| flow-volume curve | The graph produced by plotting the instantaneous flow of respiratory gas against the simultaneous lung volume, usually during maximal forced expiration. (05 Mar 2000) |
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| laminar air flow unit | An air-filtering system used at some transplant facilities to remove particulate matter and fungi from the air. (16 Dec 1997) |
| laminar flow | The relative motion of elements of a fluid along smooth parallel paths, which occurs at lower values of Reynolds number. (05 Mar 2000) |
| forced expiratory flow | Expiratory flow during measurement of forced vital capacity; subscripts specify the exact parameter measured, e.g., peak instantaneous flow, the instantaneous flow at some specified point on the curve of volume expired versus time, or on the flow-volume curve, the mean flow between two expired volumes. (05 Mar 2000) |
| forced expiratory flow rates | Measurements of rates of airflow during a forced vital capacity determination. (12 Dec 1998) |
| frozen-in flow law | <radiobiology> In a perfect conductor, the total magnetic flux through any surface is a constant. In a plasma which is nearly perfectly conducting, the relevant surfaces move with the plasma, the result is that the plasma is tied to the magnetic field, and the field is tied to the plasma. Motion of the plasma thus deforms the magnetic field, and vice versa. The magnetic flux is said to be frozen into the plasma. (09 Oct 1997) |
| low flow principle | A principle based on the observation that animals can survive prolonged vena caval occlusion without sequelae: if blood from the azygos vein alone is permitted to enter the heart, patients are perfused during cardiac and pulmonary bypass at flows much less than the normal resting cardiac output. Synonym: low flow principle. (05 Mar 2000) |
| activated clotting time | The most common test used for coagulation time in cardiovascular surgery. (05 Mar 2000) |
| activated partial thromboplastin time | The time needed for plasma to form a fibrin clot following the addition of calcium and a phospholipid reagent; used to evaluate the intrinsic clotting system. (05 Mar 2000) |
| A-H conduction time | Forward conduction of the cardiac impulse from atria to ventricles via the A-V node or any bypass tract, represented in the electrocardiogram by the P-R interval. P-H conduction time is from the onset of the P wave to the first high frequency component of the His bundle electrogram (normally 119 ± 38 msec); A-H conduction time is from the onset of the first high frequency component of the atrial electrogram to the first high frequency component of the His bundle electrogram (normally 92 ± 38 msec); P-A conduction time is from the onset of the P wave to the onset of the atrial electrogram (normally 27 ± 18 msec). (05 Mar 2000) |
| association time | Time elasping between a stimulus and the verbalised response to it. (05 Mar 2000) |
| biologic time | The concept that our appreciation of time varies with age and is governed by the neural organization of the individual; it obeys a logarithmic rather than an arithmetic law. (05 Mar 2000) |
| bleeding time | <haematology> A test which measures the time it takes for small blood vessels to close off and bleeding to stop. Abnormal results can be seen in those with congenital or acquired platelet function disorders or thrombocytopenia. (27 Sep 1997) |
| blood circulation time | Determination of the shortest time interval between the injection of a substance in the vein and its arrival at some distant site in sufficient concentration to produce a recognizable end result. It represents approximately the inverse of the average velocity of blood flow between two points. (12 Dec 1998) |
| P-A conduction time | See: atrioventricular conduction. (05 Mar 2000) |