Hyperemia

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hyperemia

[‚hī·pə′rē·mē·ə]
(medicine)
An excess of blood within an organ or tissue caused by blood vessel dilation or impaired drainage, especially of the skin.

Hyperemia

 

also plethora, an excess of blood in a tissue or organ. One may distinguish arterial and venous hyperemia. Arterial (active) hyperemia arises as a result of increased blood flow in the arteries owing to increased tonus of the vasodilator nerves or decreased tonus of the vasoconstrictor nerves. Among its causes are increased sensitivity of the blood vessels to physiological stimuli or the influence of extraordinary stimuli (such as bacterial toxins, high temperature, and products of tissue decomposition); in humans psychogenic factors (such as shame and anger) play a large role. Arterial hyperemia is characterized by dilatation of the arteries in the hyperemized area, elevation of temperature in the area, acceleration of blood flow, and reddening (for example, hyperemia of the face). It is accompanied by intensification of metabolic processes in the tissues and promotes the regeneration of tissues. Hemorrhages may occur during arterial hyperemia if there are pathological changes in the blood vessels. Arterial hyperemia is induced for therapeutic purposes by means of mustard plasters and cupping glasses. Venous (passive, static) hyperemia occurs when the outflow of blood along the veins is obstructed as a result of pressure on the venous wall (cicatrix, tumor, varicose dilatation of the veins, or edema), while the inflow remains unchanged or when there is a weakening of cardiac activity. Venous hyperemia is characterized by deceleration of blood flow to the point of complete stasis. Oxygen deficit develops in the tissues, the vascular walls become more permeable, and edema develops. Prolonged blood stasis and edema may lead to atrophy of the parenchyma of an organ.

V. A. FROLOV

References in periodicals archive ?
Pearson correlation was used to examine the relationships between reactive hyperemia and blood pressures.
We assumed a positive correlation between the finger puncture frequency and RF at the puncture site and a negative correlation between the finger puncture frequency and MRC at the puncture site because repetitive puncturing should produce a semi-permanent reactive hyperemia.
The LDF values at rest and during reactive hyperemia are shown in Table 1.
Cutaneous postocclusive reactive hyperemia monitored by laser Doppler flux metering and skin temperature.
Post-occlusive reactive hyperemia (PORH) was measured as an index of cutaneous microvascular reactivity using the laser Doppler flowmetry (DRT4 MoorLAB, Moor Instrument, UK).
A transient increase in skin blood flow after ischemia is regulated by a protective mechanism called reactive hyperemia [4850,56-57].
Postocclusive reactive hyperemia and thermal response in the skin microcirculation of subjects with spinal cord injury.
Assessment of skin blood content and oxygenation in spinal cord injured subjects during reactive hyperemia.
He and his colleagues conducted follow-up telephone interviews with 86 patients with OSA who had undergone assessment of endothelial function with the postobstruction reactive hyperemia test when their OSA was diagnosed.
Reactive hyperemia is a fast, noninvasive skin test for bedside use in the evaluation of newborns with suspected early-onset sepsis, reported Dr.
On admission, the relative perfusion increase during reactive hyperemia was greater in the sepsis group than in the group without sepsis; this finding probably resulted from lower baseline perfusion values in the babies with sepsis.

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