| back-pressure renal atrophy | <radiology> Caliectasis without obstruction, due to repeated episodes of obstruction, gradual loss of renal pyramids (12 Dec 1998) |
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| barometric pressure | The absolute pressure of the ambient atmosphere, varying with weather, altitude, etc.; expressed in millibars (meteorology) or mm Hg or torr (respiratory physiology); at sea level, one atmosphere (atm, 760 mm Hg or torr) is equivalent to: 14.69595 lb/sq in, 1013.25 millibars, 1013.25 × 106 dynes/cm2, and, in SI units, 101,325 pascals (Pa). Synonym: atmospheric pressure. (05 Mar 2000) |
| bile duct pressure | <radiology> Normal: 15-20 cm H2O (12 Dec 1998) |
| biting pressure | Any force exerted upon the occlusal surfaces of teeth. Synonym: biting pressure. (05 Mar 2000) |
| blood pressure | <cardiology, physiology> The force that the circulating blood exerts on the walls of the arteries. This measurement is divided into systolic (pressure during contraction of the heart) and diastolic (pressure during relaxation phase). Blood pressure varies with age and sex of the individual. A rough rule of thumb for normal systolic pressure is 100 + Age of individual. In children 2 x (age) + 80 = systolic BP The diastolic pressure should be roughly 2/3 the systolic pressure. (27 Sep 1997) |
| blood pressure determination | Techniques for measuring blood pressure. (12 Dec 1998) |
| blood pressure, high | High blood pressure (hypertension) is a repeatedly elevated blood pressure exceeding 140 over 90 mmHg. High blood pressure is also called the silent killer. Chronically high blood pressure can cause blood vessel changes in the back of the eye (retina), thickening of the heart muscle, kidney failure, and brain damage. No specific cause for high blood pressure is found in 95% of patients. High blood pressure is treated with salt restriction, regular aerobic exercise, and medications. (12 Dec 1998) |
| blood pressure monitoring, ambulatory | Method in which prolonged blood pressure readings are made while the patient undergoes normal daily activities. It allows quantitative analysis of the high blood pressure load over time, can help distinguish between types of hypertension, and can assess the effectiveness of antihypertensive therapy. (12 Dec 1998) |
| blood pressure monitors | Devices for continuously measuring and displaying the arterial blood pressure. (12 Dec 1998) |
| vapor pressure | The partial pressure exerted by the vapor phase of a liquid. (05 Mar 2000) |
| gauge pressure | Pressure measured relative to ambient atmospheric pressure; at sea level, it is 1 atm less than the pressure in the atmosphere. Compare: absolute pressure. (05 Mar 2000) |
| venous pressure | The blood pressure in a vein. It is usually measured to assess the filling pressure to the ventricle. (12 Dec 1998) |
| ventilators, negative-pressure | Body ventilators that assist ventilation by applying intermittent subatmospheric pressure around the thorax, abdomen, or airway and periodically expand the chest wall and inflate the lungs. They are relatively simple to operate and do not require tracheostomy. These devices include the tank ventilators ("iron lung"), portalung, pneumowrap, and chest cuirass ("tortoise shell"). (12 Dec 1998) |
| ventricular filling pressure | The pressure in the ventricle as it fills with blood, ordinarily equivalent to the mean atrial pressure when there is no A-V valvular gradient. Atrial pressure can be used in place of transmural pressure because pericardial pressure usually varies between -2 and +2 mm Hg and hence is negligible. During cardiac tamponade, pericardial and atrial pressures equilibrate so that transmural pressure is zero and the high atrial presures cannot be "filling" pressures. (05 Mar 2000) |
| ventricular pressure | The pressure within a cardiac ventricle. Ventricular pressure waveforms can be measured in the beating heart by catheterization or estimated using imaging techniques (e.g., doppler echocardiography). The information is useful in evaluating the function of the myocardium, cardiac valves, and pericardium, particularly with simultaneous measurement of other (e.g., aortic or atrial) pressures. (12 Dec 1998) |