Japanese society of hypertension (JSH) guidelines for self-monitoring of blood pressure at home. (17/125)

Home blood pressure (BP) measurements are indispensable for the improvement of hypertension management in medical practice as well as for the recognition of hypertension in the population. The Working Group for Establishment of Guidelines for Measurement Procedures of Self-Monitoring of Blood Pressure at Home of the Japanese Society of Hypertension has established standards for all techniques and procedures of home BP measurements. The recommendations are as follows. RECOMMENDATION: 1) Arm-cuff devices based on the cuff-oscillometric method that have been validated officially, and the accuracy of which has been confirmed in each individual, should be used for home BP measurement. 2) The BP should be measured at the upper arm. Finger-cuff devices and wrist-cuff devices should not be used for home BP measurements. 3) Devices for home BP measurement should be adapted to the American Association for Medical Instrumentation (AAMI) standards and the British Hypertension Society (BHS) guidelines. In addition, the difference between the BP measured by the auscultatory method and that measured using the device should be within 5 mmHg in each individual. The home measurement device should be validated before use, and at regular intervals during use. 4) Home BP should be monitored under the following conditions. The morning measurement should be made within 1 h after waking, after micturition, sitting after 1 to 2 min of rest, before drug ingestion, and before breakfast. The evening measurement should be made just before going to bed, sitting after 1 to 2 min of rest. 5) Home BP should be measured at least once in the morning and once in the evening. 6) All home BP measurements should be documented without selection, together with the date, time, and pulse rate. Use of devices with a printer or an integrated circuit memory is useful to avoid selection bias. 7) The home BP in the morning and that in the evening should be averaged separately for a certain period. The first measurement on each occasion should be used for totaling. 8) Home BP values averaged for a certain period indicate hypertension when 135/80 mmHg and over and definite hypertension when 135/85 mmHg and over. Normotension is defined as less than 125/80 mmHg and definite normotension as less than 125/75 mmHg. Home BP measurements based on these guidelines can be considered an appropriate tool for clinical decision-making, and it is hoped that these guidelines will serve to reduce confusion and confirm the place of home BP measurement in clinical practice.  (+info)

The fast flush test measures the dynamic response of the entire blood pressure monitoring system. (18/125)

The fast flush test (FT) is the only test that allows clinicians to determine in vivo the natural frequency (fn) and damping coefficient (zeta) of an invasive blood pressure monitoring system. The underlying assumption to the validity of the FT is that it activates the whole system including the distal catheter. We devised an in vitro model of a typical invasive blood pressure monitoring system to determine whether this assumption was true. The model consisted of a conventional transducer with a flush device attached to various lengths of connecting tubing (91.4, 182.9, and 274.3 cm) terminated by four different diameter catheters (5.1 cm 14 G, 16 G, 18 G, and 20 G). A microtipped transducer catheter was inserted into the distal catheter tubing system. A FT was performed and the fn and zeta were recorded from the conventional transducer and simultaneously from the microtipped transducer catheter. Similar studies were conducted using the ROSE damping device as well as with systems including 0.1 ml of air near the conventional transducer. These studies utilized 18- and 20-G catheters with each of the three lengths of connecting tubing. All measurements of fn and zeta at the proximal conventional transducer were identical to those measurements as recorded by the distal microtipped transducer catheter. We conclude that the FT activates the whole monitoring system and that fn and zeta are the same throughout the system including the distal catheter.  (+info)

Decision to treat mild hypertension after assessment by ambulatory monitoring and World Health Organisation recommendations. (19/125)

OBJECTIVE: To determine if one ambulatory blood pressure recording over 12 hours could detect those patients with mild hypertension who needed treatment according to the World Health Organisation-International Society of Hypertension (ISH) guidelines based on the causal measurement of diastolic blood pressure at successive visits to a clinic. DESIGN: Comparison of decision to treat based on one ambulatory measurement over 12 hours and standard blood pressure measurements over six months in the same patients. SETTING: Outpatient hypertension clinic. SUBJECTS: 130 men and women with diastolic blood pressure of 90-104 mm Hg at second visit to clinic. MAIN OUTCOME MEASURES: Blood pressure measurements over six months. Measurement from ambulatory monitoring. Decision to treat. RESULTS: Of the 130 patients included, 108 were followed up over the six months. Treatment was started according to WHO-ISH criteria in 44 (13 at the third visit, 13 at the fourth, 18 at the fifth). According to the selected criteria for ambulatory blood pressure monitoring 41 patients would have been treated. Both methods agreed that the same 27 patients required treatment and the same 50 did not, but they did not agree in 31 patients. When calculated at the optimal diastolic blood pressure threshold determined by a receiver operating characteristic curve, the sensitivity, specificity, and positive predictive value of ambulatory blood pressure monitoring were 71% (95% confidence interval 57% to 84%), 82% (72% to 92%), and 66% (51% to 81%), respectively. CONCLUSION: If the WHO-ISH criteria are accepted as the standard for deciding to treat patients with mild hypertension the predictive value of one ambulatory blood pressure recording over 12 hours is too low to detect with confidence those patients who need treatment when managed according to these criteria.  (+info)

Practical aspect of monitoring hypertension based on self-measured blood pressure at home. (20/125)

Devices for home blood pressure (BP) measurement are produced worldwide at a rate of more than 10 million a year and 30 million such devices have already been distributed in Japan. The clinical significance of home BP measurement is obvious; patients can recognize the effects of antihypertensive treatment. Home BP measurements encourage medication compliance, follow-up clinic visits, and active participation in the medical treatment, thus resulting in improved management of hypertension. Home BP measurements more accurately reflect damage to target organs and the prognosis of cardiovascular diseases. The purpose of home BP measurements is to obtain information on the patient's inherent BP pattern using longterm, repetitive measurement under controlled conditions. Since home BP is measured under controlled condition, values are reproducible, and thus, useful in the diagnosis and treatment of hypertension. Blood pressures measured under standardized condition are indispensable when comparing data among individuals, among groups and among institutes. Working Group of Japanese Society of Hypertension (JSH) established JSH Guidelines for Self-Monitoring of Blood Pressure at Home in 2003. Standardization of the measurement procedure may elevate the position of home BP measurements for the purpose of diagnosing and treating hypertension. As a result, home BP measurements may improve the accuracy of screening for hypertension and assessment of BP control during treatment and encourage drug compliance. Home BP measurements, under such controlled conditions, should have a beneficial effect on the economics of diagnosing and treating hypertension.  (+info)

Pulsatile pressure-flow relations and pulse-wave propagation in the umbilical circulation of fetal sheep. (21/125)

The relations between pulsatile pressures and flows in the umbilico-placental circulation have been investigated using chronically instrumented fetal sheep. Under resting conditions, mean arterial pressure fell by 30 +/- 6%, from 44 +/- 2 to 31 +/- 2 mm Hg between the aortic termination and the arteries feeding the cotyledons, and pressure waves were substantially damped during propagation between the two recording sites. This high flow resistance and wave attenuation are attributed to the very thick walls and extreme length of the umbilical arteries. Unique relations between pulsatile components of pressure and flow, characterized as vascular impedance spectra, were also observed. At rest, impedance to pulsatile flow was only slightly below resistance to steady flow, and impedance phase was positive at low frequencies. Pulse-wave reflections had more modest effects in this bed than others. Thus, oscillations in impedance spectra and percent wave transmission with increasing frequency, which are widely accepted manifestations of wave reflections, were relatively small. Positive impedance phases at low frequencies indicated that novel mechanisms influence phase relations between pressure and flow. A significant vascular compliance residing in the peripheral vascular beds could account for this findings. The vasodilator nitroprusside enhanced wave-reflection effects, whereas the vasoconstrictor angiotensin II reduced these effects. These changes were opposite to the effects of vasoactive substances in other systems, probably because these drugs act predominantly on the supply (umbilical) arteries rather than on the peripheral placental vasculature. When peripheral vascular resistance was selectively elevated by infusing 50-microns microspheres, reflection effects were enhanced: the pressure pulse in the umbilical artery was transmitted without attenuation, or was amplified, and impedance spectra more closely resembled patterns typical of other vascular beds. Specifically, impedance modulus fell sharply with increasing frequency, and impedance phase was negative at low frequency. In addition, we observed coordinated oscillations in impedance modulus and phase that are characteristic of beds that exhibit wave-reflection effects. These findings indicate that the specialized anatomy and control mechanisms observed in the umbilical circulation result in unique hemodynamic function, in which wave-propagation effects exert influences not readily predictable from studies on other systems.  (+info)

Recommendations for blood pressure measurement in humans and experimental animals: Part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research. (22/125)

Accurate measurement of blood pressure is essential to classify individuals, to ascertain blood pressure-related risk, and to guide management. The auscultatory technique with a trained observer and mercury sphygmomanometer continues to be the method of choice for measurement in the office, using the first and fifth phases of the Korotkoff sounds, including in pregnant women. The use of mercury is declining, and alternatives are needed. Aneroid devices are suitable, but they require frequent calibration. Hybrid devices that use electronic transducers instead of mercury have promise. The oscillometric method can be used for office measurement, but only devices independently validated according to standard protocols should be used, and individual calibration is recommended. They have the advantage of being able to take multiple measurements. Proper training of observers, positioning of the patient, and selection of cuff size are all essential. It is increasingly recognized that office measurements correlate poorly with blood pressure measured in other settings, and that they can be supplemented by self-measured readings taken with validated devices at home. There is increasing evidence that home readings predict cardiovascular events and are particularly useful for monitoring the effects of treatment. Twenty-four-hour ambulatory monitoring gives a better prediction of risk than office measurements and is useful for diagnosing white-coat hypertension. There is increasing evidence that a failure of blood pressure to fall during the night may be associated with increased risk. In obese patients and children, the use of an appropriate cuff size is of paramount importance.  (+info)

Relation between job strain, alcohol, and ambulatory blood pressure. (23/125)

"Job strain" (defined as high psychological demands and low decision latitude on the job) has been previously reported to be associated with increased risk of hypertension and increased left ventricular mass index (LVMI) in a case-control study of healthy employed men, aged 30-60 years, without evidence of coronary heart disease. We hypothesized that job strain would be associated with increased ambulatory blood pressure (AmBP). A total of 264 men at eight work sites wore an AmBP monitor for 24 hours on a working day. In an analysis of covariance model, job strain was associated with an increase in systolic AmBP of 6.8 mm Hg (p = 0.002) and diastolic AmBP of 2.8 mm Hg at work (p = 0.03) after adjusting for age, race, body mass index, Type A behavior, alcohol behavior, smoking, work site, 24-hour urine sodium, education, and physical demand level of the job. Alcohol use also had a significant effect on AmBP. However, among subjects not in high-strain jobs, alcohol had no apparent effect on AmBP at work. Instead, alcohol use and job strain interacted such that workers in high-strain jobs who drank regularly had significantly higher systolic AmBP at work (p = 0.007). Among the other risk factors, only age, body mass index, and smoking had significant effects on AmBP. Job strain also had significant effects on AmBP at home and during sleep as well as on LVMI.(ABSTRACT TRUNCATED AT 250 WORDS)  (+info)

Aneurysm sac pressure monitoring: effect of technique on interpretation of measurements. (24/125)

OBJECTIVES: The purpose of this study is to determine the accuracy of measuring pressure with a fluid filled pressure device (needle) and a non-fluid filled pressure device (catheter) inside a thrombosed aneurysmal sac after exclusion from circulation by endovascular grafting. METHODS: In a static environment, consisting of a syringe to which a pressure monitoring kit was connected, experiments were performed to study the influence of the type of device (either needle or catheter) and the effect of the characteristics of the medium on the accuracy and reproducibility of pressure measurements. The pressures obtained with the needle in the different kinds of media were compared with those obtained in blood. Similar experiments were performed using a pressure catheter. Subsequently, pressure measurements were performed in a dynamic and physiological environment. This environment consisted of an artificial circulation in which an aneurysm, constructed of porcine aorta and filled with human aortic thrombus, was mounted. The pressures were compared and analyzed by Bland-Altman plots. RESULTS: Under static conditions, the pressure levels obtained by a needle in blood, starch solution and thrombus were similar. Under identical conditions, pressures obtained by a catheter in starch solution were significant lower than the pressures measured in blood (P<0.05). Under dynamic pressure conditions the reproducibility of pressures obtained with the needle inserted in the human thrombus was very poor. CONCLUSION: A needle pressure measuring device, inserted into media like human fibrin thrombus, does not yield accurate and reproducible results. A catheter with a tip-sensor rather than a needle is superior to study the pressure in the aneurysm sac after EVAR.  (+info)