Arterial (strictly speaking: vascular pressure), referring to the force exerted by blood circulating in the blood vessel walls, and is one of the major vital signs. The pressure of the circulating blood decreases as blood moves through the arteries, arterioles, capillaries and veins, the term blood pressure usually mean arterial pressure, ie, the pressure in the major arteries, the arteries are the blood vessels that take blood from the heart. Blood pressure is usually measured through a sphygmomanometer, which uses the height of a column of mercury to reflect the pressure that circulate (see non-invasive measurement). While many modern devices vascular pressure no longer use mercury, vascular pressure values are still universally reported in millimeters of mercury (mmHg). The systolic blood pressure is defined as the maximum pressure in the arteries, which occurs shortly after the start of the cycle of Cardiology, diastolic blood pressure is the lowest pressure (to the rest phase of cardiac cycle). The average pressure throughout the cardiac cycle reported that the mean arterial pressure, pulse pressure reflects the difference between the maximum and minimum pressures measured. Typical values for a rest, man healthy adult is approximately 120 mm Hg (16 kPa), systolic and 80 mm Hg (11 kPa), diastolic (written as 120/80 mmHg, and talked as a twenty over eighty "), with large individual variations. These measures of blood pressure is not static, but subject to natural variations from one to another, and the heart rate during the day (in a circadian rhythm), but also change in response to stress, factors nutritional, drugs or illness. Refers to hypertension is abnormally high, as opposed to hypotension, when it is abnormally low. Along with the body temperature, blood pressure are the most commonly measured physiological parameters. Contents [hide] 1 Measures 1.1 Non-invasive measurement 1.1.1 Auscultatory methods 1.1.2 Oscillometric methods 1.2 invasive measurement 1.3 Home Monitoring 1.4 Taking exact home pressure 2 Normal Values 3 Physiology 3.1 Regulation 4 Pathophysiology 4.1 high blood pressure 4.2 low blood pressure 5 Influential factors 5.1 low blood pressure 6 Venous Pressure 7 See also 8 References 9 link [Edit] Measure Blood pressure can be measured invasive (penetrating through the skin and measuring inside the blood vessels) or non-invasive. The first is generally limited to the hospital. [Edit] non-invasive measurement The non-invasive auscultatory (Latin for listening) and oscillometric measures are simpler and faster than invasive measures, require less expertise in the installation, virtually no complications, and are less painful and unpleasant for the patient. However, non-invasive measures can yield slightly lower precision and small systematic differences in numerical results. Non-invasif measurement methods are most commonly used for routine tests and monitoring. [Edit] Auscultatory methods Auscultatory method aneroid sphygmomanometer with stethoscope Mercury manometerThe auscultatory method uses a stethoscope and sphygmomanometer. These include an inflatable (Riva-Rocci) cuff placed around the upper arm, at roughly the same height as the heart, linked to a mercury or aneroid gauge. The mercury manometer, which is considered the gold standard for measuring blood pressure, measure the height of a column of mercury, giving an absolute necessity, without result for the calibration, and therefore not subject to errors and calibration drift affecting other methods. The use of mercury manometers is often necessary in clinical trials and the clinical measurement of hypertension in patients at high risk, including pregnant women. An appropriate size cuff is in place and inflated to shake hands repeatedly by the rubber bulb until the artery is completely ignored. Listening with the stethoscope to the brachial artery in the elbow, the examiner slowly pressure in the cuff. Only when the blood starts to flow in the artery, the turbulent flow creates a "whooshing" sound or pounding (first Korotkoff sounds). The pressure at which the sound is first heard systolic blood pressure. The cuff pressure is not released until his can be heard (fifth Korotkoff sounds), diastolic blood pressure. Sometimes, the pressure is palpated (approximated by hand) to get an estimate before the inspection. With a mercury manometer of this technology is simple, which gives accurate pressure problems without calibration. [Edit] Oscillometric methods Oscillométrique methods are sometimes used in the long term, and sometimes to the extent of general practice. The equipment is functionally similar to the auscultatory method, but with a pressure sensor electronic (transducer) in the bloodstream to detect, instead of using the stethoscope and the expert from the ear. In practice, the pressure sensor is an electronic device calibrated with a digital display of blood pressure. To maintain the accuracy, the calibration should be checked periodically, unlike nature, "says mercury manometer. In most cases, the cuff is inflated and released by an electric pump and valve, which can be mounted on the wrist (high in the heart height), though his arm is better. They vary greatly in accuracy, and should be checked at specified intervals and recalibrated if necessary. Oscillométrique measure requires fewer skills than the auscultatory technique, and can be adapted for use by untrained staff and automated monitoring of the patient at home. The cuff is inflated to a pressure greater than the initial systolic blood pressure, and then reduced to less than diastolic pressure over a period of about 30 seconds. When blood flow is zero (cuff systolic pressure higher than the pressure) or free (cuff diastolic pressure below), cuff pressure will be essentially constant. It is essential that the cuff size is correct: undersized cuffs can resist pressure too high, while yields wrists oversized pressure too low. When blood flow is present, but limited, pressure cuff, which is controlled by the pressure sensor, vary periodically synchronized with the cycle of expansion and contraction of the brachial artery, ie, it will oscillate. The values of systolic and diastolic pressure were calculated, not actually measured from raw data, using an algorithm, the calculated results are displayed. Oscillométrique monitors can produce inaccurate readings in patients with heart problems and traffic, which include arterial sclerosis, arrhythmia, preeclampsia, pulse alternans, and pulse paradoxical. In practice, the different methods do not give identical results, and an algorithm experimentally obtained coefficients are used to adjust the results oscillometric to give readings that match the auscultatory as well as possible. [1] Some of the equipment used-aided analysis of the wave of instant blood pressure to determine the systolic, mean and diastolic points. For many oscillometric devices have not been validated, caution must be given, because most are not suitable in clinics and acute care facilities. The term NIBP for Non-Invasive Blood Pressure is often used to describe oscillometric monitoring equipment. [Edit] invasive measurement Blood pressure (BP) is the most accurately measured invasively. Envahissantes measuring blood pressure with intravascular cannulas involves direct measurement of blood pressure by placing a cannula needle into an artery (usually radial, femoral, brachial foot or dorsalis). This is usually done by a surgeon or anesthesiologist at the hospital. The cannula must be connected to a sterile fluid-filled system, which is connected to a pressure sensor electronics. The advantage of this system is that the pressure is constantly monitored by beating beat, and a wave (a graph of the pressure against time) can be displayed. This technique is invasive regularly employed in human and veterinary medicine, intensive care, anesthesiology, and for research purposes. Canulation vascular for invasive pressure monitoring is frequently associated with complications such as thrombosis, infection and bleeding. Patients needing invasive blood monitoring very closely, because there is a danger of bleeding if the line becomes disconnected. It is generally reserved for patients where rapid changes in blood pressure are planned. Envahissantes vascular pressure monitors pressure monitoring to acquire information systems for the display of pressure and processing. There are a variety of pressure monitors for invasive vascular trauma, intensive care, operating rooms and applications. These include the unique pressure, the pressure doubles, and multi-parameter (ie pressure / temperature). The monitors can be used for the measurement and monitoring of arterial, central venous, pulmonary artery, left ear, right ear, the femoral artery, umbilical venous, arterial blood, and the intracranial pressure. Vascular pressure parameters are derived in the monitor system microcomputer. Typically, systolic, diastolic and mean pressures are displayed simultaneously for pulse waveform (ie arterial and pulmonary artery). Some monitors also calculate and display the PPC (cerebral perfusion pressure). Normally, a key scratch on the front of zeroing pressure monitor makes it extremely fast and easy. Alarm limits can be set to help the medical profession responsible for the observation of the patient. High and low alarms can be set on the display settings temperature. [Edit] Home Monitoring Up to 25% of patients with hypertension do not suffer from it, but rather of white coat hypertension (high blood pressure specifically during medical examinations, probably as a result of anxiety). Thus, well executed, says home monitoring blood pressure may avoid unnecessary anxiety, as well as expensive and potentially dangerous in the therapy of millions of people around the world. Home monitoring of blood pressure provides a measure of a person in blood pressure at different times and in different environments, such as at home and at work, throughout the day. Home monitoring of blood pressure may help in the diagnosis of high or low blood pressure. It can also be used to monitor the effects of medication or lifestyle changes taken to lower blood pressure or to regulate levels. The 2003 US Joint National Committee recommends the use of self-monitoring of blood pressure, before considering the more expensive ambulatory monitoring of blood pressure, in order to improve the management of hypertension. [2] The National Joint Committee and the 2003 guidelines of the European Society of Hypertension and the European Society of Cardiology suggest that the autonomy of surveillance could also be used as an alternative to the ambulatory monitoring in the diagnosis of white coat hypertension [ 3]. A study published in May 2006, American Journal of Hypertension [4] compared ambulatory home and methods of monitoring blood pressure in the adjustment of antihypertensive treatment. The study showed home monitoring of blood pressure is as accurate as 24-hour ambulatory monitoring in determining the levels of blood pressure. Researchers at the University of Turku in Finland studied 98 patients with untreated hypertension. They compared patients using a home blood pressure and those wearing a 24hr ambulatory monitor. Researcher Dr. Niiranen said that "measuring blood pressure at home can be used effectively to guide antihypertensive treatment." Dr Stergiou said the home monitoring of blood pressure, "is more convenient and cheaper than monitoring ambulatory blood pressure." A clinical study published in May 2007 edition of The American Journal of Hypertension [5] compared the accuracy of 3 different methods of blood pressure with cardiovascular health. The study aimed to evaluate the accuracy of home monitoring of blood pressure (HBP), 24hr ambulatory monitoring of blood pressure (ABP) and arterial blood pressure readings taken in a doctor's office (OBP). Blood pressure tests were compared with the left ventricular mass index (LVMI). The LVMI was calculated from an echocardiogram shows the heart and cardiovascular damage, an indicator of blood pressure. Researchers at Columbia University Medical Center, New York, found that home monitoring of blood pressure, over 10 weeks was an important independent predictor of LVMI even after adjusting for age, sex and the BMI (body mass index). They found that home monitoring over time is a better indicator of cardiovascular health that ambulatory readings or readings taken by the doctors. The value of home monitoring increases over time with a number of measurements. The June 2007 AMNews; newspaper for American doctors [6] published a study that shows the blood pressure readings taken at a desk doctors are often unreliable. The American Medical Association paper quoted Professor Norman Kaplan of the University of Texas Southwestern Medical Center, who said: "Of all the procedures performed in a doctor's office, blood pressure measurement is usually the least well made, but most have important implications for the care of the patient. "newspaper said that the taking of blood pressure in an office of physicians may be falsely raised or lowered. This may be due to the presence of a doctor or clinician which results in the patient knows white coat hypertension. The American Heart Association site [7] said, "You can have what is called" white coat hypertension ", which means that your blood pressure rises when you are at the doctor's office. Surveillance at home will help you to measure your True blood pressure and the doctor can make with a record of blood pressure over time. is useful in the diagnosis and prevention of potential problems for health. " Those who use home blood pressure monitoring devices are increasingly being used also in blood pressure mapping software. [8] The methods of mapping offer printing for patients and doctors in the frequency of reminders to check blood pressure [9]. [Edit] Taking home exact pressure To pressure readings taken with a monitoring device at home to be accurate, they should be taken in the same way every time. The National Heart, Lung and Blood Institute [10] offers advice on what to do before taking a reading to ensure consistency and accuracy of reading. "Do not drink coffee or smoke cigarettes 30 minutes before measuring your blood pressure. Before the test, sit for 5 minutes with the back supported and feet flat on the ground. Rest your arm on a table at your heart. Wear short sleeves if your arm is exposed. Go to the bathroom before the reading. A full bladder can change your blood pressure. " [Edit] Normal Values While statistically normal blood pressure could be calculated for a given population, it is necessary to remember that it's not just blood pressure vary from one person to another, it also varies according to individuals get at any time. In addition, since there is no guarantee of the standard of the people in question should even be considered healthy, the relevance of these values is questionable. In children observed normal ranges are lower; in the elderly, they are often higher, mainly due to the reduction in the flexibility of the arteries. Factors such as age, sex and race of the influence of blood pressure values. Pressure also varies with the year, emotion, sleep, digestion and the time of day. In the United States, optimal blood pressure (sometimes called the 'standard') objectives are as follows: [11] [12] [13] Systolic: less than 120 mm Hg (2.32 psi or 15 kPa); Diastolic: less than 80 mmHg (1.55 psi or 10 kPa); Levels above 120 but less than 140 mmHg in systolic pressure, or over 80 but less than 95 mm Hg diastolic pressure, are referred to as "prehypertensive", and often progress frankly hypertensive levels. However, existing studies reveal that there are fewer complications when, eg, 115 mmHg systolic of 120 and, in fact, blood pressure is a continuum of a decrease in the pathology associated with levels below well within the current "optimal" range. [14] "Some data indicate that 115/75 mm Hg should be the gold standard. Once blood pressure rises above 115/75 mm Hg, the risk of cardiovascular disease begins to rise. Prehypertension is now regarded as a systolic pressure ranging from 120 to 139 or diastolic pressure ranging from 80 to 89. "(Excerpts from the Mayo Clinic site). In the past, hypertension was diagnosed only if secondary signs of high blood pressure were present, and a prolonged high systolic pressure reading on several visits. In the United States, this reactive attitude was rejected in the light of recent data. In the UK, mirrored abandoned the former practice of the United States, students in nursing continue to be taught that their patients readings should be considered "normal" if in the range: Systolic: 110-140mmHg Diastolic: 70-90 mmHg Clinical trials show that people who maintain blood pressure at the lower end of these ranges pressure have much better long-term cardiovascular health. The main debate is medical aggressiveness and the relative value of the methods used to reduce the pressure in this range for those who do not maintain such pressure on their own. Elevations, more frequently among the elderly, often regarded as normal, is associated with increased morbidity and mortality. The current trend in clinical trials, double blind (for the best strategies and agents), has been increasingly that low blood pressure was found to have fewer illnesses. [Edit] [Edit] Physiology The mean arterial pressure (MAP) is the average of pressure measured on a complete cardiac cycle. The up and down fluctuation of blood pressure results from the nature of cardiac output pulse. The pulse pressure is determined by the interplay of race against the amount of resistance to the flow of arterial tree. The major arteries, including all large enough to see without magnification, have a low resistance (assuming no changes atherosclerosis) conduits broadband that generate only small decreases in pressure. For example, with a subject in the supine position, the blood from the heart to travel toes typically only experience of 5 mm Hg drop in the average pressure. Physiology modern developed the concept of vascular pressure wave. This wave is generated by the heart during systole and origin in the ascending aorta. Much faster than blood flow itself, it is then transported through the vessel walls in the peripheral arteries. It wave pressure can be palpated as the pulse devices. As the wave is reflected at the periphery of veins he reiterates in fashion centripetal. When the peak of the reflected wave and the original answer, the pressure inside the vessel is greater than the actual pressure in the aorta. This concept explains why the blood pressure in the peripheral arteries of the legs and arms is more than blood pressure in the aorta. [15] [16] [17] [Edit] Regulation The regulation of endogenous blood pressure is not fully understood. Currently, the three mechanisms for regulating blood pressure were well characterized: Baroreceptor reflex: Baroreceptors in various organs can detect changes in blood pressure, and adjust the mean arterial pressure by modifying both the strength and speed of heart contractions, as well as the total peripheral resistance. Renin-angiotensin system (RAS): This system is generally known for his long-term adjustment of blood pressure. This system allows the kidney to compensate for the loss of volume in the blood or decreases in blood pressure by the activation of an endogenous vasoconstrictor known as angiotensin II. Aldostérone publication: This steroid hormone is released from the adrenal cortex in response to angiotensin II or high serum potassium levels. Aldostérone stimulates the retention of sodium and potassium excretion by the kidneys. Since the sodium ion is the main determining the amount of fluid in the blood vessels by osmosis, aldosterone will increase fluid retention, and indirectly in blood pressure. These mechanisms are not necessarily independent of one another, as indicated by the relationship between the SAR and aldosterone release. Currently, the system is intended SAR pharmacologically by ACE inhibitors and receptor antagonists of angiotensin II. The aldosterone system is directly affected by spironolactone, an aldosterone antagonist. The fluid retention can be controlled by diuretics, but the antihypertensive effect of diuretics is not due to its effect on blood flow. Generally, the baroreceptor reflex is not targeted in hypertension because if blocked, individuals may suffer from orthostatic hypotension and fainting. [Edit] Pathophysiology [Edit] High blood pressure Feature: Hypertension The diagnosis of abnormalities in blood pressure may require series of measurements. Since blood pressure varies throughout the day, measures should be taken at the same time of day to ensure the readings taken are comparable. Suitable times are: Immediately after awakening (before washing / dressing and taking breakfast / drink), while the body is still resting, Immediately after finishing work. It is sometimes difficult to meet these demands at the office of the doctor, but some patients become nervous when their blood pressure is taken at the office, causing readings to increase (this phenomenon is called white coat hypertension). Taking blood pressure at home or work with a home monitoring of blood pressure device can help determine a person's true range of blood pressure and to avoid false readings readings of white coat hypertension. Long-term evaluations can be done with an ambulatory blood pressure device which regularly takes readings of blood pressure every half hour throughout the course of a single day and night. Apart from the white coat effect, the readings of blood pressure outside of a clinical setting are generally slightly lower in most people. Studies that have looked at the risk of hypertension and the benefits of lowering blood pressure in patients affected were based on readings in a clinical environment. Blood pressure higher than the normal value is called hypertension. In itself, it is only an acute problem; see hypertensive crisis. But because of its long-term consequences of indirect effects (and also as an indicator of other problems), it is a serious concern for the doctors. All levels of blood pressure to mechanical stress on the arterial walls. Higher pressures increase heart progression of the workload and unhealthy tissue growth (atheroma), which develops in the arteries. The higher the pressure, more stress is present and that the trend towards more atheroma progress and the heart muscle tends to thicken, enlarge and weaken over time. Persistent hypertension is a risk factor for stroke, myocardial infarction, heart failure, arterial aneurysms, and is the leading cause of chronic renal failure. Even moderate high blood pressure led to the shortened life expectancy. At severely high blood pressure, mean arterial pressure 50% or more above average, a person can expect to live no more than a few years, unless an appropriate treatment [18]. In the past, most attention to the diastolic pressure, but today it is acknowledged that the two high systolic pressure and pulse pressure (the difference between digital systolic and diastolic pressures) are also factors risk. In some cases, it appears that a reduction in diastolic pressure excessive may actually increase the risk, probably owing to the increase in the difference between systolic and diastolic pressure (see article on pulse pressure). [Edit] Low blood pressure Feature: Hypotension Blood pressure is too low is called hypotension. The similarity in pronunciation of hypertension can cause confusion. Low blood pressure can be a sign of serious disease and requires urgent medical attention. When blood pressure and blood flow decreases beyond a certain point, becomes brain perfusion decreased (ie, the blood supply is not sufficient), which causes vertigo, dizziness, weakness and fainting. However, those who work well, while maintaining low blood pressure have lower rates of cardiovascular disease than people with normal manifestations of blood pressure. [Edit] [Edit] factors The physics of the circulatory system, like any other fluid, are very complex. That said, there are many physical factors that influence blood pressure. Each of them in turn can be influenced by physiological factors such as diet, exercise, disease, drugs or alcohol, obesity, excess weight and so forth -. In cardiac physiology, the pace and volume of traffic are accounted for in a combined cardiac output, which is the heart rate (the rate of contraction) multiplied by the volume (the amount of blood pumped by the heart with each contraction). It represents the efficiency with which the heart circulate blood throughout the body. Some physical factors are: Pumping rates. In the circulatory system, this rate is called the heart rate, the rate at which the blood (fluid) is pumped by the heart. The higher the heart rate, the highest (potentially, assuming no change in volume) in blood pressure. Volume of fluid or blood volume, the amount of blood that is present in the body. La présente plus de sang dans l'organisme est élevée, plus le taux de retour du sang vers le coeur et le débit cardiaque. Il existe une certaine relation entre le sel alimentaire et l'accroissement du volume sanguin, pouvant entraîner une hausse de pression artérielle, bien que cela varie avec l'individu et est fortement tributaire de la réaction du système nerveux autonome. Résistance. Dans le système circulatoire, il s'agit de la résistance des vaisseaux sanguins. Plus la résistance est élevée, plus la pression artérielle. La résistance est liée à la taille (la plus grande vaisseau sanguin, le plus faible de la résistance), ainsi que la fluidité de la paroi des vaisseaux sanguins. Lissé est réduit par l'accumulation de dépôts graisseux sur les parois artérielles. De substances appelées vasoconstricteurs peut réduire la taille des vaisseaux sanguins, ce qui augmente la pression sanguine. Vasodilatateurs (comme la nitroglycérine) augmenter la taille des vaisseaux sanguins, ce qui diminue la pression artérielle. Certains types d'acides gras oméga - 6, en particulier à partir de l'huile d'olive, ont été connus pour augmenter vasculaire finesse. [Modifier] Viscosité ou l'épaisseur du fluide. Si le sang est plus épais, le résultat est une augmentation de la pression artérielle. Certaines conditions médicales peuvent changer la viscosité du sang. Par exemple, une faible concentration de globules rouges, l'anémie, réduit la viscosité, alors que augmenté la concentration de globules rouges augmente la viscosité. Viscosité augmente avec la concentration de glucose dans le sang - visualiser pompage sirop. Il avait pensé que l'aspirine et les "sang mince" drogues a diminué la viscosité du sang, mais des études trouvé [19] qu'ils agissent en réduisant la tendance du sang à coaguler la place. Dans la pratique, chaque individu système nerveux autonome et réglemente répond à l'ensemble de ces facteurs interagissent de sorte que, bien que ces questions sont importantes, le montant réel de la pression artérielle réponse d'une personne varie largement raison à la fois de fraction de seconde plus lents et réponses Du système nerveux et des organes cibles. Ces réponses sont très efficaces dans la modification des variables et de la pression artérielle résultant de l'instant. [Modifier] Basse pression artérielle Parfois, la pression artérielle diminue considérablement quand un patient se lève de la séance. Cette approche est appelée hypotension posturale; gravité réduit le taux de retour du sang des veines de l'organisme en dessous du cœur à cœur, réduisant ainsi le volume et le débit cardiaque. Lorsque les gens sont en bonne santé, les veines en dessous de leur coeur contractent rapidement et le rythme cardiaque augmente afin de réduire et de compenser l'effet de gravité. Celle-ci est effectuée involontairement par le système nerveux autonome. Le système exige généralement de quelques secondes pour ajuster pleinement et si les compensations sont trop lentes ou insuffisantes, l'individu souffrira réduit le flux sanguin au cerveau, vertiges et le potentiel panne. L'augmentation des G - chargement, telles que couramment rencontrés par les pilotes de jets acrobatique "tirant Gs", augmente cet effet. Repositionnement du corps perpendiculaire à la pesanteur élimine en grande partie le problème. Autres causes de la faible pression artérielle comprennent: Sepsis Hémorragie - perte de sang Toxines y compris des doses toxiques de la pression sanguine médecine Anomalies hormonales, comme la maladie d'Addison Shock est une condition complexe qui conduit à la diminution de la perfusion critique. Les mécanismes habituels sont la perte de volume sanguin, mise en commun de sang dans les veines de la réduction de rendement adéquat pour le coeur et / ou à faible effectif pompage de coeur. Faible pression artérielle, pouls très faible pression, est un signe de choc et contribue à la diminution de la perfusion et reflète. S'il ya une différence notable entre la pression d'une branche à l'autre, qui pourraient signaler un rétrécissement (par exemple, en raison de coarctation aortique, la dissection aortique, thrombose ou embolie) d'une artère.Thursday, November 8, 2007
Blood pressure
Arterial (strictly speaking: vascular pressure), referring to the force exerted by blood circulating in the blood vessel walls, and is one of the major vital signs. The pressure of the circulating blood decreases as blood moves through the arteries, arterioles, capillaries and veins, the term blood pressure usually mean arterial pressure, ie, the pressure in the major arteries, the arteries are the blood vessels that take blood from the heart. Blood pressure is usually measured through a sphygmomanometer, which uses the height of a column of mercury to reflect the pressure that circulate (see non-invasive measurement). While many modern devices vascular pressure no longer use mercury, vascular pressure values are still universally reported in millimeters of mercury (mmHg). The systolic blood pressure is defined as the maximum pressure in the arteries, which occurs shortly after the start of the cycle of Cardiology, diastolic blood pressure is the lowest pressure (to the rest phase of cardiac cycle). The average pressure throughout the cardiac cycle reported that the mean arterial pressure, pulse pressure reflects the difference between the maximum and minimum pressures measured. Typical values for a rest, man healthy adult is approximately 120 mm Hg (16 kPa), systolic and 80 mm Hg (11 kPa), diastolic (written as 120/80 mmHg, and talked as a twenty over eighty "), with large individual variations. These measures of blood pressure is not static, but subject to natural variations from one to another, and the heart rate during the day (in a circadian rhythm), but also change in response to stress, factors nutritional, drugs or illness. Refers to hypertension is abnormally high, as opposed to hypotension, when it is abnormally low. Along with the body temperature, blood pressure are the most commonly measured physiological parameters. Contents [hide] 1 Measures 1.1 Non-invasive measurement 1.1.1 Auscultatory methods 1.1.2 Oscillometric methods 1.2 invasive measurement 1.3 Home Monitoring 1.4 Taking exact home pressure 2 Normal Values 3 Physiology 3.1 Regulation 4 Pathophysiology 4.1 high blood pressure 4.2 low blood pressure 5 Influential factors 5.1 low blood pressure 6 Venous Pressure 7 See also 8 References 9 link [Edit] Measure Blood pressure can be measured invasive (penetrating through the skin and measuring inside the blood vessels) or non-invasive. The first is generally limited to the hospital. [Edit] non-invasive measurement The non-invasive auscultatory (Latin for listening) and oscillometric measures are simpler and faster than invasive measures, require less expertise in the installation, virtually no complications, and are less painful and unpleasant for the patient. However, non-invasive measures can yield slightly lower precision and small systematic differences in numerical results. Non-invasif measurement methods are most commonly used for routine tests and monitoring. [Edit] Auscultatory methods Auscultatory method aneroid sphygmomanometer with stethoscope Mercury manometerThe auscultatory method uses a stethoscope and sphygmomanometer. These include an inflatable (Riva-Rocci) cuff placed around the upper arm, at roughly the same height as the heart, linked to a mercury or aneroid gauge. The mercury manometer, which is considered the gold standard for measuring blood pressure, measure the height of a column of mercury, giving an absolute necessity, without result for the calibration, and therefore not subject to errors and calibration drift affecting other methods. The use of mercury manometers is often necessary in clinical trials and the clinical measurement of hypertension in patients at high risk, including pregnant women. An appropriate size cuff is in place and inflated to shake hands repeatedly by the rubber bulb until the artery is completely ignored. Listening with the stethoscope to the brachial artery in the elbow, the examiner slowly pressure in the cuff. Only when the blood starts to flow in the artery, the turbulent flow creates a "whooshing" sound or pounding (first Korotkoff sounds). The pressure at which the sound is first heard systolic blood pressure. The cuff pressure is not released until his can be heard (fifth Korotkoff sounds), diastolic blood pressure. Sometimes, the pressure is palpated (approximated by hand) to get an estimate before the inspection. With a mercury manometer of this technology is simple, which gives accurate pressure problems without calibration. [Edit] Oscillometric methods Oscillométrique methods are sometimes used in the long term, and sometimes to the extent of general practice. The equipment is functionally similar to the auscultatory method, but with a pressure sensor electronic (transducer) in the bloodstream to detect, instead of using the stethoscope and the expert from the ear. In practice, the pressure sensor is an electronic device calibrated with a digital display of blood pressure. To maintain the accuracy, the calibration should be checked periodically, unlike nature, "says mercury manometer. In most cases, the cuff is inflated and released by an electric pump and valve, which can be mounted on the wrist (high in the heart height), though his arm is better. They vary greatly in accuracy, and should be checked at specified intervals and recalibrated if necessary. Oscillométrique measure requires fewer skills than the auscultatory technique, and can be adapted for use by untrained staff and automated monitoring of the patient at home. The cuff is inflated to a pressure greater than the initial systolic blood pressure, and then reduced to less than diastolic pressure over a period of about 30 seconds. When blood flow is zero (cuff systolic pressure higher than the pressure) or free (cuff diastolic pressure below), cuff pressure will be essentially constant. It is essential that the cuff size is correct: undersized cuffs can resist pressure too high, while yields wrists oversized pressure too low. When blood flow is present, but limited, pressure cuff, which is controlled by the pressure sensor, vary periodically synchronized with the cycle of expansion and contraction of the brachial artery, ie, it will oscillate. The values of systolic and diastolic pressure were calculated, not actually measured from raw data, using an algorithm, the calculated results are displayed. Oscillométrique monitors can produce inaccurate readings in patients with heart problems and traffic, which include arterial sclerosis, arrhythmia, preeclampsia, pulse alternans, and pulse paradoxical. In practice, the different methods do not give identical results, and an algorithm experimentally obtained coefficients are used to adjust the results oscillometric to give readings that match the auscultatory as well as possible. [1] Some of the equipment used-aided analysis of the wave of instant blood pressure to determine the systolic, mean and diastolic points. For many oscillometric devices have not been validated, caution must be given, because most are not suitable in clinics and acute care facilities. The term NIBP for Non-Invasive Blood Pressure is often used to describe oscillometric monitoring equipment. [Edit] invasive measurement Blood pressure (BP) is the most accurately measured invasively. Envahissantes measuring blood pressure with intravascular cannulas involves direct measurement of blood pressure by placing a cannula needle into an artery (usually radial, femoral, brachial foot or dorsalis). This is usually done by a surgeon or anesthesiologist at the hospital. The cannula must be connected to a sterile fluid-filled system, which is connected to a pressure sensor electronics. The advantage of this system is that the pressure is constantly monitored by beating beat, and a wave (a graph of the pressure against time) can be displayed. This technique is invasive regularly employed in human and veterinary medicine, intensive care, anesthesiology, and for research purposes. Canulation vascular for invasive pressure monitoring is frequently associated with complications such as thrombosis, infection and bleeding. Patients needing invasive blood monitoring very closely, because there is a danger of bleeding if the line becomes disconnected. It is generally reserved for patients where rapid changes in blood pressure are planned. Envahissantes vascular pressure monitors pressure monitoring to acquire information systems for the display of pressure and processing. There are a variety of pressure monitors for invasive vascular trauma, intensive care, operating rooms and applications. These include the unique pressure, the pressure doubles, and multi-parameter (ie pressure / temperature). The monitors can be used for the measurement and monitoring of arterial, central venous, pulmonary artery, left ear, right ear, the femoral artery, umbilical venous, arterial blood, and the intracranial pressure. Vascular pressure parameters are derived in the monitor system microcomputer. Typically, systolic, diastolic and mean pressures are displayed simultaneously for pulse waveform (ie arterial and pulmonary artery). Some monitors also calculate and display the PPC (cerebral perfusion pressure). Normally, a key scratch on the front of zeroing pressure monitor makes it extremely fast and easy. Alarm limits can be set to help the medical profession responsible for the observation of the patient. High and low alarms can be set on the display settings temperature. [Edit] Home Monitoring Up to 25% of patients with hypertension do not suffer from it, but rather of white coat hypertension (high blood pressure specifically during medical examinations, probably as a result of anxiety). Thus, well executed, says home monitoring blood pressure may avoid unnecessary anxiety, as well as expensive and potentially dangerous in the therapy of millions of people around the world. Home monitoring of blood pressure provides a measure of a person in blood pressure at different times and in different environments, such as at home and at work, throughout the day. Home monitoring of blood pressure may help in the diagnosis of high or low blood pressure. It can also be used to monitor the effects of medication or lifestyle changes taken to lower blood pressure or to regulate levels. The 2003 US Joint National Committee recommends the use of self-monitoring of blood pressure, before considering the more expensive ambulatory monitoring of blood pressure, in order to improve the management of hypertension. [2] The National Joint Committee and the 2003 guidelines of the European Society of Hypertension and the European Society of Cardiology suggest that the autonomy of surveillance could also be used as an alternative to the ambulatory monitoring in the diagnosis of white coat hypertension [ 3]. A study published in May 2006, American Journal of Hypertension [4] compared ambulatory home and methods of monitoring blood pressure in the adjustment of antihypertensive treatment. The study showed home monitoring of blood pressure is as accurate as 24-hour ambulatory monitoring in determining the levels of blood pressure. Researchers at the University of Turku in Finland studied 98 patients with untreated hypertension. They compared patients using a home blood pressure and those wearing a 24hr ambulatory monitor. Researcher Dr. Niiranen said that "measuring blood pressure at home can be used effectively to guide antihypertensive treatment." Dr Stergiou said the home monitoring of blood pressure, "is more convenient and cheaper than monitoring ambulatory blood pressure." A clinical study published in May 2007 edition of The American Journal of Hypertension [5] compared the accuracy of 3 different methods of blood pressure with cardiovascular health. The study aimed to evaluate the accuracy of home monitoring of blood pressure (HBP), 24hr ambulatory monitoring of blood pressure (ABP) and arterial blood pressure readings taken in a doctor's office (OBP). Blood pressure tests were compared with the left ventricular mass index (LVMI). The LVMI was calculated from an echocardiogram shows the heart and cardiovascular damage, an indicator of blood pressure. Researchers at Columbia University Medical Center, New York, found that home monitoring of blood pressure, over 10 weeks was an important independent predictor of LVMI even after adjusting for age, sex and the BMI (body mass index). They found that home monitoring over time is a better indicator of cardiovascular health that ambulatory readings or readings taken by the doctors. The value of home monitoring increases over time with a number of measurements. The June 2007 AMNews; newspaper for American doctors [6] published a study that shows the blood pressure readings taken at a desk doctors are often unreliable. The American Medical Association paper quoted Professor Norman Kaplan of the University of Texas Southwestern Medical Center, who said: "Of all the procedures performed in a doctor's office, blood pressure measurement is usually the least well made, but most have important implications for the care of the patient. "newspaper said that the taking of blood pressure in an office of physicians may be falsely raised or lowered. This may be due to the presence of a doctor or clinician which results in the patient knows white coat hypertension. The American Heart Association site [7] said, "You can have what is called" white coat hypertension ", which means that your blood pressure rises when you are at the doctor's office. Surveillance at home will help you to measure your True blood pressure and the doctor can make with a record of blood pressure over time. is useful in the diagnosis and prevention of potential problems for health. " Those who use home blood pressure monitoring devices are increasingly being used also in blood pressure mapping software. [8] The methods of mapping offer printing for patients and doctors in the frequency of reminders to check blood pressure [9]. [Edit] Taking home exact pressure To pressure readings taken with a monitoring device at home to be accurate, they should be taken in the same way every time. The National Heart, Lung and Blood Institute [10] offers advice on what to do before taking a reading to ensure consistency and accuracy of reading. "Do not drink coffee or smoke cigarettes 30 minutes before measuring your blood pressure. Before the test, sit for 5 minutes with the back supported and feet flat on the ground. Rest your arm on a table at your heart. Wear short sleeves if your arm is exposed. Go to the bathroom before the reading. A full bladder can change your blood pressure. " [Edit] Normal Values While statistically normal blood pressure could be calculated for a given population, it is necessary to remember that it's not just blood pressure vary from one person to another, it also varies according to individuals get at any time. In addition, since there is no guarantee of the standard of the people in question should even be considered healthy, the relevance of these values is questionable. In children observed normal ranges are lower; in the elderly, they are often higher, mainly due to the reduction in the flexibility of the arteries. Factors such as age, sex and race of the influence of blood pressure values. Pressure also varies with the year, emotion, sleep, digestion and the time of day. In the United States, optimal blood pressure (sometimes called the 'standard') objectives are as follows: [11] [12] [13] Systolic: less than 120 mm Hg (2.32 psi or 15 kPa); Diastolic: less than 80 mmHg (1.55 psi or 10 kPa); Levels above 120 but less than 140 mmHg in systolic pressure, or over 80 but less than 95 mm Hg diastolic pressure, are referred to as "prehypertensive", and often progress frankly hypertensive levels. However, existing studies reveal that there are fewer complications when, eg, 115 mmHg systolic of 120 and, in fact, blood pressure is a continuum of a decrease in the pathology associated with levels below well within the current "optimal" range. [14] "Some data indicate that 115/75 mm Hg should be the gold standard. Once blood pressure rises above 115/75 mm Hg, the risk of cardiovascular disease begins to rise. Prehypertension is now regarded as a systolic pressure ranging from 120 to 139 or diastolic pressure ranging from 80 to 89. "(Excerpts from the Mayo Clinic site). In the past, hypertension was diagnosed only if secondary signs of high blood pressure were present, and a prolonged high systolic pressure reading on several visits. In the United States, this reactive attitude was rejected in the light of recent data. In the UK, mirrored abandoned the former practice of the United States, students in nursing continue to be taught that their patients readings should be considered "normal" if in the range: Systolic: 110-140mmHg Diastolic: 70-90 mmHg Clinical trials show that people who maintain blood pressure at the lower end of these ranges pressure have much better long-term cardiovascular health. The main debate is medical aggressiveness and the relative value of the methods used to reduce the pressure in this range for those who do not maintain such pressure on their own. Elevations, more frequently among the elderly, often regarded as normal, is associated with increased morbidity and mortality. The current trend in clinical trials, double blind (for the best strategies and agents), has been increasingly that low blood pressure was found to have fewer illnesses. [Edit] [Edit] Physiology The mean arterial pressure (MAP) is the average of pressure measured on a complete cardiac cycle. The up and down fluctuation of blood pressure results from the nature of cardiac output pulse. The pulse pressure is determined by the interplay of race against the amount of resistance to the flow of arterial tree. The major arteries, including all large enough to see without magnification, have a low resistance (assuming no changes atherosclerosis) conduits broadband that generate only small decreases in pressure. For example, with a subject in the supine position, the blood from the heart to travel toes typically only experience of 5 mm Hg drop in the average pressure. Physiology modern developed the concept of vascular pressure wave. This wave is generated by the heart during systole and origin in the ascending aorta. Much faster than blood flow itself, it is then transported through the vessel walls in the peripheral arteries. It wave pressure can be palpated as the pulse devices. As the wave is reflected at the periphery of veins he reiterates in fashion centripetal. When the peak of the reflected wave and the original answer, the pressure inside the vessel is greater than the actual pressure in the aorta. This concept explains why the blood pressure in the peripheral arteries of the legs and arms is more than blood pressure in the aorta. [15] [16] [17] [Edit] Regulation The regulation of endogenous blood pressure is not fully understood. Currently, the three mechanisms for regulating blood pressure were well characterized: Baroreceptor reflex: Baroreceptors in various organs can detect changes in blood pressure, and adjust the mean arterial pressure by modifying both the strength and speed of heart contractions, as well as the total peripheral resistance. Renin-angiotensin system (RAS): This system is generally known for his long-term adjustment of blood pressure. This system allows the kidney to compensate for the loss of volume in the blood or decreases in blood pressure by the activation of an endogenous vasoconstrictor known as angiotensin II. Aldostérone publication: This steroid hormone is released from the adrenal cortex in response to angiotensin II or high serum potassium levels. Aldostérone stimulates the retention of sodium and potassium excretion by the kidneys. Since the sodium ion is the main determining the amount of fluid in the blood vessels by osmosis, aldosterone will increase fluid retention, and indirectly in blood pressure. These mechanisms are not necessarily independent of one another, as indicated by the relationship between the SAR and aldosterone release. Currently, the system is intended SAR pharmacologically by ACE inhibitors and receptor antagonists of angiotensin II. The aldosterone system is directly affected by spironolactone, an aldosterone antagonist. The fluid retention can be controlled by diuretics, but the antihypertensive effect of diuretics is not due to its effect on blood flow. Generally, the baroreceptor reflex is not targeted in hypertension because if blocked, individuals may suffer from orthostatic hypotension and fainting. [Edit] Pathophysiology [Edit] High blood pressure Feature: Hypertension The diagnosis of abnormalities in blood pressure may require series of measurements. Since blood pressure varies throughout the day, measures should be taken at the same time of day to ensure the readings taken are comparable. Suitable times are: Immediately after awakening (before washing / dressing and taking breakfast / drink), while the body is still resting, Immediately after finishing work. It is sometimes difficult to meet these demands at the office of the doctor, but some patients become nervous when their blood pressure is taken at the office, causing readings to increase (this phenomenon is called white coat hypertension). Taking blood pressure at home or work with a home monitoring of blood pressure device can help determine a person's true range of blood pressure and to avoid false readings readings of white coat hypertension. Long-term evaluations can be done with an ambulatory blood pressure device which regularly takes readings of blood pressure every half hour throughout the course of a single day and night. Apart from the white coat effect, the readings of blood pressure outside of a clinical setting are generally slightly lower in most people. Studies that have looked at the risk of hypertension and the benefits of lowering blood pressure in patients affected were based on readings in a clinical environment. Blood pressure higher than the normal value is called hypertension. In itself, it is only an acute problem; see hypertensive crisis. But because of its long-term consequences of indirect effects (and also as an indicator of other problems), it is a serious concern for the doctors. All levels of blood pressure to mechanical stress on the arterial walls. Higher pressures increase heart progression of the workload and unhealthy tissue growth (atheroma), which develops in the arteries. The higher the pressure, more stress is present and that the trend towards more atheroma progress and the heart muscle tends to thicken, enlarge and weaken over time. Persistent hypertension is a risk factor for stroke, myocardial infarction, heart failure, arterial aneurysms, and is the leading cause of chronic renal failure. Even moderate high blood pressure led to the shortened life expectancy. At severely high blood pressure, mean arterial pressure 50% or more above average, a person can expect to live no more than a few years, unless an appropriate treatment [18]. In the past, most attention to the diastolic pressure, but today it is acknowledged that the two high systolic pressure and pulse pressure (the difference between digital systolic and diastolic pressures) are also factors risk. In some cases, it appears that a reduction in diastolic pressure excessive may actually increase the risk, probably owing to the increase in the difference between systolic and diastolic pressure (see article on pulse pressure). [Edit] Low blood pressure Feature: Hypotension Blood pressure is too low is called hypotension. The similarity in pronunciation of hypertension can cause confusion. Low blood pressure can be a sign of serious disease and requires urgent medical attention. When blood pressure and blood flow decreases beyond a certain point, becomes brain perfusion decreased (ie, the blood supply is not sufficient), which causes vertigo, dizziness, weakness and fainting. However, those who work well, while maintaining low blood pressure have lower rates of cardiovascular disease than people with normal manifestations of blood pressure. [Edit] [Edit] factors The physics of the circulatory system, like any other fluid, are very complex. That said, there are many physical factors that influence blood pressure. Each of them in turn can be influenced by physiological factors such as diet, exercise, disease, drugs or alcohol, obesity, excess weight and so forth -. In cardiac physiology, the pace and volume of traffic are accounted for in a combined cardiac output, which is the heart rate (the rate of contraction) multiplied by the volume (the amount of blood pumped by the heart with each contraction). It represents the efficiency with which the heart circulate blood throughout the body. Some physical factors are: Pumping rates. In the circulatory system, this rate is called the heart rate, the rate at which the blood (fluid) is pumped by the heart. The higher the heart rate, the highest (potentially, assuming no change in volume) in blood pressure. Volume of fluid or blood volume, the amount of blood that is present in the body. La présente plus de sang dans l'organisme est élevée, plus le taux de retour du sang vers le coeur et le débit cardiaque. Il existe une certaine relation entre le sel alimentaire et l'accroissement du volume sanguin, pouvant entraîner une hausse de pression artérielle, bien que cela varie avec l'individu et est fortement tributaire de la réaction du système nerveux autonome. Résistance. Dans le système circulatoire, il s'agit de la résistance des vaisseaux sanguins. Plus la résistance est élevée, plus la pression artérielle. La résistance est liée à la taille (la plus grande vaisseau sanguin, le plus faible de la résistance), ainsi que la fluidité de la paroi des vaisseaux sanguins. Lissé est réduit par l'accumulation de dépôts graisseux sur les parois artérielles. De substances appelées vasoconstricteurs peut réduire la taille des vaisseaux sanguins, ce qui augmente la pression sanguine. Vasodilatateurs (comme la nitroglycérine) augmenter la taille des vaisseaux sanguins, ce qui diminue la pression artérielle. Certains types d'acides gras oméga - 6, en particulier à partir de l'huile d'olive, ont été connus pour augmenter vasculaire finesse. [Modifier] Viscosité ou l'épaisseur du fluide. Si le sang est plus épais, le résultat est une augmentation de la pression artérielle. Certaines conditions médicales peuvent changer la viscosité du sang. Par exemple, une faible concentration de globules rouges, l'anémie, réduit la viscosité, alors que augmenté la concentration de globules rouges augmente la viscosité. Viscosité augmente avec la concentration de glucose dans le sang - visualiser pompage sirop. Il avait pensé que l'aspirine et les "sang mince" drogues a diminué la viscosité du sang, mais des études trouvé [19] qu'ils agissent en réduisant la tendance du sang à coaguler la place. Dans la pratique, chaque individu système nerveux autonome et réglemente répond à l'ensemble de ces facteurs interagissent de sorte que, bien que ces questions sont importantes, le montant réel de la pression artérielle réponse d'une personne varie largement raison à la fois de fraction de seconde plus lents et réponses Du système nerveux et des organes cibles. Ces réponses sont très efficaces dans la modification des variables et de la pression artérielle résultant de l'instant. [Modifier] Basse pression artérielle Parfois, la pression artérielle diminue considérablement quand un patient se lève de la séance. Cette approche est appelée hypotension posturale; gravité réduit le taux de retour du sang des veines de l'organisme en dessous du cœur à cœur, réduisant ainsi le volume et le débit cardiaque. Lorsque les gens sont en bonne santé, les veines en dessous de leur coeur contractent rapidement et le rythme cardiaque augmente afin de réduire et de compenser l'effet de gravité. Celle-ci est effectuée involontairement par le système nerveux autonome. Le système exige généralement de quelques secondes pour ajuster pleinement et si les compensations sont trop lentes ou insuffisantes, l'individu souffrira réduit le flux sanguin au cerveau, vertiges et le potentiel panne. L'augmentation des G - chargement, telles que couramment rencontrés par les pilotes de jets acrobatique "tirant Gs", augmente cet effet. Repositionnement du corps perpendiculaire à la pesanteur élimine en grande partie le problème. Autres causes de la faible pression artérielle comprennent: Sepsis Hémorragie - perte de sang Toxines y compris des doses toxiques de la pression sanguine médecine Anomalies hormonales, comme la maladie d'Addison Shock est une condition complexe qui conduit à la diminution de la perfusion critique. Les mécanismes habituels sont la perte de volume sanguin, mise en commun de sang dans les veines de la réduction de rendement adéquat pour le coeur et / ou à faible effectif pompage de coeur. Faible pression artérielle, pouls très faible pression, est un signe de choc et contribue à la diminution de la perfusion et reflète. S'il ya une différence notable entre la pression d'une branche à l'autre, qui pourraient signaler un rétrécissement (par exemple, en raison de coarctation aortique, la dissection aortique, thrombose ou embolie) d'une artère.
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