pressure necrosis


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pressure necrosis

pressure

stress or strain, by compression, expansion, pull, thrust or shear.

arterial pressure
the blood pressure in the arteries.
atmospheric pressure
the pressure exerted by the atmosphere, about 15 lb per square inch (2.17 kPa) at sea level.
capillary pressure
the blood pressure in the capillaries.
central venous pressure (CVP)
see central venous pressure.
cerebrospinal pressure
the pressure of the cerebrospinal fluid, normally 100 to 150 mmHg.
diastolic pressure
the lowest pressure recorded in the arterial blood pressure cycle. Represents the minimal pressure in the left ventricle which can maintain its ejection phase. See also blood pressure.
pressure gauge
a device attached to the outlet of gas tanks to measure internal pressure which indicates the quantity of gas remaining.
pressure gradient
the rate of increase (or decrease) in the magnitude of the pressure being measured.
intracranial pressure (ICP)
see intracranial pressure.
intraocular pressure (IOP)
the pressure exerted against the outer coats by the contents of the eyeball.
pressure load
mean circulatory filling pressure
a measure of the average (arterial and venous) pressure necessary to cause filling of the circulation with blood; it varies with blood volume and is directly proportional to the rate of venous return and thus to cardiac output.
pressure natriuresis
thought to participate in regulating the volume of extracellular fluid levels when the normal neurohumoral mediators are impaired; the increase in water and sodium ion excretions which occur when blood pressure is elevated because of an increase in the circulating blood volume.
pressure necrosis
necrosis of tissue caused by exclusion of circulation by external compression, e.g. in prolonged recumbency, or due to too-tight bandage, collar, harness.
negative pressure
pressure less than that of the atmosphere.
oncotic pressure
the osmotic pressure of a colloid in solution.
osmotic pressure
the potential pressure of a solution directly related to its solute osmolar concentration; it is the maximum pressure developed by osmosis in a solution separated from another by a semipermeable membrane, i.e. the pressure that will just prevent osmosis between two such solutions.
pressure point granuloma
see pressure points (below).
pressure point pyoderma
see pressure points (below).
pressure points
parts of the body subject to pressure when the animal is recumbent, wearing harness or saddlery, or during restraint. Usually bony prominences such as the point of the hock, hip, shoulder, elbow and lateral aspects of limbs. These are predisposed to callus formation, infection pyoderma and granulomas.
positive pressure
pressure greater than that of the atmosphere.
pulse pressure
difference between systolic and diastolic pressures in arteries.
pressure receptors
e.g. the blood pressure receptors in the aortic arch and the carotid sinus.
pressure sore
decubitus ulcer.
systolic pressure
the highest reading in the arterial blood pressure cycle. A reflection of the ejection pressure of left ventricular systole, and the elasticity of the arterial system.
venous pressure
the blood pressure in the veins. See also central venous pressure.
wedge pressure
intravascular pressure as measured by a swan-ganz catheter introduced into the pulmonary artery; it permits indirect measurement of the mean left atrial pressure.
pressure wrap
bandages which apply pressure to underlying tissues; used after trauma to limit the development of edema, and in the management of lymphedema.
References in periodicals archive ?
The sacrum and greater trochanters have minimal soft tissue covering and have an inherent high compressive stiffness; these are two of the most common sites for pressure necrosis.
Retroesophageal ARSA is particularly susceptible to extrinsic compression and pressure necrosis secondary to nasogastric and endotracheal tube insertion, with a predisposition to arterio-esophageal fistula formation.
3 The pathogenic mechanisms are pressure necrosis from the tube-tip and an angulated neck of the tube rendering the anterior tracheal mucosa ischaemic and eroding the innominate-artery.
The promontory is not a common site for bone resorption because (1) it is not an area that is involved in accumulation of cholesteatoma perimatrix substances, (2) it is the densest bone of the human body, and (3) pressure necrosis from overlying tissue is uncommon.
The presumed cause of perforation in this case was impacted stone in the neck causing vascular compromise and pressure necrosis of the gall bladder wall.
When multiple individual magnets are ingested, they can conglomerate in different segments of bowel causing pressure necrosis, perforation and/or fistula formation anywhere along the gastrointestinal tract.
The ingestion of multiple magnets can be particularly dangerous, because the magnets--neodymiumiron-boron magnets that are 10-20 times stronger than traditional magnets --can link through loops of bowel and cause pressure necrosis.
Biliary-enteric fistulas may form from a stone impacted in the bladder neck, with pressure necrosis causing an erosion through the gall bladder wall and fistula formation (5), or following an attack of cholecystitis where there has been pericholecystic inflammation resulting in adhesions formed between the biliary and enteric systems, and ischaemia leading to perforation of gallbladder contents into the adjacent viscus.
Over a longer period, pressure necrosis potentiates the problem.