Non-Invasive Device for Blood Pressure Wave Acquisition by Means of Mechanical Transducer

Blood pressure wave monitoring provides interesting information about the patient’s cardiovascular function. For this reason, this article proposes a non-invasive device capable of capturing the vibrations (pressure waves) produced by the carotid artery by means of a pressure sensor encapsulated in a closed dome filled with air. When the device is placed onto the outer skin of the carotid area, the vibrations of the artery will exert a deformation in the dome, which, in turn, will lead to a pressure increase in its inner air. Then, the sensor inside the dome captures this pressure increase. By combining the blood pressure wave obtained with this device together with the ECG signal, it is possible to help the screening of the cardiovascular system, obtaining parameters such as heart rate variability (HRV) and pulse transit time (PTT). The results show how the pressure wave has been successfully obtained in the carotid artery area, discerning the characteristic points of this signal. The features of this device compare well with previous works by other authors. The main advantages of the proposed device are the reduced size, the cuffless condition, and the potential to be a continuous ambulatory device. These features could be exploited in ambulatory tests.D.Z.V. thanks the economic support of the ACIF (subsidies for the recruitment of predoctoral research staff) program with the scholarship ACIF/2019/058. The work of J.M.V.-S. was supported by Conselleria d’Educació, Investigació, Cultura i Esport (GVA) through FDGENT/2018/015 project. The work of C.G.J. was funded by the Spanish Ministry of Education, Culture, and Sport through the Research and Doctorate Supporting Program FPU, grant number FPU14/00401. This work was partially funded by Spanish Research State Agency and European Regional Development Fund through “Craneeal” Project (DPI2106-80391-C3-2-R)

Cardiovascular instrumentation for spaceflight

The observation mechanisms dealing with pressure, flow, morphology, temperature, etc. are discussed. The approach taken in the performance of this study was to (1) review ground and space-flight data on cardiovascular function, including earlier related ground-based and space-flight animal studies, Mercury, Gemini, Apollo, Skylab, and recent bed-rest studies, (2) review cardiovascular measurement parameters required to assess individual performance and physiological alternations during space flight, (3) perform an instrumentation survey including a literature search as well as personal contact with the applicable investigators, (4) assess instrumentation applicability with respect to the established criteria, and (5) recommend future research and development activity. It is concluded that, for the most part, the required instrumentation technology is available but that mission-peculiar criteria will require modifications to adapt the applicable instrumentation to a space-flight configuration

STATE OF THE ART INVESTIGATION IN MEDICAL ULTRASOUND DIAGNOSTICS USING PATENT PUBLICATIONS DATABASE

Patents are now an integral part of global economy. The creation of the world trade system has also redefined the value of intellectual property protection and generated an unprecedented demand for patent protection that is no longer limited to the traditionally patent-oriented economies of Europe, Japan and the USA. Countries like China, India and Korea, and Singapore and Israel too, are just some of the new players heavily involved in patent-driven innovative competition. Patents protect technical inventions. An invention can, for example, be a product, process or apparatus. Inventions are only patentable if they are novel, industrially applicable and involve an inventive step, but even then patent protection is not granted automatically. The application must be accompanied by a full technical description of the invention, which the Office then examines for compliance with the European Patent Convention. Patents give their owners the right to prevent others from using their invention, and are thus of major economic importance. They also help to recoup research costs, allowing the inventor to reinvest in research and development. The publication requirement allows competitors to build on patented inventions and come up with even better technical solutions. In doing so, patents boost the innovation which Europe badly needs to keep up with other economies, and contribute to the further development of a knowledge society. The 56 million or so patent documents contained in the public EPO database constitute a vast trove of technical information. The field of medical device, according to European Patent Office Annual Report of 2005, is one of the technical fields with the most filings. This state of the art investigation, performed using the patent publications database, is focused on the field of diagnostic ultrasound, a field that thanks to its non ionizing nature and low cost is a very high growing area and a lot of scientific research is made. Scope of this work is to provide an useful tool that allows to check the level of the ultrasound technology and to indicate the future direction of this technique. Scope of this work is also to provide information to all the researchers and inventors who want to set out a patent procedure of an invention. As known, the patent procedure, from the filing day until the decision of granting the patent is quite expensive, this work could be used as a primary consultation tool before to present a patent application. All chapters of this work contains an introduction that explain the technical problematic of a field and in the subsequent sections the solutions are described. In the first chapter of this work the European Patent Office and the world of patents is introduced. A special attention is revolted to several articles of the EPC (European Patent Convention) and to the classification system adopted by the EPO. Some statistics about European patent application filed in 2005 are illustrated and the difference between the first to invent system adopted by EPO (and by the majority of countries) and the first to invent system (adopted by U.S.A.) will be treated at the end of this chapter. In the second chapter the basics of ultrasound are illustrated with particular attention to the physics principles that are at the base of ultrasound devices described in this state of the art investigation. The state of the art is divided in 5 chapters, from 3 to 7, each chapter is about a specific technique. In the third chapter the ultrasound contrast agents are introduced and their main diagnostic application are disclosed. The fourth chapter is about three dimensional imaging, this field is divided in 4 section: mechanical, free-hand, 2D arrays and catheters. In the fifth chapter the technique of elastography and its application is described focusing on the stimulation protocols and methods. The sixth chapter is directed to all the devices that allow to study the blood flow inside vessels and arteries and the seventh chapter treats about the ultrasound catheters and their characteristics. At the end of each chapter statistics about the trends in European patent application in the last 25 years will be illustrated. In the conclusion of this work the future developments field of ultrasound technique will be illustrated

Advanced sensors technology survey

This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed

Evaluation of an electro-pneumatic device for artificial capillary pulse generation used in a prospective study in animals for surgical neck wound healing

The paper examines the development and testing of an electro-pneumatic device for wound healing therapy after surgery in the neck area. The device generates air pressure values in a miniaturized cuff using electronic circuitry to drive an electro-valve and air compressor. The device works in two distinct modes: continuous pressure mode and pulsating pressure mode. The pressure value setting can vary from 3 to 11 mmHg, and the pulsating pressure mode's operating frequency range is approximately 0.1 to 0.3 Hz. Laboratory measurements were conducted to evaluate the device's correct functioning in both continuous and pulsating pressure modes. A four-day prospective study with animals (n = 10) was also conducted to evaluate neck wound healing therapy using the electro-pneumatic device. Out of the twelve histological parameters analysed to reveal the differences between the experimental and control wounds, only one demonstrated a significant difference. Out of the ten animals treated with the device, three showed a significant difference in terms of benefit after therapy. We can therefore conclude that the device potentially improves the wound healing process in the neck area if the pre-set air pressure value does not exceed 8 mmHg.Web of Science9art. no. 983

Arterial Tissue Perforation Using Ultrasonically Vibrating Wire Waveguides

Chronic Total Occlusions (CTOs) are fibrous and calcified atherosclerotic lesions which completely occlude the artery. They are difficult to treat with standard dilation procedures as they cannot be traversed easily. Their treatment is also associated with a high risk of arterial perforation. Low frequency ultrasonic vibrations delivered via wire waveguides represent a minimally invasive treatment for CTOs and other tissue ablation applications. These devices typically operate at 20–50 kHz delivering wire waveguide distal tip amplitudes of vibration of 0-60 μm. The diseased tissue is ablated or disrupted by repetitive direct mechanical contact and cavitation. This research assesses the susceptibility of arterial tissue to perforation and residual damage under the action of ultrasonically energised wire waveguides. Using Finite Element Analysis (FEA), a linear acoustic model of the wire waveguide distal tips can predict the pressures for a range of operating parameters typically used for these devices. High mesh densities (140 EPW) were required to solve the entire acoustic field, including complex wave interactions. The FEA model was used to aid in the further design and modification of an ultrasonic apparatus and wire waveguide (0–34.3 μm at 22.5 kHz). Using a test rig, the effects of distal tip amplitudes of vibration, feedrate and angled entry on the perforation forces, energy and temperature were measured. The perforation forces reduced (≈ 60%, 6.13 N - 2.46 N mean) when the wire waveguide was energised at low amplitudes of vibrations (\u3c 27.8 μm). There were no significant change in tissue perforation forces above this or when the waveguide was operating above the cavitation threshold. Histological analysis also showed tissue removal. While this knowledge is useful in the prediction and avoidance of perforations during CTO operations; it is also envisaged that this information can aid in the design and development of generic ultrasonic wire waveguide tissue cutting tools

Development of a measurement procedure for the assessment of carotid blood pressure by means of Laser Doppler Vibrometry

L'ipertensione è uno dei principali fattori di rischio per numerose patologie, quali infarto del miocardio, insufficienza cardiaca e renale, ictus, e rappresenta la principale causa di morte al Mondo. Risulta, pertanto, fondamentale il monitoraggio della pressione arteriosa nell'ambito della prevenzione dell'insorgere di gravi patologie. Lo scopo del presente lavoro è di validare una procedura di misura per la determinazione della pressione arteriosa carotidea mediante la tecnica della vibrometria Laser Doppler (LDV). Essa è una tecnica di misura senza contatto ad elevata sensibilità, in grado di rilevare le vibrazioni della pelle legate all'attività cardiovascolare. Nel presente lavoro, il segnale LDV è stato acquisito su 28 soggetti sani ed è stato calibrato per mezzo di un opportuno modello matematico esponenziale per ottenere la forma d'onda di pressione carotidea a partire dallo spostamento del vaso sanguigno. I risultati ottenuti sono stati confrontati con due tecniche di riferimento, la sfigmomanometria e la tonometria arteriosa. La pressione sistolica ottenuta dal segnale LDV calibrato ha mostrato una deviazione percentuale inferiore del 4% e del 8 % rispetto a quella ottenuta tramite cuffia sfigmomanometrica e tonometria rispettivamente. L'integrazione del segnale e l'applicazione di un modello di calibrazione sono state considerate quali significative fonti di incertezza, e si è stimata un'incertezza complessiva di circa il 15 % nella misura della pressione sistolica. Dal segnale LDV sono stati determinati altri significativi parametri emodinamici quali il tempo di eiezione del ventricolo sinistro e la rigidità arteriosa. In conclusione, la tecnica di misura proposta mostra buona correlazione con i metodi di misura di riferimento, benchè vadano prese in considerazione alcune criticità quali l'individuazione del punto di misura, la presenza di artefatti da movimento e di fenomeni di riflessione non legati all'impulso pressorio oggetto di studio.High blood pressure is a great risk factor for several physiological diseases, i.e. myocardial infarction, heart failure, stroke, renal failure. Therefore, blood pressure measurement is a fundamental aspect of health monitoring. The aim of the present work is to validate a measurement procedure for the assessment of carotid blood pressure by means of Laser Doppler Vibrometry (LDV). LDV is a non-contact technique able to detect the skin vibrations due to the cardiovascular activity. In this study, LDV signal was acquired from 28 healthy participants and it was calibrated by means of an exponential mathematical model in order to obtain the carotid pressure waveform from the displacement of the vessel. The results have been compared with two standard techniques for the assessment of blood pressure, sphygmomanometric method and arterial applanation tonometry. The systolic peak of the calibrated waveform from LDV showed an average percentage deviation inferior to 10 % from the one assessed by means of reference techniques. The accuracy of the present measurement technique is discussed, considering the signal integration and the application of the calibration model as significant contributions to the total amount of uncertainty. An average percentage uncertainty of around 15 % has been obtained in the measure of carotid systolic pressure. Moreover, other hemodynamic significant parameters, such as arterial stiffness and Left Ventricular Ejection Time, have been derived from LDV data, showing good correlation with the measures of the reference methods. In conclusion, the proposed measurement technique, for the assessment of carotid blood pressure, shows good agreement with the reference techniques. Overall, some critical issues must be considered, such as the correct localization of the measurement point, the presence of movement artifacts and reflection phenomena not related to the pressure pulse in the investigated vessel

Southwest Research Institute assistance to NASA in biomedical areas of the technology utilization program

The activities are reported of the NASA Biomedical Applications Team at Southwest Research Institute between 25 August, 1972 and 15 November, 1973. The program background and methodology are discussed along with the technology applications, and biomedical community impacts