Study of Blood-Pressure Measurement Using Noninvasive Methods

The correct diagnosis of high blood pressure is important to avoid cardiovascular diseases. In this work, we propose a low-cost noninvasive blood-pressure measurement unit composed of a photoplethysmograph and an electrocardiograph. It is based on pulse transit time measurement, thus performing nonocclusive measurement. To test the effectiveness of this parameter, a total of five subjects were measured, verifying their effectiveness at all times.

Surrogate based continuous noninvasive blood pressure measurement

Arterial blood pressure is one of the most often measured vital parameters in clinical practice. State-of-the-art noninvasive ABP measurement technologies have noticeable limitations and are mainly based on uncomfortable techniques of complete or partial arterial occlusion by cuffs. Most commonplace devices provide only intermittent measurements, and continuous systems are bulky and difficult to apply correctly for nonprofessionals. Continuous cuffless ABP measurements are still an unmet clinical need and a topic of ongoing research, with only few commercially available devices. This paper discusses surrogate-based noninvasive blood pressure measurement techniques. It covers measurement methods of continuously and noninvasively inferring BP from surrogate signals without applying external pressures, except for reference or initialization purposes. The BP is estimated by processing signal features, so called surrogates, which are modulated by variations of BP. Discussed techniques include well-known approaches such as pulse transit time and pulse arrival time techniques, pulse wave analysis or combinations thereof. Despite a long research history, these methods have not found widespread use in clinical and ambulatory practice, in part due to technical limitations and the lack of a standardized regulatory framework. This work summarizes findings from an invited workshop of experts in the fields covering clinical expertise, engineering aspects, commercialization and standardization issues. The goal is to provide an application driven outlook, starting with clinical needs, and extending to technical actuality. It provides an outline of recommended research directions and includes a detailed overview of clinical use case scenarios for these technologies, opportunities, and limitations.

Blood Pressure Measurement Error in Children: Lessons in Measurement Reliability

Background and PurposeBlood pressure measurement represents the pressure exerted during heart ejection and filling. There are several ways to measure blood pressure and a valid measure is essential. The purpose of this study was to evaluate the approach to noninvasive blood pressure measurement in children.MethodsBlood pressure measurements were taken using the automatic Phillips MP30 monitor and compared against Welch Allyn blood pressure cuffs with Medline manual sphygmomanometers.ResultsA total of 492 measurements were taken on 82 subjects, and they demonstrated comparability between automatic and manual devices.ConclusionsAlthough our study indicated acceptable agreement between automatic and manual blood pressure measurement, it also revealed measurement error remains a concern, with sample size, study protocol, training, and environment all playing a role.

A comparative evaluation of the efficacy of dimethylaminoethanol derivative 7–16, C7070 and picamilon in correction of experimental hypertensive neuroretinopathy

Introduction. The efficacy of dimethylaminoethanol (DMAE) derivative 7–16, substance C7070 in comparison with picamylon in hypertensive neuroretinopathy model in white laboratory rats was evaluated. Materials and methods. For measuring the blood pressure, a system of noninvasive blood pressure measurement in small animals NIBP200 was used. Ophthalmoscopy was performed by using Bx a Neitz ophthalmoscope (Japan) and Osher MaxField 78D lens, OI-78M model. Electroretinography (ERG) was recorded in response to a single stimulation. Biopotentials were presented graphically on the screen with the help of BIOPAC SYSTEMS MP-150 with ACQKNOWLEDGE 4.2 software (USA). To assess a degree of a functional retinal disorder, the b/a coefficient was used. Results and discussion. The most pronounced protective effect on the model of hypertensive neuroretinopathy is demonstrated by C7070, which is expressed in the notable approximation to the normal eye fundus image and reaching the target values of the b/a coefficient. In the group with correction by DMAE derivative 7–16, a protective effect is observed, which exceeds picamilon, which is expressed in the elimination of soft and solid exudates, vein and venule plethora, vascular tortuosity, arterial spasm, Salus-Gunn I symptom, hemorrhages; the b/a increases significantly by 26% compared to the group without correction (p < 0.05). Conclusion. The eye fundus image and functional state of the retina are completely restored when correcting experimental hypertensive neuroretinopathy with C7070 in a dose of 50 mg/kg to laboratory rats and partially restored when correcting with DMAE derivative 7–16 in a dose of 25 mg/kg, which in both cases exceeds the protective effect of the reference drug picamilon on the model of hypertensive neuroretinopathy.