Blood Pressure Measurement Technique Research Articles

Monitoring blood vital bio signs using secondary speckle patterns

Continuous noninvasive measurement of vital bio-signs, such as cardiopulmonary parameters, is an important tool in the evaluation process of the patient's physiological condition and in the health monitoring of the patient. On the demand of new enabling technologies, some works have been done in continuous monitoring of blood pressure and pulse wave velocity. In this paper, we introduce further application of a novel technique for remote noncontact blood pulse wave velocity and pressure measurement based on tracking the temporal changes of reflected secondary speckle patterns produced in human skin when illuminated by a laser beam. The main goal of this work is to offer novel, simple and low cost measurement tool which will indicate changes in condition of the cardiovascular system after having an initial calibration.

Monitoring blood vital bio signs using secondary speckle patterns.

Continuous noninvasive measurement of vital bio-signs, such as cardiopulmonary parameters, is an important tool in the evaluation process of the patient's physiological condition and in the health monitoring of the patient. On the demand of new enabling technologies, some works have been done in continuous monitoring of blood pressure and pulse wave velocity. In this paper, we introduce further application of a novel technique for remote noncontact blood pulse wave velocity and pressure measurement based on tracking the temporal changes of reflected secondary speckle patterns produced in human skin when illuminated by a laser beam. The main goal of this work is to offer novel, simple and low cost measurement tool which will indicate changes in condition of the cardiovascular system after having an initial calibration.

Should Patients With Cardiovascular Risk Factors Receive Intensive Treatment of Hypertension to

Opposing Viewpoint, see p 1308 Epidemiologic studies show a graded increase in risk at systolic blood pressure (BP) >115 mm Hg and diastolic BP >75 mm Hg. However, it remains unclear whether pharmacologic BP lowering to these levels reduces cardiovascular (CV) events and is safe. Observational analyses raised concerns about aggressive BP lowering to levels <120/80 mm Hg, suggesting the existence of a J-curve phenomenon with increased risk especially for coronary events. However, such analyses are potentially confounded. More reliable data are provided by randomized trials. Most BP-lowering trials have evaluated patients with high pretreatment BP and have rarely achieved average systolic BP <130 to 140 mm Hg, except in patients with high-risk CV disease, such as recent myocardial infarction (MI) or heart failure (HF) or those with chronic kidney disease. Three recent trials have specifically compared intensive systolic BP lowering to targets of <120 to 130 mm Hg versus traditional guideline recommended targets of generally <140 mm Hg,1–3 while the older HOT trial (Hypertension Optimal Treatment) randomized patients to diastolic BP targets of ≤90, ≤85, or ≤80 mm Hg.4 These trials differ significantly in their design, patients’ characteristics and CV risk, BP regimens, duration of treatment, primary outcomes, BP measurement techniques, and results. The ACCORD trial (Action to Control Cardiovascular Risk in Diabetes) randomized 4733 patients with diabetes (mean 63 years of age, 34% with a previous CV event, BP 139/76 mm Hg) to intensive therapy to a systolic BP target <120 mm Hg or to a standard target <140 mm Hg.1 Intensive therapy lowered BP by …

Evaluation of anti-hypertensive activity of Ulmus wallichiana extract and fraction in SHR, DOCA-salt- and L-NAME-induced hypertensive rats

Ethnopharmacological relevanceUlmus wallichiana Planchon (Himalayan Elm), a traditional medicinal plant, used in fracture healing in folk tradition of Uttarakhand, Himalaya, India. It is also used as diuretic. U. rhynchophylla, native to China, known as Gou Teng in Chinese medicine, is used for hypertension (WHO). U. macrocarpa has antihypertensive and vasorelaxant activity. However, no detailed studies related to hypertension have been reported previously, so we have explored the antihypertensive activity of U. wallichiana. Aim of the studyTo investigate the pharmacological effect of ethanolic extract (EE) and butanolic fraction (BF) of U. wallichiana in hypertensive rats. Materials and methodsSHR, DOCA-salt- and L-NAME-induced hypertension models were used. Treatment was performed by oral administration of EE and BF of U. wallichiana (500mg/kg/day and 50mg/kg/day) for 14 days. Then blood pressure was measured by non-invasive blood pressure (NIBP) measurement technique. Invasive blood pressure (IBP) was also reported to support the NIBP data. Concentrations of plasma renin, angiotensin II (Ang II), nitrate/nitrite (NO), cGMP were estimated. Angiotensin-converting enzyme (ACE) activity and ROS activity were also estimated. ResultsBlood pressure was significantly higher in SHR as compared to normotensive wistar group (170.59±0.83mmHg vs 121.54±1.24mmHg, respectively). SBP was increased in DOCA-salt induced group compared to their control (132.77±3.90mmHg vs 107.85±5.95mmHg, respectively) and L-NAME-induced group compared to their control (168.55±5.07mmHg vs 113.03±4.13mmHg, respectively). The treatment of extract and fraction of U. wallichiana significantly decreased the blood pressure in SHR+EE (151.26±1.85mmHg, p<0.001), SHR+BF (140.44±1.16mmHg, p<0.001); DOCA+EE (113.43±5.44mmHg, p<0.05), DOCA+BF (105.09±5.12mmHg, p<0.05) and L-NAME+EE (119.76±4.39mmHg, p<0.001), L-NAME+BF (117.50±7.27mmHg, p<0.001) compared to their respective diseased control groups. The plasma renin, Ang II and ACE activity were also significantly decreased and augmented the NO and cGMP levels. It also down regulated the expression of Renin, ACE, NOS3 and TGF-β1 at mRNA levels. ConclusionsThe EE and BF probably reducing the BP via Renin-angiotensin-aldosterone system and NO/cGMP signaling pathway. The decrease in blood pressure may be due to presence of quercetin analogue flavonoids (2S,3S)-(+)−3′,4′,5,7-tetrahydroxydihydroflavonol-6-C-β-D-glucopyranoside; 6-Glucopyranosyl-3,3′,4′,5,7-pentahydroxyflavone; 6-Glucopyranosyl-4′,5,7-trihydroxyflavanone and (2S,3S)-(+)−4′,5,7-trihydroxydihydroflavonol-6-C-β-D-glucopyranoside, may be due to its antioxidant activity. Thus EE and BF of U. wallichiana found to have the potential ability to be used as herbal medicament to treat hypertension.

Blood Pressure and Mortality in Long-Term Hemodialysis-Time to Move Forward.

Contrary to the direct, graded, and causal relationship of hypertension with cardiovascular outcomes in the general population, among dialysis patients, blood pressure (BP) recorded either predialysis or postdialysis displays a U-shaped curve with mortality. This paradoxical phenomenon of lower BP or a decline in BP over time being associated with increased mortality and higher BP being associated with a lower mortality is described as "reverse" epidemiology of hypertension, raising substantial controversy on whether BP lowering causes harms or benefits among dialysis patients. Unlike the inverse relationship of peridialytic BP with mortality, elevated BP recorded outside of dialysis is directly associated with poor long-term outcomes. Apart from the timing and technique of BP measurement, the U-shaped association of BP with mortality is also modified when accounting for factors related to patient's clinical characteristics and level of illness, dialysis practices, and patterns as well as factors related to the methodology of survival analysis. Most importantly, deliberate BP lowering with antihypertensive drugs is associated with reduced cardiovascular morbidity and mortality. In this review, we explore the complex association of peridialytic, intradialytic, and interdialytic BP with outcomes among dialysis patients. We conclude with recommendations for a wider use of out-of-dialysis BP monitoring as a tool to better evaluate the cardiovascular risk and optimize the management of hypertension in this high-risk population. Rather than more cohort studies, we call for randomized trials to test the level of BP in dialysis patients that is optimal for cardiovascular outcomes.

A physics based approach to the pulse wave velocity prediction in compliant arterial segments

Pulse wave velocity (PWV) quantification commonly serves as a highly robust prognostic parameter being used in a preventative cardiovascular therapy. Being dependent on arterial elastance, it can serve as a marker of cardiovascular risk. Since it is influenced by a blood pressure (BP), the pertaining theory can lay the foundation in developing a technique for noninvasive blood pressure measurement. Previous studies have reported application of PWV, measured noninvasively, for both the estimation of arterial compliance and blood pressure, based on simplified physical or statistical models. A new theoretical model for pulse wave propagation in a compliant arterial segment is presented within the framework of pseudo-elastic deformation of biological tissue undergoing finite deformation. An essential ingredient is the dependence of results on nonlinear aspects of the model: convective fluid phenomena, hyperelastic constitutive relation, large deformation and a longitudinal pre-stress load. An exact analytical solution for PWV is presented as a function of pressure, flow and pseudo-elastic orthotropic parameters. Results from our model are compared with published in-vivo PWV measurements under diverse physiological conditions. Contributions of each of the nonlinearities are analyzed. It was found that the totally nonlinear model achieves the best match with the experimental data. To retrieve individual vascular information of a patient, the inverse problem of hemodynamics is presented, calculating local orthotropic hyperelastic properties of the arterial wall. The proposed technique can be used for non-invasive assessment of arterial elastance, and blood pressure using direct measurement of PWV, with account of hyperelastic orthotropic properties.

Single source photoplethysmograph transducer for local pulse wave velocity measurement.

Cuffless evaluation of arterial blood pressure (BP) using pulse wave velocity (PWV) has received attraction over the years. Local PWV based techniques for cuffless BP measurement has more potential in accurate estimation of BP parameters. In this work, we present the design and experimental validation of a novel single-source Photoplethysmograph (PPG) transducer for arterial blood pulse detection and cycle-to-cycle local PWV measurement. The ability of the transducer to continuously measure local PWV was verified using arterial flow phantom as well as by conducting an in-vivo study on 17 volunteers. The single-source PPG transducer could reliably acquire dual blood pulse waveforms, along small artery sections of length less than 28 mm. The transducer was able to perform repeatable measurements of carotid local PWV on multiple subjects with maximum beat-to-beat variation less than 12%. The correlation between measured carotid local PWV and brachial BP parameters were also investigated during the in-vivo study. Study results prove the potential use of newly proposed single-source PPG transducers in continuous cuffless BP measurement systems.

Diagnosis, Epidemiology, and Management of Hypertension in Children.

National guidelines for the diagnosis and management of hypertension in children have been available for nearly 40 years. Unfortunately, knowledge and recognition of the problem by clinicians remain poor. Prevalence estimates are highly variable because of differing standards, populations, and blood pressure (BP) measurement techniques. Estimates in the United States range from 0.3% to 4.5%. Risk factors for primary hypertension include overweight and obesity, male sex, older age, high sodium intake, and African American or Latino ancestry. Data relating hypertension in childhood to later cardiovascular events is currently lacking. It is known that BP in childhood is highly predictive of BP in adulthood. Compelling data about target organ damage is available, including the association of hypertension with left ventricular hypertrophy, carotid-intima media thickness, and microalbuminuria. Guidelines from both the United States and Europe include detailed recommendations for diagnosis and management. Diagnostic standards are based on clinic readings, ambulatory BP monitoring is useful in confirming diagnosis of hypertension and identifying white-coat hypertension, masked hypertension, and secondary hypertension, as well as monitoring response to therapy. Research priorities include the need for reliable prevalence estimates based on diverse populations and data about the long-term impact of childhood hypertension on cardiovascular morbidity and mortality. Priorities to improve clinical practice include more education among clinicians about diagnosis and management, clinical decision support to aid in diagnosis, and routine use of ambulatory BP monitoring to aid in diagnosis and to monitor response to treatment.

A preliminary study on multi-wavelength PPG based pulse transit time detection for cuffless blood pressure measurement.

Pulse transit time (PTT) has been widely studied as an index of blood pressure (BP) changes. In recent years, some prototypes of PTT-based wearable BP measurement devices have been developed, which can relieve users from the discomfort caused by the inflating cuff used in auscultatory and oscillometric BP measurement techniques. However, in the common practice for PTT detection, multi-site sensor implementation on human body is required, making it difficult for the integration of wearable devices. Since multi-wavelength (MW) photoplethysmogram (PPG) signals carry blood pulsation information of different blood vessels embedded in different skin depths, the time difference between different wavelength PPG signals collected at the same body site can be treated as a special PTT on a short length of blood vessels beneath the skin. In this work, the time difference between MW PPG, denoted as PTT_MW, was explored to track BP changes as a substitute of infrared (IR) PTT_EP. (PTT_EP is the time interval between electrocardiogram (ECG) and IR PPG.) Ten healthy adult subjects participated in the experiment, and their continuous BP, ECG and fingertip MW PPG signals generated from blue, green, yellow and IR light were recorded after 2-minute static handgrip exercise at 33% maximal voluntary contraction. The results showed that the correlation between Systolic BP (SBP) and IR-Blue PTT_MW (|r|= 0.52) was comparable to the correlation between SBP and IR PTT_EP (|r|= 0.59). Moreover, we optimized the wavelength combination of PTT_MWs for each subject and found the average value of optimal correlation between SBP and PTT_MW reached 0.76, which was significantly (p<;0.01) higher than the correlation between IR PTT_EP and SBP. This study reveals that the time difference between MW PPG can be potentially used as PTT for cuffless BP measurement with its unique advantage in simple sensor implementation at only one body site.

Characteristic Ratio-Independent Arterial Stiffness-Based Blood Pressure Estimation.

Noninvasive blood pressure (BP) measurement is an important tool for managing hypertension and cardiovascular disease. However, automated noninvasive BP measurement devices, which are usually based on the oscillometric method, do not always provide accurate estimation of BP. It has been found that change in arterial stiffness (AS) is an underlying mechanism of disagreement between an oscillometric BP monitor and a sphygmomanometer. This problem is addressed by incorporating parameters related to AS in the algorithm for BP measurement. Pulse transit time (PTT) is first used to estimate AS parameters, which are fixed into a model of the oscillometric envelope. This model can then be used to perform curve fitting to the measured signal using only four parameters: systolic BP, diastolic BP, mean BP, and lumen area at zero transmural pressure. The proposed technique is independent of the experimentally determined characteristic ratios that are commonly used in existing oscillometric methods. The accuracy of the proposed technique was evaluated by comparing with the same model without incorporation of AS, and with reference BP device measurements. The new method achieved standard deviation of error less than 8 mmHg and mean error less than 5 mmHg. The results show consistency with ANSI/AAMI SP-10 standard for noninvasive BP measurement techniques.

Assessing the eligibility of a non-invasive continuous blood pressure measurement technique for application during total intravenous anaesthesia.

To assess the eligibility for replacement of invasive blood pressure as measured "within" the arterial vessel (IBP) with non-invasive continuous arterial blood pressure (cNIP) monitoring during total intravenous anaesthesia (TIVA), the ability of cNiP to track fast blood pressure changes needs to be quantified. A new method of statistical data analysis is developed for this purpose. In a pilot study on patients undergoing neurosurgical anaesthesia, mean arterial pressure MAPIBP measured with IBP was compared to MAPCNP measured by the CNAP Monitor 500 in ten patients (age: 63±13 a). Correlation analysis of changes of device differences ΔeMAP=ΔMAPCNP-ΔMAPIBP with changes of MAPIBP (ΔMAPIBP) during intervals of vasoactivity was conducted. An innovative technique, of linear trend analysis (LTA) applied to two signals, is described to perform this analysis without a priori knowledge of intervals of vasoactivity. Analysis of ΔeMAP during vasoactivity revealed that ΔMAPCNP systematically underestimated ΔMAPIBP by 37%. This was confirmed in the complete data set using LTA technique showing a systematic, yet patient specific, underestimation in tracking ΔMAPIBP (16…120%). The proposed LTA technique is able to detect systematic errors in tracking short-term blood pressure changes otherwise masked by established analysis. LTA may thus be a useful tool to assess the eligibility of cNIP to replace IBP during TIVA.

Hypertension in Chronic Kidney Disease Part 2: Role of Ambulatory and Home Blood Pressure Monitoring for Assessing Alterations in Blood Pressure Variability and Blood Pressure Profiles.

Blood pressure (BP) is characterized by high variability, including changes beat-to-beat (very short term), within 24 hours (short term), from day to day (midterm), and between visits spaced by weeks, months, seasons, and even years (long term). These variations can be estimated by means of continuous beat-to-beat BP recordings, repeated conventional office BP measures, 24-hour ambulatory BP monitoring (ABPM), or home BP monitoring (HBPM) over longer time windows (Table). A main advantage of ABPM over other BP measurement techniques is represented by its ability to track BP changes occurring in daily life conditions and during 24 hours, thus allowing assessment of overall BP variability (BPV) as well as identification of its specific components, such as nocturnal hypertension and altered day-to-night BP profiles (ie, morning BP rise, nondipping pattern of BP) which become manifest early in the course of chronic kidney disease (CKD). These alterations are even more significant in subjects with end-stage renal disease (ESRD) mainly, but not exclusively, because of the marked reduction in intravascular volume immediately after hemodialysis followed by the progressive increase in volemia throughout the interdialytic period,2 combined with an enhanced sympathetic activity. The higher frequency of alterations in 24-hour BP profiles and BPV in subjects with CKD and in those with ESRD not only makes a proper assessment and achievement of BP control more difficult in these subjects but may be prognostically relevant on the background of the evidence from longitudinal and observational studies indicating that increased BPV may predict the development of cardiovascular and renal disease, over and above the contribution of elevated mean BP levels per se3–11 (Figure 1). The purpose of this review is to address the currently available evidence on the role of ABPM and HBPM for the assessment and management of alterations in circadian BP profiles …

Generalized Response of the Exercise Pressor Reflex

Autonomic responsiveness to reflex stimuli varies considerably between individuals, with implications for predicting cardiovascular disease. PURPOSE: To standardize blood pressures to activation of the exercise pressor reflex using isometric handgrip exercise followed by post-exercise circulatory arrest (PECA). METHODS: Using specific search terms including “metaboreflex”, “ergoreflex”, “handgrip”, “reflex”, “static”, and “isometric”, we identified 151 studies that quantified the pressor response to handgrip exercise followed by PECA in healthy humans aged 19-44 years. We characterized these studies by exercise mode (static vs. dynamic), percentage of maximum voluntary contraction, blood pressure measurement technique, duration of exercise, duration of PECA, and method of data presentation (absolute values vs. changes from baseline). Preliminary analysis revealed distinct effects of exercise intensity and duration. We constrained further analysis to studies including healthy adults completing isometric handgrip exercise at 30-33% of maximum for 3 minutes and 2 or more minutes of PECA, with blood pressure measured from the wrist or finger of the resting arm (total of 4 studies). RESULTS: Using the reported means and variation we employed bootstrapping with weighted re-sampling (n=10,000) to create a statistically comparable normal distribution of responses. Based on these criteria, the average population mean arterial pressure response for the second minute of PECA is 19 mmHg. The first quartile response is 13 mmHg, and the third quartile is 26 mmHg. CONCLUSIONS: The autonomic response following ischemic handgrip varies considerably between individuals, even when experimental conditions are standardized. The possible foundation for these differences may be neural (e.g., afferent, central, or efferent) or extra-neural (e.g., genetic, muscle fiber type, or vascular).

Nursing care for women with pre-eclampsia and/or eclampsia: integrative review.

To analyze the available evidence in the literature on nursing care for women with pre-eclampsia and/or eclampsia. Integrative review searching for primary studies in the databases PubMed, CINAHL, LILACS and SciELO. The sample size consisted of 17 primary studies published between January 2000 and December 2014, grouped into four categories: standardizing blood pressure measurement technique; training with simulation; instruments for standardization of care and quality of care The main nursing actions were: physical examination, early detection of signs of pre-eclampsia/eclampsia, monitoring of laboratory tests, fetal assessment, qualification and training of professionals. We identified the need for standardization of care from instruments, protocols and blood pressure measurement technique, early identification and treatment of hypertensive crisis through institutional protocols and review of cases and work processes. Women with pre-eclampsia and/or eclampsia require specific nursing care, which must be guided by care protocols based on scientific evidence. Analisar as evidências disponíveis na literatura sobre assistência de enfermagem às mulheres com pré-eclâmpsia e/ou eclâmpsia. Revisão integrativa cuja busca dos estudos primários foi realizada nas bases de dados PubMed, CINAHL, LILACS e SciELO. Amostra foi composta por 17 estudos primários, publicados entre janeiro de 2000 e dezembro de 2014, agrupados em quatro categorias: padronização da técnica de mensuração da pressão arterial; treinamentos com simulação; instrumentos para padronização da assistência e qualidade da assistência As principais ações de enfermagem foram: exame físico, identificação precoce de sinais de pré-eclâmpsia/eclâmpsia, acompanhamento de exames laboratoriais, avaliação fetal, capacitação e treinamento dos profissionais. Identificou-se a necessidade de padronização do atendimento a partir de instrumentos e protocolos e da técnica de aferição da pressão arterial, identificação e tratamento precoces da crise hipertensiva mediante protocolos institucionais e revisão de casos e processos de trabalho. Mulheres com pré-eclâmpsia e/ou eclâmpsia exigem cuidados de enfermagem específicos, os quais devem ser pautados em protocolos de cuidados baseados em evidências científicas.

Prevalence of pseudoresistant hypertension due to blood pressure measurement technique in a hypertension specialty clinic

Prevalence of pseudoresistant hypertension due to blood pressure measurement technique in a hypertension specialty clinic

How to measure blood pressure manually.

Rationale and key points This article aims to help nurses to measure blood pressure (BP) manually using an aneroid sphygmomanometer. ▶ BP measurement is an essential clinical skill, and nurses must be competent in performing this procedure and taking accurate readings. ▶ Nurses should be aware of manual BP measurement techniques and understand the patient and environmental factors that may result in inaccurate readings that could compromise patient care. ▶ Nurses should regularly undertake manual BP measurement to ensure they remain competent to perform the procedure. Reflective activity Clinical skills articles can help update your practice and ensure it remains evidence based. Apply this article to your practice. Reflect on and write a short account of: 1. How reading this article will change your practice. 2. Further learning needs to extend your professional development. Subscribers can upload their reflective accounts at: rcni.com/portfolio .

Quality control of the blood pressure phenotype in the Gaoyou population study

The Korotkoff approach is the only blood pressure (BP) measurement technique that allows contemporary data to be compared with decades of research. We randomly recruited 4483 people (53.3% women; mean age 52.1 years) from Gaoyou County, Jiangsu Province, China. Nine observers recorded the participants™ BP three times consecutively following Chinese Society of Hypertension guidelines. We assessed the BP phenotype based on five criteria: completeness of readings, percentage of identical BP readings, odd BP readings, end-digit preference and trends in BP from the first to the third reading. The proportion of participants with identical readings were 2.0% and 3.1% for systolic (SBP) and diastolic blood pressure (DBP), respectively. Among 26,898 BP values, 0.3% ended in an odd number. Among observers, the prevalence of identical readings varied from 0% to 5.3% for SBP and from 0% to 6.8% for DBP. Compared with the expected frequency of 20%, those ending in 0 had a lower frequency (17.2%; p < 0.001), whereas those ending in 8 had a higher frequency (22.4%; p < 0.001). From the first to the third measurement, SBP and DBP decreased (p < 0.001) by 0.87 and 0.55 mmHg, respectively. In conclusion, the procedures set up in the Gaoyou study produced a high-quality BP phenotype.

Performance of SuperSTAT Method of Non Invasive Blood Pressure (NIBP) Measurement Technique at Different Inflation Levels

Performance of SuperSTAT Method of Non Invasive Blood Pressure (NIBP) Measurement Technique at Different Inflation Levels

Con: Ambulatory blood pressure measurement in patients receiving haemodialysis: a sore arm and a waste of time?

Ambulatory blood pressure monitoring (ABPM) has become popular in the investigation and management of patients with essential hypertension. In patients receiving haemodialysis, ABPM identifies patients who may fare worse in the long term. However, the available studies are small, and when conventional risk factors are included, there is no added value to ABPM over conventional BP measurements. In haemodialysis, ABPM remains an experimental investigation, and in the absence of specific, evidence-based targets for blood pressure in this population, it would be better to invest in large-scale trials to provide specific blood pressure targets and strategies, rather than concentrating on an alternative technique for blood pressure measurement.

2013 Korean Society of Hypertension guidelines for the management of hypertension: part I-epidemiology and diagnosis of hypertension.

The standardized techniques of blood pressure measurement in the clinic are emphasized and the indications for ambulatory and/or home blood pressure monitoring are specified more broadly. The epidemiologic findings specific to Korean population related to blood pressure are reviewed. Cardiovascular risk of hypertensive patients are stratified based upon the data of a Korean population cohort study.