filter | <radiology> Introduced 1982; Cook Inc., Bloomington, IN advantages, low profile: 14.5 Fr introducer sheath, low recurrent PE rates (1.1 - 2.7% by clinical history), low IVC thrombosis rates (2.9 - 5.0% by clinical history), placement in large diameter IVCs (not greater than40mm), free-form configuration does not require centreing in IVC disadvantages: stainless steel: ferromagnetic = magnetic susceptibility artifact, more operator dependent, difficult to place in short IVCs (need about 7cm for proper placement), prolapse of filter wires (? clinical significance) see also: indications (12 Dec 1998) |
| vena cava filter | A filter used for interruption of IVC to prevent pulmonary embolism; e.g., Greenfield filter. Synonym: venocaval filter. (05 Mar 2000) |
| vena-tech ivc filter | <radiology> Introduced as LGM (L.G. Medical, France), 1985; FDA aprroval 1991: Vena-Tech, Evanston, IL, 6-leg conical design with 6 stabilizing side bars, biocompatible metal known as Phynox (cobalt,chromium,iron,nickel,moly) Efficacy, recurrent PE: 2-6%, IVC occlusion: 8-24%, migration: 0-12% Advantages, ease of placement, excellent clot trapping efficiency, low profile, lacks ferromagnetic activity: minimal MRI artifacts Disadvantages, incomplete opening (6-19%): decreases clot-trapping efficiency, increased incidence from IJ approach, decreased with rapid deployment, increased IVC thrombosis rates: 8% initial reports; 22-24% on subsequent reports by ultrasound/MRI: 2-19% clinically symptomatic (12 Dec 1998) |
| venocaval filter | A filter used for interruption of IVC to prevent pulmonary embolism; e.g., Greenfield filter. Synonym: venocaval filter. (05 Mar 2000) |
| Rheinberg filter | <equipment> A colour-filter disk to be placed, as a dark field stop would be placed, below the substage condenser. The central circular area, that is filled with one of the two or three colour filters, should safely subtend the objective aperture. The annular quadrants around this are normally contrasting in colour. This is/are the colour shown by the organisms or other specimen detail against the coloured field. The effect is one kind of optical staining. (05 Aug 1998) |
| Greenfield filter | A multistrutted spring-styled filter usually placed in the inferior vena cava to prevent venous emboli from reaching the pulmonary circulation from the lower extremity. (05 Mar 2000) |