Oscillometric blood pressure measurement: progress and problems

Cuff-based blood pressure measurement: challenges and solutions

OBJECTIVE

Accurate measurement of arterial blood pressure (BP) is crucial for the diagnosis, monitoring, and treatment of hypertension. This narrative review highlights the challenges associated with conventional (cuff-based) BP measurement and potential solutions. This work covers each method of cuff-based BP measurement, as well as cuffless alternatives, but is primarily focused on ambulatory BP monitoring.

RESULTS

Manual BP measurement requires stringent training and standardized protocols which are often difficult to ensure in stressful and time-restricted clinical office blood pressure monitoring (OBPM) scenarios. Home Blood pressure monitoring (HBPM) can identify white-coat and masked hypertension but strongly depends on patient adherence to measurement techniques and procedure. The widespread use of nonvalidated automated HBPM devices raises further concerns about measurement accuracy. Ambulatory blood pressure measurement (ABPM) may be used in addition to OBPM. It is recommended to diagnose white-coat and masked hypertension as well as nocturnal BP and dipping, which are the BP values most predictive for major adverse cardiac events. Nonetheless, ABPM is limited by its non-continuous nature and susceptibility to measurement artefacts. This leads to poor overall reproducibility of ABPM results, especially regarding clinical parameters such as BP variability or dipping patterns.

CONCLUSIONS

Cuff-based BP measurement, despite some limitations, is vital for cardiovascular health assessment in clinical practice. Given the wide range of methodological limitations, the paradigm's potential for improvement is not yet fully realized. There are impactful and easily incorporated opportunities for innovation regarding the enhancement of measurement accuracy and reliability as well as the clinical interpretation of the retrieved data. There is a clear need for continued research and technological advancement to improve BP measurement as the premier tool for cardiovascular disease detection and management.

Practical Application of a New Cuffless Blood Pressure Measurement Method

It would be useful to develop a reliable method for the cuffless measurement of blood pressure (BP), as such a method could be made available anytime and anywhere for the effective screening and monitoring of arterial hypertension. The purpose of this study is to evaluate blood pressure measurements through a CardioQVARK device in clinical practice in different patient groups.

METHODS

This study involved 167 patients aged 31 to 88 years (mean 64.2 ± 7.8 years) with normal blood pressure, high blood pressure, and compensated high blood pressure. During each session, three routine blood pressure measurements with intervals of 30 s were taken using a sphygmomanometer with an appropriate cuff size, and the mean value was selected for comparison. The measurements were carried out by two observers trained at the same time with a reference sphygmomanometer using a Y-shaped connector. In the minute following the last cuff-based measurements, an electrocardiogram (ECG) with an I-lead and a photoplethysmocardiogram were recorded simultaneously for 3 min with the CardioQVARK device. We compared the systolic and diastolic BP obtained from a cuff-based mercury sphygmomanometer and smartphone-case-based BP device: the CardioQVARK monitor. A statistical analysis plan was developed using the IEEE Standard for Wearable Cuffless Blood Pressure Devices. Bland-Altman plots were used to estimate the precision of cuffless measurements.

RESULTS

The mean difference between the values defined by CardioQVARK and the cuff-based sphygmomanometer for systolic blood pressure (SBP) was 0.31 ± 3.61, while that for diastolic blood pressure (DBP) was 0.44 ± 3.76. The mean absolute difference (MAD) for SBP was 3.44 ± 2.5 mm Hg, and that for DBP was 3.21 ± 2.82 mm Hg. In the subgroups, the smallest error (less than 3 mm Hg) was observed in the prehypertension group, with a slightly larger error (up to 4 mm Hg) found among patients with a normal blood pressure and stage 1 hypertension. The largest error was found in the stage 2 hypertension group (4-5.5 mm Hg). The largest error was 4.2 mm Hg in the high blood pressure group. We, therefore, did not record an error in excess of 7 mmHg, the upper boundary considered acceptable in the IEEE recommendations. We also did not reach a mean error of 5 mmHg, the upper boundary considered acceptable according to the very recent ESH recommendations. At the same time, in all groups of patients, the systolic blood pressure was determined with an error of less than 5 mm Hg in more than 80% of patients. While this study shows that the CardioQVARK device meets the standards of IEEE, the Bland-Altman analysis indicates that the cuffless measurement of diastolic blood pressure has significant bias. The difference was very small and unlikely to be of clinical relevance for the individual patient, but it may well have epidemiological relevance on a population level. Therefore, the CardioQVARK device, while being worthwhile for monitoring patients over time, may not be suitable for screening purposes. Cuffless blood pressure measurement devices are emerging as a convenient and tolerable alternative to cuff-based devices. However, there are several limitations to cuffless blood pressure measurement devices that should be considered. For instance, this study showed a high proportion of measurements with a measurement error of <5 mmHg, while detecting a small, although statistically significant, bias in the measurement of diastolic blood pressure. This suggests that this device may not be suitable for screening purposes. However, its value for monitoring BP over time is confirmed. Furthermore, and most importantly, the easy measurement method and the device portability (integrated in a smartphone) may increase the self-awareness of hypertensive patients and, potentially, lead to an improved adherence to their treatment.

CONCLUSION

The cuffless blood pressure technology developed in this study was tested in accordance with the IEEE protocol and showed great precision in patient groups with different blood pressure ranges. This approach, therefore, has the potential to be applied in clinical practice.

Validation of the JOYTECH DBP-6279B blood pressure monitor in adults and adolescents according to the AAMI/ESH/ISO universal standard(ISO 81060-2:2018 + Amd.1:2020)

This study aimed to validate the accuracy of DBP-6279B, an automated inflationary oscillometric upper-arm blood pressure (BP) monitor, in the sitting position according to the AAMI/ESH/ISO (81060-2 : 2018 + Amd.1 : 2020) universal standard protocol. SBPs and DBPs were measured simultaneously on the same arm in 88 adults (female : male = 47 : 41) with a mean age of 56.85 years using a mercury sphygmomanometer (two observers) and a DBP-6279B device (one supervisor). The AAMI/ESH/ISO 81060-2 : 2018 and Amd.1 : 2020 universal standards for the validation of BP-measuring devices in adults and adolescents were followed. A total of 259 valid pairs of data were used in the analysis. According to Criterion 1, the mean difference of SBP between the test device (DBP-6279B) and the reference device (the mercury sphygmomanometer) was 0.75 mmHg, with a SD of 7.66 mmHg. The mean difference in DBP was 1.13 mmHg, with a SD of 6.14 mmHg. The mean difference of both SBP and DBP was less than 5 mmHg, and the SD was less than 8 mmHg, which met the requirements. According to Criterion 2, the mean difference of SBP between the test device and the reference device was 0.85 mmHg, and the SD was 6.56 mmHg, which was less than 6.88 mmHg and met the requirements. The mean difference in DBP was 1.27 mmHg, and the SD was 5.42 mmHg, which was less than 6.82 mmHg and met the requirements. DBP-6279B fulfilled the requirements of the AAMI/ESH/ISO universal standard (ISO 81060-2 : 2018 + Amd.1 : 2020); hence, it can be recommended for both clinical and self/home BP measurement in adults and adolescents.

Impact of atrial fibrillation on the accuracy of oscillometric blood pressure monitoring in ICU patients from a large real-world database

OBJECTIVES

Oscillometric blood pressure (BP) measurement in atrial fibrillation patients is controversial due to stroke volume variation. Here, we performed a cross-sectional study to investigate the impact of atrial fibrillation on the accuracy of oscillometric BP in the ICU setting.

METHODS

Adult patients with atrial fibrillation or sinus rhythm records were enrolled from Medical Information Mart for Intensive Care-III database. Concurrently recorded noninvasive oscillometric BPs (NIBPs) and intra-arterial BPs (IBPs) were classified as atrial fibrillation or sinus rhythm group according to heart rhythm. Bland-Altmann plots assessed bias and limits of agreement of NIBP to IBP. Pairwise comparison was performed on NIBP/IBP bias between atrial fibrillation and sinus rhythm. Linear mixed-effect model was used to assess the impact of heart rhythm on NIBP/IBP bias after adjusting confounders.

RESULTS

Two thousand, three hundred and thirty-five patients (71.95 ± 11.23 years old, 60.90% were men) were included. Systolic, diastolic, and mean NIBP/IBP biases were not clinically different between atrial fibrillation and sinus rhythm circumstances (SBP bias: 0.66 vs. 1.21 mmHg, P  = 0.002; DBP: -5.29 vs. -5.17, P  = 0.1; mean BP: -4.45 vs. -4.19, P  = 0.01). After adjusting for age, sex, heart rate, arterial BP, and vasopressor usage, the effect of heart rhythm on NIBP/IBP bias was within ±5 mmHg for SBP and DBP [effect on SBP bias: 3.32 mmHg (95% confidence interval (CI) 2.89-3.74), P  < 0.001; DBP: -0.89 (-1.17 to -0.60), P  < 0.001], while the effect on mean BP bias was not significant [0.18 mmHg (-0.10 to 0.46), P  = 0.2].

CONCLUSION

Atrial fibrillation would not influence the agreement of oscillometric BP to IBP in ICU patients compared with sinus rhythm.

Mathematical Modeling of Oscillometric Blood Pressure Measurement: A Complete, Reduced Oscillogram Model

OBJECTIVE

Oscillogram modeling is a powerful tool for understanding and advancing popular oscillometric blood pressure (BP) measurement. A reduced oscillogram model relating cuff pressure oscillation amplitude ( ∆O) to external cuff pressure of the artery ( Pe) is: [Formula: see text], where g(P) is the arterial compliance versus transmural pressure ( P) curve, Ps and Pd are systolic and diastolic BP, and k is the reciprocal of the cuff compliance. The objective was to determine an optimal functional form for the arterial compliance curve.

METHODS

Eight prospective, three-parameter functions of the brachial artery compliance curve were compared. The study data included oscillometric arm cuff pressure waveforms and invasive brachial BP from 122 patients covering a 20-120 mmHg pulse pressure range. The oscillogram measurements were constructed from the cuff pressure waveforms. Reduced oscillogram models, inputted with measured systolic and diastolic BP and each parametric brachial artery compliance curve function, were optimally fitted to the oscillogram measurements in the least squares sense.

RESULTS

An exponential-linear function yielded as good or better model fits compared to the other functions, with errors of 7.9±0.3 and 5.1±0.2% for tail-trimmed and lower half-trimmed oscillogram measurements. Importantly, this function was also the most tractable mathematically.

CONCLUSION

A three-parameter exponential-linear function is an optimal form for the arterial compliance curve in the reduced oscillogram model and may thus serve as the standard function for this model henceforth.

SIGNIFICANCE

The complete, reduced oscillogram model determined herein can potentially improve oscillometric BP measurement accuracy while advancing foundational knowledge.

Concept, hardware development, and clinical trials of a Galinstan based Mercury free sphygmomanometer: Merkfree

The aim of this work is to develop Merkfree-a mercury-free sphygmomanometer that looks, feels, and operates just like a traditional mercury sphygmomanometer (MS). For this we use Galinstan as a substitute for mercury, which is a non-toxic alloy of Gallium, Indium and Tin. Galinstan is nearly half as dense as mercury and sticks to class. To work with the lower density, we designed an enclosure and scale that is nearly double the length of MS. The issue of stickiness with glass was resolved by maintaining a small meniscus of a reducing agent in the measuring tube and tank of Merkfree. Clinical trials to validate the accuracy of Merkfree against MS and oscillometric sphygmomanometer (OS) were conducted over 252 patients. The results show a good correlation of the systolic and diastolic BP measurements from Merkfree with respect to MS and the OS. The mean absolute percentage error is less than 10% for both SBP and DBP. We also found that Merkfree has lower rounding-off errors compared to MS. Merkfree can be a viable alternative to mercury sphygmomanometer that can help achieve the goal of WHO in eliminating mercury from healthcare, while simultaneously making sure that gold standard technique of sphygmomanometry continues to be available to the clinicians.

Tracking Peripheral Artery Motion and Vascular Resistance with a Multi-Modal Wearable Sensor Under Pressure Perturbations

Peripheral artery status is a key physiological indicator of the body's cardiovascular response to both acute and chronic medical conditions. In this paper, peripheral artery behavior is tracked non-invasively by combining a photo plethysmograph (PPG) sensor and a piezoelectric (polyvinylidene difluoride, PVDF) sensor, while applying an outside pressure-varying cuff. A simple mechanical model for the local artery and tissue captures time- and pressure-dependent features present in the PPG and PVDF signals with respect to applied cuff pressure, during maneuvers applied to multiple swine subjects to perturb blood pressure and vascular resistance. These behaviors provide insight into feasibility and robustness of cardiovascular property identification by multi-modal non-invasive wearable sensing. This is found to help refine non-invasive blood pressure measurements and estimation of systemic vascular resistance (SVR) and blood pressure (BP) using selected features of sensor amplitude versus applied cuff pressure.

Evaluation of correlation between digital vs. mercury sphygmomanometer in a middle-income country: The role of socio-economic situation

BACKGROUND

Using manometer sphygmomanometers as standard measurement tool, there are controversial data regarding accuracy and validity of digital manometers for measurement of systolic (SBP) and diastolic blood pressure (DBP). Thus, we aimed to compare the accuracy of readings of digital sphygmomanometer in reference to mercury sphygmomanometer in a large population of healthy adults.

METHODS AND MATERIALS

This cross-sectional study was performed on 1119 healthy adults. We measured participant's blood pressure once with mercury sphygmomanometer, as gold standard and again with digital mercury sphygmomanometer. Blood pressure was measured in sitting position after 5 min of rest and preferentially from right arm unless deformed.

RESULTS

The mean ± standard deviation of age of participants was 37.25 ± 10.45 years. Majority of participants were male 588 (52.5%). The right/left SBP measured by digital sphygmomanometer were significantly higher compared with those measured by mercury sphygmomanometer: 115.37 ± 12.33 vs 110.95 ± 10.06/113.69 ± 11.77 vs 110.23 ± 10.34, respectively (P < .001), while an opposite result was observed about right/left DBP: 68.60 ± 8.55 vs 70.60 ± 8.31/69.39 ± 8.31 vs 70.75 ± 8.41, respectively (P < .001). In subgroup analysis in terms of marital status, education, and income, we observed similar findings.

CONCLUSION

According to the results of our data analysis, it was shown that the digital device measurements had significant incompatibility with the mercury sphygmomanometers and it seems that digital devices still cannot be used as the gold standard in blood pressure measurement.

Influence of aging and increased blood pressure on oscillometric cuff pressure waveform characteristics

BACKGROUND

The oscillometric blood pressure (BP) measurement technique estimates BPs from analyzing the envelop of oscillometric cuff pressure waveform. The oscillometric waveform envelope shape is associated with physiological changes and influences BP measurement accuracy. The aim of this study was to comprehensively quantify BP- and age-related changes of oscillometric waveform envelope characteristics.

METHOD

Manual systolic and diastolic BPs were measured from 472 patients (219 female, 253 male), and the cuff pressure were digitally recorded during linear cuff deflation that was used to derive oscillometric waveform envelopes. All patients were divided into different categories according to their BP level and age. The envelope width in high-pressure region (above mean arterial pressure, MAP) and low-pressure region (below MAP) were compared between different BP and age categories to qualify their changes with increased BP and aging.

RESULTS

The envelop widths increased significantly with increased BPs (P < 0.001 between optimal, normotensive and hypertensive groups) and aging (P < 0.001 for >50 years old group in comparison with younger groups). The envelope widths in high-pressure region were significantly larger than in low-pressure region in normal and hypertensive categories (all P < 0.05) and elderly patients aged over 60 years (all P < 0.001), and the envelope width ratios between them increased with increased BP and aging.

CONCLUSION

This study has concluded an asymmetrical oscillometric waveform envelope in normotensive and hypertensive categories, as well as in elderly group (aged over 60 years), and their asymmetrical features were significantly more obvious with increased BP and aging.

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.

From palpation of the pulse to cuff-free methods: evolution of arterial pressure measurement methods

The arterial pressure is an important physiological indicator. The review describes the different techniques of measurement of arterial pressure, their advantages and limitations. Moreover, it also represents a historical reference about the main stage of the development of clinical sphygmomanometrya that nowadays is a relevant method for measuring arterial pressure. The emergence and the development of devices for daily monitoring of arterial pressure and modern techniques for non-invasive arterial pressure measurement are described too.

Optimum waveform envelopes and amplitude ratios in oscillometric blood pressure estimation

OBJECTIVE

To determine if, when using the oscillometric method, there is a specific range of amplitude ratios in the fixed-ratio algorithm that will result in blood pressure estimates that consistently fall within a mean error ≤5 mmHg and a SD of the error <8 mmHg. Additionally, to apply different representations of the oscillometric waveform envelope to verify if this will affect the accuracy of the results.

METHODS

SBP and DBP were obtained using the fixed-ratios method applied to a dataset of 219 oscillometric measurements obtained from 73 healthy volunteers and compared to their corresponding auscultation values. Ratio and envelope analysis were done on Matlab (The MathWorks, Inc., Natick, Massachusetts, USA).

RESULTS

Depending on the envelope representation, ratios between 0.44-0.74 for systolic pressure and 0.51-0.85 for diastolic pressure yield results within the limits mentioned above. When a set of optimum envelope representations and ratios are selected based on population mean, the highest percentage of subjects presenting blood pressure estimates within the limits were 72.6% for systolic and 69.9% for diastolic.

CONCLUSION

The range of ratios presenting optimum results appears to be independent of the degree of arterial stiffness given the wide range of ages of the subjects in the study. Different representations of the oscillometric waveform envelope may improve the accuracy of the method. However, there remains a considerable percentage of the population with unreliable results. It is therefore important to only use devices that have been properly validated according to standard protocol.

Formulas to Explain Popular Oscillometric Blood Pressure Estimation Algorithms

Oscillometry is the blood pressure (BP) measurement principle of most automatic cuff devices. The oscillogram (which is approximately the blood volume oscillation amplitude-external pressure function) is measured, and BP is then estimated via an empirical algorithm. The objective was to establish formulas to explain three popular empirical algorithms in the literature—the maximum amplitude, derivative, and fixed ratio algorithms. A mathematical model of the oscillogram was developed and analyzed to derive parametric formulas for explaining each algorithm. Exemplary parameter values were obtained by fitting the model to measured oscillograms. The model and formulas were validated by showing that their predictions correspond to measurements. The formula for the maximum amplitude algorithm indicates that it yields a weighted average of systolic and diastolic BP (0.45 and 0.55 weighting) instead of commonly assumed mean BP. The formulas for the derivative algorithm indicate that it can accurately estimate systolic and diastolic BP (<1.5 mmHg error), if oscillogram measurement noise can be obviated. The formulas for the fixed ratio algorithm indicate that it can yield inaccurate BP estimates, because the ratios change substantially (over a 0.5–0.6 range) with arterial compliance and pulse pressure and error in the assumed ratio translates to BP error via large amplification (>40). The established formulas allow for easy and complete interpretation of perhaps the three most popular oscillometric BP estimation algorithms in the literature while providing new insights. The model and formulas may also be of some value toward improving the accuracy of automatic cuff BP measurement devices.

Smartphone-based blood pressure monitoring via the oscillometric finger-pressing method

High blood pressure (BP) is a major cardiovascular risk factor that is treatable, yet hypertension awareness and control rates are low. Ubiquitous BP monitoring technology could improve hypertension management, but existing devices require an inflatable cuff and are not compatible with such anytime, anywhere measurement of BP. We extended the oscillometric principle, which is used by most automatic cuff devices, to develop a cuff-less BP monitoring device using a smartphone. As the user presses her/his finger against the smartphone, the external pressure of the underlying artery is steadily increased while the phone measures the applied pressure and resulting variable-amplitude blood volume oscillations. A smartphone application provides visual feedback to guide the amount of pressure applied over time via the finger pressing and computes systolic and diastolic BP from the measurements. We prospectively tested the smartphone-based device for real-time BP monitoring in human subjects to evaluate usability (n = 30) and accuracy against a standard automatic cuff-based device (n = 32). We likewise tested a finger cuff device, which uses the volume-clamp method of BP detection. About 90% of the users learned the finger actuation required by the smartphone-based device after one or two practice trials. The device yielded bias and precision errors of 3.3 and 8.8 mmHg for systolic BP and -5.6 and 7.7 mmHg for diastolic BP over a 40 to 50 mmHg range of BP. These errors were comparable to the finger cuff device. Cuff-less and calibration-free monitoring of systolic and diastolic BP may be feasible via a smartphone.

Calibration methods of new device for human blood pressure measurement

The paper presents two methods of determining calibration curve of a new device for blood pressure measurement. The device was developed at Wrocław University of Science and Technology. First method is based on parallel measurement of systolic and diastolic pressure measurement with use of reference device such as sphygmomanometer and researched new device with pneumatic sensor equipped with voltage type output. Obtained data (systolic ps and diastolic pd pressure, maximum us and minimum ud voltage) was then used to determine individual pressure-voltage characteristic of the device, which can be represented as a linear equation. Second method is based on substitution of experimentally proved coefficient b with its analytical equivalent extracted from mathematical model of described pneumatic sensor. Described methods were verified experimentally and compared. Metrological parameters of the device were designated.

Improvements in Body Composition after 4 Years of Growth Hormone Treatment in Adult-Onset Hypopituitarism Compared to Age-Matched Controls

BACKGROUND/AIMS

It is unknown whether long-term growth hormone replacement therapy (GHRT) affects body composition in an age- or sex-dependent manner. We aimed to study the effects of 4 years of GHRT on body composition in a large cohort of patients with hypopituitarism compared to a reference population matched by age and sex.

METHODS

A total of 964 GH-deficient adults from KIMS (Pfizer International Metabolic Database) with adult-onset hypopituitarism, adequately replaced with all pituitary hormones except for GH at baseline were included. A random sample of the general population (2,301 subjects) from a similar time period was used as reference. Patients and controls were grouped by sex in 5 age cohorts of 10 years. Main outcome measures were changes in BMI and waist circumference after 4 years of GHRT.

RESULTS

In younger patients (28-47 years), 4 years of GHRT resulted in a BMI increase similar to that observed in the reference population, but older patients (48-67 years) had significantly less BMI increase than age-matched healthy controls. Significant differences were seen in waist circumference in patients of all age cohorts who showed virtually no change after 4 years of GHRT compared to approximately 4 cm of increase in the reference population.

CONCLUSION

Four years of GHRT resulted in improvements in BMI and waist circumference in patients with adult-onset hypopituitarism compared to age-matched controls observed during the same follow-up time. Despite these beneficial effects on body composition, BMI and waist circumference remained higher in patients on GHRT compared to healthy controls.

Noninvasive Blood Pressure Estimation Using Ultrasound and Simple Finite Element Models

OBJECTIVE

Many commercially available arterial blood pressure measurement devices suffer from a range of weaknesses. For example, common weaknesses include being inaccurate, invasive, and ad hoc; many also require explicit user calibration or cut off blood flow to a limb. A novel algorithmic approach is presented to accurately estimate systolic and diastolic blood pressure in a way that does not require any explicit user calibration, is noninvasive, and does not cut off blood flow.

METHODS

The approach uses ultrasound images of the arterial wall and corresponding contact force data to obtain blood pressure estimates. To acquire data, an ultrasound probe was placed on the patient's carotid artery and the contact force was increased from 1.5 to 12 N. The artery was then algorithmically segmented from the recorded DICOM B-Mode data. The segmentation data and the contact force were used as input into the Levenberg-Marquardt optimization method to solve for the parameters, including blood pressure, of a simple finite element model of the carotid artery.

RESULTS

The algorithm was validated on 24 healthy volunteers. Algorithm arterial blood pressure predictions were compared to oscillometric blood pressure cuff readings. Regression and Bland-Altman analyses were performed on the data.

CONCLUSION

Both systolic pressure and diastolic pressure can be estimated using this novel noninvasive ultrasound-based method (systolic accuracy/precision: $-$ 2.36 mmHg/10.21 mmHg; diastolic accuracy/precision: $-$ 0.32/8.23 mmHg).

SIGNIFICANCE

The method occupies a clinical middle ground between the arterial catheter and cuff-based techniques. It has the potential to give accurate results for patients with hypertension and atherosclerosis.

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.

Development and Validation of a Novel Cuff-Less Blood Pressure Monitoring Device

•

As a joint project between industry and academia, we are developing a CLB that enables BP measurement continuously and noninvasively by capturing photoplethysmographical biosignals.

•

To validate the estimation of BP using a CLB in accordance with the latest wearable device standard issued by the Institute of Electrical and Electronics Engineers (IEEE 1708-2014).

•

We found that CLB is technically comparable to the ordinary cuff-based BP-measuring device.

•

CLB will apply for wearable health care monitoring device that may change landscape of BP measurements in terms of continuous and stress-free monitoring.

Ordinary cuff-based blood pressure–monitoring devices remain a technical limitation that disturbs activities of daily life. Here we report a novel system for the cuff-less blood pressure estimation (CLB) that requires only 1 sensor for photoplethysmography. The present study is the first report to validate and assess the clinical application of the CLB in accordance with the latest wearable device standard (issued by the Institute of Electrical and Electronics Engineers, standard 1708-2014). Our CLB is expected to offer a flexible and wearable device that permits blood pressure monitoring in more continuous and stress-free settings.

Stroke Volume Monitoring: Novel Continuous Wave Doppler Parameters, Algorithms and Advanced Noninvasive Haemodynamic Concepts

PURPOSE OF REVIEW

Adequate oxygen delivery is essential for life, with hypoxia resulting in dysfunction, and ultimately death, of the cells, organs and organism. Blood flow delivers the oxygen bound in the blood, while haemodynamics is the science of blood flow. Stroke volume (SV) is the fundamental unit of blood flow, and reflects the interdependent performance of the heart, the vessels and the autonomic nervous system. However, haemodynamic management remains generally poor and predominantly guided by simple blood pressure observations alone.

RECENT FINDINGS

Doppler ultrasound measures SV with unequalled clinical precision when operated by trained personnel. Combining SV with BP measurements allows calculation of flow-pressure based measures which better reflect cardiovascular performance and allows personalised physiologic and pathophysiologic modelling consistent with Frank's and Starling's observations.

SUMMARY

Doppler SV monitoring and novel flow-pressure parameters may improve our understanding of the cardiovascular system and lead to improved diagnosis and therapy. This review examines the physics and practice of Doppler SV monitoring and its application in advanced haemodynamics.

Central Blood Pressure Monitoring via a Standard Automatic Arm Cuff

Current oscillometric devices for monitoring central blood pressure (BP) maintain the cuff pressure at a constant level to acquire a pulse volume plethysmography (PVP) waveform and calibrate it to brachial BP levels estimated with population average methods. A physiologic method was developed to further advance central BP measurement. A patient-specific method was applied to estimate brachial BP levels from a cuff pressure waveform obtained during conventional deflation via a nonlinear arterial compliance model. A physiologically-inspired method was then employed to extract the PVP waveform from the same waveform via ensemble averaging and calibrate it to the brachial BP levels. A method based on a wave reflection model was thereafter employed to define a variable transfer function, which was applied to the calibrated waveform to derive central BP. This method was evaluated against invasive central BP measurements from patients. The method yielded central systolic, diastolic, and pulse pressure bias and precision errors of -0.6 to 2.6 and 6.8 to 9.0 mmHg. The conventional oscillometric method produced similar bias errors but precision errors of 8.2 to 12.5 mmHg (p ≤ 0.01). The new method can derive central BP more reliably than some current non-invasive devices and in the same way as traditional cuff BP.

More accurate systolic blood pressure measurement is required for improved hypertension management: a perspective

The commonly used techniques for systolic blood pressure (SBP) and diastolic blood pressure (DBP) measurement are the auscultatory Korotkoff-based sphygmomanometry and oscillometry. The former technique is relatively accurate but is limited to a physician's office because its automatic variant is subject to noise artifacts. Consequently, the Korotkoff-based measurement overestimates the blood pressure in some patients due to white coat effect, and because it is a single measurement, it cannot properly represent the variable blood pressure. Automatic oscillometry can be used at home by the patient and is preferred even in clinics. However, the technique's accuracy is low and errors of 10-15 mmHg are common. Recently, we have developed an automatic technique for SBP measurement, based on an arm pressure cuff and a finger photoplethysmographic probe. The technique was found to be significantly more accurate than oscillometry, and comparable to the Korotkoff-based technique, the reference-standard for non-invasive blood pressure measurements. The measurement of SBP is a mainstay for the diagnosis and follow-up of hypertension, which is a major risk factor for several adverse events, mainly cardiovascular. Lowering blood pressure evidently reduces the risk, but excessive lowering can result in hypotension and consequently hypoperfusion to vital organs, since blood pressure is the driving force for blood flow. Erroneous measurement by 10 mmHg can lead to a similar unintended reduction of SBP and may adversely affect patients treated to an SBP of 120-130 mmHg. In particular, in elderly patients, unintended excessive reduction of blood pressure due to inaccurate SBP measurement can result in cerebral hypoperfusion and consequent cognitive decline. By using a more accurate technique for automatic SBP measurement (such as the photoplethysmographic-based technique), the optimal blood pressure target can be achieved with lower risk for hypotension and its adverse events.

Patient-Specific Oscillometric Blood Pressure Measurement: Validation for Accuracy and Repeatability

Oscillometric devices are widely used for automatic cuff blood pressure (BP) measurement. These devices estimate BP from the oscillometric cuff pressure waveform using population average methods. Hence, the devices may only be accurate over a limited BP range. The objective was to evaluate a new patient-specific method, which estimates BP by fitting a physiologic model to the same waveform. One-hundred and forty-five cardiac catheterization patients and normal adults were included for study. The oscillometric cuff pressure waveform was obtained with an office device, while reference BP was measured via brachial artery catheterization or auscultation, during baseline and/or nitroglycerin administration. Fifty-seven of the subject records were utilized for refining the patient-specific method, while the remaining 88 subject records were employed for evaluation. The precision errors for all BP levels of the patient-specific method ranged from 6.3 to 7.6 mmHg. These errors were significantly lower than those of the office device (by 29% on average) in subjects with high pulse pressure (>50 mmHg) while being comparable to those of the device in subjects with normal pulse pressure (<50 mmHg). The bias and precision of the differences in repeated estimates for all BP levels of the patient-specific method ranged from 0.1 to 1.1 and 2.1 to 5.9 mmHg, respectively. These precision differences were significantly lower than those of the office device (by 64% on average). The patient-specific method may afford more accurate automatic cuff BP measurement in patients with large artery stiffening while limiting the number of required cuff inflations/deflations per measurement.

The agreement between oscillometric and intra-arterial technique for blood pressure monitoring in the lower extremities for infants and toddlers undergoing aortic coarctation repair

OBJECTIVE

Anesthetic management for patients undergoing surgical repair of aortic coarctation (CoA) should include constant blood pressure monitoring of the right upper extremity and a lower extremity. The delayed or absent pulse in the lower limbs often leads to unsuccessful arterial cannulation in infants and the oscillometric technique used for blood pressure measurement. The aim of this study was to evaluate the agreement between the oscillometric method and intra-arterial technique for blood pressure monitoring in the lower limbs of infants undergoing CoA.

METHODS

A total of 45 infants diagnosed with isolated CoA were initially enrolled in this study and five were excluded because of cannulation failure. Thus, 40 patients had their blood pressure measured simultaneously by both oscillometric technique on the thigh and femoral artery catheterization. After induction and intubation, five pairs of blood pressure readings from each patient were collected in an interval of 3 min. Statistical analysis was accomplished by revised Bland-Altman analysis.

RESULTS

There was a strong correlation between oscillometric and invasive blood pressure measurements [systolic blood pressure (SBP) r = 0.771, diastolic blood pressure (DBP) r = 0.704 and mean artery pressure (MAP) r = 0.850]. The mean difference and 95% limits of agreement (95% LOA) between oscillometric and femoral artery blood pressure readings was 3.830 mmHg (-19.297, 26.957) for SBP, -8.725 mmHg (-26.236, 8.786) for DBP, and -3.235 mmHg (-18.842, 12.372) for MAP. There were only one pair of MAP (1/40) and two pairs of SBP readings (2/40) out of range (95% LOA), and all of paired DBP readings were within 95% LOA.

CONCLUSION

There was a good agreement between oscillometric and invasive blood pressure measurements of lower extremities in infants with isolated CoA statistically. However, the oscillometry-measured SBP showed a tendency to overestimate the intra-arterial blood pressure reference, while oscillometry-measured DBP underestimated its reference. MAP measurement provided the most accurate and reliable results in this study.

Validation of inflationary noninvasive blood pressure monitoring in the emergency room

Objective

The aim of this study was to compare the values of a noninvasive blood pressure (NIBP) measurement during cuff inflation (inflationary NIBP) and deflationary NIBP measurements and to verify whether inflationary NIBP is equivalent to conventional deflationary NIBP and is acceptable for clinical use in the emergency room (ER).

Materials and methods

A total of 2981 NIBP data points were collected from 175 patients (age, 56.5±22.2 years; range, 7–92 years) who had been treated in the resuscitation area of the ER at Keio University Hospital. The data points were obtained using two alternate algorithms with a standard monitor (BSM-6000). One algorithm consisted of continuous inflationary and deflationary measurements in a single cycle (dual algorithm, 1502 data points); this algorithm was used to verify the success rate and the precision of the data. The second algorithm (1479 data points) consisted of only conventional deflationary measurements and was used to verify the duration of the measurement cycle.

Results

The success rate of the inflationary NIBP (completed using only the inflationary method) was 69.0%. Failures in the inflationary measurements were caused by arrhythmia and/or body motions. The mean difference and SD of the systolic pressure and the diastolic pressure between inflationary NIBP and deflationary NIBP were −0.6±8.8 and 3.5±7.5 mmHg, respectively. The confidence intervals were −0.6 (95% confidence interval=−1.1 to −0.1) and 3.5 (95% confidence interval=3.0 to 4.0) mmHg. The coefficients of correlation were 0.96 and 0.93. Inflationary NIBP was capable of determining the NIBP more quickly compared with deflationary NIBP (average of 15.9 vs. 34.2 s; P<0.05).

Conclusion

Inflationary NIBP measurements have a reasonable accuracy and a sufficient rapidity, compared with deflationary NIBP measurements, in ER patients.

A new automatic blood pressure kit auscultates for accurate reading with a smartphone: A diagnostic accuracy study

The widely used oscillometric automated blood pressure (BP) monitor was continuously questioned on its accuracy. A novel BP kit named Accutension which adopted Korotkoff auscultation method was then devised. Accutension worked with a miniature microphone, a pressure sensor, and a smartphone. The BP values were automatically displayed on the smartphone screen through the installed App. Data recorded in the phone could be played back and reconfirmed after measurement. They could also be uploaded and saved to the iCloud. The accuracy and consistency of this novel electronic auscultatory sphygmomanometer was preliminarily verified here. Thirty-two subjects were included and 82 qualified readings were obtained. The mean differences ± SD for systolic and diastolic BP readings between Accutension and mercury sphygmomanometer were 0.87 ± 2.86 and -0.94 ± 2.93 mm Hg. Agreements between Accutension and mercury sphygmomanometer were highly significant for systolic (ICC = 0.993, 95% confidence interval (CI): 0.989-0.995) and diastolic (ICC = 0.987, 95% CI: 0.979-0.991). In conclusion, Accutension worked accurately based on our pilot study data. The difference was acceptable. ICC and Bland-Altman plot charts showed good agreements with manual measurements. Systolic readings of Accutension were slightly higher than those of manual measurement, while diastolic readings were slightly lower. One possible reason was that Accutension captured the first and the last korotkoff sound more sensitively than human ear during manual measurement and avoided sound missing, so that it might be more accurate than traditional mercury sphygmomanometer. By documenting and analyzing of variant tendency of BP values, Accutension helps management of hypertension and therefore contributes to the mobile heath service.

A survey of blood pressure parameters after aneurysmal subarachnoid hemorrhage

Purpose/aim: Blood pressure (BP) regulation is recommended following aneurysmal subarachnoid hemorrhage (aSAH) to prevent re-bleeding and to treat delayed cerebral ischemia. However, optimal BP thresholds are not well established. There is also variation with regard to the BP component (e.g. systolic vs. mean) that is targeted or manipulated.

MATERIALS AND METHODS

An 18-question survey was distributed to physicians and advanced practitioner members of the Neurocritical Care Society. Respondents were asked which BP parameter they manipulated and what their thresholds were in different clinical scenarios. They were also asked whether they were influenced by the presence of incidental aneurysms. Answers were analyzed for differences in training background and treatment setting.

RESULTS

There were 128 responses. The majority were neurointensivists (47 neurology and 37 non-neurology) and treated patients in dedicated neurointensive care units (n = 98). Systolic BP (SBP) was preferred over mean arterial pressure (MAP). Prior to aneurysm treatment, SBP limits ranged from 140 to 180 mm Hg. After aneurysm treatment, SBP limits ranged from 160 to 240 mm Hg. The maximum and minimum MAPs varied by as much as 50%. Nearly two-thirds of the respondents were influenced by the presence of incidental aneurysms. Training background influenced tolerance to BP limits with neurology-trained neurointensivists accepting higher BP limits when treating delayed ischemia ( p = .018). They were also more likely to follow SBP ( p = .018) and have a limit of 140 mm Hg prior to aneurysm treatment ( p = .001).

CONCLUSIONS

There is large practice variability in BP management following aSAH. There is also uncertainty over the importance of incidental aneurysms. Further research could evaluate whether this variability has clinical significance.

Patient-Specific Oscillometric Blood Pressure Measurement

OBJECTIVE

Most automatic cuff blood pressure (BP) measurement devices are based on oscillometry. These devices estimate BP from the envelopes of the cuff pressure oscillations using fixed ratios. The values of the fixed ratios represent population averages, so the devices may only be accurate in subjects with normal BP levels. The objective was to develop and demonstrate the validity of a patient-specific oscillometric BP measurement method.

METHODS

The idea of the developed method was to represent the cuff pressure oscillation envelopes with a physiologic model, and then estimate the patient-specific parameters of the model, which includes BP levels, by optimally fitting it to the envelopes. The method was investigated against gold standard reference BP measurements from 57 patients with widely varying pulse pressures. A portion of the data was used to optimize the patient-specific method and a fixed-ratio method, while the remaining data were used to test these methods and a current office device.

RESULTS

The patient-specific method yielded BP root-mean-square-errors ranging from 6.0 to 9.3 mmHg. On an average, these errors were nearly 40% lower than the errors of each existing method.

CONCLUSION

The patient-specific method may improve automatic cuff BP measurement accuracy.

SIGNIFICANCE

A patient-specific oscillometric BP measurement method was proposed and shown to be more accurate than the conventional method and a current device.

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.

Effect of peripheral edema on oscillometric blood pressure measurement

INTRODUCTION

Blood pressure (BP) measurement is essential for epidemiological studies and clinical decisions. It seems that tissue characteristics can affect BP results and we try to find edema effect on BP results taken by different methods.

METHODS

BP of 55 children before open heart surgery were measured and compared according to three methods: Arterial as standard and reference, oscillometric and auscultatory methods. Peripheral edema as a tissue characteristic was defined in higher than +2 as marked edema and in equal or lower than +2 as no edema.

STATISTICAL ANALYSES

data was expressed as Mean and 95% of confidence interval (CI 95%). Comparison of two groups was performed by T independent test and of more than two groups by ANOVA test. Mann-Whitney U and paired T-test were used for serially comparisons of changes. P less than 0.05 was considered significant.

RESULTS

Fifty five children aged 29.4±3.9 months were divided into two groups: 10 children with peripheral edema beyond +2 and 45 cases without edema. Oscillometric method overestimated systolic BP and the Mean (CI 95%) difference of oscillometric to arterial was 4.8 (8/-1, P=0.02) in edematous and 4.2 (7/1, p=0.004) in non edematous. Oscillometric method underestimated diastolic BP as -9 (-1.8/-16.5, P=0.03) in edematous group and 2.6 (-0.7/+5, P= 0.2) in non edematous compared to arterial method.

CONCLUSION

Oscillometric device standards cannot cover all specific clinical conditions. It underestimates diastolic BP significantly in edematous children, which was 9.2 mmHg in average beyond the acceptable standards.

Noninvasive techniques for blood pressure measurement are not a reliable alternative to direct measurement: a randomized crossover trial in ICU

INTRODUCTION

Noninvasive blood pressure (NIBP) monitoring methods are widely used in critically ill patients despite poor evidence of their accuracy. The erroneous interpretations of blood pressure (BP) may lead to clinical errors.

OBJECTIVES

To test the accuracy and reliability of aneroid (ABP) and oscillometric (OBP) devices compared to the invasive BP (IBP) monitoring in an ICU population.

MATERIALS AND METHODS

Fifty adult patients (200 comparisons) were included in a randomized crossover trial. BP was recorded simultaneously by IBP and either by ABP or by OBP, taking IBP as gold standard.

RESULTS

Compared with ABP, IBP systolic values were significantly higher (mean difference ± standard deviation 9.74 ± 13.8; P < 0.0001). Both diastolic (-5.13 ± 7.1; P < 0.0001) and mean (-2.14 ± 7.1; P=0.0033) IBP were instead lower. Compared with OBP, systolic (10.80 ± 14.9; P < 0.0001) and mean (5.36 ± 7.1; P < 0.0001) IBP were higher, while diastolic IBP (-3.62 ± 6.0; P < 0.0001) was lower. Bland-Altman plots showed wide limits of agreement in both NIBP-IBP comparisons.

CONCLUSIONS

BP measurements with different devices produced significantly different results. Since in critically ill patients the importance of BP readings is often crucial, noninvasive techniques cannot be regarded as reliable alternatives to direct measurements.

Characteristics of hypertension subtypes and treatment outcome among elderly Korean hypertensives

There are limited data about characteristics of hypertension subtypes in Asian hypertensive patients and their impacts on treatment of hypertension. This prospective, multi-center, observational study evaluated 2439 hypertensive patients. (≥60 years) Inadequately controlled and drug-naïve patients were categorized into three hypertension subtypes (isolated systolic hypertension [ISH], combined systolic/diastolic hypertension [SDH], and isolated diastolic hypertension [IDH]), and proportions of each hypertension subtype were evaluated. After 6-month strict treatments, we compared the characteristics of patients who did not achieve target BP with those who did. In overall population, ISH was the most common subtype (53.2%; 1297/2439). However, in drug-naïve patients, SDH was the predominant hypertension subtype (59.6%; 260/436). Notably, the proportion of ISH was substantially lower than previously known data. Predictors associated with failure of reaching target BP were old age (>70 years), hypertension awareness, and baseline systolic blood pressure (≥160 mm Hg) for total patients. In drug naïve patients, hypertension awareness, ISH, and microalbuminuria were associated with treatment failure. These findings might have an impact on the evaluations and antihypertensive treatments of elderly Korean patients.

Fluid challenge: tracking changes in cardiac output with blood pressure monitoring (invasive or non-invasive)

PURPOSE

To assess whether invasive and non-invasive blood pressure (BP) monitoring allows the identification of patients who have responded to a fluid challenge, i.e., who have increased their cardiac output (CO).

METHODS

Patients with signs of circulatory failure were prospectively included. Before and after a fluid challenge, CO and the mean of four intra-arterial and oscillometric brachial cuff BP measurements were collected. Fluid responsiveness was defined by an increase in CO ≥10 or ≥15% in case of regular rhythm or arrhythmia, respectively.

RESULTS

In 130 patients, the correlation between a fluid-induced increase in pulse pressure (Δ500mlPP) and fluid-induced increase in CO was weak and was similar for invasive and non-invasive measurements of BP: r² = 0.31 and r² = 0.29, respectively (both p < 0.001). For the identification of responders, invasive Δ500mlPP was associated with an area under the receiver-operating curve (AUC) of 0.82 (0.74-0.88), similar (p = 0.80) to that of non-invasive Δ500mlPP [AUC of 0.81 (0.73-0.87)]. Outside large gray zones of inconclusive values (5-23% for invasive Δ500mlPP and 4-35% for non-invasive Δ500mlPP, involving 35 and 48% of patients, respectively), the detection of responsiveness or unresponsiveness to fluid was reliable. Cardiac arrhythmia did not impair the performance of invasive or non-invasive Δ500mlPP. Other BP-derived indices did not outperform Δ500mlPP.

CONCLUSIONS

As evidenced by large gray zones, BP-derived indices poorly reflected fluid responsiveness. However, in our deeply sedated population, a high increase in invasive pulse pressure (>23%) or even in non-invasive pulse pressure (>35%) reliably detected a response to fluid. In the absence of a marked increase in pulse pressure (<4-5%), a response to fluid was unlikely.

Impact of Atrial Fibrillation on the Accuracy of Oscillometric Blood Pressure Monitoring

The introduction of automated oscillometric blood pressure monitors was the basis for today’s widespread use of blood pressure self-measurement. However, in atrial fibrillation, there is a controversial debate on the use of oscillometry because there is a high variability of heart rate and stroke volume. To date, the accuracy of oscillometric blood pressure monitoring in atrial fibrillation has only been investigated using auscultatory sphygmomanometry as reference method, which may be biased by arrhythmia as well. We performed a cross-sectional study in 102 patients (52 sinus rhythm, 50 atrial fibrillation) assessing the accuracy of an automated and validated oscillometric upper arm (M5 Professional, Omron) and wrist device (R5 Professional, Omron) to invasively assessed arterial pressure. Blood pressure values were calculated as the mean of 3 consecutive measurements. Systolic and diastolic blood pressure did not significantly differ in patients with sinus rhythm and atrial fibrillation, independent of the method of measurement ( P >0.05 each). The within-subject variability of the oscillometric measurements was higher in patients with atrial fibrillation compared with sinus rhythm ( P <0.01 each). The biases of systolic and diastolic blood pressure, however, did not significantly differ in presence or absence of atrial fibrillation in Bland-Altmann analysis ( P >0.05 each). In conclusion, atrial fibrillation did not significantly affect the accuracy of oscillometric measurements, if 3 repeated measurements were performed.

Patterns of care and persistence after incident elevated blood pressure

BACKGROUND AND OBJECTIVE

Screening for hypertension in children occurs during routine care. When blood pressure (BP) is elevated in the hypertensive range, a repeat measurement within 1 to 2 weeks is recommended. The objective was to assess patterns of care after an incident elevated BP, including timing of repeat BP measurement and likelihood of persistently elevated BP.

METHODS

This retrospective study was conducted in 3 health care organizations. All children aged 3 through 17 years with an incident elevated BP at an outpatient visit during 2007 through 2010 were identified. Within this group, we assessed the proportion who had a repeat BP measured within 1 month of their incident elevated BP and the proportion who subsequently met the definition of hypertension. Multivariate analyses were used to identify factors associated with follow-up BP within 1 month of initial elevated BP.

RESULTS

Among 72,625 children and adolescents in the population, 6108 (8.4%) had an incident elevated BP during the study period. Among 6108 with an incident elevated BP, 20.9% had a repeat BP measured within 1 month. In multivariate analyses, having a follow-up BP within 1 month was not significantly more likely among individuals with obesity or stage 2 systolic elevation. Among 6108 individuals with an incident elevated BP, 84 (1.4%) had a second and third consecutive elevated BP within 12 months.

CONCLUSIONS

Whereas >8% of children and adolescents had an incident elevated BP, the great majority of BPs were not repeated within 1 month. However, relatively few individuals subsequently met the definition of hypertension.