| high-pressure liquid chromatography | <investigation> A lab technique, a type of column chromatography, which uses a combination of several separation techniques to separate substances at higher resolution. Extremely sharp peaks on the elution profile can be produced with high-performance liquid chromatography (HPLC). (09 Oct 1997) |
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| high pressure nervous syndrome | <syndrome> A syndrome of tremors, nausea, dizziness, and decreased motor and mental performance which develops in those who dive deeply (c. 1000 ft) usually breathing a mixture of oxygen and helium. Nitrogen is not a factor as it is in inert gas narcosis. (12 Dec 1998) |
| pulmonary capillary wedge pressure | The pressure obtained when a catheter is passed from the right side of the heart into the pulmonary artery as far as it will go and "wedged" into an end artery. PCWP is measured by letting pulmonary blood flow guide a balloon-flotation catheter into a small pulmonary end artery. The pressure distal to the wedged catheter is an approximation of cardiac left atrial pressure. The pressure recorded with the balloon deflated is pulmonary artery pressure. (05 Mar 2000) |
| selection pressure | Impact of effective reproduction due to environmental impact on the phenotype. (05 Mar 2000) |
| pulmonary pressure | The blood pressure in the pulmonary artery. (05 Mar 2000) |
| pulmonary wedge pressure | The blood pressure as recorded after wedging a catheter in a small pulmonary artery; believed to reflect the pressure in the pulmonary capillaries. (12 Dec 1998) |
| pulp pressure | The pressure in the dental pulp cavity associated with extracellular fluid pressure, but showing pulsatile variations during the cardiac cycle because of the encasement of the pulp within the tooth. (05 Mar 2000) |
| pulse pressure | The variation in blood pressure occurring in an artery during the cardiac cycle; it is the difference between the systolic or maximum and diastolic or minimum pressure's. (05 Mar 2000) |
| hydrostatic pressure | The pressure exerted by a liquid as a result of its potential energy, ignoring its kinetic energy; frequently used to distinguish a true pressure from an osmotic pressure or to emphasize the variation in pressure in a column of fluid due to the effect of gravity. (05 Mar 2000) |
| solution pressure | The force driving atoms or molecules to leave a solid particle and enter into solution (i.e., to dissolve). (05 Mar 2000) |
| sound pressure level | A measure of sound energy relative to 0.0002 dynes/cm2, expressed in decibels. (05 Mar 2000) |
| standard pressure | The absolute pressure to which gases are referred under standard conditions (STPD), i.e., 760 mm Hg, 760 torr, or 101,325 newtons/m2 (i.e., 101,325 Pa). (05 Mar 2000) |
| negative end-expiratory pressure | A subatmospheric pressure at the airway at the end of expiration. (05 Mar 2000) |
| negative pressure | Pressure less than that of the ambient atmosphere. (05 Mar 2000) |
| normal pressure hydrocephalus | <neurology> A brain disorder caused by blockage of the flow of cerebrospinal fluid (CSF), with enlargement of the ventricles of the brain (keep the pressure normal) and compression of brain tissue. Brain atrophy is the result. In this condition the CSF is produced normally but not reabsorbed. Symptom onset is gradual. A key feature is dementia. Treatment is surgical (VP shunt). (13 Nov 1997) |