Mercury sphygmomanometers should not be abandoned: An advisory statement from the Council for High Blood Pressure Research, American Heart Association

Blood pressure measurements and hypertension in infants, children, and adolescents: from the postmercury to mobile devices

A mercury sphygmomanometer (MS) has been the gold standard for pediatric blood pressure (BP) measurements, and diagnosing hypertension is critical. However, because of environmental issues, other alternatives are needed. Noninvasive BP measurement devices are largely divided into auscultatory and oscillometric types. The aneroid sphygmomanometer, the currently used auscultatory method, is inferior to MS in terms of limitations such as validation and regular calibration and difficult to apply to infants, in whom Korotkoff sounds are not audible. The oscillometric method uses an automatic device that eliminates errors caused by human observers and has the advantage of being easy to use; however, owing to its measurement accuracy issues, the development of an international validation protocol for children is important. The hybrid method, which combines the auscultatory and electronic methods, solves some of these problems by eliminating the observer bias of terminal digit preference while maintaining measurement accuracy; however, the auscultatory method remains limited. As the age-related characteristics of the pediatric group are heterogeneous, it is necessary to reconsider the appropriate BP measurement method suitable for this indication. In addition, the mobile application-based BP measurement market is growing rapidly with the development of smartphone applications. Although more research is still needed on their accuracy, many experts expect that mobile application-based BP measurement will effectively reduce medical costs due to increased ease of access and early BP management.

A survey to gauge confidence of Indian clinicians on three primary devices for blood pressure measurement

PURPOSE

As per its commitment at Minamata convention, and in line with other developed economies, the Indian government is set to ban the use of mercury sphygmomanometers by end of the year 2020. However, the Mercury sphygmomanometer is still widely used by clinicians in India. We conducted a survey to gauge the confidence of Indian clinicians on three primary devices of blood pressure (BP) measurement - mercury sphygmomanometer, aneroid sphygmomanometer and automatic digital BP monitor.

MATERIALS AND METHODS

We conducted an anonymous online survey through various clinician forums asking questions related to accuracy, reliability and expectations from BP monitors.

RESULTS

A total of 139 responses were received from clinicians across specialties. The results show that more than 80% of clinicians believe that mercury sphygmomanometers are the most accurate and nearly 50% find it most reliable. For most respondents, accuracy is the most important parameter and convenience of use and portability are secondary considerations. If a mercury-free sphygmomanometer is offered with the same accuracy and reliability, 88% of respondents said they are willing to buy it.

CONCLUSIONS

Mercury sphygmomanometer is still perceived favorably over other non-mercury alternatives by most Indian clinicians. Validated oscillometric devices should be promoted to bring about change in the perspectives of clinicians towards adopting non-mercury alternatives of BP measurement in India.

Acute blood pressure change with methylphenidate is associated with improvement in attention performance in children with ADHD

This exploratory study aims to determine whether the change in systolic blood pressure (sBP) after acute methylphenidate (MPH) administration (ΔBP_MPH) is associated with the neurocognitive response to MPH in the Conners Continuous Performance Test (CPT) in 513 children with ADHD (aged 6 to 12 years old). We noted that higher increases in sBP were associated with larger improvement in CPT performance with MPH. In the univariate regression model, the ΔBP_MPH accounted for an additional 2% of the variance in the change in CPT-Overall Index (OI) after controlling for covariates (p < .001). Linear regression analysis also indicated that ΔBP_MPH significantly contributed to predict a change in omission errors, reaction time, and reaction time variability (p < .001, p < .01, p = .001, respectively), but not in commission errors or detectability index (d`). Participants with a clinically meaningful sBP increase of at least 5 mmHg (n = 191) improved by 4.8 points on the CPT-OI score (p < .001), compared to an improvement of only 0.6 points for participants whose sBP declined by at least 5 mmHg (n = 121). In conclusion, larger sBP increases after MPH administration were associated with greater enhancement in CPT performance. These results could be useful in informing MPH dosing in clinical practice.

Effects of room environment and nursing experience on clinical blood pressure measurement: an observational study

OBJECTIVE

This study aimed to examine the effects of measurement room environment and nursing experience on the accuracy of manual auscultatory blood pressure (BP) measurement.

MATERIALS AND METHODS

A training database with 32 Korotkoff sounds recordings from the British Hypertension Society was played randomly to 20 observers who were divided into four groups according to the years of their nursing experience (i.e. ≥10 years, 1-9 years, nursing students with frequent training, and those without any medical background; five observers in each group). All the observers were asked to determine manual auscultatory systolic blood pressure (SBP) and diastolic blood pressure (DBP) both in a quiet clinical assessment room and in a noisy nurse station area. This procedure was repeated on another day, yielding a total of four measurements from each observer (i.e. two room environments and two repeated determinations on 2 separate days) for each Korotkoff sound. The measurement error was then calculated against the reference answer, with the effects of room environment and nursing experience of the observer investigated.

RESULTS

Our results showed that there was no statistically significant difference for BPs measured under both quiet and noisy environments (P>0.80 for both SBP and DBP). However, there was a significant effect on the measurement accuracy between the observer groups (P<0.001 for both SBP and DBP). The nursing students performed best with overall SBP and DBP errors of -0.8±2.4 and 0.1±1.8 mmHg, respectively. The SBP measurement error from the nursing students was significantly smaller than that for each of the other three groups (all P<0.001).

CONCLUSION

Our results indicate that frequent nursing trainings are important for nurses to achieve accurate manual auscultatory BP measurement.

Assessing agreement of blood pressure-measuring devices in Tibetan areas of China: a systematic review

BACKGROUND

The validity of blood pressure (BP)-measuring tools at very high altitudes is uncertain. Therefore, the objective of this review was to examine the degree of agreement of BP-measuring devices in Tibet.

METHODS

We conducted electronic searches in Medline, Embase, Cinahl, Cochrane Library, Global Health Library and the ISI Web of Science. Randomised and observational studies were considered for inclusion. The methodological characteristics of included studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 criteria. Our primary outcome was the difference in mean BP measurements between the new device and the gold standard.

RESULTS

We identified three eligible studies, out of which two with a total of 162 participants were included. The studies differed in their methodology. One study reported significantly higher systolic blood pressure (SBP) measurement with electronic sphygmomanometer (Omron) compared with mercury sphygmomanometer (mean difference 5.8±4.7 mm Hg; p<0.001), with no significant difference in diastolic blood pressure (DBP) measurement (0.4±3.9 mm Hg; p=0.23). The second study reported mean differences of 1.0±5.9 mm Hg and -3.1±4.6 mm Hg for SBP and DBP, respectively.

CONCLUSION

The limited evidence from published studies suggests that automated (Omron) BP monitors show a high degree of agreement for DBP when compared against mercury sphygmomanometer at high altitudes. However, the degree of such agreement for SBP is not consistent. Few studies assessing the validity of automated BP monitors at high altitudes have been conducted, and they differ in design and methodology. Further research assessing the suitability of BP-measuring instruments at high altitudes is therefore warranted.

Measuring Respiratory Pressures with Mercury Manometer in Low Economic Health Care Settings- An Analytical Study

INTRODUCTION

Health care economics restricts many health centers from using hi-tech diagnostics equipment. Mercury manometers are used for calibration of pressure transducers. If standardized it would be a cost effective, simple alternative to transducers in low economic settings.

AIM

To analyse the feasibility of mercury manometer usage in respiratory pressure measurement.

MATERIALS AND METHODS

The experimental study was conducted with 30 healthy volunteers of age group 17-19 yrs. They were recruited by using simple random sampling method. The volunteers were made familiarized to lab environment, instrument and techniques of maximum inspiratory (Pimax) and expiratory pressures (Pemax). Then parameters were recorded using mercury manometer connected to different syringes as mouth piece (2.5 ml, 10 ml, and 20 ml) and with sphygmomanometer. Statistical analysis was done by using IBM SPSS statistics version 21.

RESULTS

The Pimax was 111.07 ± 6.53 with a 2.5 ml syringe as mouth piece. With 20 ml syringe it was 61.47 ± 9.98. PEmax with 2.5 ml syringe was 70.33 ± 8.19 with a confidence limit of 2.93 and with sphygmomanometer was 99.33 ± 8.16 with a confidence limit of 2.92. There was a change in recorded pressure and the correlation analysis result showed a significant difference from both above and below 10 ml mouth piece range.

CONCLUSION

Mercury manometers could be used for recording respiratory pressures in low economic facilities once standardized. Size of syringe to be used as mouth piece needs further more works although this study finds 10 ml syringe as suitable.

Comparison of mercury sphygmomanometry blood pressure readings with oscillometric and central blood pressure in predicting target organ damage in youth

OBJECTIVE

Hypertension (HT) is an important risk factor for target organ damage (TOD). New methods for measuring BP are replacing mercury sphygmomanometry in many clinics. We examined the utility of different BP measurement techniques in predicting subclinical TOD in adolescents and young adults.

METHODS

Participants in a study of the cardiovascular effects of obesity and type 2 diabetes were evaluated (N=677, 18±3.3 years, 35% male, 60% non-White, 30% with type 2 diabetes). We measured adiposity, laboratory data, left ventricular mass, carotid intima-media thickness, and pulse wave velocity. BP was measured three times by mercury sphygmomanometry (BPm), using an oscillometric device (BPo), and by arterial tonometry to measure central aortic BP (BPc). Participants were stratified as normotensive, prehypertensive, or hypertensive.

RESULTS

The prevalence of HT in this cohort with a mean BMI of 31 was the highest on BPo measurement (16%), followed by BPm (11%) and BPc (9%; P≤0.001) measurements. BPm was the most consistent in differentiating left ventricular mass and pulse wave velocity among participants in the prehypertensive group as compared with the normotensive and hypertensive groups. Mercury BP measurement was also more sensitive and specific at predicting greater left ventricular mass, pulse wave velocity, and carotid thickness compared with other BP measurement techniques in logistic regression.

CONCLUSION

We conclude that mercury sphygmomanometry should remain the gold standard for evaluation of HT and the risk for TOD in adolescents and young adults.

Quality Control and Validation of Oscillometric Blood Pressure Measurements Taken During an Epidemiological Investigation

This study aims to validate blood pressure (BP) values measured by an oscillometric BP monitor and seek possible calibration methods if discrepancies exist. Noninvasive BP measurement outcomes were determined using an oscillometric BP monitor (Omron HBP-1300) versus a mercury sphygmomanometer (standard device). Two percent of subjects enrolled in an epidemiological investigation were systematically sampled in this study. Intraclass correlation coefficient (ICC) was used to evaluate measurement reliability, paired t-test was used to evaluate trueness, and linear regression was used for calibration. The Association for the Advancement of Medical Instrumentation (AAMI) standards and British Hypertension Society (BHS) protocols were used for validation quality assessment. Both mercury sphygmomanometer (standard device) and oscillometric BP monitor (test device) displayed high reliability. A significant difference in systolic blood pressure (SBP) was observed between devices. SBP calibration was achieved by using an effective linear regression model (B = 0.803 and constant = 19.592, P < 0.001). The calibrated model was corroborated by verification samples (P = 0.120) and was found to pass AAMI standards and BHS protocol requirements. Calibrated SBP measurements from the Omron HBP-1300 device were valid. Use of a combination of statistical methods, such as ICC for reliability assessment as well as paired t-test for trueness evaluation can be used to validate data from the oscillometric BP monitors.

End digit preference in blood pressure measurement in a hypertension specialty clinic in southwest Nigeria

Background

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.

Methods

A retrospective review was undertaken of BP readings of 114 patients seen over a two-month period at our hypertension specialty clinic.

Results

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.

Conclusion

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.

Brachial artery waveforms for automatic blood pressure measurement

Theoretically the auscultatory method using Korotkoff sounds is more related to the maximum artery closure status, while the oscillometric method is more related to the overall artery closure status under the cuff. Therefore, the latter is less accurate than the former. This work introduces a new method, which is more accurate than the oscillometric method and suitable for automatic devices. To monitor the maximum artery closure status, a piezoelectric film sensor is attached to the skin just above the brachial artery and under the central section of the cuff where maximum cuff pressure is transferred to the arm. Using the waveform features obtained by this sensor, measurement errors of 0.7±2.5 and 1.27±4.53 mmHg were obtained for the systolic and diastolic pressure, respectively. These reflect small deviations from auscultatory clinical data.

Oscillometric measurement of systolic and diastolic blood pressures validated in a physiologic mathematical model

Background

The oscillometric method of measuring blood pressure with an automated cuff yields valid estimates of mean pressure but questionable estimates of systolic and diastolic pressures. Existing algorithms are sensitive to differences in pulse pressure and artery stiffness. Some are closely guarded trade secrets. Accurate extraction of systolic and diastolic pressures from the envelope of cuff pressure oscillations remains an open problem in biomedical engineering.

Methods

A new analysis of relevant anatomy, physiology and physics reveals the mechanisms underlying the production of cuff pressure oscillations as well as a way to extract systolic and diastolic pressures from the envelope of oscillations in any individual subject. Stiffness characteristics of the compressed artery segment can be extracted from the envelope shape to create an individualized mathematical model. The model is tested with a matrix of possible systolic and diastolic pressure values, and the minimum least squares difference between observed and predicted envelope functions indicates the best fit choices of systolic and diastolic pressure within the test matrix.

Results

The model reproduces realistic cuff pressure oscillations. The regression procedure extracts systolic and diastolic pressures accurately in the face of varying pulse pressure and arterial stiffness. The root mean squared error in extracted systolic and diastolic pressures over a range of challenging test scenarios is 0.3 mmHg.

Conclusions

A new algorithm based on physics and physiology allows accurate extraction of systolic and diastolic pressures from cuff pressure oscillations in a way that can be validated, criticized, and updated in the public domain.

Community-based blood pressure measurement by non-health workers using electronic devices: a validation study

Introduction

Population monitoring and screening of blood pressure is an important part of any population health strategy. Qualified health workers are expensive and often unavailable for screening. Non-health workers with electronic blood pressure monitors are increasingly used in community-based research. This approach is unvalidated. In a poor, urban community we compared blood pressure measurements taken by non-health workers using electronic devices against qualified health workers using mercury sphygmomanometers.

Method

Fifty-six adult volunteers participated in the research. Data were collected by five qualified health workers, and six non-health workers. Participants were randomly allocated to have their blood pressure measured on four consecutive occasions by alternating a qualified health worker with a non-health worker. Descriptive statistics and graphs, and mixed effects linear models to account for the repeated measurement were used in the analysis.

Results

Blood pressure readings by non-health workers were more reliable than those taken by qualified health workers. There was no significant difference between the readings taken by qualified health workers and those taken by non-health workers for systolic blood pressure. Non-health workers were, on average, 5–7 mmHg lower in their measures of blood pressure than the qualified health workers (95%HPD: −2.9 to −10.0) for diastolic blood pressure.

Conclusion

The results provide empirical evidence that supports the practice of non-health workers using electronic devices for BP measurement in community-based research and screening. Non-health workers recorded blood pressures that differed from qualified health workers by no more than 10 mmHg. The approach is promising, but more research is needed to establish the generalisability of the results.

Avaliação das condições de uso de esfigmomanômetros em serviços hospitalares

OBJETIVO: Avaliar as condições de uso dos esfigmomanômetros em hospitais públicos e privados. MÉTODOS: Estudo descritivo de abordagem- quantitativa realizado em quatro hospitais de grande porte do Estado de São Paulo, no período entre 2009 e 2010. Os manômetros aneroides foram- testados contra manômetro de mercúrio calibrado. Foram considerados descalibrados quando as diferenças foram > a 4 mmHg. RESULTADOS: Foram avaliados 162 esfigmomanômetros, (78 de um hospital público e 84 de instituições filantrópicas e privada) e 98,1% eram do tipo aneróide.- Verificou-se que 56,2% dos manômetros estavam descalibrados (48,6% do hospital privado e 63,1% dos hospitais públicos). Analisando-se as- médias das diferenças negativas da descalibração, houve diferença significativa entre os manômetros do hospital privado e os dos hospitais públicos- (-6,14±2,66 mmHg vs -8,97±6,74 mmHg, respectivamente, p<0,05). Observou-se ainda que em 70,2% não era feita avaliação periódica; 26,7%- tinham extensão de borracha envelhecida; 20,5% das válvulas apresentaram vazamento; e 27% dos manômetros não estavam com o ponteiro na- marca zero. CONCLUSÃO: A descalibração dos esfigmomanômetros aneróides foi expressiva e pode acarretar avaliação incorreta da pressão arterial.

Alternatives to the mercury sphygmomanometer

The mercury sphygmomanometer was introduced over 100 years ago. Mercury, however, is a potent human neurotoxin. An international effort has developed to eliminate health-care sources of mercury--the thermometer and sphygmomanometer--and replace them with less toxic alternatives. There is concern regarding the accuracy of these alternative devices. We conducted a literature review of articles published between 1995 and 2009 evaluating the accuracy of mercury, aneroid, and oscillometric blood pressure devices. Mercury sphygmomanometers fared the best although they do not always perform as expected, failing calibration tests between 1 and 28 per cent of the time. Up to 61 per cent of aneroid sphygmomanometers failed. Recently calibrated aneroid devices performed well. Oscillometric devices were less studied and their performance was variable. All three devices showed variable performance. They should be validated before purchase and calibrated on a regular basis.

End-digit preference and the quality of blood pressure monitoring in diabetic adults

OBJECTIVE

Although tight blood pressure (BP) control is proven to reduce diabetes-related cardiovascular risk, it has been difficult to achieve in practice, perhaps in part because of low-quality monitoring data. We hypothesized that low-quality BP data, reflected in end-digit preference (EDP), remains common in primary care of diabetic adults.

RESEARCH DESIGN AND METHODS

Data were abstracted from the charts of 404 adults with type 2 diabetes seen at 16 academically affiliated clinics from 1999 to 2001. End-digits of systolic and diastolic BPs taken with nonautomated sphygmomanometers were extracted, and prevalence of EDP for zero was calculated. Associations between EDP and selected patient characteristics were determined using multiple logistic regressions.

RESULTS

EDP was highly prevalent in the BP measurements taken by nonphysicians (4,333 BPs; 50% of systolic, 50% of diastolic readings ended in zero; P < 0.001) and physicians (1,347 BPs; 69% of systolic, 64% of diastolic readings ended in zero; P < 0.001). In multivariate analysis, nonphysicians showed greater EDP for systolic BP in older patients (odds ratio [OR] 1.07 per 5 years) and women (OR 1.36 vs. men) and for diastolic BP in African-Americans (OR 1.25 vs. whites; all P < 0.05); physicians showed greater EDP for diastolic BP in less obese patients (OR 0.97 per 5 kg/m2 increment in BMI; P = 0.02).

CONCLUSIONS

Low-quality BP measurement is common in primary care of diabetic adults. Procedural and technological improvements to BP measurement deserve attention as part of an overall strategy to tighten BP control and reduce cardiovascular risk.

The effects of anatomical structures on adult forearm and upper arm noninvasive blood pressures

OBJECTIVE

The purpose of this study was to determine the effects of anatomical structures, specifically limb subcutaneous tissue and vessels on differences between forearm and upper arm oscillometric noninvasive blood pressure measurements.

METHODS

Nineteen volunteers with a mean age of 21.7+/-3.7 years and without peripheral vascular disease or coronary artery disease participated. Circumference and skinfolds were measured for the upper arm and forearm. Body mass indices were calculated. Ultrasound measured vessel depth and diameter in the upper arm and forearm. Dual energy X-ray absorptiometry determined percentage of subcutaneous tissue in the arm. With participants seated, American Heart Association guidelines were used to measure blood pressures, first by auscultatory method (upper arm only) and then by oscillometric method (upper arm and forearm) with a Dinamap 100 oscillometric blood pressure monitor.

RESULTS

Statistically significant differences were seen between upper arm auscultatory and oscillometric systolic blood pressures (t=-4.88; P=0.000) and mean arterial pressures (t=-3.07; P=0.007). Differences between oscillometric forearm and upper arm blood pressure readings were statistically significant for mean arterial pressures (t=-2.39; P=0.028). A regression model suggested that forearm and upper arm vessel depth, forearm vessel diameter, and upper arm circumference explained a statistically significant portion of the difference between forearm and upper arm blood pressures.

CONCLUSIONS

Differences between forearm and upper arm oscillometric blood pressures can be partially explained by vessel size, depth and upper arm circumference.

Utility of ambulatory blood pressure monitoring in children and adolescents

Diagnosis of hypertension is critically dependent on accurate blood pressure measurement. "Accurate" refers to carefully following the guidelines for blood pressure measurement laid out for children and adults to minimize observer and subject errors that commonly occur in clinical blood pressure measurement. Accurate blood pressure measurement is more important in children and adolescents as the misdiagnosis of hypertension may have a life-long adverse impact on insurability and employment. Automated blood pressure measurement offers multiple advantages in achieving high-quality blood pressure determinations by reducing observer errors. The most commonly used form of automated blood pressure measurement is 24-h ambulatory blood pressure measurement (ABPM). Information on ABPM in children has grown exponentially over the last decade. Normative data exists for diagnosis of hypertension in children using ABPM including a novel method for determining normal values with the LMS method. There is further information about the utility of different determinants of 24-h blood pressure such as dipping status, morning surge and blood pressure load. ABPM has been able to detect significant differences in blood pressure in many disease states in children including chronic renal failure, polycystic kidney disease, solitary functioning kidney, and after renal transplantation. Increasingly nonambulatory automated blood pressure determinations have been used in management of hypertension in children. Although nonambulatory automated readings lack information about nocturnal blood pressure or blood pressure during daily activity, studies have suggested that home automated blood pressure measurements are a helpful adjunct to the usual office blood pressure reading.

Aferição da pressão arterial: experiência de treinamento de pessoal e controle de qualidade no Estudo Pró-Saúde

A adequação das condutas terapêuticas e a validade das inferências epidemiológicas sobre a hipertensão arterial dependem crucialmente da acurácia dos procedimentos para sua aferição. Este artigo relata a experiência dos procedimentos adotados para o treinamento e controle de qualidade da aferição da pressão arterial na Fase 2 do Estudo Pró-Saúde, conduzido entre 3.574 funcionários de uma universidade no Rio de Janeiro, Brasil, em 2001. Foram utilizados aparelhos de coluna de mercúrios e técnicas padronizadas de aferição, baseada em protocolos internacionais. Foram monitoradas a adesão dos aferidores às técnicas preconizadas, a preferência por dígitos terminais, a diferença entre aferições consecutivas e a proporção de dados faltantes. O conjunto de procedimentos utilizados contribuiu para minimizar possíveis erros sistemáticos associados à técnica auscultatória de aferição da pressão arterial, possibilitando análises válidas acerca de fatores associados à ocorrência da hipertensão arterial.

The trained observer better predicts daytime ABPM diastolic blood pressure in hypertensive patients than does an automated (Omron) device

OBJECTIVES

Accurate blood pressure measurement is critical to successful clinical trials. Concerns about observer errors have led to the use of automated oscillometric devices without evidence that their performance is similar to that of trained observers. This study compares blood pressures obtained by trained observers and with an oscillometric device (Omron 705CP) to 24-h ambulatory blood pressure monitoring.

METHODS

We performed a post-hoc analysis of 313 untreated hypertensive patients at the end of the washout phase of a Novartis hypertension trial. Patients had three seated trained observer mercury auscultatory blood pressure measurements followed by 24-h ambulatory blood pressure monitoring. The next day, the ambulatory blood pressure monitoring was removed and three seated readings were obtained with an Omron 705CP. Correlations for systolic blood pressure and diastolic blood pressure were obtained between daytime ambulatory blood pressure monitoring (0900 and 2100) and the two office methods. In addition, we investigated the degree of difference of trained observer and Omron measurements from ambulatory blood pressure monitoring.

RESULTS

For systolic blood pressure, the correlation with ambulatory blood pressure monitoring of the trained observer was significantly better than with that of the Omron 705CP (0.641 vs. 0.555, P=0.01). For diastolic blood pressure values, even greater disparity between the two office method correlations with ambulatory blood pressure monitoring was observed (trained observer=0.593 vs. Omron=0.319, P<0.0001). Both trained observer and Omron readings were consistently higher than ambulatory blood pressure monitoring for systolic blood pressure (P<0.0001) and diastolic blood pressure (P<0.0001). Omron measurements, however, deviated from ambulatory blood pressure monitoring more than those of the trained observer (P<0.0001 for systolic blood pressure and diastolic blood pressure).

CONCLUSIONS

For clinical trials using diastolic blood pressure targets, the Omron 705CP cannot replace the auscultatory blood pressure measurements of a trained observer. For systolic blood pressure, the Omron device and the trained observer had similar correlations with ambulatory blood pressure monitoring; however, both methods gave consistently higher systolic blood pressure values. Further study of oscillometric devices should be conducted before universally replacing auscultatory blood pressure determinations by trained observers in clinical trials.

A survey of validated automated home blood pressure monitors available for the Internet shopper

OBJECTIVE

Self-measurement of blood pressure using an automated home blood pressure monitoring (AHBPM) is increasingly used in hypertension management. Internet commerce increases dramatically each year. This study looked to identify the availability of validity of AHBPM and the correct cuff size to go with the AHBPM.

METHODS AND RESULTS

Using the search engine 'Google.com', the author identified 124 consecutive unique sites offering at least one AHBPM. Validated AHBPM were those devices that had published studies showing that they had passed a recognized validation protocol. Each site was evaluated for all forms of sphygmomanometer, number of AHBPM, manual blood pressure devices, all cuff sizes available, additional cost of large adult cuff, number of validated AHBPM offered, and whether the site mentioned device validation. Of the 124 sites, 109 (81%) offered arm AHBPM and 66 (53%) offered one or more (range, 1-11) validated AHBPM. Only six of the 66 (9%) offering a validated AHBPM mentioned that fact; 58 of the 109 (53%) sites offering arm AHBPM offered more than one size of cuff; and 46 of the 58 (80%) charged extra for a large adult cuff (average US dollars 23.75, range, US dollars 4.80-98).

CONCLUSIONS

Validated AHBPMs are readily available on the Internet. Currently, these sites do little to aid the consumer in purchasing a validated AHBPM. Large adult cuffs, commonly needed by hypertensive patients, are not always available for purchase. Charging extra for large adult cuffs is a potential hindrance to consumers purchasing the correct cuff size for accurate blood pressure measurement and should be eliminated.

Beyond the Evidence of the New Hypertension Guidelines. Blood pressure measurement - is it good enough for accurate diagnosis of hypertension? Time might be in, for a paradigm shift (I)

Despite widespread availability of a large body of evidence in the area of hypertension, the translation of that evidence into viable recommendations aimed at improving the quality of health care is very difficult, sometimes to the point of questionable acceptability and overall credibility of the guidelines advocating those recommendations.

The scientific community world-wide and especially professionals interested in the topic of hypertension are witnessing currently an unprecedented debate over the issue of appropriateness of using different drugs/drug classes for the treatment of hypertension. An endless supply of recent and less recent "drug-news", some in support of, others against the current guidelines, justifying the use of selected types of drug treatment or criticising other, are coming out in the scientific literature on an almost weekly basis. The latest of such debate (at the time of writing this paper) pertains the safety profile of ARBs vs ACE inhibitors.

To great extent, the factual situation has been fuelled by the new hypertension guidelines (different for USA, Europe, New Zeeland and UK) through, apparently small inconsistencies and conflicting messages, that might have generated substantial and perpetuating confusion among both prescribing physicians and their patients, regardless of their country of origin.

The overwhelming message conveyed by most guidelines and opinion leaders is the widespread use of diuretics as first-line agents in all patients with blood pressure above a certain cut-off level and the increasingly aggressive approach towards diagnosis and treatment of hypertension. This, apparently well-justified, logical and easily comprehensible message is unfortunately miss-obeyed by most physicians, on both parts of the Atlantic.

Amazingly, the message assumes a universal simplicity of both diagnosis and treatment of hypertension, while ignoring several hypertension-specific variables, commonly known to have high level of complexity, such as:

- accuracy of recorded blood pressure and the great inter-observer variability,

- diversity in the competency and training of diagnosing physician,

- individual patient/disease profile with highly subjective preferences,

- difficulty in reaching consensus among opinion leaders,

- pharmaceutical industry's influence, and, nonetheless,

- the large variability in the efficacy and safety of the antihypertensive drugs.

The present 2-series article attempts to identify and review possible causes that might have, at least in part, generated the current healthcare anachronism (I); to highlight the current trend to account for the uncertainties related to the fixed blood pressure cut-off point and the possible solutions to improve accuracy of diagnosis and treatment of hypertension (II).

New national guidelines on hypertension

BACKGROUND

Periodically, the National Heart, Lung, and Blood Institute publishes recommendations on the prevention, detection, evaluation and treatment of high blood pressure. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure--known as "JNC 7"--substantially revises previous recommendations.

METHODS

This report represents the consensus opinion of a coalition of 39 major professional, public and voluntary organizations and seven federal agencies. All currently available literature on hypertension was reviewed by a select committee of experts on hypertension (including one of the authors [L.M.P.]) and was used to formulate this new report.

RESULTS

The authors present highlights of the JNC 7 report. In addition, they offer the findings of their review of dental literature dealing with patients who have hypertension, into which they integrate information from the JNC 7, and update dental management recommendations. These new guidelines provide key messages to all health care professionals and are designed to improve the diagnosis and treatment of people with hypertension.

CONCLUSIONS

Because hypertension affects nearly 50 million people in the United States and underlies most cardiovascular disease, its diagnosis and control should be of concern to all health care providers. Many people have undetected hypertension, and current levels of detection and control need to be improved.

CLINICAL IMPLICATIONS

All health care providers, including dentists and members of the dental team, need to be involved in detection and management of this important public health problem. The dentist can play an important role in the detection and management of hypertension.

The Accoson Greenlight 300???, the first non-automated mercury-free blood pressure measurement device to pass the International Protocol for blood pressure measuring devices in adults

BACKGROUND

Accurate blood pressure measurement is critical to successful care of the hypertensive patient. The mercury manometer is rapidly being removed from clinical practice due to concerns about environmental contamination. The Accoson Greenlight 300 device is the first non-automated mercury-free device for auscultatory blood pressure measurement to pass the International Protocol for validation of blood pressure measuring devices in adults.

METHODS

Fifty-one patients were enrolled to obtain the 33 patients required to fill the three systolic blood pressure (SBP) ranges (low 90-129 mmHg, medium 130-160 mmHg, high 161-180 mmHg) and diastolic blood pressure (DBP) ranges (low 40-79 mmHg, medium 80-100 mmHg, high 101-130 mmHg). Nine sequential blood pressure measurements by two observers with the mercury manometer and the supervisor with the Greenlight 300 were taken. The first two observer blood pressures were used to classify the SBP and DBP range. The readings were then analyzed in two phases to determine whether the device passed the International Protocol.

RESULTS

The device passed Phase 1 using 15 subjects. In Phase 2.1 (n=33) for the 99 readings of SBP, 84 of 99 were within 5 mmHg, 95 of 99 were within 10 mmHg, and 98 of 99 were within 15 mmHg. For the 99 readings of DBP, 74 of 99 were within 5 mmHg, 90 of 99 were within 10 mmHg, and 96 of 99 were within 15 mmHg. In Phase 2.2 (n=33) for SBP, 33 of 33 had 2 of 3 SBP within 5 mmHg and none had all three readings >or=5 mmHg. For DBP, 27 of 33 had 2 of 3 of their DBP within 5 mmHg and only three had all three readings > or =5 mmHg.

CONCLUSIONS

The Accoson Greenlight 300 is the first electronic non-automated blood pressure measurement device to pass the International Protocol.

The Maxi Stabil 3: validation of an aneroid device according to a modified British Hypertension Society protocol

BACKGROUND

Measuring blood pressure with mercury-independent alternatives is rapidly gaining attention. Mercury will be phased out of clinical use as a result of environmental, health and safety concerns and it is of vital importance that any alternative to mercury has to be of a recognized standard. We assessed the accuracy of the Maxi Stabil 3 aneroid device in an adult population according to a modified British Hypertension Society protocol (with the low systolic category changed from less than 90 mmHg to less than 100 mmHg).

POPULATION

Eighty-five subjects were recruited from among staff and patients at Guy's and St Thomas' Hospitals, London, UK.

METHODS

The aneroid device was connected in parallel to two mercury sphygmomanometers. Nine sequential same-arm measurements were taken from each subject by two trained observers, alternating between mercury sphygmomanometry and the aneroid device. Simultaneous mercury readings were also recorded for additional analysis.

RESULTS

The device achieved an A grade for both systolic and diastolic pressures and fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The mean and standard deviation for systolic and diastolic pressures respectively were -0.6 (4.6) mmHg and -1.3 (3.5) mmHg in sequential analysis, and -1.3 (2.2) mmHg and -1.9 (2.7) mmHg in simultaneous analysis.

CONCLUSION

The Maxi Stabil aneroid device can be recommended for use in an adult population.

What will replace the mercury sphygmomanometer?

Mercury sphygmomanometers are gradually being phased out, not because of any technological advances but because of environmental concerns. While mercury is still accepted as the 'gold standard' for routine clinical measurement, it suffers from two deficiencies: poor observer technique, and problems due to poor maintenance of the devices. At the same time, there is no generally accepted alternative; the most widely advocated candidates are aneroid or oscillometric devices. Oscillometric devices have the advantages of eliminating observer error and mechanical drift, but it is suggested that the inherent limitations of the oscillometric method mean that it cannot become the gold standard for clinical measurement in individual patients. Aneroid monitors have been found in practice to be frequently deficient, and are subject to the same deficiencies in observer technique as mercury devices. Two possible but so far untested techniques are a 'hybrid' sphygmomanometer, whereby the mercury column is replaced by an electronic transducer and display, and the wideband recording technique, which has the potential of using the same basic principle as the auscultatory technique, while eliminating the human observer.

Limitations of current validation protocols for home blood pressure monitors for individual patients

BACKGROUND

Automatic blood pressure monitoring conducted at home is increasingly used in the diagnosis and management of hypertension. We assessed the adequacy of existing British Hypertension Society (BHS) and Association for the Advancement of Medical Instrumentation (AAMI) validation standards for automatic blood pressure monitoring devices.

SUBJECT AND METHODS

A theoretical study and an empirical test are presented to estimate the proportion of persons for whom a blood pressure monitor validated according to existing BHS and AAMI standards would be inaccurate.

RESULTS

The results suggest that a major limitation of both protocols is the lack of attention given to the number of individual patients for whom a monitor may be inaccurate. A blood pressure monitor that meets the AAMI and BHS validation criteria may report blood pressures in error by more than 5 mmHg for more than half of the people.

CONCLUSIONS

A validation standard that does not take account of the person-effects on error will lead to a substantial proportion of persons using self-monitors that are systematically inaccurate for that person.

Hypertension magnitude and management in the elderly population of Spain

OBJECTIVE

The present study assessed the prevalence, awareness, treatment and control of hypertension among the elderly population of Spain.

DESIGN

Based on a nationally representative sample of 4009 individuals aged 60 years, two sets of six blood pressure measurements were obtained by trained observers at each subject's home, using standardized methods. In each set, three mercury-based measurements were alternated with three automated measurements.

RESULTS

The mean systolic blood pressure (SBP)/diastolic blood pressure (DBP) was 143/79 mmHg, and the pulse pressure was 64 mmHg. The prevalence rate of hypertension (SBP 140 mmHg, DBP 90 mmHg, or current drug treatment) was 68.3%. No result obtained was sensitive to a particular measurement device. Of the hypertensives, 65% were aware of their condition, 55.3% were treated and 16.3% were controlled. Among treated hypertensives, SBP control (32.2%) was much lower than DBP control (82.3%). Control was lower in men than in women, in older than in younger subjects, and in those with lowest than in those with higher educational levels. About 57% of uncontrolled treated hypertensives were on monotherapy. Weight loss was among the least heeded items of advice (39% among overweight hypertensives).

CONCLUSIONS

Hypertension is a major public health problem in elderly Spaniards. Most hypertensives had their hypertension uncontrolled. Greater emphasis should be laid on the most disadvantaged (the older, men, and those with lowest education) in terms of hypertension management, and on reinforcing weight loss and combining drugs for enhanced hypertension control.

Principles and techniques of blood pressure measurement

The gold standard for clinical blood pressure measurement continues to be readings taken by a physician using a mercury sphygmomanometer, but this is changing as mercury is gradually being phased out. The oscillometric technique, which primarily detects mean arterial pressure, is increasingly popular for use in electronic devices. Other methods include ultrasound (used mainly to detect systolic pressure) and the finger cuff method of Penaz, which can record beat-to-beat pressure noninvasively from the finger. The preferred location of measurement is the upper arm, but errors may occur because of changes in the position of the arm. Other technical sources of error include inappropriate cuff size and too rapid deflation of the cuff. Clinic readings may be unrepresentative of the patient's true blood pressure because of the white coat effect, which is defined as the difference between the clinic readings and the average daytime blood pressure. Patients with elevated clinic pressure and normal daytime pressure are said to have white coat hypertension. There are three commonly used methods for measuring blood pressure for clinical purposes: clinic readings, self-monitoring by the patient at home, and 24-hour ambulatory readings. Self-monitoring is growing rapidly in popularity and is generally carried out using electronic devices that work on the oscillometric technique. Although standard validation protocols exist, many devices on the market have not been tested for accuracy. Such devices can record blood pressure from the upper arm, wrist, or finger, but the arm is preferred. Twenty-four-hour ambulatory monitoring has been found to be the best predictor of cardiovascular risk in the individual patient and is the only technique that can describe the diurnal rhythm of blood pressure accurately. Ambulatory monitoring is mainly used for diagnosing hypertension, whereas self-monitoring is used for following the response to treatment. Different techniques of blood pressure measurement may be preferred in certain situations. In infants the ultrasound technique is best, whereas in pregnancy and after exercise the diastolic pressure may be hard to measure using the conventional auscultatory method. In obese subjects it is important to use a cuff of the correct size.

Has conventional sphygmomanometry ended with the banning of mercury?

The banning of mercury from clinical practice will lead to the inevitable demise of traditional clinical sphygmomanometry. There are differences in approach to this important issue between European countries on the one hand, which generally have accepted that the mercury sphygmomanometer must be replaced with alternative devices, and the U.S. on the other, where the view is that the mercury sphygmomanometer should remain as the mainstay of blood pressure measurement. The availability of alternative devices for the mercury sphygmomanometer is improving but the problem of independent validation is a serious issue, which is being addressed by the European Society of Hypertension Working Party on Blood Pressure Monitoring, which has drafted an International Protocol for validating blood pressure measuring devices. The removal of the mercury sphygmomanometer from clinical practice has other implications, which merit careful consideration; the advent of automated devices must lead inevitably to the disappearance of the traditional clinical auscultatory technique of blood pressure measurement, and with the disappearance of mercury it will be argued that the Système International(SI) unit of measurement -- the kilopascal -- should replace the millimetre of mercury.

Cardiovascular disease risk factors and atherosclerosis in children and adolescents

As more is learned about the natural history of the development of atherosclerosis, it is clear that the process that results in morbidity and mortality in adults has its origins in childhood and adolescence. It is also clear that the traditional risk factors, such as hypertension and dyslipidemia, are important in the early stages of the process. It appears that the prevalence and severity of obesity are increasing in children and adolescents in the United States. This trend is associated with increasing blood pressure and the occurrence of type 2 diabetes mellitus in young individuals. These trends may result in increased cardiovascular morbidity and mortality as these overweight pediatric patients become obese adults. Intervention and prevention strategies should be directed at the pediatric population as a whole, as well as at higher-risk individuals. For the latter, it will be necessary to identify those at highest risk. Both nonpharmacologic and pharmacologic approaches may be necessary for treatment of pediatric patients with hyperlipidemia and hypertension. Studies are needed that evaluate the longer-term impact of intervention on cardiovascular risk factors in young patients.