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Korotkoff Sound
Korotkoff sounds are the sounds that medical personnel listen for when they are taking blood pressure using a non-invasive procedure. They are named after Nikolai Korotkov, a Russian physician who discovered them in 1905, when he was working at the Imperial Medical Academy in St. Petersburg, the Russian Empire. Description The sounds heard during the measurement of blood pressure are not the same as the heart sounds heard during chest auscultation that are due to vibrations inside the ventricles associated with the snapping shut of the valves. If a stethoscope is placed over the brachial artery in the antecubital fossa in a normal person (without arterial disease), no sound should be audible. As the heart beats, these pulses are transmitted smoothly via laminar (non-turbulent) blood flow throughout the arteries, and no sound is produced. Similarly, if the cuff of a sphygmomanometer is placed around a patient's upper arm and inflated to a pressure above the patient's systolic blo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systolic Blood Pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" refers to the pressure in the large arteries. Blood pressure is usually expressed in terms of the systolic pressure (maximum pressure during one heartbeat) over diastolic pressure (minimum pressure between two heartbeats) in the cardiac cycle. It is measured in millimeters of mercury ( mmHg) above the surrounding atmospheric pressure. Blood pressure is one of the vital signs—together with respiratory rate, heart rate, oxygen saturation, and body temperature—that healthcare professionals use in evaluating a patient's health. Normal resting blood pressure, in an adult is approximately systolic over diastolic, denoted as "120/80 mmHg". Globally, the average blood pressure, age standardized, has remained about the same since 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse Pressure
Pulse pressure is the difference between systolic and diastolic blood pressure. It is measured in millimeters of mercury (mmHg). It represents the force that the heart generates each time it contracts. Resting blood pressure is normally approximately 120/80 mmHg, which yields a pulse pressure of approximately 40 mm Hg. Causes High High sodium intake may cause high pulse pressure. Calculation Pulse pressure is the (higher) systolic blood pressure minus the (lower) diastolic blood pressure. The systemic pulse pressure is approximately proportional to stroke volume, or the amount of blood ejected from the left ventricle during systole (pump action) and inversely proportional to the compliance (similar to Elasticity) of the aorta. The aorta has the highest compliance in the arterial system due in part to a relatively greater proportion of elastin fibers versus smooth muscle and collagen. This serves the important function of damping the pulsatile ( max pump pressure) ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auscultatory Gap
An auscultatory gap, also known as the silent gap, is a period of diminished or absent Korotkoff sounds during the manual measurement of blood pressure. It is associated with reduced peripheral blood flow caused by changes in the pulse wave. The improper interpretation of this gap may lead to blood pressure monitoring errors, such as an underestimation of systolic blood pressure and/or an overestimation of diastolic blood pressure. In order to correct for an auscultatory gap, the radial pulse should be monitored by palpation. It is therefore recommended to palpate and auscultate when manually recording a patient's blood pressure. Typically, the blood pressure obtained via palpation is around 10 mmHg lower than the pressure obtained via auscultation. In general, the examiner can avoid being confused by an auscultatory gap by always inflating a blood pressure cuff to 20-40 mmHg higher than the pressure required to occlude the brachial pulse. Cause There is evidence that auscu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diastole
Diastole ( ) is the relaxed phase of the cardiac cycle when the chambers of the heart are re-filling with blood. The contrasting phase is systole when the heart chambers are contracting. Atrial diastole is the relaxing of the atria, and ventricular diastole the relaxing of the ventricles. The term originates from the Greek word (''diastolē''), meaning "dilation", from (''diá'', "apart") + (''stéllein'', "to send"). Role in cardiac cycle A typical heart rate is 75 beats per minute (bpm), which means that the cardiac cycle that produces one heartbeat, lasts for less than one second. The cycle requires 0.3 sec in ventricular systole (contraction)—pumping blood to all body systems from the two ventricles; and 0.5 sec in diastole (dilation), re-filling the four chambers of the heart, for a total of 0.8 sec to complete the cycle. Early ventricular diastole During early ventricular diastole, pressure in the two ventricles begins to drop from the peak reached during systo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paediatrics
Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until the age of 18. The American Academy of Pediatrics recommends people seek pediatric care through the age of 21, but some pediatric subspecialists continue to care for adults up to 25. Worldwide age limits of pediatrics have been trending upward year after year. A medical doctor who specializes in this area is known as a pediatrician, or paediatrician. The word ''pediatrics'' and its cognates mean "healer of children," derived from the two Greek words: (''pais'' "child") and (''iatros'' "doctor, healer"). Pediatricians work in clinics, research centers, universities, general hospitals and children's hospitals, including those who practice pediatric subspecialties (e.g. neonatology requires resources available in a NICU). History The earlie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lippincott Williams & Wilkins
Lippincott Williams & Wilkins (LWW) is an American imprint of the American Dutch publishing conglomerate Wolters Kluwer. It was established by the acquisition of Williams & Wilkins and its merger with J.B. Lippincott Company in 1998. Under the LWW brand, Wolters Kluwer, through its Health Division, publishes scientific, technical, and medical content such as textbooks, reference works, and over 275 scientific journals (most of which are medical or other public health journals). Publications are aimed at physicians, nurses, clinicians, and students. Overview LWW grew out of the gradual consolidation of various earlier independent publishers by Wolters Kluwer. Predecessor Wolters Samson acquired Raven Press of New York in 1986. Wolters Samson merged with Kluwer in 1987. The merged company bought J. B. Lippincott & Co. of Philadelphia in 1990; it merged Lippincott with the Raven Press to form Lippincott-Raven in 1995. In 1997 and 1998, Wolters Kluwer acquired Thomson Science (owner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auscultatory Gap
An auscultatory gap, also known as the silent gap, is a period of diminished or absent Korotkoff sounds during the manual measurement of blood pressure. It is associated with reduced peripheral blood flow caused by changes in the pulse wave. The improper interpretation of this gap may lead to blood pressure monitoring errors, such as an underestimation of systolic blood pressure and/or an overestimation of diastolic blood pressure. In order to correct for an auscultatory gap, the radial pulse should be monitored by palpation. It is therefore recommended to palpate and auscultate when manually recording a patient's blood pressure. Typically, the blood pressure obtained via palpation is around 10 mmHg lower than the pressure obtained via auscultation. In general, the examiner can avoid being confused by an auscultatory gap by always inflating a blood pressure cuff to 20-40 mmHg higher than the pressure required to occlude the brachial pulse. Cause There is evidence that auscu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinical Significance
In medicine and psychology, clinical significance is the practical importance of a treatment effect—whether it has a real genuine, palpable, noticeable effect on daily life. Types of significance Statistical significance Statistical significance is used in hypothesis testing, whereby the null hypothesis (that there is no relationship between variables) is tested. A level of significance is selected (most commonly ''α'' = 0.05 or 0.01), which signifies the probability of incorrectly rejecting a true null hypothesis. If there is a significant difference between two groups at ''α'' = 0.05, it means that there is only a 5% probability of obtaining the observed results under the assumption that the difference is entirely due to chance (i.e., the null hypothesis is true); it gives no indication of the magnitude or clinical importance of the difference. When statistically significant results are achieved, they favor rejection of the null hypothesis, but they do not prove that the nul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between those layers. Turbulence is commonly observed in everyday phenomena such as surf, fast flowing rivers, billowing storm clouds, or smoke from a chimney, and most fluid flows occurring in nature or created in engineering applications are turbulent. Turbulence is caused by excessive kinetic energy in parts of a fluid flow, which overcomes the damping effect of the fluid's viscosity. For this reason turbulence is commonly realized in low viscosity fluids. In general terms, in turbulent flow, unsteady vortices appear of many sizes which interact with each other, consequently drag due to friction effects increases. This increases the energy needed to pump fluid through a pipe. The onset of turbulence can be predicted by the dimensionless Rey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systole (medicine)
Systole ( ) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. The term originates, via New Latin, from Ancient Greek (''sustolē''), from (''sustéllein'' 'to contract'; from ''sun'' 'together' + ''stéllein'' 'to send'), and is similar to the use of the English term ''to squeeze''. The mammalian heart has four chambers: the left atrium above the left ventricle (lighter pink, see graphic), which two are connected through the mitral (or bicuspid) valve; and the right atrium above the right ventricle (lighter blue), connected through the tricuspid valve. The atria are the receiving blood chambers for the circulation of blood and the ventricles are the discharging chambers. In late ventricular diastole, the atrial chambers contract and send blood to the larger, lower ventricle chambers. This flow fills the ventricles with blood, and the resulting pressure closes the valves to the atria. The ventricles now perform i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rate Of Fluid Flow
In physics and engineering, in particular fluid dynamics, the volumetric flow rate (also known as volume flow rate, or volume velocity) is the volume of fluid which passes per unit time; usually it is represented by the symbol (sometimes ). It contrasts with mass flow rate, which is the other main type of fluid flow rate. In most contexts a mention of ''rate of fluid flow'' is likely to refer to the volumetric rate. In hydrometry, the volumetric flow rate is known as '' discharge''. Volumetric flow rate should not be confused with volumetric flux, as defined by Darcy's law and represented by the symbol , with units of m3/(m2·s), that is, m·s−1. The integration of a flux over an area gives the volumetric flow rate. The SI unit is cubic metres per second (m3/s). Another unit used is standard cubic centimetres per minute (SCCM). In US customary units and imperial units, volumetric flow rate is often expressed as cubic feet per second (ft3/s) or gallons per minute (either ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
