Noninvasive Blood Pressure Measurement Methods Research Articles

Non-Invasive Blood Pressure Tracking of Spontaneous Hypertension Rats Using an Electronic Nose.

Traditional noninvasive blood pressure measurement methods in experimental animals are time consuming and difficult to operate, particularly for large numbers of animals. In this study, the possibility of sensing fecal odor to estimate the blood pressure status of spontaneous hypertension rats (SHRs) was explored with the aim of establishing a new method for non-invasive monitoring of blood pressure. The body weight and blood pressure of SHRs kept increasing with growth, and the odor information monitored using an E-nose varied with the blood pressure status, particularly for sensors S6 and S7. The fecal information was analyzed using principal component analysis, canonical discriminant analysis and multilayer perception neural networks (MLP) to discriminate SHRs from normal ones, with a 100% correct classification rate. For better prediction of blood pressure, the model built using multiple linear regression analysis, partial least squares regression analysis and multilayer perceptron neural network analysis were used, with coefficients of determination (R2) ranging from 0.8036 to 0.9926. Moreover, the best prediction model for blood pressure was established using MLP analysis with an R2¬ higher than 0.91. Thus, changes in blood pressure levels can be tracked non-invasively, and normotension can be distinguished from hypertension or even at different hypertension levels based on the odor information of rat feces, providing a foundation for non-invasive health monitoring. This work might provide potential instructions for functional food research aimed at lowering blood pressure.

Cuff‐less blood pressure estimation using hetero‐core optical fibers

AbstractIn this study, we proposed a cuff‐less blood pressure measurement using a medical tape sensor with an embedded hetero‐core optical fiber. The tape sensor pasted on the skin can directly detect pulse wave signals with a simple measuring device. Pulse transit time (PTT) was obtained from the time difference between the two pulse waveforms at the neck and foot. Systolic blood pressure (SBP) was estimated from PTT and the regression equation. The result shows that the maximum prediction error was 3.8 mmHg in five healthy young subjects. The SBP data were evaluated using a Bland‐Altman method to assess the agreement of SBP data estimated by the proposed method with those measured by the cuff‐based electronic sphygmomanometer. The mean ± 1.96 standard deviation of the estimated SBP against the reference was −1.3 ± 5.1 mmHg. The results show that the proposed noninvasive blood pressure measurement method can measure blood pressure, and its accuracy is comparable to that of the cuff‐based electronic sphygmomanometer.

Highly sensitive resistance-type flexible pressure sensor for cuffless blood-pressure monitoring by using neural network techniques

Blood pressure is an important parameter of a heart-pumping function, vascular peripheral resistance, and blood volume in human body. The non-invasive blood pressure measurement method has attracted tremendous attention due to its advantages of simple operation and comfort. In this paper, graft-modified MWCNTs and water-based polyurethane are used as filler and matrix, which are combined with simple dipping process to produce a resistance-type flexible pressure sensor with crack structure. The sensor with crack structure exhibits a high gauge factor (∼1582.7), fast response time (∼58 ms) and good repeatability (>2000 cycles) under 0–5% strain. By attaching the sensor to the radial artery of human wrist, the pulse waveform is accurately captured. By adopting the time-domain analysis method, in addition to the fast Fourier transform and threshold method which is employed to position and extract the characteristic value of pulse signal, a three-layer back propagation neural network is constructed to regress blood pressure value. The correlation coefficients of systolic blood pressure, diastolic blood pressure and mean blood pressure were 0.950, 0.875 and 0.947, respectively, which could meet the A-level standards of British Hypertension Society and Association for the Advancement of Medical Instrumentation. This study provides a good real-time and portable technology for home blood pressure measurement.

Piezoelectric Sensor for the Monitoring of Arterial Pulse Wave: Detection of Arrhythmia Occurring in PAC/PVC Patients.

Previous studies have found that the non-invasive blood pressure measurement method based on the oscillometric method is inaccurate when an arrhythmia occurs. Therefore, we propose a high-sensitivity pulse sensor that can measure the hemodynamic characteristics of the pulse wave and then estimate the blood pressure. When an arrhythmia occurs, the hemodynamics of the pulse wave are abnormal and change the morphology of the pulse wave. Our proposed sensor can measure the occurrence of ectopic beats from the radial artery, and the detection algorithm can reduce the error of blood pressure estimation caused by the distortion of ectopic beats that occurs when the pulse wave is measured. In this study, we tested patients with premature atrial contraction (PAC) or premature ventricular contraction (PVC) and analyzed the morphology of the pulse waves when the sensor detected the ectopic beats. We discuss the advantages of using the Moens–Korteweg equation to estimate the blood pressure of patients with arrhythmia, which is different from the oscillometric method. Our research provides a possible arrhythmia detection method for wearable devices and can accurately estimate blood pressure in a non-invasive way during an arrhythmia.

In vitro validation of a non-invasive continuous blood pressure measurement method for the perioperative application

Abstract Hypotensive periods during surgery lead to an increase in postoperative complications. To further avoid the adverse events associated with the invasive measurement of the blood pressure, a perioperative, continuous, non-invasive blood pressure measurement method was developed. The precision of the method was tested for different mean pressure values and different thicknesses of the tissue model using a specifically designed and validated simulator that has the characteristics of the lower arm. The mean pressure difference between the pressure determined by the proposed method and simulated blood pressure from the simulator was 3.93 mmHg (±4.75 mmHg) for the systole and 4.89 mmHg (±6.10 mmHg) for the diastole. The results showed that the method can be a promising alternative to invasive blood pressure measurement methods.

PTT-based Contact-less Blood Pressure Measurement using an RGB-Camera

Abstract Commonly used blood pressure measurement devices have noticeable limitations in accuracy, measuring time, comfort or safety. To overcome these limitations, we developed and tested a surrogate-based, non-invasive blood pressure measurement method using an RGB-camera. Our proposed method employs the relation between the pulse transit time (PTT) and blood pressure. Two remote photoplethysmography (rPPG) signals at different distances from the heart are extracted to calculate the temporal delay of the pulse wave. In order to establish the correlation between the PTT values and the blood pressure, a regression model is trained and evaluated. Tests were performed with five subjects, where each subject was recorded fifteen times for 30 seconds. Since the physiological parameters of the cardiac system are different for each person, an individual calibration is required to obtain the systolic and diastolic blood pressure from the PTT values. The calibration results are limited by the small number of samples and the accuracy of the reference system. However, our results show a strong correlation between the PTT values and the blood pressure and we obtained a mean error of 0.18 +/- 5.50 mmHg for the diastolic blood pressure and 0.01 +/- 7.71 mmHg for the systolic pressure, respectively.

Nikolai Sergeevich Korotkov - Russian surgeon, pioneer of modern vascular surgery (to the 145th of birthday)

N.S. Korotkov was born in 1874 in the city of Kursk. In 1893, after graduating from high school, he entered the medical faculty of Kharkov University, transferred to the medical faculty of Moscow University, which he graduated in 1898 with a degree in medicine with honors. In 1900, N.S. Korotkov became a supernumerary order of a surgical clinic for a term. Further N.S. Korotkov became a doctor of the sanitary unit of the Iberian Red Cross community. For participation in this trip N.S. Korotkov was granted the right to wear the honorary sign of the Red Cross, and in 1902 he was awarded the Order of St. Anne of the III degree. Nikolai Korotkov again works as a supernumerary, since 1903 - a regular intern at the surgical clinic of Professor A.A. Bobrov, then a supernumerary resident at the surgical clinic of Professor SPPedorov of the Imperial Military Medical Academy.In 1904, in the St. George community of the sisters of mercy of the Red Cross Society, a sanitary squad was formed to be sent to the Russian-Japanese war, NS was appointed as the senior physician. Korotkov. Systematically listening to the vessels in the wounded, the young surgeon discovered five regular phases of changes in sounds during compression of the brachial artery with a Riva-Rocci cuff, which later formed the basis of his proposed method for determining blood pressure (Korotkov method). November 8, 1905 N.S. Korotkov for the first time made a historical report “On the issue of blood pressure research methods”. At the end of 1905, he left Petersburg for his parents in the city of Kursk. In 1908, N.S. Korotkov successfully passes the examinations for the degree of doctor of medicine and leaves for Siberia in the mines of the Lena gold mining association for the position of doctor at the Andreevsky hospital. In 1910, N.S. Korotkov defends his doctoral thesis on the topic: "The experience of determining the strength of arterial collaterals." Since 1914, N.S. Korotkov worked as a senior physician at the Petersburg Clinical Hospital. Peter the Great, and with the outbreak of World War I, a surgeon in the Charity House for Wounded Soldiers in Tsarskoe Selo. After the Great October Revolution until the death of N.S. Korotkov served as chief physician at the Mechnikovsky hospital in Petrograd. Nikolai Sergeevich died on March 14, 1920 and was buried in the Theological Cemetery of St. Petersburg. The exact burial place of N.S. Korotkova has not been established, in 2011 a cenotaph was installed on the site of the Military Medical Academy. The Korotkov method was the only official non-invasive blood pressure measurement method approved by WHO in 1935. In honor of N.S. Korotkova is named the street in St. Petersburg, the city hospital of Kursk, the Memorial Society in St. Petersburg.

Numerical study to evaluate the effect of a surface-based sensor on arterial tonometry

Arterial tonometry is a widely used non-invasive blood pressure measurement method. In contrast to the cuff-based method, it is possible to obtain a continuous pressure profile with respect to systolic and diastolic pressures using this method. However, due to a requirement of arterial tonometry—that a sensor needs to be placed directly above a blood vessel—placement error is inevitable if the measurement device is only capable of measuring local regions. This study assumed that the plate sensor is flexible, thus reducing the placement error. We investigated the pressure distribution along the wrist surface rather than the local region through the contact simulation between the flexible plate sensor and the wrist. As a result, we concluded that there is a unique pressure distribution for any specific wrist, regardless of the length and position of the plate, and that it is possible to measure the blood pressure using the response at the wrist surface to the pressure inside the radial artery.

[Noninvasive Continuous Blood Pressure Measurement Method Based on EEMD and ANN].

Blood pressure is an important index to measure the function of human cardiovascular system. In order to solve the problem of non-invasive continuous measurement of blood pressure in electronic sphygmomanometer, a noninvasive blood pressure measurement method based on EEMD (ensemble empirical mode decomposition) and ANN (artificial neural networks) were proposed. In the experiment, a total of 19 500 pulse wave signals from THE MIMIC DATABASE were analyzed and subsequently the pulse wave was decomposed by EEMD. Furthermore, 10 characteristic parameters of the 4th layer decomposition signal were extracted as the input of ANN. The blood pressure corresponding to the pulse wave was taken as the output of ANN to train the BP (blood pressure) model. The error analysis of the model was carried out. The results indicated that the error of the model meets the standards of the American Association for the advancement of medical instrumentation (AAMI). Therefore, this method can be employed in noninvasive continuous measurement of blood pressure.

Comparison of ultrasonic Doppler flow monitor, oscillometric, and direct Comparison of ultrasonic Doppler flow monitor, oscillometric, and direct arterial blood pressure measurements in anesthetized dogs

This study was performed to evaluate three different noninvasive blood pressure measurement methods (NIBP) in comparison with direct blood pressure measurements in anesthetized dogs. Ten normal healthy Beagle dogs (mean age; 3.7 ± 1.01 yrs, mean body weight 10.2 ± 1.15 kg) were enrolled in this study. The BP was measured by three different methods, i.e., Doppler (DOP), oscillometric and high density oscillometric (HDO), simultaneously for 5 times in each subject under anesthesia at three different locations (right, left front legs and tail). The blood pressure value measured by Doppler method was the most close to the value measured by the direct method. Although the accuracy and consistency of the BP measured by 3 different non-invasive methods were differed by the method, all methods except conventional oscillometric method were acceptable for monitoring systolic blood pressure in anesthetic dogs and the inter-measurement variations in DOP and HDO was minimal enough not to affect the consistency of test result.

1127 Measuring Blood Pressure and Managing “Hypotension” in Newborn Babies: Variation in Practices

Background and AimsMeasuring blood pressure (BP) is an important part of cardiovascular assessment in newborns. Although arterial BP is considered as a gold standard, various methods of non-invasive BP measurements...

Invasive versus non-invasive monitoring of acute severe hypertension in women with pre-eclampsia

ObjectiveTo compare the accuracy of two non-invasive methods of blood-pressure measurement with intra-arterial measurement in women with pre-eclampsia and acute severe hypertension. MethodsThis descriptive, cross-sectional study prospectively enrolled 23 women with pre-eclampsia and acute severe hypertension for continuous intra-arterial blood-pressure monitoring. Simultaneous monitoring was performed with a manual and an automated, non-invasive device during episodes of severe hypertension. The paired T-test was used to compare measured values. The accuracy of a MAP⩾125mmHg in detecting a systolic blood pressure⩾160mmHg was determined. ResultsThere was a weak correlation between intra-arterial and automated as well as intra-arterial and manual systolic values (r=0.34, p<0.01; r=0.41, p<0.00, respectively). Better correlation was found amongst diastolic values. The differences between the mean intra-arterial (94±11mmHg) and automated (96±12mmHg) diastolic values as well as intra-arterial and manual diastolic measurements (94±14mmHg) were not significant (p=0.20, 0.65, respectively). A mean arterial pressure⩾125mmHg was not accurate in detecting a systolic value⩾160mmHg, with low sensitivities (17.2–35.9%) and specificities (0–50%) for all three methods. ConclusionsWhen compared to intra-arterial monitoring, the automated and manual methods showed weak correlation with systolic but better correlation with diastolic values. A mean arterial pressure⩾125mmHg was not accurate in detecting systolic peaks. When protection against cerebral haemorrhage is paramount, intra-arterial measurement of systolic values is best.

An Investigation of Pulse Transit Time as a Non-Invasive Blood Pressure Measurement Method

The objective of this paper is to examine the Pulse Transit Method (PTT) as a non-invasive means to track Blood Pressure over a short period of time. PTT was measured as the time it takes for an ECG R-wave to propagate to the finger, where it is detected by a photoplethysmograph sensor. The PTT method is ideal for continuous 24-hour Blood Pressure Measurement (BPM) since it is both cuff-less and non-invasive and therefore comfortable and unobtrusive for the patient. Other techniques, such as the oscillometric method, have shown to be accurate and reliable but require a cuff for operation, making them unsuitable for long term monitoring. Although a relatively new technique, the PTT method has shown to be able to accurately track blood pressure changes over short periods of time, after which re-calibration is necessary. The purpose of this study is to determine the accuracy of the method.

Validation of a new non-invasive blood pressure measurement method on mice via pulse wave propagation time measurement on a cuff

In the present article, we describe the validation of a new non-invasive method for measuring blood pressure (BP) which also enables to determine the three BP values: systolic, diastolic and mean value. Our method is based on the pulse transit time (PTT) measurement along an artery directly at the BP cuff. The accuracy of this method was evaluated by comparison with the direct simultaneous measurement of blood pressure from 40 anesthetized female mice. Close correlation between the gained data from these two methods was observed.

A rapid noninvasive blood pressure measurement method for discrete value and full waveform determination

A new noninvasive measurement method providing rapid measurement of systemic arterial blood pressure (BP) and its validation is described. The method combines precisely timed electrocardiographic-gated rapid release of occluding counter-pressure (600 mmHg/s) with photoplethysmographic detection of radial artery filling to measure arterial opening pressure. A complete BP waveform is reconstructed from multiple repetitions of the measurement cycle at successively increasing time intervals relative to the electrocardiographic signal. Systolic and diastolic values can be measured within two to four cardiac cycles at the peak and trough of the BP wave. The new method was compared with sphygmomanometry in 26 randomly selected subjects over a sphygmomanometric pressure range of 53-110 (diastolic) and 100-190 mmHg (systolic). The mean pressure differences between the sphygmomanometric and new methods were -1.3 +/- 15.2 (SD) (systolic) and 0.7 +/- 9.9 mmHg (diastolic), and corresponding BP values measured by these methods were highly correlated [P < 0.001; R2 = 0.87 (systolic); R2 = 0.80 (diastolic)]. The new method was compared with sphygmomanometry and intra-arterial BP in six patients. These tests confirmed the method's validity compared with established methods. The new method was ostensibly immune to mechanical perturbations when tested during cycle ergometry at 60 W. The new method may facilitate the study of circulatory phenomena previously inaccessible by available noninvasive methods and minimizes patient discomfort and circulatory arrest at the measurement site.

Ambulatory Monitoring and Blood Pressure Variability

Ambulatory blood pressure monitoring is a relatively new clinical and research technique that uses invasive and noninvasive blood pressure measurement methods combined with computer technology for data analysis to evaluate the variability of blood pressure. While the intra-arterial technique for ambulatory blood pressure monitoring has been around for 30 years, the automatic noninvasive devices have only come into regular use in the last several years. The amount of information in the medical literature derived from ambulatory blood pressure monitoring has grown impressively in the past decade, however, as numerous investigators around the globe have carried out studies of blood pressure variability, especially with regard to diagnostic and therapeutic utility. Prior to Dr Pickering's book, there were a few volumes of collected papers on ambulatory blood pressure monitoring from research meetings in the early and middle 1980s. However, none of these symposia proceedings are a set piece that comprehensively reviews the