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force per unit area.
arterial pressure (arterial blood pressure) blood pressure (def. 2).
atmospheric pressure the pressure exerted by the atmosphere, usually considered as the downward pressure of air onto a unit of area of the earth's surface; the unit of pressure at sea level is one atmosphere. Pressure decreases with increasing altitude.
barometric pressure atmospheric p.
1. see blood pressure.
2. pressure of blood on walls of any blood vessel.
capillary pressure the blood pressure in the capillaries.
central venous pressure see central venous pressure.
cerebral perfusion pressure the mean arterial pressure minus the intracranial pressure; a measure of the adequacy of cerebral blood flow.
cerebrospinal pressure the pressure of the cerebrospinal fluid, normally 100 to 150 mm Hg.
continuous positive airway pressure see continuous positive airway pressure.
filling pressure see mean circulatory filling pressure.
high blood pressure hypertension.
intracranial pressure see intracranial pressure.
intraocular pressure the pressure exerted against the outer coats by the contents of the eyeball.
intrapleural pressure (intrathoracic pressure) pleural pressure.
intrinsic positive end-expiratory pressure elevated positive end-expiratory pressure and dynamic pulmonary hyperinflation caused by insufficient expiratory time or a limitation on expiratory flow. It cannot be routinely measured by a ventilator's pressure monitoring system but is measurable only using an expiratory hold maneuver done by the clinician. Its presence increases the work needed to trigger the ventilator, causes errors in the calculation of pulmonary compliance, may cause hemodynamic compromise, and complicates interpretation of hemodynamic measurements. Called also auto-PEEP and intrinsic PEEP.
maximal expiratory pressure maximum expiratory pressure.
maximal inspiratory pressure the pressure during inhalation against a completely occluded airway; used to evaluate inspiratory respiratory muscle strength and readiness for weaning from mechanical ventilation. A maximum inspiratory pressure above −25 cm H2O is associated with successful weaning.
maximum expiratory pressure (MEP) a measure of the strength of respiratory muscles, obtained by having the patient exhale as strongly as possible against a mouthpiece; the maximum value is near total lung capacity.
maximum inspiratory pressure (MIP) the inspiratory pressure generated against a completely occluded airway; used to evaluate inspiratory respiratory muscle strength and readiness for weaning from mechanical ventilation. A maximum inspiratory pressure above −25 cm H2O is associated with successful weaning.
mean airway pressure the average pressure generated during the respiratory cycle.
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.
negative pressure pressure less than that of the atmosphere.
oncotic pressure the osmotic pressure of a colloid in solution.
osmotic pressure the pressure required to stop osmosis through a semipermeable membrane between a solution and pure solvent; it is proportional to the osmolality of the solution. Symbol π.
partial pressure the pressure exerted by each of the constituents of a mixture of gases.
peak pressure in mechanical ventilation, the highest pressure that occurs during inhalation.
plateau pressure in mechanical ventilation, the pressure measured at the proximal airway during an end-inspiratory pause; a reflection of alveolar pressure.
pleural pressure the pressure between the visceral pleura and the thoracic pleura in the pleural cavity. Called also intrapleural or intrathoracic pressure.
positive pressure pressure greater than that of the atmosphere.
positive end-expiratory pressure (PEEP) a method of control mode ventilation in which positive pressure is maintained during expiration to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange. A PEEP higher than the critical closing pressure prevents alveolar collapse and can markedly improve the arterial Po2 in patients with a lowered functional residual capacity, as in acute respiratory failure.
pulmonary artery wedge pressure (PAWP) (pulmonary capillary wedge pressure (PCWP)) intravascular pressure, reflecting the left ventricular end diastolic pressure, measured by a swan-ganz catheter wedged into a small pulmonary artery to block the flow from behind.
pulse pressure the difference between the systolic and diastolic pressures. If the systolic pressure is 120 mm Hg and the diastolic pressure is 80 mm Hg, the pulse pressure is 40 mm Hg; the normal pulse pressure is between 30 and 40 mm Hg.
urethral pressure the pressure inwards exerted by the walls of the urethra, which must be counteracted in order for urine to flow through; see also urethral pressure profile.
venous pressure the blood pressure in the veins; see also central venous pressure.
water vapor pressure the tension exerted by water vapor molecules, 47 mm Hg at normal body temperature.
wedge pressure blood pressure measured by a small catheter wedged into a vessel, occluding it; see also pulmonary capillary wedge pressure and wedged hepatic vein pressure.
wedged hepatic vein pressure the venous pressure measured with a catheter wedged into the hepatic vein. The difference between wedged and free hepatic vein pressures is used to locate the site of obstruction in portal hypertension; it is elevated in that due to cirrhosis, but low in cardiac ascites or portal vein thrombosis.
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 pressures.
the difference between the systolic and diastolic blood pressures, normally 30 to 50 mm Hg.
pulse pres·sure(pŭls presh'ŭr)
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, pressures. A reading of 30-50 is considered in the normal range.
pulse pressureThe difference between the diastolic and the systolic blood pressure.
pulse pressurethe difference between the highest (systolic) and lowest (diastolic) arterial blood pressure during each cardiac cycle.
pulse pres·sure(pŭls presh'ŭr)
Variation in blood pressure occurring in an artery during cardiac cycle.
stress or strain, by compression, expansion, pull, thrust or shear.
the blood pressure in the arteries.
the pressure exerted by the atmosphere, about 15 lb per square inch (2.17 kPa) at sea level.
the blood pressure in the capillaries.
central venous pressure (CVP)
see central venous pressure.
the pressure of the cerebrospinal fluid, normally 100 to 150 mmHg.
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.
a device attached to the outlet of gas tanks to measure internal pressure which indicates the quantity of gas remaining.
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.
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.
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.
necrosis of tissue caused by exclusion of circulation by external compression, e.g. in prolonged recumbency, or due to too-tight bandage, collar, harness.
pressure less than that of the atmosphere.
the osmotic pressure of a colloid in solution.
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).
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.
pressure greater than that of the atmosphere.
difference between systolic and diastolic pressures in arteries.
e.g. the blood pressure receptors in the aortic arch and the carotid sinus.
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.
the blood pressure in the veins. See also central venous 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.
bandages which apply pressure to underlying tissues; used after trauma to limit the development of edema, and in the management of lymphedema.
1. a rhythmic wave.
2. any leguminous seed used in animal feed or human food. Contain about 20% protein.
3. the beat of the heart as felt through the walls of arteries. What is felt is not the blood pulsing through the arteries but a shock wave, generated by the abrupt ejection of blood from the heart, that travels along the arteries. The arterial pulse wave can be measured by a sphygmograph. The resulting tracing shows ascending and descending limbs.
that over the abdominal aorta.
includes irregularity of timing and amplitude, large or small amplitude, waterhammer pulse, Corrigan's pulse, dropped pulse, pulse deficit, alternating pulse and many others.
pulsus alternans; one with regular alteration of weak and strong beats without changes in cycle length.
indicative of arterial blood pressure; estimated on the difference of pressure exerted by the fingers to occlude and then reopen the arterial pulse.
one in which the ascending limb of the tracing shows a transient drop in amplitude, or a notch.
one in which the ascending limb of the tracing shows two small additional waves or notches.
one in which the ascending limb of the tracing shows three small additional waves or notches.
the wave of pressure generated by the ejection of blood from the left ventricle into the aorta. Although the size (amplitude) of the pulse depends on the volume ejected it is not the blood passing the finger that is palpated, it is only the pressure wave. The pulse is a good indicator of the heart's activity with respect to amplitude, rate and regularity. It may also provide information on the state of the vessel walls and the efficiency of the aortic semilunar valves. It may be palpated in the median, facial, femoral or coccygeal arteries, the preferred site varying with the species and the occasion.
atrial venous pulse
atriovenous pulse, a cervical pulse having an accentuated 'a' wave during atrial systole, owing to increased force of contraction of the right atrium; a characteristic of tricuspid stenosis.
B-B shot pulse
see water-hammer pulse (below).
one in which two beats occur in rapid succession, the groups of two being separated by a longer interval, usually related to regularly occurring ventricular premature beats.
to study the movement of macromolecules, cells are incubated with a radiolabeled precursor (pulse) and then replaced with unlabeled precursor (chase). The label can be followed as it is incorporated into newly synthesized compounds and through different cellular compartments.
see corrigan's pulse.
the difference between the apical pulse and the radial pulse. Obtained by counting apical beats as heard through a stethoscope over the heart and counting the arterial pulse at the same time. A characteristic of several arrhythmias.
a pulse characterized by two peaks, the second peak occurring in diastole and being an exaggeration of the dicrotic wave.
the administration of drugs, usually antibiotics or corticosteroids, in a single, large dose which might be repeated after an interval of days. Thought to have the advantage of high tissue levels and fewer of the undesirable side-effects associated with more frequent dosing.
that which is located at the site where the femoral artery passes through the groin in the femoral triangle; the usual site for palpating the pulse in dogs and cats.
fetal pulse detector
an ultrasound detector based on the Doppler principle used to detect the presence of a living fetus in utero.
the arterial tide in the umbilical cord.
the power source for a cardiac pacemaker system, usually powered by a lithium battery. It supplies electrical impulses to the implanted electrodes. See also pacemaker.
one characterized by high tension.
see water-hammer pulse (below).
comprises the movements of the wall of the jugular vein in response to pressure changes in the right atrium. Much more visible if the vein is distended. A reflection of increased pressure in the right atrium or insufficiency of the right A-V valve. A small pulse is normal in most food animals. A large pulse which goes high up the neck when the head is in the normal position, and which is synchronous with the heart cycle and is systolic in time, indicates insufficiency of the right atrioventricular valve.
a pulse detector which uses the Doppler principle.
one that markedly decreases in amplitude during inspiration.
that palpable in the extremities, e.g. legs, neck and head; the usual sites for measuring the pulse rate.
one in which the arteries are subject to sudden distention and collapse.
the difference between the systolic and diastolic pressures.
that felt over the radial artery.
the number of pulsations per minute palpable in an artery, usually of a limb. The normal rates per minute for the common domestic animal species are: horses, 30 to 40; young horses up to one year of age, 70 to 80; cattle, 60 to 80; young calves, 100 to 120; sheep and goats, 70 to 120; pigs (heart rate), 60 to 70; dogs, 100 to 130; cats, 110 to 140; adult fowls 250 to 300.
regularity of the pulse in time and amplitude.
one that is very fine and barely perceptible.
one with a pause after every third beat.
one giving the sensation of successive waves.
a slow pulse.
the pulsation over a vein.
one in which the artery is suddenly and markedly distended and relaxed. Characteristic of patent ductus arteriosus. Called also Corrigan's, jerky and B-B shot pulse.
a small, tense pulse.