What will replace the mercury sphygmomanometer?

Noninvasive Hemodynamic Monitors, What Is New and Old

This article reviews the evolution of noninvasive hemodynamic monitoring technologies, highlighting their importance in perioperative and critical care settings. Initially dominated by invasive methods, the field has shifted toward noninvasive techniques to reduce risks and improve patient safety. These advancements encompass various technologies, including bioimpedance/bioreactance, pulse contour analysis, and photoplethysmography, offering anesthesiologists dynamic tools for patient management. The article explores historical developments, traditional and advanced noninvasive monitors, and future trends, emphasizing the potential of integrating artificial intelligence and wearable technology in patient care.

Applicability of electronic sphygmomanometer use in high-altitude areas according to the AAMI/ESH/ISO collaboration statement

Objective

Mercury sphygmomanometer (MS) has now been less and less used and no new devices have been manufactured (according to Minamata convention 2013). The application of the electronic sphygmomanometer (ES) in clinical practice has become increasingly common. However, reliable evidence for the use of the ES in high-altitude areas remains scarce. The purpose of this study was to validate the applicability of the ES in high altitude areas.

Methods

In Luhuo County, Sichuan Province, China, 3,400 m above the sea level, two trained physicians measured the blood pressure (BP) of participants using both the mercury sphygmomanometer and the ES. Pearson correlation analysis and paired T-test, respectively, were used to compare the correlation and the difference between the BP values measured by the two devices. The applicability of the ES in high-altitude areas was evaluated according to the validation standards of the 2018 Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Collaboration Statement.

Results

In this study, 257 participants were included. There was a strong correlation between BP values measured by the two devices, with correlation coefficients for systolic blood pressure (SBP) and diastolic blood pressure (DBP) of 0.97 and 0.93, respectively. Compared with the MS, the ES tended to measure the subjects' DBP (76.21 ± 13.29 mmHg vs. 76.53 ± 14.07 mmHg; P = 0.557) accurately, but overestimate the SBP of the subjects (123.32 ± 22.25 mmHg vs. 121.34 ± 22.88 mmHg; P < 0.001) to some extent. The consistency of the two devices in the classification of normal BP, prehypertension, and hypertension was 88.9%, 80.7%, and 89.2%, respectively.

Conclusions

In general, the utilization of ES at 3,400 m altitude successfully met the validation standards of the AAMI/ESH/ISO Collaboration Statement. The use of ES can be recommended at a high altitude, including up to 3,400 m. In addition, because the ES tended to overestimate SBP, we speculate that it may need to be calibrated in high-altitude areas.

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.

Perception and Knowledge of Mercury by Occupationally Exposed Health Care Personnel

Thermometers and baumanometers frequently contain mercury, a toxic heavy metal. Inadequate management of this substance can constitute an occupational hazard by exposing health care professionals to health risks including memory loss, psychosomatic symptoms, fatigue, and other signs of cognitive dysfunction as reported in several studies.

PURPOSE

To assess Mexico's health care professionals' health and mercury-related knowledge and risk perception and to explore the measurement properties of a questionnaire assessing that level of knowledge.

MATERIALS AND METHODS

Mixed methodology. A quantitative, cross-sectional study was conducted to measure health care professionals' knowledge of mercury and to validate an instrument using a Rasch analysis in 160 professionals. A qualitative study involving in-depth interviews was conducted to identify participants' risk perception for mercury exposure.

RESULTS

The total knowledge of mercury was 19.0 ± 2.0 on a scale of 0 to 28 points. The scores for medical specialists were significantly (P < .001) higher, ranging between 20.0 ± 2.05 and 23.0 ± 1.63. In general, the level of risk perception for mercury exposure was low. The questionnaire presented a reasonable fit to the Rasch model (good item fit with a Bonferroni-adjusted P = .000714). The response categories of three items were collapsed, and two pairs of items were bundled into two super items.

CONCLUSION

The levels of the knowledge of the health and safety risks and risk perception for mercury exposure in the Mexican health care professionals evaluated were low. Health care professionals should receive comprehensive training in the safe use and health risks of mercury.

No effect of sleeved arms on the accuracy of blood pressure measurement

BACKGROUND

It is recommended that blood pressure should be measured on a bare upper arm with an appropriately sized cuff. However, in practice, it is more convenient to measure blood pressure on sleeved arms.

AIMS

We aim to examine the effect of sleeved arms on the accuracy of blood pressure measurement.

METHODS

Patients aged 18 years or older were enrolled. Participants underwent three blood pressure measurements in each of the following sleeve conditions in random order (bare arm; arm covered with a single-layer cotton shirt sleeve,1 mm; arm covered with two layers sleeve containing a cotton shirt and a polar fabric sweater, 3 mm; arm covered with two layers sleeve containing a cotton shirt and a thick cardigan, 4 mm).

RESULTS

Of the 300 participants, 155 (52%) were men. The mean age was 62.9 (10.7) years, and 226 (75%) had hypertension. There were no significant differences in either systolic blood pressure or diastolic blood pressure among the four kinds of sleeve conditions in all the participants (P > 0.5), and the mean blood pressure differences between measurements made on the sleeved arms and bare arm were within 1.0 mmHg. Blood pressure of sleeved arms was positively correlated with that of the bare arm (P < 0.001; r > 0.95), and showed good consistency.

CONCLUSIONS

In the present study, we concluded that there was no significant effect of sleeved arms on the accuracy of blood pressure measurement by using an electronic oscillometric sphygmomanometer equipped with a conventional cuff.

Multimodal Photoplethysmography-Based Approaches for Improved Detection of Hypertension

Elevated blood pressure (BP) is a major cause of death, yet hypertension commonly goes undetected. Owing to its nature, it is typically asymptomatic until later in its progression when the vessel or organ structure has already been compromised. Therefore, noninvasive and continuous BP measurement methods are needed to ensure appropriate diagnosis and early management before hypertension leads to irreversible complications. Photoplethysmography (PPG) is a noninvasive technology with waveform morphologies similar to that of arterial BP waveforms, therefore attracting interest regarding its usability in BP estimation. In recent years, wearable devices incorporating PPG sensors have been proposed to improve the early diagnosis and management of hypertension. Additionally, the need for improved accuracy and convenience has led to the development of devices that incorporate multiple different biosignals with PPG. Through the addition of modalities such as an electrocardiogram, a final measure of the pulse wave velocity is derived, which has been proved to be inversely correlated to BP and to yield accurate estimations. This paper reviews and summarizes recent studies within the period 2010–2019 that combined PPG with other biosignals and offers perspectives on the strengths and weaknesses of current developments to guide future advancements in BP measurement. Our literature review reveals promising measurement accuracies and we comment on the effective combinations of modalities and success of this technology.

Multi-Site Photoplethysmography Technology for Blood Pressure Assessment: Challenges and Recommendations

Hypertension is one of the most prevalent diseases and is often called the “silent killer” because there are usually no early symptoms. Hypertension is also associated with multiple morbidities, including chronic kidney disease and cardiovascular disease. Early detection and intervention are therefore important. The current routine method for diagnosing hypertension is done using a sphygmomanometer, which can only provide intermittent blood pressure readings and can be confounded by various factors, such as white coat hypertension, time of day, exercise, or stress. Consequently, there is an increasing need for a non-invasive, cuff-less, and continuous blood pressure monitoring device. Multi-site photoplethysmography (PPG) is a promising new technology that can measure a range of features of the pulse, including the pulse transit time of the arterial pulse wave, which can be used to continuously estimate arterial blood pressure. This is achieved by detecting the pulse wave at one body site location and measuring the time it takes for it to reach a second, distal location. The purpose of this review is to analyze the current research in multi-site PPG for blood pressure assessment and provide recommendations to guide future research. In a systematic search of the literature from January 2010 to January 2019, we found 13 papers that proposed novel methods using various two-channel PPG systems and signal processing techniques to acquire blood pressure using multi-site PPG that offered promising results. However, we also found a general lack of validation in terms of sample size and diversity of populations.

Reproducibility of the European Society of Hypertension - International Protocol for validation of blood pressure measuring devices in obese patients

BACKGROUND

Electronic devices for blood pressure (BP) measurements need to go through independent clinical validation as recommended by different authorities, both in general and special populations. Reproducibility of such validation protocols is unknown.

OBJECTIVE

The aim of this study was to assess the inter-centre reproducibility of the European Society of Hypertension-International protocol (ESH-IP) in patients with large arm circumference at least 32 cm or obesity.

METHODS

Two independent validation studies were performed in parallel according to the ESH-IP protocol in two centres (Serbia and Armenia). The two studies were performed blindly and independently. The ESH-IP criteria were applied for the analysis. The OMRON RS7 wrist oscillometric devices were used in both studies.

RESULTS

The distribution of the mean differences values of 5 or less, 10 or less and 15 mmHg or less between the observers and the device were for the Serbia team: 74, 95 and 98 for SBP and 78, 95 and 99 for DBP; and for the Armenia team: 86, 95 and 99 for SBP and 90, 99 and 99 for DBP. The mean differences (SD) of BP values between the observers and the device were for the Serbia team of 1.7 ± 4.8 mmHg for SBP and 1.2 ± 4.6 mmHg for DBP and for the Armenia team of -1.1 ± 4.2 mmHg for SBP and -0.3 ± 3.5 mmHg for DBP.

CONCLUSION

This study showed that the ESH-IP validation protocol presents a good inter-centre reproducibility. The OMRON RS7 device showed similar results, fulfilling the validation criteria in two independent studies in patients with arm circumference at least 32 cm.

Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association

The accurate measurement of blood pressure (BP) is essential for the diagnosis and management of hypertension. This article provides an updated American Heart Association scientific statement on BP measurement in humans. In the office setting, many oscillometric devices have been validated that allow accurate BP measurement while reducing human errors associated with the auscultatory approach. Fully automated oscillometric devices capable of taking multiple readings even without an observer being present may provide a more accurate measurement of BP than auscultation. Studies have shown substantial differences in BP when measured outside versus in the office setting. Ambulatory BP monitoring is considered the reference standard for out-of-office BP assessment, with home BP monitoring being an alternative when ambulatory BP monitoring is not available or tolerated. Compared with their counterparts with sustained normotension (ie, nonhypertensive BP levels in and outside the office setting), it is unclear whether adults with white-coat hypertension (ie, hypertensive BP levels in the office but not outside the office) have increased cardiovascular disease risk, whereas those with masked hypertension (ie, hypertensive BP levels outside the office but not in the office) are at substantially increased risk. In addition, high nighttime BP on ambulatory BP monitoring is associated with increased cardiovascular disease risk. Both oscillometric and auscultatory methods are considered acceptable for measuring BP in children and adolescents. Regardless of the method used to measure BP, initial and ongoing training of technicians and healthcare providers and the use of validated and calibrated devices are critical for obtaining accurate BP measurements.

Clinical accuracy of the Omron M3 Comfort® and the Omron Evolv® for self-blood pressure measurements in pregnancy and pre-eclampsia - validation according to the Universal Standard Protocol

BACKGROUND

Electronic devices for blood pressure (BP) measurements need to go through independent clinical validation as recommended by different authorities, both in general and in special populations such as pregnancy.

OBJECTIVE

To evaluate the accuracy of the Omron Evolv® (HEM-7600T-E) and the Omron M3 Comfort® (HEM-7134-E) devices in pregnancy and pre-eclampsia according to the Universal Standard Validation Protocol.

METHODS

Both devices, the Evolv and the M3 Comfort, measure BP at the brachial level using the oscillometric method. The study was performed according to the recently published protocol, the so-called "modified Advancement of Medical Instrumentation (AAMI)/British Hypertension Society (BHS)/European Society of Hypertension (ESH) protocol" or the "Universal Standard Protocol." Validation of each device included 45 pregnant women in the second and third gestational trimester of whom 15 had pre-eclampsia, 15 had gestational hypertension and 15 were normotensives. BP differences between the observer and the device BP values were classified into three categories (≤5, ≤10, and ≤15 mmHg) and the mean BP differences (test vs reference) and its SD were calculated.

RESULTS

Both devices, the Evolv and the M3 Comfort, achieved a grade A/A in both pregnancy and pre-eclampsia. The mean difference (SD) between the mercury standard and the device BP values in pregnancy were: 1) for the Evolv of -0.7±2.3 mmHg for systolic blood pressure (SBP) and -0.1±1.8 mmHg for diastolic blood pressure (DBP); 2) for the M3 Comfort of -1.6±2.8 mmHg for SBP and -0.1±2.3 mmHg for DBP.

CONCLUSION

Both devices, the Evolv and the M3 Comfort, achieved a grade A/A for both SBP and DBP and fulfill the validation protocol criteria in pregnancy and pre-eclampsia. Consequently, these two devices can be recommended for home BP measurements in this specific population.

Blood pressure measurement techniques: Assessing performance in outpatient settings of a tertiary-level hospital in Rwanda

Cardiovascular diseases (CVD) are the leading cause of mortality globally. Hypertension is a known modifiable risk factor for CVD. Diagnosis and management of hypertension hinges upon accurate blood pressure (BP) measurement. In this study, we assessed performance to recommended guidelines for BP measurement in Rwanda. In 2017, a cross-sectional study investigating performance on 11 techniques recommended for BP measurement was undertaken across outpatient settings of 3 departments at the University Teaching Hospital of Kigali, Rwanda. Performance was checked by an inside observer. The study enrolled 164 patients. The overall mean performance on the 11 BP measurement techniques was 5.69 (±1.02) out of the 11 possible points. There was no significant difference in performance across departments (P = .28). The findings suggest that performance on currently recommended guidelines for BP measurement is not optimal. Going forward, it is important to implement interventions that will enhance performance given that diagnosis and management of hypertension depend upon accurate BP measurement.

Validation of a smartphone auscultatory blood pressure kit Accutension XYZ-110 in adults according to the ANSI/AAMI/ISO 81060-2: 2013 standard

OBJECTIVE

The aim of this study was to validate the accuracy of the Accutension XYZ-110 blood pressure (BP) kit according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization (ANSI/AAMI/ISO) 81060-2:2013 standard.

PARTICIPANTS AND METHODS

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured simultaneously on the same arm in 85 Chinese adults (female : male=48 : 37) with a mean age of 43.2 years using the mercury sphygmomanometer (two observers) and the Accutension XYZ-110 device (one supervisor). The ANSI/AAMI/ISO 81060-2:2013 standard for the validation of BP-measuring devices in adults was followed precisely. A total of 255 comparison pairs were obtained for analysis.

RESULTS

The mean device-observer difference in the 255 separate BP data pairs was 2.45±2.24 mmHg for SBP and 0.69±2.09 mmHg for DBP. The data were in accordance with the criterion 1 of the ANSI/AAMI/ISO 81060-2:2013 standard requirements (≤5±8 mmHg). In addition, the mean device-observer difference of the 85 participants was 2.45±1.47 mmHg for SBP and 0.69±1.36 mmHg for DBP. The device accuracy also fulfilled the criterion 2 with the SD of less than or equal to 6.47 for SBP and less than or equal to 6.90 mmHg for DBP.

CONCLUSION

The Accutension XYZ-110 BP kit fulfilled the requirements of the ANSI/AAMI/ISO 81060-2:2013 standard, and hence could be recommended for both clinical and self/home BP measurement in adults.

Diagnostic precision of mentally estimated home blood pressure means

CONTEXT

Paper home blood pressure (HBP) charts are commonly brought to physicians at office visits. The precision and accuracy of mental calculations of blood pressure (BP) means are not known.

METHODS

A total of 109 hypertensive patients were instructed to measure and record their HBP for 1 week and to bring their paper charts to their office visit. Study section 1: HBP means were calculated electronically and compared to corresponding in-office BP estimates made by physicians. Study section 2: 100 randomly ordered HBP charts were re-examined repetitively by 11 evaluators. Each evaluator estimated BP means four times in 5, 15, 30, and 60 s (random order) allocated for the task. BP means and diagnostic performance (determination of therapeutic systolic and diastolic BP goals attained or not) were compared between physician estimates and electronically calculated results.

RESULTS

Overall, electronically and mentally calculated BP means were not different. Individual analysis showed that 83% of in-office physician estimates were within a 5-mmHg systolic BP range. There was diagnostic disagreement in 15% of cases. Performance improved consistently when the time allocated for BP estimation was increased from 5 to 15 s and from 15 to 30 s, but not when it exceeded 30 s.

CONCLUSION

Mentally calculating HBP means from paper charts can cause a number of diagnostic errors. Chart evaluation exceeding 30 s does not significantly improve accuracy. BP-measuring devices with modern analytical capacities could be useful to physicians.

Hemodynamic response to muscle reflex is abnormal in patients with heart failure with preserved ejection fraction

The aim of the present investigation was to assess the role of cardiac diastole on the hemodynamic response to metaboreflex activation. We wanted to determine whether patients with diastolic function impairment showed a different hemodynamic response compared with normal subjects during this reflex. Hemodynamics during activation of the metaboreflex obtained by postexercise muscle ischemia (PEMI) was assessed in 10 patients with diagnosed heart failure with preserved ejection fraction (HFpEF) and in 12 age-matched healthy controls (CTL). Subjects also performed a control exercise-recovery test to compare data from the PEMI test. The main results were that patients with HFpEF achieved a similar mean arterial blood pressure (MAP) response as the CTL group during the PEMI test. However, the mechanism by which this response was achieved was markedly different between the two groups. Patients with HFpEF achieved the target MAP via an increase in systemic vascular resistance (+389.5 ± 402.9 vs. +80 ± 201.9 dynes·s^-1·cm^-5 for HFpEF and CTL groups respectively), whereas MAP response in the CTL group was the result of an increase in cardiac preload (-1.3 ± 5.2 vs. 6.1 ± 10 ml in end-diastolic volume for HFpEF and CTL groups, respectively), which led to a rise in stroke volume and cardiac output. Moreover, early filling peak velocities showed a higher response in the CTL group than in the HFpEF group. This study demonstrates that diastolic function is important for normal hemodynamic adjustment to the metaboreflex. Moreover, it provides evidence that HFpEF causes hemodynamic impairment similar to that observed in systolic heart failure.NEW & NOTEWORTHY This study provides evidence that diastolic function is important for normal hemodynamic responses during the activation of the muscle metaboreflex in humans. Moreover, it demonstrates that diastolic impairment leads to hemodynamic consequences similar to those provoked by systolic heart failure. In both cases the target blood pressure is obtained mainly by means of exaggerated vasoconstriction than by a flow-mediated mechanism.

[Usefulness of different techniques of blood pressure measurements in 2016]

The management of hypertensive patients is greatly influenced by blood pressure levels and accurate measurement of blood pressure is crucial in this context. Mercury sphygmomanometer has been progressively replaced by more precise oscillometric devices that can be widely used in the clinic and ambulatory setting. The purpose of this review was to detail the different methods for evaluating blood pressure, and to refine their indications and clinical benefit. Office blood pressure measurement has a great variability and should follow a strict protocol to give consistent results. National and international guidelines focus on blood pressure measurement in the ambulatory setting. When used by trained patients, home blood pressure monitoring is reproducible and can provide substantial prognostic information, even if ambulatory blood pressure monitoring remains the gold standard. The role of central blood pressure and pulse wave velocity monitoring in the therapeutic strategy of hypertension needs further assessment.

Validation of the RisingSun RS-651 Blood Pressure Monitor Based on Auscultation in Adults According to the ANSI/AAMI/ISO 81060-2:2013 Standard

This study validated the RisingSun RS‐651 blood pressure (BP) monitor based on auscultation in adults according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization (ANSI/AAMI/ISO) 81060‐2:2013 standard. The RS‐651 device was evaluated in a study of 97 participants. The same arm simultaneous method, as defined in the ANSI/AAMI/ISO standard, was used. The mean differences±standard deviation for criterion 1 were 0.8±2.3 mm Hg for systolic BP (SBP) and −0.1±2.9 mm Hg for diastolic BP (DBP). Analysis for criterion 2 resulted in values of 0.8±1.5 mm Hg for SBP and −0.1±2.1 mm Hg for DBP. All of the data fulfilled the ANSI/AAMI/ISO 81060‐2:2013 standard requirements to pass the validation. The RisingSun RS‐651 device can be recommended for both clinical and self/home use in adults according to the ANSI/AAMI/ISO 81060‐2:2013 standard.

The emerging epidemic of hypertension in Asian children and adolescents

Hypertension has become a serious global public health burden because of its high incidence and concomitant risk of cardiovascular disease. Many studies have verified that risk factors, such as hypertension and obesity which are responsible for cardiovascular disease, start in early childhood. In Asian countries, the prevalence of hypertension in the pediatric age group has become more prevalent than ever before with the increasing obesity epidemic. To tackle the epidemic of cardiovascular disease, a leading cause of death and disability of non-communicable diseases in Asian countries, population-based measures aiming at reducing harmful environmental factors to blood pressure and body weight must be applied to individuals in their early childhood, as early as the fetal stage. This review focused on the prevalence of pediatric hypertension in Asian countries and outlined several considerations for accurate blood pressure (BP) measurement and evaluation, along with an overview of pathophysiology of fetal programming and obesity related with childhood hypertension.

Validation of the OMRON M3500 Blood Pressure Measuring Device Using Normal- and High-Speed Modes in Adult and Specific Populations (Obese and Children) According to AAMI Protocol

The present study aimed to validate the accuracy of blood pressure (BP) measurements of the OMRON M3500 automatic oscillometric BP device by using normal- and high-speed modes in adult and specific populations (obese and children) according to American National Standards Institute/Association for the Advancement of Medical Instrumentation (AAMI)/International Organization for Standardization/81060-2:2009 protocol. The validation was performed in 135 patients: 100 adults and 35 children (aged 3-12 years). The results showed a mean error of the individual paired determinations of the OMRON device and mercury sphygmomanometers within values of criterion 1 (5±8 mm Hg). Analysis of the averaged paired determinations per subject of the OMRON device and standard mercury sphygmomanometer fit within the acceptable ranges of criterion 2 (<6.71 systolic BP and <5.77 diastolic BP). Readings of the OMRON M3500 BP device fulfill criteria 1 and 2 of the AAMI protocol in both speed modes.

Measurement of the ankle brachial index with a non-mercury sphygmomanometer in diabetic patients: a concordance study

BACKGROUND

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).

METHODS

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).

RESULTS

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.

CONCLUSION

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.

Blood pressure measurement: clinic, home, ambulatory, and beyond

Blood pressure traditionally has been measured in the clinic setting using the auscultatory method and a mercury sphygmomanometer. Technologic advances have led to improvements in measuring clinic blood pressure and allowed for measuring blood pressures outside the clinic. This review outlines various methods for evaluating blood pressure and the clinical utility of each type of measurement. Home blood pressures and 24-hour ambulatory blood pressures have improved our ability to evaluate the risk of target-organ damage and hypertension-related morbidity and mortality. Measuring home blood pressures may lead to more active participation in health care by patients and has the potential to improve blood pressure control. Ambulatory blood pressure monitoring enables measuring nighttime blood pressures and diurnal changes, which may be the most accurate predictors of risk associated with elevated blood pressure. Additionally, reducing nighttime blood pressure is feasible and may be an important component of effective antihypertensive therapy. Finally, estimating central aortic pressures and pulse wave velocity are 2 of the newer methods for assessing blood pressure and hypertension-related target-organ damage.

Validation study of the Dinamap ProCare 200 upper arm blood pressure monitor in children and adolescents

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

The inaccuracy of automatic devices taking postural measurements in the emergency department

Automatic devices are used to take postural blood pressures in the emergency department despite research proving their inaccuracy in taking single blood pressures. This study assessed the accuracy of an automatic device compared with a manual aneroid reference standard for determining orthostatic hypotension and postural drops at triage. Supine and standing blood pressures were taken with an automatic and a manual device in a sequential and random order, and postural drops were calculated. The manual device indicated 10/150 emergency department patients had orthostatic hypotension (7%) and the automatic device detected this with a sensitivity of 30% and a specificity of 91%. The automatic-manual differences were clinically significant in 13% of systolic drops and 37% of diastolic drops. Findings suggest that automatic devices cannot reliably detect or rule out orthostatic hypotension, indicating that triage nurses need to use manual devices to take accurate postural blood pressures for optimal patient care.

Comparative assessment of four blood pressure measurement methods in hypertensives

INTRODUCTION

Discordance between blood pressure (BP) measurement methods can occur and create ambiguity. New automated office BP monitors (AOBPs) are widely available, but their role is presently unclear. The objectives of this study are to quantify concordance among BP measurement methods and to define the diagnostic sensitivity, specificity, and predictive value of AOBPs in a population of hypertensive patients.

METHODS

The office mercury sphygmomanometer, the AOBP, an ambulatory BP monitor (ABPM), and home self-measurement with an automatic device were compared in a randomized, crossover study. BP averages and achievement of therapeutic goals were defined. Comparisons and agreement tests were performed. Diagnostic indices were calculated for the AOBP.

RESULTS

A total of 101 patients were enrolled. Average BP results were similar between measurement methods with the exception of daytime ABPM, which was significantly higher; figures are mean ± standard deviation (SD): sphygmomanometer, 129.9 ± 13.7/80.9 ± 9.3 mm Hg; AOBP, 128.4 ± 13.9/80.0 ± 9.4 mm Hg; 24-hour ABPM, 131.4 ± 11.7/78.7 ± 9.7 mm Hg; day ABPM, 135.5 ± 11.4/82.0 ± 11.9 mm Hg; home self-measurement, 131.0 ± 14.3/82.5 ± 8.2 mm Hg. Discordance in the achievement of therapeutic goals was observed in 58 patients, with only 26 cases being explained by masked hypertension or "white coat syndrome" according to all measurements. Disagreement was greater when office methods were compared with ambulatory methods.

CONCLUSIONS

This study shows that the 4 measurement strategies provide similar average BP estimates but generate many discordant results. The AOBP device can be very valuable as a replacement for the sphygmomanometer.

Validation of inflationary non-invasive blood pressure monitoring in adult surgical patients

Oscillometric determination of blood pressure may be advantageous, as cuff inflation requires lower cuff pressure and shorter duration than deflation. In this observational study, we compared the blood pressure value, cuff pressure, and duration of cuff inflation between a prototype of inflationary non-invasive blood pressure (NIBP) and conventional deflationary NIBP in adult patients during anesthesia. Three hundred and twenty-three pairs of measurements were obtained from 64 subjects. The bias and precision of systolic pressure and diastolic pressure were 2.9 ± 8.3 and 5.6 ± 6.1 mmHg, respectively. Inflationary NIBP could better determine NIBP with lower cuff pressure than deflationary NIBP (124 ± 22 vs. 160 ± 33 mmHg, p < 0.05). Inflationary NIBP could also determine NIBP more quickly (13.0 ± 2.3 vs. 32.7 ± 13.6 s, p < 0.05). These data suggest that inflationary NIBP may reduce cuff-related discomfort and complications, and has reasonable accuracy compared to deflationary NIBP in adult surgical patients.

Accuracy of oscillometric devices in children and adults

Clinical validation of blood pressure oscillometric devices are almost exclusively conducted in adults. Because oscillometric devices are used in children, it is critical to assess their accuracy also in this population. We compared blood pressure readings using an oscillometric automated device (Dinamap XL, model CR9340) with readings obtained with the mercury auscultatory method in children and adults. Blood pressure was measured in 30 children (15 boys and 15 girls; 9.5+/-1.0 years old) and their parents (25 mothers and 15 fathers; 41.0+/-5.0 years old). In children, mean difference (+/-SD) in systolic blood pressure (DeltaBP) readings (oscillometric-auscultatory) was +0.6+/-4.7 mmHg (range: -10 to +11); mean diastolic DeltaBP was 21.3+/-7.5 mmHg (range: -18 to +19) and decreased with increasing diastolic BP. In adults, mean systolic DeltaBP was +0.4+/-5.2 mmHg (range: -12 to +15) and mean diastolic DeltaBP was -5.2+/-6.0 mmHg (range: -25 to +8) (p<0.001). While the device was not accurate enough to be recommended, our study also shows that the accuracy of blood pressure oscillometric devices can differ between children and adults. Clinical accuracy of oscillometric devices should be tested in the specific populations in whom blood pressure is measured.

[Blood pressure monitors in primary healthcare centres]

BACKGROUND

Blood pressure monitoring is one of the most common procedures in clinical medicine. Evaluation and treatment of hypertension are costly and have considerable implications for the individuals involved. Mercury manometers have been dominant for a century, but are currently being replaced by other types of equipment. No national guidelines/recommendations exist on types of blood pressure monitors to be used. The aim of this study was to assess the types of blood pressure monitors used in Norwegian general practice, and to what extent routines have been established for control and calibration of the equipment.

MATERIAL AND METHODS

In 2007, a questionnaire was distributed to 65 university-affiliated primary healthcare centres in Mid-Norway. The questions included what type of blood pressure monitors are in use and whether routines exist for calibration of them.

RESULTS

45 healthcare centres with a total of 173 general practitioners (corresponding to 74 % of the doctors) responded. 18 (6 %) of the 320 monitors identified were of the mercury type, the rest were aneroid or oscillometric. Many centres had 24-hour monitors. Two healthcare centres (4 % of the doctors) had established routines for calibration of their blood pressure monitors.

INTERPRETATION

Routines should be established for quality assurance of blood pressure monitors in Norwegian primary healthcare services.

Determining the accuracy of blood pressure measurement by the Omron HEM-907 before and after hemodialysis

BACKGROUND

The accuracy of oscillometric blood pressure (BP) measuring devices determined in resting conditions may be distorted in those under hemodialysis (HD).

METHODS

The evaluation of accuracy of the Omron HEM-907 was performed in accordance with the International Protocol for validation of BP measuring devices (IP). Out of a group of 49 patients with end-stage renal disease (ESRD) (56.7 +/- 15.6 years), four groups of 33 patients each were selected to ascertain their BP before and after HD.

RESULTS

The Omron HEM-907 fulfilled the IP accuracy requirements for systolic BP measurements before and after HD. In the case of diastolic BP before HD, the Omron HEM-907 did not fulfill both requirements for phase 2.2 IP. In only 21 out of 33 patients, the difference between the mean of two observers and the Omron HEM-907 device (Diff) was not more than 5 mmHg, while the requirement was 22 patients. In seven patients, all three Diff were over 5 mmHg, while the accepted limit is three. After HD, the Omron HEM-907 did not fulfill one out of two criteria of phase 2.2 IP - in five people, all three Diff were over 5 mmHg.

CONCLUSION

The Omron HEM-907 oscillometric method of BP measurement should not be used to measure BP before and after HD in ESRD patients. In ESRD patients, an alternative method of BP measurement, in the event of a lack of a mercury sphygmomanometer, could be a classical auscultatory method together with the Omron HEM-907, which allows for this type of BP measurement.

Development and validation of a blinded hybrid device according to the European Hypertension Society protocol: Nissei DM-3000

Both automated and auscultatory blood pressure (BP) devices have their strengths and accuracy limitations. Hybrid devices, such as the Nissei DM-3000, are mercury free and provide both automated and auscultatory measurement modes. The aim of this study was to validate all measurement modes of the Nissei DM-3000 device according to the European Society of Hypertension (ESH) protocol, as well as to develop and validate a 'blinded' auscultatory measurement mode. Different measurement modes were developed and evaluated in separate studies. Nine sequential same-arm BP measurements were taken alternating between simultaneous mercury sphygmomanometer readings and the device. The latter seven measurements were analysed according to the requirements of the ESH protocol. All measurement modes of the device passed the ESH protocol. The blinded mode achieved the best results with a mean difference+/-s.d. of -0.1+/-2.6 and 0.04+/-2.4 mm Hg for systolic BP (SBP) and diastolic BP (DBP), respectively. The most accurate auscultatory measurement results were obtained with a deflation rate of 2.5 mm Hg s(-1) achieving a mean difference+/-s.d. of -0.6+/-4.4 (for SBP) and -1.4+/-2.8 mm Hg (for DBP). The automated mode achieved a mean difference+/-s.d. of -0.8+/-6.0 (SBP) and 0.8+/-4.8 mm Hg (DBP). The Nissei DM-3000 device is a suitable replacement for the mercury sphygmomanometer.

Clinical applications of pulse transit time in paediatric critical care

A simple and non-invasive technique, termed pulse transit time (PTT), has shown its potential in long-term investigations such as respiratory sleep studies and cardiovascular studies. Based on these findings, the PTT technique shows relevance for continuous haemodynamic monitoring in critical care. The objective of this review is to understand the potential, applications and limitations of PTT in this clinical setting. Present non-invasive haemodynamic monitoring methods such as automated oscillometric blood pressure (BP) and auscultatory techniques have their known limitations. They tend to underestimate systolic BP while overestimating diastolic BP. Due to the periodic increase in cuff pressure cycles during data acquisition, these techniques may cause much discomfort in elderly geriatric patients, or lessen the cooperation of younger paediatric patients. Thus, there can be adverse effects on therapeutic decisions and possibly clinical outcomes. Documented evidences have indicated that changes observed in PTT are inversely correlated to the corresponding BP changes. In critical care, a simple and accommodating technique like PTT may be useful in providing better comfort for patients during extended monitoring. Being a semi-quantitative measure, blanket recommendations for its utility can then become possible. The basic instrumentations needed are often part of standard critical care monitoring system. Furthermore, PTT also has the potential to monitor the often tachypnoeic respiratory dependent BP changes seen in small infants during critical care.

Automated device that complies with current guidelines for office blood pressure measurement: design and pilot application study of the Microlife WatchBP Office device

OBJECTIVE

Current guidelines for office blood pressure (BP) measurement recommend mercury devices, both arms measurement in the initial assessment and at least duplicate measurements at follow-up visits. This study presents the design and a pilot application study of an automated device that fulfils American, European, and International guidelines for office BP measurement.

DESIGN AND FUNCTIONS

The Microlife WatchBP Office is a professional electronic mercury-free device with three function modes designed for: (a) initial assessment: triplicate automated simultaneous oscillometric both arms measurement at 60-s intervals and when there is a consistent interarm difference more than 20 mmHg systolic and/or more than 10 mmHg diastolic, the arm with the higher BP is indicated. (b) Follow-up assessment: triplicate automated oscillometric single arm measurements at 60-s intervals and their average is displayed. (c) Auscultatory measurement: by an observer using a stethoscope and a digital countdown BP display for patients with arrhythmias and other individuals in whom the oscillometric measurement is not accurate.

PILOT APPLICATION STUDY

The 'initial assessment' mode was applied by three physicians in 63 patients (189 readings). Average interarm systolic BP difference was 0.04+/-5.1 mmHg and diastolic 0.4+/-3.2 mmHg. A value more than 10 mmHg interarm difference in nine systolic BP readings (5%) and three (2%) diastolic. No patient had a consistent interarm difference more than 10 mmHg in all three or two of the three readings.

CONCLUSION

The Microlife WatchBP Office professional device fulfils current international requirements for office BP measurement and seems to overcome several limitations of this method when applied in clinical practice.

Evaluation and effects of the Omron 725 CIC device for measuring blood pressure in a hypertension clinic

BACKGROUND

We compared the Omron 725 CIC device (Omron Healthcare Inc., Vernon Hills, Illinois, USA), which is designed to register the blood pressure on the arm, with a mercury sphygmomanometer. In addition, we evaluated the possible impact that this device might have on the decisions made in a hypertension clinic.

METHODS

Patients (n=183) older than 18 years (range 18-84 years) with a wide range of systolic (87-197 mmHg) and diastolic (48-108 mmHg) blood pressures were included. Some of the standards of the Association for the Advancement of Medical Instrumentation and of the British Hypertension Society were used to evaluate the results of the automated device in clinical practice.

RESULTS

Using Bland-Altman analysis, an underestimation of both measures was observed with the automated Omron 725 CIC device; the systolic pressure was 3.6+/-8.8 mmHg too low with a very wide range of -13.7 to 20.9 and the diastolic pressure was also 4.4+/-6.3 mmHg too low with a range of -8.1 to 16.9. Clinical decisions could have been changed in 24 of the 116 hypertensive patients (20.6%) if the readings of the automated device had been used instead of using the readings of a mercury sphygmomanometer. These could have included modifying the dosage or changing the medicine used.

CONCLUSION

The blood pressure measurements by Omron 725 CIC are different from those of blood pressure readings taken with a mercury sphygmomanometer and this could affect clinical decisions in the diagnosis and follow-up of a hypertensive patient in an office environment.

Arterial blood pressure monitoring in overweight critically ill patients: invasive or noninvasive?

Introduction

Blood pressure measurements frequently guide management in critical care. Direct readings, commonly from a major artery, are considered to be the gold standard. Because arterial cannulation is associated with risks, alternative noninvasive blood pressure (NIBP) measurements are routinely used. However, the accuracy of NIBP determinations in overweight patients in the outpatient setting is variable, and little is known about critically ill patients. This prospective, observational study was performed to compare direct intra-arterial blood pressure (IABP) with NIBP measurements obtained using auscultatory and oscillometric methods in overweight patients admitted to our medical intensive care unit.

Method

Adult critically ill patients with a body mass index (BMI) of 25 kg/m² or greater and a functional arterial line (assessed using the rapid flush test) were enrolled in the study. IABP measurements were compared with those obtained noninvasively. A calibrated aneroid manometer (auscultatory technique) with arm cuffs compatible with arm sizes and a NIBP monitor (oscillometric technique) were used for NIBP measurements. Agreement between methods was assessed using Bland-Altman analysis.

Results

Fifty-four patients (23 males) with a mean (± standard error) age of 57 ± 3 years were studied. The mean BMI was 34.0 ± 1.4 kg/m². Mean arm circumference was 32 ± 0.6 cm. IABP readings were obtained from the radial artery in all patients. Only eight patients were receiving vasoactive medications. Mean overall biases for the auscultatory and oscillometric techniques were 4.1 ± 1.9 and -8.0 ± 1.7 mmHg, respectively (P < 0.0001), with wide limits of agreement. The overestimation of blood pressure using the auscultatory technique was more important in patients with a BMI of 30 kg/m² or greater. In hypertensive patients both NIBP methods underestimated blood pressure as determined using direct IABP measurement.

Conclusion

Oscillometric blood pressure measurements underestimated IABP readings regardless of patient BMI. Auscultatory measurements were also inaccurate, tending to underestimate systolic blood pressure and overestimate mean arterial and diastolic blood pressure. NIBP can be inaccurate among overweight critically ill patients and lead to erroneous interpretations of blood pressure.

[Factors related to the differences in blood pressure values assessed by auscultatory or oscillometric methods]

BACKGROUND AND OBJECTIVE

Measurement of blood pressure by using the auscultatory method coupled with mercury sphygmomanometer is rapidly being replaced for monitor using the oscillometric one. Discrepancies between the two methods and the factors related to them were analyzed in a large subset of adults.

MATERIAL AND METHOD

Blood pressure values were obtained sequentially in the same arm by using a mercury sphygmomanometer and a Spacelabs monitor devices. The relationship between both kinds of measurements was assessed by the Pearson's correlation coefficients and the concordance by using the Bland and Altman method. Differences between the two methods were calculated and the factors related to the differences were sought by multiple regression models.

RESULTS

A total of 1,742 adult subjects were analyzed. Pearson's correlation coefficients were 0.927, 0.922, 0.886, 0.962 for SBP, DBP, MBP and PR, respectively. Oscillometric method overestimate and infraestimate SBP values in the two extreme of SBP values, the lowest SBP the highest the values and vice versa. A similar trend was observed for DBP although the differences were minor. Pulse wave amplitude explains the 24% of the variance observed for SBP and arm circumference the 8% for DBP.

CONCLUSIONS

Blood pressure values measured by oscillometric methods are influenced for pulse wave amplitude and by the arm circumference. These need to be taken in account when blood pressure assessment is obtained by using this method.

[Blood pressure measurement devices used in primary care office]

OBJECTIVE

To know different blood pressure (BP) measurement devices used in primary care (PC).

DESIGN

Cross-sectional study, multilocated, with a non probabilistic sample of consecutive cases selection, all over the country.

SETTING

Primary care practices from all the country.

PARTICIPANTS

PC patients treated and they all were of age.

METHODS

Two consecutive BP measures were made and measurement devices used in this process by physicians were booked.

RESULTS

In this study participated 3592 PC physicians, BP were measured to 14,137 subjects. To a 69.8% of subjects BP were measured with a mercury sphygmomanometer; 16.5% with an electronic device; 11.8% with an aneroid manometer; and a 1.9% were measured with more than one measurement method. In rural environmental, electronic devices and aneroid manometer were used more, and some differences were noted in the different self ruled community in our country. There were differences in BP values in order to measurement methods, a third measurement was made often by physicians who managed electronic devices, and utilization of digits 0 and 5 was higher when measurement method was not an electronic device.

CONCLUSIONS

In PC office, mercury sphygmomanometer is being used preferably and that aneroid manometers are still in use. Their utilization involves important bias in measurement process, so that electronic devices should be promoted.