A flexible multimodal pulse sensor for wearable continuous blood pressure monitoring.

Monitoring of arterial blood pressure via cuffless pulse waveform measurement at the wrist has an important clinical value for the early diagnosis and prevention of cardiovascular disease. However, accurate measurement of the radial pulse waveform is challenging owing to its subtle, wideband, and preload-dependent variation characteristics. Evidence shows that uncertainties or variations of wearing pressure and skin temperature can cause artifact signals in wrist pulse measurements, thus degrading blood pressure estimate accuracy and hindering precise clinical diagnosis. Herein, we report a flexible multisensory pulse sensor utilizing natural piezo-thermic transduction of human skin in conjunction with thin-film thermistors for the accurately measuring radial artery pulse waves with high fidelity and good anti-artifact performance. The flexible pulse sensor achieved a wide pressure measuring range (228.2 kPa), low detection limit (4 Pa), good linearity (R2 = 0.999), low hysteresis (2.45%), fast response (88 ms), and good durability and stability, thereby enabling accurate pulse measurement with high fidelity. The pulse sensor also monolithically integrated the simultaneous detections of skin temperature and wearing pressure for resisting artifact effects in pulse measurements. Through the fusion of multiple features extracted from the pulse waveform, wearing pressure, skin temperature and user's personal physical characteristics using an efficient multilayer perceptron, blood pressure is accurately estimated and good generalizability is achieved.

Blood pressure pulsations modulate central neuronal activity via mechanosensitive ion channels.

The transmission of the heartbeat through the cerebral vascular system causes intracranial pressure pulsations. We discovered that arterial pressure pulsations can directly modulate central neuronal activity. In a semi-intact rat brain preparation, vascular pressure pulsations elicited correlated local field oscillations in the olfactory bulb mitral cell layer. These oscillations did not require synaptic transmission but reflected baroreceptive transduction in mitral cells. This transduction was mediated by a fast excitatory mechanosensitive ion channel and modulated neuronal spiking activity. In awake animals, the heartbeat entrained the activity of a subset of olfactory bulb neurons within ~20 milliseconds. Thus, we propose that this fast, intrinsic interoceptive mechanism can modulate perception-for example, during arousal-within the olfactory bulb and possibly across various other brain areas.

Pulse rate variability estimation method based on imaging-photoplethysmography and application to telepsychiatry.

The worldwide adoption of telehealth services may benefit people who otherwise would not be able to access mental health support. In this paper, we present a novel algorithm to obtain reliable pulse and respiration signals from non-contact facial image sequence analysis. The proposed algorithm involved a skin pixel extraction method in the image processing part and signal reconstruction using the spectral information of RGB signal in the signal processing part. The algorithm was tested on 15 healthy subjects in a laboratory setting. The results show that the proposed algorithm can accurately monitor respiration rate (RR), pulse rate (PR), and pulse rate variability (PRV) in rest conditions.Clinical Relevance- The main achievement of this study is enabling non-contact PR and RR signal extraction from facial image sequences, which has potential for future use and support for psychiatrists in telepsychiatry.

Heart rate measurement through carotid pulse by primary school children / Medición de la frecuencia cardíaca mediante pulso carotídeo por niños de primaria

This study aimed to determine whether primaryschool children can accurately monitor their heart rate (HR) through manual pulse measurement. Children aged 9 to 12 years manually assessed their HR through the carotid pulse three times in a physical education session; lying down, after submaximal effort and one minute later. Simultaneously, HR was measured by pulsometers. Of 417 children (10.58±0.93 years, 44.8% girls), 40% provided accurate values (<10% error). Concordance analysis showed wide limits of agreement (95% of measurements between 44.76% below and 78.64% above actual HR values). Sex, age and level of effort had no significant influence on the results. Primary school children are not able to accurately measure their HR through the carotid pulse (AU)

Este estudio tuvo como objetivodeterminar si los niños de primaria pueden controlar con precisión su frecuencia cardíaca (FC)mediante la medición manual del pulso. Niños de 9 a 12 años evaluaron manualmente su FC a través del pulso carotídeo tres veces en una sesión deeducación física; tumbados, trasun esfuerzo submáximo y un minuto después. Simultáneamente, se midió la FC mediante pulsómetros. De 417 niños (rango de edad 9 a 12 años, 44,8% niñas), un40% proporcionóvalores precisos (<10% de error). El análisis de concordancia mostró amplios límites de acuerdo (95% de las mediciones situadas entre un 44,76% por debajo y un 78,64% por encima de los valores reales de la FC). El sexo, la edad y el nivel de esfuerzo no tuvieron una influencia significativa en los resultados. Los niños de primaria no son capaces de medir con precisión su FC a través del pulso carotídeo (AU)

THE OUTCOME OF PULSELESS PINK HAND FOLLOWING CLOSED SUPRACONDYLAR FRACTURE HUMERUS IN PEDIATRICS.

Management of children with supracondylar humeral fractures with pulseless pink hands is still controversial, whether to choose operative or conservative treatment. Proponents of conventional treatment mentioned that most patients can restore the motor and sensory function of the hand shortly after the injury without the need to restore distal pulse by surgery. Opponents of this treatment strategy claim that many patients will develop limb shortening a few years after the injury leading to functional and psychological problems. In this study, we made a comparison of the outcomes of each treatment to help in making policy for the treatment of such types of injuries in our center. This study answers the question "Which method is preferred for treating supracondylar humeral fracture with suspected vascular injury represented by pulseless pink hand, and what are the short and long-term outcomes of each treatment method. The main objective of the study is to settle a policy for the treatment of such types of injuries in our center. This study is a retrospective for the 10-year period from 2010 to 2020, it included 74 patients with blunt trauma to one upper extremity. All patients were children aged one year to fourteen years. Patients with penetrating trauma, combined penetrating and blunt trauma, victims of burns and explosions, and patients with other co-morbidities were excluded. We have two treatment strategies: Conservative (watchful waiting) and Operative exploration. We compared the outcomes of these two strategies regarding the short-term outcome (6 months follow-up) and the long-term outcome (5 years follow-up). We looked for acute and chronic limb ischemia and chronic pain syndrome as the short-term follow-up, while we took limb shortening and chronic limb ischemia and limb function as variables of the long-term follow-up. We don't have the ability to control patients for the psychological examination by a psychiatrist, therefore; we excluded this variable from our study.

Non-contact high precision pulse-rate monitoring system for moving subjects in different motion states.

Remote photoplethysmography (rPPG) enables contact-free monitoring of the pulse rate by using a color camera. The fundamental limitation is that motion artifacts and changes in ambient light conditions greatly affect the accuracy of pulse-rate monitoring. We propose use of a high-speed camera and a motion suppression algorithm with high computational efficiency. This system incorporates a number of major improvements including reproduction of pulse wave details, high-precision pulse-rate monitoring of moving subjects, and excellent scene scalability. A series of quantization methods were used to evaluate the effect of different frame rates and different algorithms in pulse-rate monitoring of moving subjects. The experimental results show that use of 180-fps video and a Plane-Orthogonal-to-Skin (POS) algorithm can produce high-precision pulse-rate monitoring results with mean absolute error can be less than 5 bpm and the relative accuracy reaching 94.5%. Thus, it has significant potential to improve personal health care and intelligent health monitoring.

A Self-Powered Multifunctional Bracelet for Pulse Monitoring and Personal Rescue.

For outdoor workers or explorers who may be exposed to extreme or wild environments for a long time, wearable electronic devices with continuous health monitoring and personal rescue functions in emergencies could play an important role in protecting their lives. However, the limited battery capacity leads to a limited serving time, which cannot ensure normal operation anywhere and at any time. In this work, a self-powered multifunctional bracelet is proposed by integrating a hybrid energy supply module and a coupled pulse monitoring sensor with the inherent structure of the watch. The hybrid energy supply module can harvest rotational kinetic energy and elastic potential energy from the watch strap swinging simultaneously, generating a voltage of 69 V and a current of 87 mA. Meanwhile, with a statically indeterminate structure design and the coupling of triboelectric and piezoelectric nanogenerators, the bracelet enables stable pulse signal monitoring during movement with a strong anti-interference ability. With the assistance of functional electronic components, the pulse signal and position information of the wearer can be transmitted wirelessly in real-time, and the rescue light and illuminating light can be driven directly by flipping the watch strap slightly. The universal compact design, efficient energy conversion, and stable physiological monitoring demonstrate the wide application prospects of the self-powered multifunctional bracelet.

Dielectric modulation strategy of carbon nanotube field effect transistors based pressure sensor: towards precise monitoring of human pulse.

Continuous monitoring of arterial pulse has great significance for detecting the early onset of cardiovascular disease and assessing health status, while needs pressure sensors with high sensitivity and signal-to-noise ratio (SNR) to accurately capture more health information concealed in pulse waves. Field effect transistors (FETs) combined with the piezoelectric film is an ultrahigh sensitive pressure sensor category, especially when the FET works in the subthreshold regime, where the signal enhancement effect on the piezoelectric response is the most effective. However, controlling the work regime of FET needs extra external bias assistance which will interfere with the piezoelectric response signal and complicate the test system thus making the scheme difficult to implement. Here, we described a gate dielectric modulation strategy to match the subthreshold region of the FET with the piezoelectric output voltage without external gate bias, finally enhancing the sensitivity of the pressure sensor. A carbon nanotube field effect transistor and polyvinylidene fluoride (PVDF) together form the pressure sensor with a high sensitivity of 7 × 10-1kPa-1for a pressure range of 0.038-0.467 kPa and 6.86 × 10-2kPa-1for a pressure range of 0.467-15.5 kPa, SNR, and the ability to continuously monitor pulse in real-time. Additionally, the sensor enables high-resolution detection of weak pulse signals under large static pressure.

A fast sample entropy for pulse rate variability analysis.

Sample entropy is an effective nonlinear index for analyzing pulse rate variability (PRV) signal, but it has problems with a large amount of calculation and time consumption. Therefore, this study proposes a fast sample entropy calculation method to analyze the PRV signal according to the microprocessor process of data updating and the principle of sample entropy. The simulated data and PRV signal are employed as experimental data to verify the accuracy and time consumption of the proposed method. The experimental results on simulated data display that the proposed improved sample entropy can improve the operation rate of the entropy value by a maximum of 47.6 times and an average of 28.6 times and keep the entropy value unchanged. Experimental results on PRV signal display that the proposed improved sample entropy has great potential in the real-time processing of physiological signals, which can increase approximately 35 times.

Intelligent Wearable Wrist Pulse Detection System Based on Piezoelectric Sensor Array.

The human radial artery pulse carries a rich array of biomedical information. Accurate detection of pulse signal waveform and the identification of the corresponding pulse condition are helpful in understanding the health status of the human body. In the process of pulse detection, there are some problems, such as inaccurate location of radial artery key points, poor signal noise reduction effect and low accuracy of pulse recognition. In this system, the pulse signal waveform is collected by the main control circuit and the new piezoelectric sensor array combined with the wearable wristband, creating the hardware circuit. The key points of radial artery are located by an adaptive pulse finding algorithm. The pulse signal is denoised by wavelet transform, iterative sliding window and prediction reconstruction algorithm. The slippery pulse and the normal pulse are recognized by feature extraction and classification algorithm, so as to analyze the health status of the human body. The system has accurate pulse positioning, good noise reduction effect, and the accuracy of intelligent analysis is up to 98.4%, which can meet the needs of family health care.

Monitoring Pulse Rate in the Background Using Front Facing Cameras of Mobile Devices.

We propose a novel framework to passively monitor pulse rate during the time spent by users on their personal mobile devices. Our framework is based on passively capturing the user's pulse signal using the front-facing camera. Signal capture is performed in the background, while the user is interacting with the device as he/she normally would, e.g., watch movies, read emails, text, and play games. The framework does not require subject participation with the monitoring procedure, thereby addressing the well-known problem of low adherence with such procedures. We investigate various techniques to suppress the impact of spontaneous user motion and fluctuations in ambient light conditions expected in non-participatory environments. Techniques include traditional signal processing, machine learning classifiers, and deep learning methods. Our performance evaluation is based on a clinical study encompassing 113 patients with a history of atrial fibrillation (Afib) who are passively monitored at home using a tablet for a period of two weeks. Our results show that the proposed framework accurately monitors pulse rate, thereby providing a gateway for long-term monitoring without relying on subject participation or the use of a dedicated wearable device.

Point-of-Care Ultrasound for Pulse Checks in Pediatric Cardiac Arrest: Two Illustrative Cases.

ABSTRACT: Cardiac arrest is an infrequent but high-stakes scenario in pediatrics. Manual central pulse checks are unreliable. Point-of-care ultrasound is a noninvasive technique to visualize the heart and central vessels during resuscitation. We describe 2 cases in which point-of-care ultrasound helped aid management decisions in pediatric cardiac arrest.

Entrapment of the brachial artery in the cancellous bone in pulseless supracondylar humerus fractures with well-perfused hands: Report of three cases.

Management of pediatric pulseless supracondylar humerus fractures is a point of continuous debate. In this article, we present three cases admitted to the emergency department with pulseless, but well-perfused hands. The fractures were reduced and fixed using the antecubital approach. Prior to reduction, the brachial arteries of all three patients were entrapped in the cancellous bone of the proximal fragment segment. The arteries could only be released after freeing the adventitia by carefully scraping the adjacent bone with the tip of a hemostat. One case required thrombectomy through an arteriotomy using No. 3 Fogarty catheter. In two cases, the pulse returned after a brief period of waiting with no need for vascular intervention. Proceeding with closed reduction, as proposed by the recent guidelines, would result in further damage to the entrapped vasculature, which may go unnoticed due to collateral circulation.

A Modern Day Timeline for In-Hospital Monitoring in Perfused, Pulseless Pediatric Supracondylar Humerus Fractures.

BACKGROUND: The perfused, pulseless supracondylar humerus fracture (ppSCHF) remains a consistent topic of discussion in the literature. Inpatient observation of these patients postoperatively for worsening vascular exam or compartment syndrome is frequently recommended but not well studied. The purpose of this study was to evaluate the postoperative complications in a cohort of ppSCHF patients and their timeline to discharge. METHODS: This study is a retrospective review of a prospectively maintained database of all operatively treated supracondylar humerus fractures from a tertiary pediatric hospital from 2013 to 2019. All patients without a palpable pulse were included. We excluded patients with <4 weeks follow-up. Demographic, operative, and postoperative data were collected, including time from presentation to operating room (OR), time from OR to discharge, and incidence of postoperative complications, including return to OR, compartment syndrome, new neurovascular deficits, and Volkmann contractures. The descriptive statistics were used to summarize the data. RESULTS: Among 1371 operatively treated supracondylar humerus fractures, 39 (2.8%) presented with a ppSCHF. Five (15%) had a signal on doppler ultrasound, whereas 34 (85%) had no signal. Thirty-seven (95%) patients had a Gartland type III fracture and 2 (5%) had type IV fractures. Twenty-two (56%) patients had a neurological deficit, of which 14 had an anterior interosseous nerve deficit. The average time to OR was 6.9 (range 2.2 to 15) hours; 6 (15%) required open reduction. At the time of discharge, 85% of patients had a palpable pulse and 13% had a dopplerable signal. Postoperatively, no patients were returned to the OR for any secondary procedures. The average length of stay after the operation was 25 (range 8.5 to 40) hours, with 92% of patients being discharged by 36 hours postoperatively. No patients developed compartment syndrome, new neurological deficits, or Volkmann contractures at a mean follow-up of 112 (range 34 to 310) days. CONCLUSIONS: In our study of 39 patients presenting with ppSCHF, no patient required an unexpected return to the OR, or developed post-treatment compartment syndrome, neurological deficits, or Volkmann contractures. The average time from OR to discharge for ppSCHF was 25 hours. LEVEL OF EVIDENCE: Level II.

Chip-less wireless electronic skins by remote epitaxial freestanding compound semiconductors.

Recent advances in flexible and stretchable electronics have led to a surge of electronic skin (e-skin)-based health monitoring platforms. Conventional wireless e-skins rely on rigid integrated circuit chips that compromise the overall flexibility and consume considerable power. Chip-less wireless e-skins based on inductor-capacitor resonators are limited to mechanical sensors with low sensitivities. We report a chip-less wireless e-skin based on surface acoustic wave sensors made of freestanding ultrathin single-crystalline piezoelectric gallium nitride membranes. Surface acoustic wave-based e-skin offers highly sensitive, low-power, and long-term sensing of strain, ultraviolet light, and ion concentrations in sweat. We demonstrate weeklong monitoring of pulse. These results present routes to inexpensive and versatile low-power, high-sensitivity platforms for wireless health monitoring devices.