摘要:

BackgroundThe reproducibility of postural changes in blood pressure of a healthy elderly population determined using standard clinical measurements is not known.ObjectiveTo assess the differences in reproducibility of postural changes in blood pressure in healthy elderly subjects 1 and 3 min after standing within a day and between visits spaced 6 weeks apart.MethodsCasual readings of blood pressures of supine and standing subjects were measured twice during the day by the same observer on two occasions 6 weeks apart using a semiautomatic syphgmomanometer. Twenty-two subjects with no known risk factors for orthostatic hypotension (13 men) aged 69±3 years (mean±SD) with a mean initial screening supine blood pressure of 153±19/88±11 mmHg were recruited.ResultsThere were significant differences (P<0.001) between the postural changes both for systolic and for diastolic blood pressure between 1 and 3 min of standing, the largest falls occurring after 1 min of standing, though we found no variation between morning and afternoon measurements and between visits. The coefficients of reproducibility between visits for the postural changes in blood pressure after 1 and 3 min of standing were large both for systolic and for diastolic blood pressure, ranging from 9.8 to 29.3 mmHg.ConclusionsThere was a consistent and significant difference between the postural changes in blood pressure after 1 and 3 min of standing for this healthy elderly population, but there was no significant difference between the postural changes in morning and afternoon measurements and between visits. This marked variability in the postural change in blood pressure with duration of standing must be taken into account when assessing the prevalence of orthostatic hypotension and the effects of treatment in patients with orthostatic falls in blood pressure.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo determine whether the use of patients' individual awake/asleep patterns instead of fixed day/night intervals would influence the correlations between blood pressure values and left ventricular morpho-functional characteristics.MethodsWe enrolled 167 never-treated hypertensives (clinic blood pressures > 160 mmHg systolic or 90 mmHg diastolic, or both): 32 had 24 h blood pressures < 130/80 mmHg [white-coat hypertensives (WCH)] and 135 had 24 h blood pressures > 130 mmHg systolic or 80 mmHg diastolic, or both (hypertensives). Each patient underwent left ventricular echocardiographic examination and 24 h ambulatory blood pressure monitoring, evaluated twice, using standard day/night intervals (daytime 0700–2200 h, nighttime 2200–0700 h) and using the patient's individual awake/asleep pattern (an individualized scheme).ResultsDaytime and night-time blood pressures in WCH and daytime and night-time diastolic blood pressures in hypertensives were not affected by choice of using individualized or standard intervals; daytime systolic blood pressure in hypertensives was significantly higher and night-time systolic blood pressure lower with individualized intervals. The non-dippers (nocturnal decrease in blood pressure < 10% of daytime blood pressure) were 31 hypertensives and six WCH with standard day/night intervals and 25 hypertensives and four WCH with individualized intervals; nocturnal falls in systolic and diastolic blood pressures were significantly greater with individualized intervals for both groups. Left ventricular hypertrophy was present in 68 hypertensives and seven WCH; left ventricular systolic function was normal in all and left ventricular diastolic function was impaired in 53 hypertensives and seven WCH. Left ventricular characteristics of WCH were not correlated to blood pressure parameters; left ventricular mass index of hypertensives was directly correlated to 24 h, daytime and night-time systolic blood pressures, whereas left ventricular diastolic function was inversely correlated to night-time systolic and diastolic blood pressures. The correlations were not affected by choice of using individual awake/asleep patternsConclusionsTiming day and night in an individualized way seems to improve the evaluation of nocturnal fall in blood pressure, but does not improve the ability to predict the left ventricle's involvement with ambulatory blood pressure monitoring

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo show how structural equation models might be used to better understand the ways in which risk factors influence blood pressure.MethodsNine measurements on 2009 women and 1518 men for whom there was complete data both at time 1 and at time 8 of the Framingham Heart Study were used to test a hypothetical model of how risk factors such as age, obesity, smoking, vital capacity, and heart rate influence each other and blood pressure. The hypothetical model was translated into structural equations and tested against the data.ResultsThe hypothetical model fits the data for women at time 1 very well with aχ2=5.41 which, with 14 degrees of freedom, hasP=0.32 and indicates there is no difference between the covariance structure generated by the hypothetical model and the covariance structure generated by the data. The same model was tested for women at time 8 and for men at times 1 and 8 also and fit almost as well. Age and percentage of ideal weight of subjects exert the strongest influence on systolic blood pressure, whereas the effect of age on diastolic blood pressure seems less consistent. Smoking has no direct effect on blood pressure, but it does have a small effect on heart rate and a negative effect on obesity, suggesting, perhaps, that, while it has no direct effect, it does play an indirect role.ConclusionsStructural equation models can be used by researchers trying to understand how risk factors can influence blood pressure in complex ways. The methodology is especially appropriate for testing competing conceptual models.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundThe validation of self-measurement devices for clinical use by elderly patients has been recommended. The Omron HEM-722C device has recently been validated according to the British Hypertension Society (BHS) protocol for use for general populations and the Omron HEM-735C is a new fully automatic device with a high capacity for storage of measurements that is integrated with a personal computer.ObjectiveTo perform a clinical validation for use by elderly people of the Omron HEM-722C and HEM-735C devices according to the revised protocol of the BHS and the criteria of the Association for the Advancement of Medical Instrumentation (AAMI).MethodsWe carried out a main validation test according to the revised BHS protocol for validation procedures for special groups on two groups of 30 subjects aged more than 65 years (29 men and 31 women), 11 of 30 with systolic blood pressures (SBP)<110 mmHg, 10 of 30 with SBP>200mmHg, 15 of 30 with diastolic blood pressures (DBP)<70mmHgand 10 of 30 with DBP>110mmHg. The results were graded according to the BHS system from A to D.ResultsThe Omron HEM 722C achieved an overall A/A grading and satisfied the AAMI criteria for accuracy whereas the Omron HEM-735C achieved an overall B/A grading and satisfied the AAMI criteria for accuracy. The sphygmomanometer measurements were 147±31/79±15 and 144±30/78±15 mmHg (means±SD) respectively, for the models 722C and 735C. The average differences between mercury sphygmomanometer and HEM-722C readings for SBP and DBP were, respectively, 0.76±5 and 0.41±8 mmHg; those for HEM-735C were, respectively, 0.24±8 and 0.9±8mmHg. Readings of the HEM-722C device differed by less than 5 mmHg for 76% of systolic readings and 96% of the readings differed by less than 10 mmHg. Diastolic measurements differed by less than 5 mmHg for 71% and less than 10 mmHg for 71 and 87% of all readings. Readings of the HEM-735C device differed by less than 5 mmHg for 68% of systolic readings and 74% of the readings differed by less than 10 mmHg. Diastolic measurements differed by less than 5 mmHg in 74% and less than 10 mmHg in 88 and 87% of all readings.ConclusionsOn the basis of these results, for elderly subjects both self-measurement devices (Omron HEM-722C and HEM-735C) satisfied the validation criteria of the BHS and therefore can be recommended for the clinical measurement of blood pressure in elderly patients.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundThe majority of monitors for non-invasive measurement of blood pressure in neonates and infants use the oscillometric method.ObjectiveTo use a simulator to investigate the overall system accuracy for three oscillometric blood pressure monitors. The tested devices are DINAMAP 8100 (Critikon), SpaceLabs M90426 (SpaceLabs Medical) and the module HP M 1008B (Hewlett-Packard).MethodsThe blood pressure values obtained by the three devices were compared with those of the invasive reference. A blood pressure simulator was used for testing the performance of the three blood pressure monitors.ResultsThe Dinamap and SpaceLabs readings are generally in good agreement with the invasive reference. In contrast, the HP M 1008B readings for the diastolic and mean arterial pressures are inaccurate (the mean errors are 21 and 15 mmHg, respectively).ConclusionThese results contradict our previously published data obtained when a different simulator (Cufflink) was used. These findings are important, because blood pressure values that are too low can result in a different therapeutic approach being applied, for newborn babies have only a small range of mean arterial pressure for the autoregulation of the cerebral blood flow.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo evaluate the Schiller BR-102 monitor for ambulatory blood pressure measurement according to the protocols of the British Hypertension Society (BHS) and the Association for the Advancement of Medical Instrumentation (AAMI).DesignThe BHS protocol is divided into two parts. Part I, which is the part applicable to this study, comprises the main validation procedure and has five phases: before-use device calibration; in-use (field) phase; after-use device calibration; static device validation; and report of evaluation.MethodThree Schiller BR-102 recorders passed the before-use device calibration test, after which they entered the in-use (field) assessment phase during which the three recorders were each worn by 10 subjects for 24 h, after which calibration was again assessed. Because there was no difference in results of calibration testing among the three devices, one was selected randomly and the main validation test was carried out on 85 subjects with a wide range of blood pressures both for the auscultatory mode and for the oscillometric mode using the Sphygmocorder. The results were analysed according to the BHS grading system from A to D. The data were also analysed according to the standard of the Association for the Advancement of Medical Instrumentation (AAMI), which stipulates that the mean difference between the test device and the standard shall be ≤5 mmHg with a standard deviation of ≤8 mmHg.ResultsThe Schiller BR-102 achieved a BHS grade B rating for systolic and diastolic blood pressures in the auscultatory mode and satisfied the criteria for accuracy of the AAMI protocol for systolic and diastolic blood pressures. In the oscillometric mode, the Schiller BR-102 achieved grade D for systolic blood pressure and grade B for diastolic blood pressure according to the BHS protocol and satisfied the AAMI criteria for diastolic but not systolic blood pressure. Applying the BHS and AAMI criteria to tertiles of blood pressure (low-pressure range<130/80 mmHg, medium-pressure range 130–160/80– 100 mmHg, high-pressure range>160/100 mmHg) the Schiller BR-102 was less accurate in the high pressure range for diastolic blood pressure but more accurate for systolic blood pressure, achieving A/C grading, while satisfying the AAMI criteria both for systolic and for diastolic blood pressure in the auscultatory mode. In the oscillometric mode the device performed less accurately in the high-pressure range, achieving grade D/C, while failing to satisfy the AAMI criteria both for systolic and for diastolic blood pressure. The means±SD of the first mercury sphygmomanometer measurements were 143±32 mmHg for systolic blood pressure and 88±21 mmHg for diastolic blood pressure. Acceptability to subjects was good and the manufacturer's manual was satisfactory.ConclusionOn the basis of these results, the Schiller BR-102 can be recommended for ambulatory blood pressure measurement in clinical practice using the auscultatory mode, but the oscillometric mode, which operates only if the device fails in the auscultatory mode, does not provide accurate measurements.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundPatients and doctors often use home blood pressure monitoring (HBPM) to assess the control of hypertension. Despite its popularity there has always been some uncertainty with regard to its accuracy, reliability, reproducibility, and comparability. Although there are premarket HBPM standards of accuracy, there are no standards to assure accuracy of individual HBPM units after they have been brought home.ObjectiveDetermination of reliability, reproducibility, and comparability of 10 models of home blood pressure monitors.MethodsWe used a Biotek BP Pump as an oscillometric simulator of systolic and diastolic blood pressures to determine reliability, reproducibility, and comparability of 10 devices.ResultsAll of the units tested, except the Pollonex BP1000, produced reproducible readings with the pooled SD of four blood pressure settings less than 3.10 mmHg both for systolic and for diastolic measurements. The oscillometric blood pressure pump method was found to be very reproducible, with pooled differences of less than 2 mmHg and SD of less than 0.5 mmHg for a repeated series of measurements using the same monitor. Different machines of the same model were also very comparable, with pooled differences of less than 3.6 mmHg and pooled SD less than 0.7 mmHg both for systolic and for diastolic readings. There were 11–14 mmHg differences between models for all of the simulated blood pressure readings except that a 27 mmHg difference was measured at the 200 mmHg systolic blood pressure level. These differences will not necessarily be the same for measurements with humans instead of oscillometric signal generation. A system for grading the accuracy of the tested HBPM that defines accuracy of HBPM as within±2 SD of the average of 85 measurements is described.ConclusionAll models of home blood pressure monitors tested, with the exceptions of the Pollonex BP1000, produced reproducible readings and different machines of the same model were comparable.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID