The random-zero sphygmomanometer has been widely used in observational studies and clinical trials for blood pressure measurement. We examined the agreement of blood pressure measurements between random-zero and standard mercury sphygmomanometers among 2,007 Chinese study participants aged 15–60 years. Three blood pressure readings were obtained by trained observers using random-zero and standard mercury sphygmomanometers, respectively, in a random order. Overall, blood pressure readings obtained using the random-zero device were significantly lower than those obtained with the standard mercury sphygmomanometer, with a mean difference ranging from −3.0 to −2.7 mm Hg for systolic and −1.4 to −0.9 mm Hg for diastolic blood pressure (all p <0.01). Correlation coefficients between mean blood pressure measurements obtained using the random-zero and standard mercury sphygmomanometers were high (0.90 for systolic and 0.85 for diastolic blood pressure, both p< 0.0001). In conclusion, our study indicated that there was strong agreement between blood pressure measurements obtained using the random-zero and standard mercury sphygmomanometers although blood pressure values were on average lower with the random-zero sphygmomanometer.
blood pressure measurements; random-zero sphygmomanometer; standard mercury sphygmomanometer; agreement
The Hawksley random zero sphygmomanometer is used in all aspects of blood pressure research, from clinical trials to evaluation of new blood pressure recorders. It is designed to reduce observer bias in blood pressure measurement. The problem is that it also underestimates blood pressure. Furthermore, this was first reported more than two decades ago. In this paper Rónán Conroy and colleagues explore the consequences of using an inaccurate instrument for important research and why prestigious organisations like the World Health Organisation continue to use it.
STUDY OBJECTIVE--The aim was to compare the performance of the Dinamap 1846SX automated oscillometric blood pressure recorder with that of the Hawksley random zero sphygmomanometer during use under field study conditions. DESIGN--Two independent within subject measurement comparisons were made, one in adults and one in children, each conducted in three stages over several months while the Dinamap instruments were being used in epidemiological field surveys. SETTING--The studies were done in outpatients clinics (adults) and primary schools (children). PARTICIPANTS--141 adults (20-85 years) and 152 children (5-7 years) took part. MEASUREMENTS AND MAIN RESULTS--In adults a pair of measurements was made with each instrument, the order alternating for consecutive subjects. In children one measurements was made with each instrument, in random order. Measurements with the Dinamap 1846SX were higher than those with the random zero sphygmomanometer both in adults (mean difference 8.1 mm Hg; 95% CI 6.5 to 9.7 mm Hg) and in children (mean difference 8.3 mm Hg; 95% CI 6.9 to 9.7 mm Hg). Diastolic measurements were on average very similar both in adults and in children. The results were consistent at all three stages of both studies. The differences in systolic measurement were independent of blood pressure level. However, the extent of agreement in diastolic pressure depended on the diastolic blood pressure level; in both studies Dinamap diastolic measurements were higher at low diastolic pressures while random zero diastolic measurements were higher at high diastolic pressures. CONCLUSIONS--Systolic measurements made with the Dinamap 1846SX instrument are not directly comparable with those of the Hawksley random zero sphygmomanometer and are unlikely to be comparable with those of earlier Dinamap models. These differences have important implications for clinical practice and for comparisons of blood pressure measurement between epidemiological studies. However, the consistency of measurement by the Dinamap 1846SX over time suggests that the instrument may have a place in standardised blood pressure measurement in the research setting.
The mercury sphygmomanometer, the “gold” standard for blood pressure measurements, has been gradually phased out in many institutions because of environmental concerns. Our on-going clinical trial compared the use of mercury vs. aneroid sphygmomanometers, before implementing a study-wide transition to the aneroid sphygmomanometer.
The Diabetes Prevention Program Outcomes Study (DPPOS) studied the accuracy of the Welch allyn Tycos 767-Series Mobile aneroid sphygmomanometer from 20 March 2006 to 21 June 2006 at multiple clinic centers. We compared readings from 997 participants in 24 clinic centers using both mercury and aneroid sphygmomanometers.
The study found no statistically significant difference for systolic blood pressure (SBP) (P > 0.05) and a small but significantly (P < 0.0001) lower (0.8 mm hg) reading for diastolic blood pressure (DBP) using the aneroid sphygmomanometer. Regression analysis of aneroid vs. mercury showed regression lines (Y = 4.8 + 0.96X for SBP, Y = 3.1 + 0.95X for DBP) slightly but statistically significantly different from the line of equality (P < 0.001). Participants’ age, sex, race/ethnicity, body mass index, blood pressure, and clinical center together explain about 8−10% of the variation of the difference between readings from the two sphygmomanometers. Based on the above result, on 1 august 2006, DPPOS clinics began the conversion from mercury to aneroid sphygmomanometers.
The Welch allyn Tycos 767-Series Mobile aneroid model 7670−04 tested in this validation study can be used to replace mercury model in clinical trials.
We evaluated the agreement between office blood pressure (OBP) measured by mercury sphygmomanometer (Sphyg) and automatic (Auto) device without any observers, and compared Auto and Sphyg OBP to ambulatory (ABP) and home blood pressure (HBP).
OBP was measured in 75 hypertensive patients at 2 sites using an automatic monitor without a doctor or nurse present and by Sphyg during 3 clinic visits. Between visits, ABP and HBP monitoring were also performed.
Mean Auto OBP was similar to Sphyg OBP and they were closely correlated (ICC=0.84 for systolic and 0.91 for diastolic OBPs); however, the difference between Auto and Sphyg systolic OBP (1.6±8.2 mmHg) varied by the first office visit, gender, and the site. Auto systolic OBP was lower than both systolic awake ABP (137.1±14.7 mmHg) and HBP (139.2±15.6 mmHg). Auto systolic OBP and Sphyg OBP were similarly correlated with systolic awake ABP (both r=0.59, P<0.001). Mean Auto diastolic OBP was similar to Sphyg OBP (81.1±11.3 vs. 80.3±13.3 mmHg, P=0.20, ICC=0.91), diastolic awake ABP and HBP. Auto diastolic OBP and Sphyg OBP were related to diastolic awake ABP (both r>0.68, P<0.001). In multivariable analyses, neither OBP measure was a significantly stronger predictor of out-of-office BP than the other.
Auto systolic OBP measured without a doctor or nurse present was lower than systolic awake ABP and HBP. Auto and rigorously assessed Sphyg OBP had similar means and were similarly related to awake ABP. Auto OBP might be an advantageous alternative to Sphyg measurements in the usual clinic setting.
Ambulatory blood pressure monitoring; home blood pressure; self-measured blood pressure; office blood pressure
Automated devices are widely available in the community for people to measure their blood pressure. We assessed the accuracy and reproducibility of a brand of community-based automated device against the standard mercury sphygmomanometer.
Same-arm pairs of blood pressure readings were obtained with the Vita-Stat 90550 automated device, a sphygmomanometer and the Omron HEM-705CP automated device in random order on volunteers in 3 community pharmacies using a modified protocol for evaluating blood pressure devices. Comparison of readings between the Omron device and the sphygmomanometer served as a positive control of how well a laboratory-validated automated device could perform in the community. Both the Association for the Advancement of Medical Instrumentation (AAMI) and British Hypertension Society (BHS) criteria were used to assess the accuracy and reproducibility of readings.
The mean blood pressure reading and standard error (SE) of the mean for the 108 volunteers (66 women and 42 men) was 133/77 (SE 2/1) mm Hg with the Vita-Stat device, 131/77 (SE 2/1) mm Hg with the Omron device and 129/76 (SE 2/1) mm Hg with the sphygmomanometer. The mean difference in readings was 4.4/1.0 (standard deviation [SD] 9.4/6.2) mm Hg between the Vita-Stat device and the sphygmomanometer and 1.6/0.6 (SD 9.3/6.4) mm Hg between the Omron device and the sphygmomanometer. Neither automated device met the AAMI accuracy criteria for the systolic readings. The BHS grades were C/A (systolic unacceptable/diastolic acceptable) for each automated device. According to the BHS analytical criterion, all devices achieved acceptable reproducibility grades.
Neither automated device met the AAMI or BHS criteria for accuracy while in use in the community, and neither performed as well in the community as in the laboratory.
The removal of mercury sphygmomanometers from health centers requires the validation of other instruments to measure blood pressure in the limbs to calculate the ankle-brachial index (ABI).
Descriptive cross-sectional study of agreement between two measurement methods in type 2 diabetes patients from three urban primary healthcare centres in the Barcelonès Nord i Maresme area (Catalonia, Spain).
ABI was determined with Doppler and mercury sphygmomanometer and Doppler and the “hybrid” sphygmomanometer OMRON HEM-907 model. Agreement was evaluated using the weighted kappa index. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated using the mercury sphygmomanometer as the gold standard.
211 patients were included, from these, 421 limbs were available for study. The mean age of the participants was 67 years (SD = 10), 51.7% were women.
The index of agreement between ABI measured with a mercury sphygmomanometer and with the OMRON HEM-907 blood pressure monitor was good (weighted kappa index = 0.68; CI 95%: [0.55–0.79]) and improved when the ABI cut-off value was set at ≤0.70 (weighted kappa index = 0.92; CI 95%: [0.81–1.00]). Sensitivity and specificity were 77.5% and 98.2%, respectively. PPV was 83.8% and NPV was 97.3%. With the ABI cut-off value ≤0.70, sensitivity and specificity increased to 85.7% and 100%, respectively, PPV to 100% and NPV to 99.4%.
The combination of a Doppler device with the hybrid sphygmomanometer is a simple and reliable method to measure ABI showing that hybrid sphygmomanometer is a good alternative to the use of mercury sphygmomanometers.
Ankle brachial blood pressure index; Peripheral arterial disease; Blood pressure; Type 2 diabetes mellitus; Doppler; Sensitivity and specificity
OBJECTIVE: To assess the precision and integrity of all aneroid and mercury sphygmomanometers regularly used by family physicians practising outside hospitals. DESIGN: Cross-sectional study. SETTING: Private medical clinics and local community health centres in Bas-Saint-Laurent, Qué. PARTICIPANTS: A total of 151 of the 166 physicians in this administrative region. MAIN OUTCOME MEASURES: Precision of the mercury sphygmomanometers was measured using the difference between a reading in the absence of pressure and level 0. Precision of the aneroid sphygmomanometers was measured using variations at pressures of 140 mm Hg and 90 mm Hg compared with those on a calibrated mercury sphygmomanometer. Integrity of sphygmomanometers, arm cuffs, and inflating bulbs was also assessed. RESULTS: In all, 258 sphygmomanometers met the inclusion criteria (111 mercury sphygmomanometers and 147 aneroid sphygmomanometers). Discrepancies of > or = 4 mm Hg were found in 15.5% of these instruments (12.6% and 17.7% of the mercury and aneroid sphygmomanometers, respectively). In 31.0% of the instruments (52.3% and 15.0% of the mercury and aneroid sphygmomanometers, respectively), one component was malfunctioning. CONCLUSION: Sphygmomanometers that measure patients' blood pressure inaccurately could result in an incorrect diagnosis of hypertension or in a normal blood pressure reading in a hypertensive patient.
STUDY OBJECTIVE: To assess agreement between two Takeda UA-731 automatic blood pressure measuring devices (referred to as machines A and B) and two manual mercury sphygmomanometers. DESIGN: A 'Y' connector attached each Takeda UA-731 to a manual mercury sphygmomanometer. Simultaneous measurements were made on adult subjects. SETTING: A population based cardiovascular disease survey in Newcastle upon Tyne, UK. PARTICIPANTS: Measurements on machine A were compared in 71 individuals (all women), and on machine B in 75 individuals (9 men, 66 women). The age range of subjects was 28 to 76 years and median ages were 59 years for machine A and 50 years for machine B. MAIN RESULTS: Blood pressure (mmHg) ranged from 72 to 212 systolic and 44 to 102 diastolic. Both Takedas gave significantly lower readings than the manual devices for systolic and diastolic pressures: differences were mean (SD: 95% CI) 3.7 mmHg (6.5: 2.2, 5.2) for machine A systolic, 2.3 mmHg (4.5: 1.3, 3.4) machine A diastolic; 1.8 mmHg (6.2: 0.4, 3.3) machine B systolic, and 1.8 (4.4: 0.8, 2.8) machine B diastolic. On the British Hypertension Society criteria, machine A was graded C on systolic measurements and B on diastolic; machine B was graded B on both systolic and diastolic measurements. CONCLUSIONS: The performance of these machines compares favourably with the Dinamap 8100, recently adopted for survey work by the Department of Health. The Takeda UA-731 looks promising for epidemiological survey work but before it can be fully recommended further evaluations are needed.
To validate the Dinamap ProCare 200 blood pressure (BP) monitor against a mercury sphygmomanometer in children 7 to 18 years old in accordance with the 2010 International Protocol of European Society of Hypertension (ESH-IP2) and the British Hypertension Society (BHS) protocol.
Forty-five children were recruited for the study. A validation procedure was performed following the protocol based on the ESH-IP2 and BHS protocols for children and adolescents. Each subject underwent 7 sequential BP measurements alternatively with a mercury sphygmomanometer and the test device by trained nurses. The results were analyzed according to the validation criteria of ESH-IP2.
The mean (±SD) difference in the absolute BP values between test device and mercury sphygmomanometer readings was 1.85±1.65 mmHg for systolic BP (SBP) and 4.41±3.53 mmHg for diastolic BP (DBP). These results fulfilled the Association for the Advancement of Medical Instrumentation criterion of a mean±SD below 5±8 mmHg for both SBP and DBP. The percentages of test device-observer mercury sphygmomanometer BP differences within 5, 10, and 15 mmHg were 96%, 100%, and 100% for SBP, and 69%, 92%, and 100% for DBP, respectively, in the part 1 analysis; both SBP and DBP passed the part 1 criteria. In the part 2 analysis, SBP passed the criteria but DBP failed.
Although the Dinamap ProCare 200 BP monitor failed an adapted ESH-IP2, SBP passed. When comparing BP readings measured by oscillometers and mercury sphygmomanometers, one has to consider the differences between them, particularly in DBP, because DBP can be underestimated.
Blood pressure; Oscillometric device; Dinamap; Validation studies; International protocol
Both systolic and diastolic pressures can be measured in children with the mercury sphygmomanometer, the Arteriosonde and the Infrasonde. Estimates made blindly with these instruments were compared with directly measured intra-arterial blood pressures in 50 children aged between 4 days and 14 years. Systolic and diastolic estimates with the three techniques showed highly significant correlations with simultaneous intra-arterial measurements (P less than 0.001). The Infrasonde diastolic estimates were least satisfactory and the slope of the regression line against the intra-arterial pressure differed significantly from unity (y=0.54x+29.53). In 11 small children a satisfactory diastolic estimate could not be obtained with the mercury sphygmomanometer. While the mercury sphygmomanometer should remain the standard hospital equipment, an Arteriosonde would be valuable if it is difficult to hear Korotkoff's sounds on auscultation and if a diastolic pressure is required. For research investigations into childhood blood pressure an Arteriosonde or mercury sphygmomanometer, coupled with a device to exclude observer bias, is probably most suitable. Although the Infrasonde is not sufficiently accurate for research purposes, it is acceptable for routine ward use.
To compare oscillometric blood pressure devices with mercury sphygmomanometry in children.
Patients and methods
Blood pressure measurements were obtained with a mercury sphygmomanometer and one of two oscillometric devices. Correlations within each device and agreement between the two devices were evaluated.
In children, blood pressure measured by the oscillometric device was poorly correlated and had wide limits of agreements with the sphygmomanometer. Furthermore, the oscillometric devices overestimated systolic blood pressure in children with higher readings.
The applicability of automated blood pressure measuring devices in children has limitations and cannot be recommended.
blood pressure determination; developing countries; epidemiologic methods; pediatric; Peru
Automated blood pressure (BP) devices are used by many hypertensive patients in Hong Kong, with or without medical advice. At two community clinics, we invited hypertensive patients aged between 40 and 70 years who used such a device to fill in a questionnaire and to have four sets of BP measurements, automated and mercury, at two visits. Of 290 hypertensive patients 120 fulfilled the criteria, and 73 of these agreed to participate.
53 devices measured arm BP, 21 measured forearm BP. The agreement between the mercury sphygmomanometer and the automated devices was poor, with average differences of 9.5 mmHg for systolic and 9.4 mmHg for diastolic and no clear advantage for either site of measurement. As a means of screening for BP >140/90 mmHg the sensitivity of the automated devices was 81% and the specificity was 80%. There were large variations in how often and under what circumstances the devices had been used. One-fifth of the devices had been acquired on medical advice but only 11% of the participants were aware of the three important conditions for operating such devices.
Discussion of automated devices, their role and proper use, should now be part of routine hypertensive care.
Allowing patients to measure their blood pressure at home is recognized as being of clinical value. However, it is not known how often these measurements are taken correctly. Blood pressure monitors for home use fall into two types based on the position of the cuff, ie, at the upper arm or the wrist. The latter is particularly convenient, as measurements can be taken fully clothed. This study aimed to evaluate the performance of the wrist-type blood pressure monitors Omron RS8 (HEM-6310F-E), Omron RS6 (HEM-6221-E), and Omron RS3 (HEM-6130-E).
A team of three trained doctors validated the performance of these devices by comparing the measurements obtained from these devices with those taken using a standard mercury sphygmomanometer. All the devices met the validation requirements of the European Society of Hypertension International Protocol revision 2010.
The difference in blood pressure readings between the tested device and the standard mercury sphygmomanometer was within 3 mmHg, which is acceptable according to the European Society of Hypertension guidelines.
All the home devices tested were found to be suitable for measuring blood pressure at home because their performance fulfilled the requirement of the guidelines.
blood pressure; device; European Society of Hypertension; guideline; measurement; validation
One of the observer errors associated with blood pressure (BP) measurement using a mercury sphygmomanometer is end digit preference (EDP) which refers to the occurrence of a particular end digit more frequently than would be expected by chance alone. Published reports, mainly from outside Africa, have shown a high prevalence ranging from 22 to 90% of end digit zero in BP readings taken by healthcare workers (HCWs). This study examined the prevalence of EDP and patients’ and physicians’ characteristics influencing the occurrence of EDP.
A retrospective review was undertaken of BP readings of 114 patients seen over a two-month period at our hypertension specialty clinic.
Nurses and physicians displayed a high frequency of preference for end digit zero in systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings. The preference for end digit zero was, however, higher for nurses than for physicians (SBP: 98.5 vs 51.2%, p < 0.001; DBP: 98.5 vs 64.3%, p < 0.001). Among the physicians, the consultant staff displayed the least preference for end digit zero compared to resident doctors. There was no statistically significant difference in gender, age, weight, height and BMI of those with BP readings with end digit zero compared with those with non-zero end digits.
The high prevalence of EDP for zero argues for the training, retraining and certification of HCWs in BP measurement and the institution of a regular monitoring and feedback system on EDP in order to minimise this observer error.
end digit preference; blood pressure measurement; hypertension specialty clinic; southwest Nigeria
Ambulatory blood pressure monitoring (ABPM) in adults is proving to be useful. The aim of this study was to determine if ABPM is accurate in the lower blood pressure range encountered in children and, equally important, whether it is acceptable to children. Thirty one children, between the ages of 6 and 18 years, were assessed using an ambulatory blood pressure monitor that uses an auscultatory method. Blood pressure was measured in the contralateral arm with a mercury sphygmomanometer and an oscillometric device at the beginning and end of the study for comparison. Over a blood pressure range of 90-130 mm Hg systolic and 40-80 mm Hg diastolic, a close agreement was found with the sphygmomanometer; the limits of agreement (+/- 2 SD) were 11.6 mm Hg for systolic blood pressure and 13.6 mm Hg for diastolic blood pressure. The bias was less than 1.0 mm Hg. The ambulatory device was worn by all patients for at least 16 hours with an average of 52 recordings per patient. The majority found the device comfortable to wear and were not woken from sleep.
Direct biofeedback of blood pressure was compared with frontal EMG biofeedback and with self-instructed relaxation for the treatment of essential hypertension in a controlled group outcome study. Patients were followed up for four months after the end of treatment. Generalization of treatment effects was assessed through pre- and posttreatment measurements of blood pressure under clinical conditions in a physician's office. There were no significant reductions in diastolic blood pressure. The systolic blood pressure (SBP) of the patients receiving blood pressure biofeedback decreased 8.1 mm mercury (p = 0.07) and the SBP of the patients in the relaxation condition decreased 9.5 mm mercury (p = 0.05). In the generalization measures, there were significant reductions in SBP for the relaxation group. The results are discussed in terms of the general lack of replicability within the area of biofeedback treatment of hypertension.
Seven types of sphygmomanometer were used in random order on each of nine hypertensive patients and the readings compared with simultaneous intra-arterial blood-pressure recordings. All the devices gave significantly different values for systolic pressure, and only two measured diastolic pressure without significant error. Systolic pressure was consistently underestimated (range 31-7 mm Hg), and all but one instrument overestimated diastolic pressure (range 10-2 mm Hg). The variability of readings was least with the standard mercury sphygmomanometer and the random-zero machine, while with some of the more automated devices single readings were in error up to -68/33 mm Hg. The strong correlations found between intra-arterial and cuff systolic pressures with all devices tested and significant correlations for diastolic pressure with all but one device indicate that, with one possible exception, the sphygmomanometers would give accurate results where a change in blood pressure was the main concern.
Blood pressure (BP) recording is the most commonly measured clinical parameter. Standing mercury sphygmomanometer is the most widely used equipment to record this. However, recording by sphygmomanometer is subject to observer and instrumental error. The different sources of equipment error are faulty manometer tube calibration, baseline deviations and improper arm bladder cuff dimensions. This is further compounded by a high prevalence of arm bladder miss-cuffing in the target population.
The study was designed to assess the presence of equipment malcalibrations, cuff miss-matching and their effect on BP recording.
Materials and Methods:
A cross-sectional check of all operational sphygmomanometers in a health university was carried out for the length of the manometer tube, deviation of resting mercury column from “0” level, the width and length of arm bladder cuff and extent of bladder cuff-mismatch with respect to outpatient attending population.
From the total of 50 apparatus selected, 39 (78%) were from hospital setups and 11 (22%) from pre-clinical departments. A manometer height deficit of 13 mm was recorded in 36 (92.23%) of the equipment in hospital and 11 (100%) from pre-clinical departments. Instruments from both settings showed significant deviation from recommended dimensions in cuff bladder length, width and length to width ratio (P < 0.001). Significant number of apparatus from hospital setups showed presence of mercury manometer baseline deviation either below or above 0 mmHg at the resting state (χ2 = 5.61, D. F. = 1, P = 0.02). Positive corelationship was observed between manometer height deficit, baseline deviation and width of arm cuff bladder (Pearson correlation, P < 0.05). Bladder cuff mismatching in response to the target population was found at 48.52% for males and 36.76% for females. The cumulative effect of these factors can lead to an error in the range of 10-12 mmHg.
Faulty equipments and prevalent arm bladder cuff-mismatching can be important barriers to accurate BP measurement.
Blood pressure; instrument error; miss-cuffing
In adults, hypertension has been shown to be inversely correlated with bone mineral content (BMC); however, the association between blood pressure (BP) and BMC has not been studied in pediatrics.
Total body BMC of 187 overweight (mean BMI=28.7 kg/m2) Latino children and adolescents (mean age=11.2 years) were measured using dual-energy x-ray absorptiometry. Seated systolic (SBP) and diastolic (DBP) blood pressure were measured using a standard mercury sphygmomanometer. Hypertension was defined by SBP or DBP above the 90th percentile for height, age, and gender.
Partial correlations revealed an inverse association between SBP and BMC (r=- 0.24, p=0.02) in boys (n=105); results were non-significant (p=0.27) in girls (n=82). There were no significant correlations between DBP and BMC. When BMI and insulin sensitivity were adjusted for, hypertensive boys (n=21) had lower BMC (1435 versus 1636 g; p=0.03) than normotensive boys (n=84); similarly, hypertensive girls (n=25) had lower BMC (1438 versus 1618 g; p=0.02) than normotensive girls (n=57). In post-pubertal adolescents (Tanner stage 4-5; n= 48), inverse correlations were stronger (r=- 0.40, p=0.007); results were non-significant in pre-pubertal and pubertal children (Tanner stage 1-3; n=139, p=0.57). In post-pubertal girls (n=37), there were no significant correlations (p=0.14); inverse correlations in post-pubertal boys (n=11) became markedly stronger (r= -0.80, p=0.02).
SBP is inversely correlated with BMC in overweight adolescents; additionally, hypertensives have lower adjusted means of BMC than normotensives. These promising new findings suggest that hypertension may be a risk factor for osteopenia in overweight children and adolescents; this risk may be exacerbated in post-pubertal boys.
Pediatric; Latino; Bone Mineral Content; Blood Pressure; Osteopenia
Extensive marketing of devices for self-measurement of blood pressure has created a need for purchasers to be able to satisfy themselves that such devices have been evaluated according to agreed criteria. The Oregon Scientific BPU 330 blood pressure monitor is an electronic device for upper arm measurement. This study assessed the accuracy of the Oregon Scientific BPU 330 blood pressure monitor according to the International Protocol by the Working Group on Blood Pressure Monitoring of the European Society of Hypertension for validation of blood pressure measuring devices.
52 participants over 30 years of age were studied in the validation. Nine blood pressure measurements were taken alternately with a mercury sphygmomanometer by two observers, and by the supervisor, using the BPU 330 device. A total of 33 participants were selected for the analysis. The validation was divided into two phases. Phase 1 included 15 participants. If the device passed phase 1, 18 more participants were included. The 99 pairs of measurements were compared according to the International Protocol. The device was given a pass/fail recommendation based on its accuracy compared with the mercury standard (within 5, 10, and 15 mmHg), as well as the number met in the ranges specified by the International Protocol.
The mean and standard deviation of the difference between the mean of the observers and the BPU 330 device were 1.7 ± 4.7 mmHg and 2.8 ± 3.9 mmHg for systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively. In phase 1, the device passed with a total of 33, 43, and 44 SBP readings; 38, 44, and 45 DBP readings were within 5, 10, and 15 mmHg, respectively. In phase 2.1, 81, 95, and 96 for SBP, and 83, 95, and 98 for DBP readings fell within the zones of 5, 10, and 15 mmHg, respectively. In phase 2.2, the last phase, 28 participants fell within the zone of two of the three comparisons, lying within 5 mmHg for SBP and 29 participants for DBP. No participants fell within the zone of all three of their comparisons over 5 mmHg apart for both SBP and DBP.
The BPU 330 can be recommended for self-monitoring of blood pressure in the adult population, according to the International Protocol.
blood pressure; self-monitoring; hypertension; International Protocol
We measured ambulatory blood pressure using the AM5600 in children and adolescents participating in a research study to assess the relationship of BP to risk factors for cardiovascular disease. Although this use of this monitor has been previously reported in adults, it has not been validated in pediatric subjects. In this study, we assess the accuracy of the monitor as compared to the mercury sphygmomanometer in children ages 7-18 years of age. We found that the mean of the difference between the monitor and the mercury device was 0.29 ± 3.5 and 0.045 ± 3.7 mmHg for systolic and diastolic BP respectively, which fulfills the AAMI standard for use of a device. The cumulative percent of readings between the two devices which differed assigned the device a grade of A according to the British Hypertension Society..
hypertension; ambulatory blood pressure monitoring; Blood pressure measuring device
Despite the increasing popularity of blood pressure (BP) wrist monitors for self-BP measurement at home, device validation and the effect of arm position remains an issue. This study focused on the validation of the Omron HEM-609 wrist BP device, including an evaluation of the impact of arm position and pulse pressure on BP measurement validation. Fifty patients at high risk for cardiovascular disease were selected (age 65 ± 10 years). Each patient had two measurements with a mercury sphygmomanometer and three measurements with the wrist BP device (wrist at the heart level while the horizontal arm supported [HORIZONTAL], hand supported on the opposite shoulder [SHOULDER], and elbow placed on a desk [DESK]), in random order. The achieved systolic BP (SBP) and diastolic BP (DBP) wrist-cuff readings were compared to the mercury device and the frequencies of the readings within 5, 10, and 15 mmHg of the gold standard were computed and compared with the British Hypertension Society (BHS) and Association for the Advancement of Medical Instrumentation (AAMI) protocols. The results showed while SBP readings with HORIZONTAL and SHOULDER positions were significantly different from the mercury device (mean difference = 7.1 and 13.3 mmHg, respectively; P < 0.05), the DESK position created the closest reading to mercury (mean difference = 3.8, P > 0.1). Approximately 71% of SBP readings with the DESK position were within ±10 mmHg, whereas it was 62.5% and 34% for HORIZONTAL and SHOULDER positions, respectively. Wrist DBP attained category D with BHS criteria with all three arm positions. Bland–Altman plots illustrated that the wrist monitor systematically underestimated SBP and DBP values. However a reading adjustment of 5 and 10 mmHg for SBP and DBP (DESK position) resulted in improvement with 75% and 77% of the readings being within 10 mmHg (grade B), respectively. AAMI criteria were not fulfilled due to heterogeneity. The findings also showed that the mismatch between the mercury and wrist-cuff systolic BP readings was directly associated with pulse pressure. In conclusion the DESK position produces the most accurate readings when compared to the mercury device. Although wrist BP measurement may underestimate BP measured compared to a mercury device, an adjustment by 5 and 10 mmHg for SBP and DBP, respectively, creates a valid result with the DESK position. Nevertheless, considering the observed variations and the possible impact of arterial stiffness, individual clinical validation is recommended.
blood pressure; device validation; position
Several healthful dietary patterns appear to be effective at lowering blood pressure and preventing hypertension. However, the relationship between dietary patterns and hypertension among a representative Chinese population sample is unclear.
A nationally representative sample of 23 671 participants aged 18-59 years were recruited by the 2002 China National Nutrition and Health Survey. All participants had their blood pressure measured with standardized mercury sphygmomanometers. Hypertension was defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg. We conducted factor analysis using dietary information from a validated food frequency questionnaire to derive dietary patterns. Information of participants on physical activities, education level, annual household income, smoking status and family history of hypertension was collected by interviewer-administrated questionnaires.
Three major dietary patterns, defined as 'Western', 'traditional northern', and 'traditional southern', were identified. Participants with the highest quartile for the score of the Western pattern had significantly higher blood pressure comparing with counterparts in the lowest quartile. In contrast, participants in the top quartile for the score of the traditional southern pattern presented significantly lower blood pressure comparing with counterparts in the lowest quartile. In multivariate analyses the traditional northern pattern score was associated with an odds ratio (OR) of 1.30 (95% confidence interval (CI) 1.11-1.53, P for trend = 0.0001) comparing with the lowest quartile. The OR for the top quartile of score for the traditional southern pattern was 0.73 (95% CI, 0.59-0.89, P for trend = 0.0040) compared with the lowest quartile of traditional southern pattern score. However, the significant association between the traditional northern pattern and prevalence of hypertension disappeared after further adjusting for body mass index (BMI) (P for trend = 0.3), whereas the association between the traditional southern pattern and prevalence of hypertension persisted after further adjusting for BMI (P for trend = 0.01).
We observed a positive relationship between the traditional northern pattern and hypertension that was mediated through differences in BMI. In addition, the traditional southern pattern was significantly associated with lower odds of presenting with hypertension.
Populations which diet is rich in seafood are highly exposed to contaminants such as mercury, which could affect cardiovascular risk factors
To assess the associations between mercury and blood pressure (BP), resting heart rate (HR) and HR variability (HRV) among French Polynesians
Data were collected among 180 adults (≥ 18 years) and 101 teenagers (12-17 years). HRV was measured using a two-hour ambulatory electrocardiogram (Holter) and BP was measured using a standardized protocol. The association between mercury and HRV and BP parameters was studied using analysis of variance (ANOVA) and analysis of covariance (ANCOVA)
Among teenagers, the high frequency (HF) decreased between the 2nd and 3rd tertile (380 vs. 204 ms2, p = 0.03) and a similar pattern was observed for the square root of the mean squared differences of successive R-R intervals (rMSSD) (43 vs. 30 ms, p = 0.005) after adjusting for confounders. In addition, the ratio low/high frequency (LF/HF) increased between the 2nd and 3rd tertile (2.3 vs. 3.0, p = 0.04). Among adults, the standard deviation of R-R intervals (SDNN) tended to decrease between the 1st and 2nd tertile (84 vs. 75 ms, p = 0.069) after adjusting for confounders. Furthermore, diastolic BP tended to increase between the 2nd and 3rd tertile (86 vs. 91 mm Hg, p = 0.09). No significant difference was observed in resting HR or pulse pressure (PP)
Mercury was associated with decreased HRV among French Polynesian teenagers while no significant association was observed with resting HR, BP, or PP among teenagers or adults
Methymercury; blood pressure; heart rate variability; resting heart rate; n-3 fatty acids; French Polynesia