रविवार, 29 अगस्त 2010

blood pressure, force exerted by the blood upon the walls of the arteries. The pressure in the arteries originates in the pumping action of the heart, and pressure waves can be felt at the wrist and at other points where arteries lie near the surface of the body (see pulse pulse, alternate expansion and contraction of artery walls as heart action varies blood volume within the arteries. Artery walls are elastic. Hence they become distended by increased blood volume during systole, or contraction of the heart.
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). Since the heart can pump blood into the large arteries more quickly than it can be absorbed and released by the tiny arterioles and capillaries, considerable inner pressure always exists in the arteries. The contraction of the heart (systole) causes the blood pressure to rise to its highest point, and relaxation of the heart (diastole) brings the pressure down to its lowest point.

Blood pressure is strongest in the aorta, where the blood leaves the heart. It diminishes progressively in the smaller blood vessels and reaches its lowest point in the veins (see circulatory system circulatory system, group of organs that transport blood and the substances it carries to and from all parts of the body. The circulatory system can be considered as composed of two parts: the systemic circulation, which serves the body as a whole except for the
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). Blood pressure manifests itself dramatically when an artery is severed or pierced and the blood (under pressure) ejects in spurts.

Since blood pressure varies in different arteries, the pressure in the brachial artery of the forearm serves as a standard. A sphygmomanometer measures blood pressure in millimeters of mercury; blood pressure gauges that do not use mercury also produce readings that are expressed in terms of millimeters of mercury. Normal blood pressure readings for healthy young people should be below 120 mm for systolic pressure and 80 mm for diastolic pressure, commonly written as 120/80 and read as "one-twenty over eighty." With age, and the constriction of the small arteries and then the larger ones, blood pressure increases, so that at 50 years, a person may typically have a systolic pressure between 140 and 150, and a diastolic pressure of about 90.

Blood pressure
See Hypertension for more information about recognition and treatment of high blood pressure.
A sphygmomanometer, a device used for measuring arterial pressure.Enlarge picture
A sphygmomanometer, a device used for measuring arterial pressure.

Blood pressure refers to the force exerted by circulating blood on the walls of blood vessels, and constitutes one of the principal vital signs. The pressure of the circulating blood decreases as blood moves through arteries, arterioles, capillaries, and veins; the term blood pressure generally refers to arterial pressure, i.e., the pressure in the larger arteries, arteries being the blood vessels which take blood away from the heart. Arterial pressure is most commonly measured via a sphygmomanometer, which uses the height of a column of mercury to reflect the circulating pressure (see Non-invasive measurement). Blood pressure values are reported in either kilopascals (kPa) or in millimetres of mercury (mmHg), despite the fact that many modern vascular pressure devices no longer use mercury.

The systolic arterial pressure is defined as the peak pressure in the arteries, which occurs near the beginning of the cardiac cycle; the diastolic arterial pressure is the lowest pressure (at the resting phase of the cardiac cycle). The average pressure throughout the cardiac cycle is reported as mean arterial pressure; the pulse pressure reflects the difference between the maximum and minimum pressures measured.

Typical values for a resting, healthy adult human are approximately 120 mmHg (16 kPa) systolic and 80 mmHg (11 kPa) diastolic (written as 120/80 mmHg, and spoken as "one twenty over eighty") with large individual variations. These measures of arterial pressure are not static, but undergo natural variations from one heartbeat to another and throughout the day (in a circadian rhythm); they also change in response to stress, nutritional factors, drugs, or disease. Hypertension refers to arterial pressure being abnormally high, as opposed to hypotension, when it is abnormally low. Along with body temperature, blood pressure measurements are the most commonly measured physiological parameters.

Measurement

Arterial pressures can be measured invasively (by penetrating the skin and measuring inside the blood vessels) or non-invasively. The former is usually restricted to a hospital setting.

Non-invasive measurement

The non-invasive auscultatory (from the Latin for listening) and oscillometric measurements are simpler and quicker than invasive measurements, require less expertise in fitting, have virtually no complications, and are less unpleasant and painful for the patient. However, non-invasive measures may yield somewhat lower accuracy and small systematic differences in numerical results. Non-invasive measurement methods are more commonly used for routine examinations and monitoring.

Palpation methods

A minimum systolic value can be roughly estimated without any equipment by palpation, most often used in emergency situations. Palpation of a radial pulse indicates a minimum blood pressure of 80 mmHg (11 kPa), a femoral pulse indicates at least 70 mmHg (9.3 kPa), and a carotid a minimum of 60 mmHg (8.0 kPa). However, one study indicated that this method was not accurate enough and often overestimated patient's systolic blood pressure.[1] A more accurate value of systolic blood pressure can be obtained by with a sphygmomanometer and palpating for when a radial pulse returns.[2] Because a diastolic pressure cannot be obtained by this method, blood pressures obtained by palpation are noted as "/P".[3]

Auscultatory methods

Auscultatory method aneroid sphygmomanometer with stethoscopeEnlarge picture
Auscultatory method aneroid sphygmomanometer with stethoscope
Mercury manometerEnlarge picture
Mercury manometer

The auscultatory method uses a stethoscope and a sphygmomanometer. This comprises an inflatable (Riva-Rocci) cuff placed around the upper arm at roughly the same vertical height as the heart, attached to a mercury or aneroid manometer. The mercury manometer, considered to be the gold standard for arterial pressure measurement, measures the height of a column of mercury, giving an absolute result without need for calibration, and consequently not subject to the errors and drift of calibration which affect other methods. The use of mercury manometers is often required in clinical trials and for the clinical measurement of hypertension in high risk patients, such as pregnant women.

A cuff of appropriate size is fitted and inflated manually by repeatedly squeezing a rubber bulb until the artery is completely occluded. Listening with the stethoscope to the brachial artery at the elbow, the examiner slowly releases the pressure in the cuff. When blood just starts to flow in the artery, the turbulent flow creates a "whooshing" or pounding (first Korotkoff sound). The pressure at which this sound is first heard is the systolic blood pressure. The cuff pressure is further released until no sound can be heard (fifth Korotkoff sound), at the diastolic arterial pressure. Sometimes, the pressure is palpated (felt by hand) to get an estimate before auscultation.

Oscillometric methods

Oscillometric methods are sometimes used in the long-term measurement and sometimes in general practice. The equipment is functionally similar to that of the auscultatory method, but with an electronic pressure sensor (transducer) fitted in to detect blood flow, instead of using the stethoscope and the expert's ear. In practice, the pressure sensor is a calibrated electronic device with a numerical readout of blood pressure. To maintain accuracy, calibration must be checked periodically, unlike the inherently accurate mercury manometer. In most cases the cuff is inflated and released by an electrically operated pump and valve, which may be fitted on the wrist (elevated to heart height), although the upper arm is preferred. They vary widely in accuracy, and should be checked at specified intervals and if necessary recalibrated.

Oscillometric measurement requires less skill than the auscultatory technique, and may be suitable for use by untrained staff and for automated patient home monitoring.

The cuff is inflated to a pressure initially in excess of the systolic arterial pressure, and then reduces to below diastolic pressure over a period of about 30 seconds. When blood flow is nil (cuff pressure exceeding systolic pressure) or unimpeded (cuff pressure below diastolic pressure), cuff pressure will be essentially constant. It is essential that the cuff size is correct: undersized cuffs may yield too high a pressure, whereas oversized cuffs yields too low a pressure. When blood flow is present, but restricted, the cuff pressure, which is monitored by the pressure sensor, will vary periodically in synchrony with the cyclic expansion and contraction of the brachial artery, i.e., it will oscillate. The values of systolic and diastolic pressure are computed, not actually measured from the raw data, using an algorithm; the computed results are displayed.

Oscillometric monitors may produce inaccurate readings in patients with heart and circulation problems, that include arterial sclerosis, arrhythmia, preeclampsia, pulsus alternans, and pulsus paradoxus.

In practice the different methods do not give identical results; an algorithm and experimentally obtained coefficients are used to adjust the oscillometric results to give readings which match the auscultatory as well as possible.[4] Some equipment uses computer-aided analysis of the instantaneous arterial pressure waveform to determine the systolic, mean, and diastolic points. Since many oscillometric devices have not been validated, caution must be given as most are not suitable in clinical and acute care settings.

The term NIBP, for Non-Invasive Blood Pressure, is often used to describe oscillometric monitoring equipment.

Invasive measurement

Arterial blood pressure (BP) is most accurately measured invasively through an arterial line. Invasive arterial pressure measurement with intravascular cannulae involves direct measurement of arterial pressure by placing a cannula needle in an artery (usually radial, femoral, dorsalis pedis or brachial). This is usually done by an anesthesiologist or surgeon in a hospital.

The cannula must be connected to a sterile, fluid-filled system, which is connected to an electronic pressure transducer. The advantage of this system is that pressure is constantly monitored beat-by-beat, and a waveform (a graph of pressure against time) can be displayed. This invasive technique is regularly employed in human and veterinary intensive care medicine, anesthesiology, and for research purposes.

Cannulation for invasive vascular pressure monitoring is infrequently associated with complications such as thrombosis, infection, and bleeding. Patients with invasive arterial monitoring require very close supervision, as there is a danger of severe bleeding if the line becomes disconnected. It is generally reserved for patients where rapid variations in arterial pressure are anticipated.

Invasive vascular pressure monitors are pressure monitoring systems designed to acquire pressure information for display and processing. There are a variety of invasive vascular pressure monitors for trauma, critical care, and operating room applications. These include single pressure, dual pressure, and multi-parameter (i.e. pressure / temperature). The monitors can be used for measurement and follow-up of arterial, central venous, pulmonary arterial, left atrial, right atrial, femoral arterial, umbilical venous, umbilical arterial, and intracranial pressures.

Vascular pressure parameters are derived in the monitor's microcomputer system. Usually, systolic, diastolic, and mean pressures are displayed simultaneously for pulsatile waveforms (i.e. arterial and pulmonary arterial). Some monitors also calculate and display CPP (cerebral perfusion pressure). Normally, a zero key on the front of the monitor makes pressure zeroing extremely fast and easy. Alarm limits may be set to assist the medical professional responsible for observing the patient. High and low alarms may be set on displayed temperature parameters.

Home monitoring

Up to 25% of patients diagnosed with hypertension do not suffer from it, but rather from white coat hypertension (elevated arterial pressure specifically during medical exams, probably as a result of anxiety). Thus, well-performed, accurate home arterial pressure monitoring can prevent unnecessary anxiety, as well as costly and potentially dangerous therapy in many millions of people worldwide. Home arterial pressure monitoring provides a measurement of a person's arterial pressure at different times and in different environments, such as at home and at work, throughout the day. Home arterial pressure monitoring may assist in the diagnosis of high or low arterial pressure. It may also be used to monitor the effects of medication or lifestyle changes taken to lower or regulate arterial pressure levels.

Automatic self-contained blood pressure monitors are available at reasonable prices, some of which are capable of Korotkoff's measurement in addition to oscillometric methods, enabling irregular heartbeat patients to accurately measure their blood pressure at home, which was not possible using the traditional devices.

The 2003 US Joint National Committee recommends the use of self monitoring of arterial pressure, before considering the more expensive ambulatory monitoring of arterial pressure, to improve hypertension management.[5] Both the Joint National Committee and the 2003 guidelines from the European Society of Hypertension and the European Society of Cardiology suggest that self monitoring might also be used as an alternative to ambulatory monitoring for the diagnosis of white coat hypertension.[6]

A study published in the May 2006 American Journal of Hypertension[7] compared home and ambulatory blood pressure monitoring methods in the adjustment of antihypertensive treatment. The study showed home arterial pressure monitoring is as accurate as a 24 hour ambulatory monitoring in determining arterial pressure levels. Researchers at the University of Turku, Finland studied 98 patients with untreated hypertension. They compared patients using a home arterial pressure device and those wearing a 24-hour ambulatory monitor. Researcher Dr. Niiranen said that, "home blood pressure measurement can be used effectively for guiding anti-hypertensive treatment". Dr. Stergiou added that home tracking of arterial pressure, "is more convenient and also less costly than ambulatory blood pressure monitoring".

A clinical study published in the May 2007 edition of The American Journal of Hypertension[8] compared the accuracy of three different methods of taking arterial pressure in indicating cardiovascular health. The study aim was to assess the accuracy of home blood pressure monitoring (HBP), 24-hour ambulatory blood pressure monitoring (ABP) and arterial pressure readings taken in a doctor’s office (OBP). The arterial pressure tests were compared to the left-ventricular mass index (LVMI). The LVMI was calculated from an echocardiogram of the heart and indicates cardiovascular organ damage, an indicator of arterial pressure. Researchers at The Columbia University Medical Center, New York found that home arterial pressure monitoring, over a ten-week period was a significant independent predictor of LVMI even after adjusting for age, sex and BMI (body mass index). They found that home monitoring over time is a better indicator of cardiovascular health than ambulatory readings or readings taken at the doctors’ office. The value of home monitoring increases over time with a number of measurements taken.

The June 2007 AMNews; Newspaper for America's Physicians[9] released a study which showed arterial pressure readings taken in a doctors office are often unreliable. The American Medical Association newspaper quoted Prof Norman Kaplan from the University of Texas Southwestern Medical Center who said, "Of all the procedures done in a doctor's office, measurement of blood pressure is usually the least well performed but has the most important implications for the care of the patient." The paper explained that arterial pressure readings taken in a Doctors office can be falsely raised or lowered. This can be due to the presence of a Doctor or clinician which results in the patient experiencing white coat hypertension.

The American Heart Association website[10] states, "You may have what's called 'white coat hypertension'; that means your blood pressure goes up when you're at the doctor's office. Monitoring at home will help you measure your true blood pressure and can provide your doctor with a log of blood pressure measurements over time. This is helpful in diagnosing and preventing potential health problems."

Those using home arterial pressure monitoring devices are increasingly also making use of arterial pressure charting software.[11] These charting methods provide print outs for the patients physician and reminders on how often to check arterial pressure.[12][13]

Accuracy of Home Monitoring

The National Heart, Lung and Blood Institute has issued guidelines for taking blood pressure using home monitoring devices.[14] Obtaining an accurate reading requires that the patient should not drink coffee, smoke cigarettes, or engage in strenuous exercise for 30 minutes before taking the reading. For 5 minutes before the test, the patient should be sitting upright in a chair with his or her feet flat on the floor and without any limbs crossed. The arm should be relaxed and kept at heart level during the reading. The blood pressure cuff should always be against bare skin, as readings taken over a shirt sleeve are less accurate. A full bladder may have a small effect on blood pressure readings, so if the urge to urinate exists, the patient should be encouraged to void the bladder before the reading.[15]

Normal Values

While statistically normal values for arterial pressure could be computed for any given population, there is often a large variation from person to person; arterial pressure also varies in individuals from moment to moment. Additionally, the norm of any given population may have a questionable correlation with its general health, thus the relevance of such statistical values is equally questionable. In a study of 100 subjects with no known history of hypertension, an average systolic blood pressure of 112.4 mmHg (14.99 kPa) and an average diastolic pressure of about 64.0 mmHg (8.53 kPa) was found.[16]

In children the observed normal ranges are lower; in the elderly, they are often higher, largely because of reduced flexibility of the arteries. Factors such as age, gender and race influence blood pressure values. Pressure also varies with exercise, emotional reactions, sleep, digestion and time of the day.

In the U.S., the optimal arterial pressure (sometimes referred to as the ‘gold standard’) targets are:[17][18][19]

Levels above 120 mmHg (16 kPa) but below 140 mmHg (19 kPa) in systolic pressure, or above 80 (11 kPa) but below 95 mmHg (13 kPa) in diastolic pressure, are referred to as "prehypertensive" and often progress to frankly hypertensive levels. However studies already extant reveal that there are fewer complications at, e.g., 115 mmHg (15 kPa) systolic than 120 mmHg (16 kPa), and in fact arterial pressure is a continuum with decreasing pathology associated with lower levels to well within the current "optimum" range. The risk of cardiovascular disease increases progressively throughout the range of arterial pressure, beginning at 115/75 mm Hg.[20] "Some data indicates that 115/75 mm Hg should be the gold standard. Once arterial pressure rises above 115/75 mm Hg, the risk of cardiovascular disease begins to increase. Prehypertension is now considered to be a systolic pressure ranging from 120 to 139 or a diastolic pressure ranging from 80 to 89." (Excerpts from Mayo Clinic website). In the past, hypertension was only diagnosed if secondary signs of high arterial pressure were present, along with a prolonged high systolic pressure reading over several visits. In the US, this reactive stance has been soundly rejected in the light of recent evidence.

In the UK, mirroring abandoned earlier US practice, nursing students continue to be taught that their patients’ readings should be considered ‘normal’ if in the range:

Clinical trials demonstrate that people who maintain arterial pressures at the low end of these pressure ranges have much better long term cardiovascular health. The principal medical debate concerns the aggressiveness and relative value of methods used to lower pressures into this range for those who do not maintain such pressure on their own. Elevations, more commonly seen in older people, though often considered normal, are associated with increased morbidity and mortality. The clear trend from double blind clinical trials (for the better strategies and agents) demonstrates that lower arterial pressure correlates with lower rates of disease.

Physiology

The mean arterial pressure (MAP) is the average pressure measured over one complete cardiac cycle.

The up and down fluctuation of the arterial pressure results from the pulsatile nature of the cardiac output. The pulse pressure is determined by the interaction of the stroke volume versus the resistance to flow in the arterial tree.

The larger arteries, including all large enough to see without magnification, are low resistance (assuming no advanced atherosclerotic changes) conduits with high flow rates that generate only small drops in pressure. For instance, with a subject in the supine position, blood travelling from the heart to the toes typically only experiences a 5 mmHg (0.67 kPa) drop in mean pressure.

Modern physiology developed the concept of the vascular pressure wave (VPW). This wave is created by the heart during the systole and originates in the ascending aorta. Much faster than the stream of blood itself, it is then transported through the vessel walls to the peripheral arteries. There the pressure wave can be palpated as the peripheral pulse. As the wave is reflected at the peripheral veins it runs back in a centripetal fashion. Where the crests of the reflected and the original wave meet, the pressure inside the vessel is higher than the true pressure in the aorta. This concept explains why the arterial pressure inside the peripheral arteries of the legs and arms is higher than the arterial pressure in the aorta,[21][22][23] and in turn for the higher pressures seen at the ankle compared to the arm with normal ankle brachial pressure index values.

Regulation

The endogenous regulation of arterial pressure is not completely understood. Currently, three mechanisms of regulating arterial pressure have been well-characterized:

  • Aldosterone release: This steroid hormone is released from the adrenal cortex in response to angiotensin II or high serum potassium levels. Aldosterone stimulates sodium retention and potassium excretion by the kidneys. Since sodium is the main ion that determines the amount of fluid in the blood vessels by osmosis, aldosterone will increase fluid retention, and indirectly, arterial pressure.

These different mechanisms are not necessarily independent of each other, as indicated by the link between the RAS and aldosterone release. Currently, the RAS system is targeted pharmacologically by ACE inhibitors and angiotensin II receptor antagonists. The aldosterone system is directly targeted by spironolactone, an aldosterone antagonist. The fluid retention may be targeted by diuretics; the antihypertensive effect of diuretics is due to its effect on blood volume. Generally, the baroreceptor reflex is not targeted in hypertension because if blocked, individuals may suffer from orthostatic hypotension and fainting.

Pathophysiology

High arterial pressure


The diagnosis of abnormalities in arterial pressure may require serial measurement. Since arterial pressure varies throughout the day, measurements 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 requirements at the doctor's office; also, some patients become nervous when their arterial pressure is taken at the office, causing readings to increase (this phenomenon is called white coat hypertension). Taking blood pressure levels at home or work with a home blood pressure monitoring device may help determine a person's true range of arterial pressure readings and avoid false readings from the white coat hypertension effect. Long term assessments may be made with an ambulatory blood pressure device that takes regular arterial pressure readings every half an hour throughout the course of a single day and night.

Aside from the white coat effect, arterial pressure readings outside of a clinical setting are usually slightly lower in the majority of people. The studies that looked into the risks from hypertension and the benefits of lowering the arterial pressure in affected patients were based on readings in a clinical environment.

Arterial pressure exceeding normal values is called arterial hypertension. In itself it is only an acute problem; see hypertensive emergency. But because of its long-term indirect effects (and also as an indicator of other problems) it is a serious worry to physicians diagnosing it.

All levels of arterial pressure put mechanical stress on the arterial walls. Higher pressures increase heart workload and progression of unhealthy tissue growth (atheroma) that develops within the walls of arteries. The higher the pressure, the more stress that is present and the more atheroma tend to progress and the heart muscle tends to thicken, enlarge and become weaker over time.

Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure, arterial aneurysms, and is the leading cause of chronic renal failure. Even moderate elevation of arterial pressure leads to shortened life expectancy. At severely high pressures, mean arterial pressures 50% or more above average, a person can expect to live no more than a few years unless appropriately treated.[24]

In the past, most attention was paid to diastolic pressure; but nowadays it is recognised that both high systolic pressure and high pulse pressure (the numerical difference between systolic and diastolic pressures) are also risk factors. In some cases, it appears that a decrease in excessive diastolic pressure can actually increase risk, due probably to the increased difference between systolic and diastolic pressures (see the article on pulse pressure).

Low arterial pressure


Blood pressure that is too low is known as hypotension. The similarity in pronunciation with hypertension can cause confusion.

Low arterial pressure may be a sign of severe disease and requires urgent medical attention.

When arterial pressure and blood flow decrease beyond a certain point, the perfusion of the brain becomes critically decreased (i.e., the blood supply is not sufficient), causing lightheadedness, dizziness, weakness and fainting.

However, people who function well, while maintaining low arterial pressures have lower rates of cardiovascular disease events than people with normal arterial pressures.

Influential factors

The physics of the circulatory system, as of any fluid system, are very complex. That said, there are many physical factors that influence arterial pressure. Each of these may in turn be influenced by physiological factors, such as diet, exercise, disease, drugs or alcohol, obesity, excess weight and so-forth.

In cardiac physiology, the rate and volume of flow are accounted for in a combined fashion by cardiac output which is the heart rate (the rate of contraction) multiplied by the stroke volume (the amount of blood pumped out from the heart with each contraction). It represents the efficiency with which the heart circulates blood throughout the body.

Some physical factors are:

  • Rate of pumping. In the circulatory system, this rate is called heart rate, the rate at which blood (the fluid) is pumped by the heart. The higher the heart rate, the higher (potentially, assuming no change in stroke volume) the arterial pressure.
  • Volume of fluid or blood volume, the amount of blood that is present in the body. The more blood present in the body, the higher the rate of blood return to the heart and the resulting cardiac output. There is some relationship between dietary salt intake and increased blood volume, potentially resulting in higher arterial pressure, though this varies with the individual and is highly dependent on autonomic nervous system response.
  • Resistance. In the circulatory system, this is the resistance of the blood vessels. The higher the resistance, the higher the arterial pressure. Resistance is related to size (the larger the blood vessel, the lower the resistance), as well as the smoothness of the blood vessel walls. Smoothness is reduced by the buildup of fatty deposits on the arterial walls. Substances called vasoconstrictors can reduce the size of blood vessels, thereby increasing blood pressure. Vasodilators (such as nitroglycerin) increase the size of blood vessels, thereby decreasing arterial pressure. Some types of omega-6 fatty acids, particularly from olive oil, have been known to increase vascular smoothness.
  • Viscosity, or thickness of the fluid. If the blood gets thicker, the result is an increase in arterial pressure. Certain medical conditions can change the viscosity of the blood. For instance, low red blood cell concentration, anemia, reduces viscosity, whereas increased red blood cell concentration increases viscosity. Viscosity also increases with blood sugar concentration—visualize pumping syrup. It had been thought that aspirin and related "blood thinner" drugs decreased the viscosity of blood, but studies found[25] that they act by reducing the tendency of the blood to clot instead.

In practice, each individual's autonomic nervous system responds to and regulates all these interacting factors so that, although the above issues are important, the actual arterial pressure response of a given individual varies widely because of both split-second and slow-moving responses of the nervous system and end organs. These responses are very effective in changing the variables and resulting blood pressure from moment to moment.

Low arterial pressure

Sometimes the arterial pressure drops significantly when a patient stands up from sitting. This is known as orthostatic hypotension (postural hypotension); gravity reduces the rate of blood return from the body veins below the heart back to the heart, thus reducing stroke volume and cardiac output.

When people are healthy, the veins below their heart quickly constrict and the heart rate increases to minimize and compensate for the gravity effect. This is carried out involuntarily by the autonomic nervous system. The system usually requires a few seconds to fully adjust and if the compensations are too slow or inadequate, the individual will suffer reduced blood flow to the brain, dizziness and potential blackout. Increases in G-loading, such as routinely experienced by acrobatic jet pilots "pulling Gs", greatly increases this effect. Repositioning the body perpendicular to gravity largely eliminates the problem.

Other causes of low arterial pressure include:

Shock is a complex condition which leads to critically decreased perfusion. The usual mechanisms are loss of blood volume, pooling of blood within the veins reducing adequate return to the heart and/or low effective heart pumping. Low arterial pressure, especially low pulse pressure, is a sign of shock and contributes to and reflects decreased perfusion.

If there is a significant difference in the pressure from one arm to the other, that may indicate a narrowing (for example, due to aortic coarctation, aortic dissection, thrombosis or embolism) of an artery.

Venous pressure

Venous pressure is the vascular pressure in a vein or in the atria of the heart. It is much less than arterial pressure, with common values of 5 mmHg (0.7 kPa) in the right atrium and 8 mmHg (1 kPa) in the left atrium. Measurement of pressures in the venous system and the pulmonary vessels plays an important role in intensive care medicine but requires an invasive central venous catheter.the pressure

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आराम करो

एक मित्र मिले, बोले, "लाला, तुम किस चक्की का खाते हो?
इस डेढ़ छटांक के राशन में भी तोंद बढ़ाए जाते हो।
क्या रक्खा माँस बढ़ाने में, मनहूस, अक्ल से काम करो।
संक्रान्ति-काल की बेला है, मर मिटो, जगत में नाम करो।"
हम बोले, "रहने दो लेक्चर, पुरुषों को मत बदनाम करो।
इस दौड़-धूप में क्या रक्खा, आराम करो, आराम करो।

आराम ज़िन्दगी की कुंजी, इससे न तपेदिक होती है।
आराम सुधा की एक बूंद, तन का दुबलापन खोती है।
आराम शब्द में 'राम' छिपा जो भव-बंधन को खोता है।
आराम शब्द का ज्ञाता तो विरला ही योगी होता है।
इसलिए तुम्हें समझाता हूँ, मेरे अनुभव से काम करो।
ये जीवन, यौवन क्षणभंगुर, आराम करो, आराम करो।

यदि करना ही कुछ पड़ जाए तो अधिक न तुम उत्पात करो।
अपने घर में बैठे-बैठे बस लंबी-लंबी बात करो।
करने-धरने में क्या रक्खा जो रक्खा बात बनाने में।
जो ओठ हिलाने में रस है, वह कभी न हाथ हिलाने में।
तुम मुझसे पूछो बतलाऊँ, है मज़ा मूर्ख कहलाने में।
जीवन-जागृति में क्या रक्खा जो रक्खा है सो जाने में।

मैं यही सोचकर पास अक्ल के, कम ही जाया करता हूँ।
जो बुद्धिमान जन होते हैं, उनसे कतराया करता हूँ।
दीए जलने के पहले ही घर में आ जाया करता हूँ।
जो मिलता है, खा लेता हूँ, चुपके सो जाया करता हूँ।
मेरी गीता में लिखा हुआ, सच्चे योगी जो होते हैं,
वे कम-से-कम बारह घंटे तो बेफ़िक्री से सोते हैं।

अदवायन खिंची खाट में जो पड़ते ही आनंद आता है।
वह सात स्वर्ग, अपवर्ग, मोक्ष से भी ऊँचा उठ जाता है।
जब 'सुख की नींद' कढ़ा तकिया, इस सर के नीचे आता है,
तो सच कहता हूँ इस सर में, इंजन जैसा लग जाता है।
मैं मेल ट्रेन हो जाता हूँ, बुद्धि भी फक-फक करती है।
भावों का रश हो जाता है, कविता सब उमड़ी पड़ती है।

मैं औरों की तो नहीं, बात पहले अपनी ही लेता हूँ।
मैं पड़ा खाट पर बूटों को ऊँटों की उपमा देता हूँ।
मैं खटरागी हूँ मुझको तो खटिया में गीत फूटते हैं।
छत की कड़ियाँ गिनते-गिनते छंदों के बंध टूटते हैं।
मैं इसीलिए तो कहता हूँ मेरे अनुभव से काम करो।
यह खाट बिछा लो आँगन में, लेटो, बैठो, आराम करो।

- गोपालप्रसाद व्यास

रविवार, 25 अप्रैल 2010

राज्य: UTTAR PRADESH
वित्तीय वर्ष 2009-2010 के दौरान उत्पन्न रोजगार
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परिवारों की संख्या जो रोजगार की मांग कर चुके हैं (रिपोर्टिंग महीने तक)
परिवारों की संख्या जिनको रोजगार उपलब्ध कराया जा चुका है (रिपोर्टिंग महीने तक)
नरेगा के अर्न्तगत कार्य कर रहे परिवारों की संख्या (रिपोर्टिंग महीने में)
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क्रम संख्या
जिला
परिवारों की संख्या जिनको जॉब कार्ड जारी हो चुका है (रिपोर्टिंग महीने तक)
कुल उत्पन्न व्यक्ति दिवस (रिपोर्टिंग महीने तक)
100 दिन का रोजगार पूर्ण कर चुके परिवारों की कुल संख्या (रिपोर्टिंग महीने तक)
परिवारों की संख्या जो भूमि सुधार/ इंदिरा आवास योजना के लाभार्थी हैं
लाभार्थी विकलांग व्यक्तियों की संख्या
अनुसूचित जाति
अनुसूचित जनजाति
अन्य
कुल
अनुसूचित जाति
अनुसूचित जनजाति
अन्य
कुल
महिला
प्रथम चरण
1 AZAMGARH 32741 486 248212 281439 143115 145208 30900 353198 7126 4113311 4473635 565856 4331 5 208
2 BANDA 29225 272 122732 152229 77151 77376 8253 546060 4156 2796363 3346579 1049309 7049 23 42
3 CHANDAULI 56679 1748 109431 167858 94876 95736 29745 1053017 27765 1915142 2995924 441560 3544 245 94
4 CHITRAKOOT 10114 147 78424 88685 48769 48706 3428 201581 2267 1921109 2124957 668929 4281 188 19
5 FATEHPUR 27341 106 127723 155170 120713 120517 9246 771034 3519 4388949 5163502 1037818 8618 6 81
6 GORAKHPUR 40496 632 179341 220469 100384 100529 37479 586562 12334 3019105 3618001 576675 5192 48 62
7 HAMIRPUR 19775 142 97618 117535 83155 83136 12493 679485 3405 3645610 4328500 1322610 10370 123 50
8 HARDOI 124374 975 238561 363910 158861 159367 31054 1736906 18905 4169010 5924821 137934 8415 163 108
9 JALAUN 37847 1217 110509 149573 98650 98776 3779 1023058 22351 3007087 4052496 797472 7103 1143 280
10 JAUNPUR 85423 3869 86543 175835 82611 82988 15016 1253475 61904 1619913 2935292 356287 5215 78 103
11 KAUSHAMBI 83049 474 48293 131816 69673 69660 17502 1835525 12587 902056 2750168 675396 5593 12 77
12 KHERI 79968 2707 198246 280921 180689 180683 38537 1723609 45287 4508201 6277097 119732 9260 104 133
13 KUSHI NAGAR 16819 497 153108 170424 104089 104062 35615 568022 21306 2683420 3272748 335621 3066 1 79
14 LALITPUR 4463 2437 151754 158654 86121 86528 11865 166008 80323 3841345 4087676 1001047 9121 22 93
15 MAHOBA 13515 59 55613 69187 34623 34631 953 225453 1049 1012302 1238804 324759 1934 5 44
16 MIRZAPUR 107540 2678 117841 228059 129181 129566 35226 2412837 52592 2249612 4715041 1555931 9076 268 80
17 PRATAPGARH 42367 138 119082 161587 88136 88413 9930 764119 2293 2390974 3157386 607754 5258 425 104
18 RAE BARELI 6849 641 219324 226814 178618 178915 52154 171773 14961 6121917 6308651 1116180 8124 0 324
19 SITAPUR 125014 3510 263587 392111 234039 234970 51704 2271705 78652 5382009 7732366 337386 8780 228 419
20 SONBHADRA 90047 67373 104739 262159 207380 207655 50235 3593948 2701842 3640609 9936399 3658074 27181 709 423
21 UNNAO 52711 1317 199590 253618 146575 146665 35523 667153 19538 4625179 5311870 382457 8616 6 63
22 वारावंकी 6767 3674 205093 215534 147541 147408 36839 230301 129545 5295261 5655107 139747 8930 0 69
द्वितीय चरण
23 AMBEDKAR NAGAR 78329 349 86707 165385 61746 61718 17504 803533 2399 701229 1507161 254366 1050 37 53
24 BAHRAICH 23996 537 237341 261874 118591 118497 16066 186476 4365 3652764 3843605 296852 4393 194 110
25 BALLIA 807 217 119441 120465 62730 62707 13835 15160 3917 2333257 2352334 224342 3043 12 31
26 BALRAMPUR 129 60 96091 96280 54947 54825 10882 3368 922 2331119 2335409 225963 4051 0 32
27 BASTI 51833 444 150466 202743 132347 132212 40297 1458929 10735 3290685 4760349 901280 6035 292 161
28 BUDAUN 23631 485 172909 197025 101126 101044 24479 407780 7068 3215671 3630519 63998 6038 346 81
29 ETAH 18511 754 73718 92983 47035 46765 19024 259057 7872 1189376 1456305 34046 2052 65 17
30 FARRUKHABAD 9599 290 68718 78607 35573 35570 9076 41769 664 1067103 1109536 17129 1520 8 19
31 GONDA 31680 141 117653 149474 60682 60824 8016 489730 2795 1555062 2047587 190211 2231 1461 46
32 JHANSI 33503 860 99610 133973 75767 75817 22499 917367 24673 2671223 3613263 1114221 9773 208 99
33 KANPUR DEHAT 50293 1966 52657 104916 79331 79652 12515 1183943 54431 1325539 2563913 169385 3983 473 128
34 MAHARAJGANJ 105 0 154467 154572 106688 106641 16402 432 0 2430039 2430471 434546 1730 0 77
35 MAU 32429 556 88975 121960 73887 73854 12622 732495 12487 1897984 2642966 406090 4450 37 109
36 SANT KABEER NAGAR 10709 82 104478 115269 82982 82740 16800 42415 336 3090319 3133070 656106 4330 3 34
37 SHRAVASTI 9247 317 89038 98602 42614 42617 3098 44270 842 784127 829239 10975 179 98 28
38 SIDDHARTH NAGAR 50362 435 143286 194083 110175 119507 40500 1632771 11339 4085059 5729169 1377054 13809 390 61
39 SULTANPUR 36549 824 176406 213779 117936 117050 13545 492535 19281 3059929 3571745 503931 4223 269 198
तीसरा चरण
40 AGRA 36728 1606 55859 94193 49023 48783 8058 603504 24393 1021542 1649439 174563 2016 1416 169
41 ALIGARH 10115 90 74176 84381 49132 49147 10005 193157 1088 1479047 1673292 79379 1511 27 48
42 ALLAHABAD 133607 3031 116707 253345 91796 93300 18023 1690511 23703 1145958 2860172 624083 2628 1139 78
43 AURAIYA 41826 257 39577 81660 64533 64718 10534 1122905 5191 920842 2048938 68816 2167 5 113
44 BAGHPAT 6079 181 14875 21135 6277 6272 1902 61855 940 162798 225593 29464 280 47 0
45 BAREILLY 9447 627 154807 164881 139482 139509 30684 218235 12752 3184896 3415883 66949 1917 3 196
46 BIJNOR 10890 507 102406 113803 98917 98971 11590 196017 9508 2392106 2597631 128275 1120 0 176
47 BULANDSHAHR 17542 122 58816 76480 32667 32688 11439 284220 1592 876551 1162363 89921 1310 121 61
48 DEORIA 2988 97 92423 95508 70087 70748 9222 97756 1217 2588714 2687687 370955 3091 0 38
49 ETAWAH 56628 238 53717 110583 40404 40468 2834 595045 1553 521094 1117692 30679 1141 5 14
50 FAIZABAD 7907 255 97370 105532 81589 81588 15963 153282 3925 2124751 2281958 450652 1555 0 39
51 FIROZABAD 17429 87 35722 53238 32159 32158 2045 372628 2694 888064 1263386 49871 2257 1011 92
52 GAUTAM BUDDHA NAGAR 8505 130 17360 25995 1791 1789 604 24579 38 28821 53438 5598 44 112 1
53 GHAZIABAD 8873 64 9035 17972 5439 5429 1859 71206 786 137571 209563 17566 299 28 5
54 GHAZIPUR 50016 679 123313 174008 67918 67769 5063 409633 4110 1215663 1629406 201492 745 28 38
55 JYOTIBA PHOOLE NAGAR 26269 34 52436 78739 46882 47147 6468 432706 650 804602 1237958 40066 1116 32 91
56 KANNAUJ 30472 110 57648 88230 54805 54806 10611 653578 2408 1099201 1755187 21910 1330 744 62
57 KASHIRAM NAGAR 17023 106 65837 82966 63295 63365 29551 391972 1728 1660802 2054502 54533 2768 24 187
58 LUCKNOW 235 50 103506 103791 70865 71007 16688 6650 740 2745159 2752549 242494 5569 0 115
59 MAHAMAYA NAGAR 1305 7 32269 33581 27365 27355 6276 36336 123 956249 992708 33454 1027 0 32
60 MAINPURI 44385 494 95241 140120 46394 46223 3023 555636 824 1036903 1593363 47694 1812 17 76
61 MATHURA 40307 293 27141 67741 34973 35018 2991 755071 3244 580517 1338832 379184 1830 7 22
62 MEERUT 10493 15 7520 18028 7436 7421 3183 148897 476 99388 248761 14512 326 51 11
63 MORADABAD 16903 343 97110 114356 74015 73629 11103 241291 7909 1870944 2120144 69798 2324 55 70
64 MUZAFFARNAGAR 16499 157 21709 38365 18671 18670 5267 268197 2920 421030 692147 59491 870 47 8
65 PILIBHIT 980 77 217625 218682 166103 168483 24323 6628 989 2581002 2588619 56789 572 2 450
66 RAMPUR 4920 163 59766 64849 55144 55137 2323 87264 6374 1187296 1280934 31104 378 1 55
67 SAHARANPUR 33658 41 67066 100765 57998 59107 24379 602215 918 1274757 1877890 314831 1734 7 57
68 SANT RAVIDAS NAGAR 28875 306 46450 75631 58531 58668 30182 896373 7361 1374795 2278529 500155 3782 12 41
69 SHAHJAHANPUR 4514 111 202884 207509 129655 129659 16310 29046 1341 3196056 3226443 40352 1913 3 38
70 VARANASI 37239 216 70268 107723 59530 59530 21265 776975 3363 1168978 1949316 331332 1932 343 71
71 कानपुर नगर 22795 2112 99022 123929 88548 88553 14128 639868 49613 1992749 2682230 235799 3689 6 65
कुल
2310288 116022 7636986 10063296 5870531 5890650 1222532 44170095 3672304 154667815 202510214 28950790 297000 12988 6758