mean arterial pressure

pressure /pres·sure/ (P ) (presh´er) force per unit area.

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arterial pressure  blood p. (2).

blood pressure 

1. the pressure of blood against the walls of any blood vessel.

2. the pressure of blood on the walls of the arteries, dependent on the energy of the heart action, elasticity of the arterial walls, and volume and viscosity of the blood; the maximum or systolic pressure occurs near the end of the stroke output of the left ventricle, and the minimum or diastolic late in ventricular diastole.

central venous pressure  (CVP) the venous pressure as measured at the right atrium, done by means of a catheter introduced through the median cubital vein to the superior vena cava.

cerebrospinal pressure  the pressure or tension of the cerebrospinal fluid, normally 100–150 mm. as measured by the manometer.

detrusor pressure  the pressure exerted inwards by the detrusor urinae muscles of the bladder wall.

diastolic pressure , diastolic blood pressure see blood p.

end-diastolic pressure  the pressure in the ventricles at the end of diastole, usually measured in the left ventricle as an approximation of the end-diastolic volume, or preload.

intracranial pressure  (ICP) pressure of the subarachnoidal fluid.

intraocular pressure  the pressure exerted against the outer coats by the contents of the eyeball.

intravesical pressure  the pressure exerted on the contents of the urinary bladder; the sum of the intra-abdominal pressure from outside the bladder and the detrusor pressure.

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) a measure of the strength of respiratory muscles, obtained by having the patient inhale as strongly as possible with the mouth against a mouthpiece; the maximum value is near the residual volume.

mean arterial pressure  (MAP) the average pressure within an artery over a complete cycle of one heartbeat.

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 due to the presence of colloids in solution.

osmotic pressure  the pressure required to prevent 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.

positive pressure  pressure greater than that of the atmosphere.

positive end-expiratory pressure  (PEEP) a method of mechanical ventilation in which pressure is maintained to increase the volume of gas left in the lungs at the end of exhalation, reducing shunting of blood through the lungs and improving gas exchange.

pulmonary artery wedge pressure  (PAWP), pulmonary capillary wedge pressure (PCWP) intravascular pressure as measured by a catheter wedged into the distal pulmonary artery ; used to measure indirectly the mean left atrial pressure.

pulse pressure  the difference between systolic and diastolic pressures.

systolic pressure , systolic blood pressure see blood p.

Valsalva leak point pressure  the amount of pressure on the bladder by a Valsalva maneuver at which leakage of urine occurs; a measure of strength of the urethral sphincters.

venous pressure  the pressure of blood in the veins.

wedge pressure  blood pressure measured by a small catheter wedged into a vessel, occluding it, e.g., pulmonary capillary wedge p.

wedged hepatic vein pressure  the venous pressure measured with a catheter wedged into the hepatic vein; used to locate the site of obstruction in portal hypertension.

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mean arterial pressure (MAP),

the arithmetic mean of the blood pressure in the arterial part of the circulation, it is calculated by adding the systolic pressure reading to two times the diastolic reading and dividing the sum by 3.

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mean

an average; a numerical value intermediate between two extremes. Called also arithmetic mean.

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mean arterial pressure

average pressure in artery for one heartbeat.

mean cell constants

see erythrocyte indices.

mean corpuscular hemoglobin (MCH)

see mch.

mean corpuscular hemoglobin concentration (MCHC)

see mchc.

mean corpuscular volume (MCV)

see mcv.

mean deviation

the average value of a set of absolute deviations from the mean of a set of observations.

mean electrical axis (MEA)

in electrocardiography, a calculation based on the relative amplitude of Q, R and S waves in the three bipolar limb leads. It is an aid to recognizing right ventricular enlargement and various intraventricular conduction defects.

geometric mean

the antilog of the mean of the logarithm of the calculated values, the same as the n^th root of the product of the values. It is often a more useful mean for growth curves.

harmonic mean

the reciprocal of the arithmetic mean of values converted to their reciprocals (used in dealing with skewed data).

rolling mean

see moving average.