Using HL7 FHIR to achieve interoperability in patient health record.

In the last decades, photoplethysmography (PPG) has been used as a noninvasive technique for monitoring arterial oxygen saturation by pulse oximetry (PO), whereas near-infrared spectroscopy (NIRS) has been employed for monitoring tissue blood perfusion. While NIRS offers more parameters to evaluate oxygen delivery and consumption in deep tissues, PO only assesses the state of oxygen delivery. For a broader assessment of blood perfusion, this paper explores the utilization of dual-wavelength PPG by using the pulsatile (ac) and continuous (dc) PPG for the estimation of arterial oxygen saturation (SpO2) by conventional PO. Additionally, the Beer–Lambert law is applied to the dc components only for the estimation of changes in deoxyhemoglobin (HHb), oxyhemoglobin (HbO2), and total hemoglobin (tHb) as in NIRS. The system was evaluated on the forearm of 21 healthy volunteers during induction of venous occlusion (VO) and total occlusion (TO). A reflectance PPG probe and NIRS sensor were applied above the brachioradialis, PO sensors were applied on the fingers, and all the signals were acquired simultaneously. While NIRS and forearm SpO2 indicated VO, SpO2 from the finger did not exhibit any significant drop from baseline. During TO, all the indexes indicated the change in blood perfusion. HHb, HbO2, and tHb changes estimated by PPG presented high correlation with the same parameters obtained by NIRS during VO ( r 2 = 0.960, r 2 = 0.821, and r 2 = 0.974, respectively) and during TO ( r 2 = 0.988, r 2 = 0.940, and r 2 = 0.938, respectively). The system demonstrated the ability to extract valuable information from PPG signals for a broader assessment of tissue blood perfusion.

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Reflectance Photoplethysmography as Noninvasive Monitoring of Tissue Blood Perfusion

For the last two decades, pulse oximetry has been used as a standard procedure for monitoring arterial oxygen saturation (SpO2). However, SpO2 measurements made from extremities such as the finger, ear lobe and toes become susceptible to inaccuracies when peripheral perfusion is compromised. To overcome these limitations, the external auditory canal has been proposed as an alternative monitoring site for estimating SpO2, on the hypothesis that this central site will be better perfused. Therefore, a dual wavelength optoelectronic probe along with a processing system was developed to investigate the suitability of measuring photoplethysmographic (PPG) signals and SpO2 in the human auditory canal. A pilot study was carried out in 15 healthy volunteers to validate the feasibility of measuring PPGs and SpO2 from the ear canal (EC), and comparative studies were performed by acquiring the same signals from the left index finger (LIF) and the right index finger (RIF) in conditions of induced peripheral vasoconstriction (right hand immersion in ice water). Good quality baseline PPG signals with high signal-to-noise ratio were obtained from the EC, the LIF and the RIF sensors. During the ice water immersion, significant differences in the amplitude of the red and infrared PPG signals were observed from the RIF and the LIF sensors. The average drop in amplitude of red and infrared PPG signals from the RIF was 52.7% and 58.3%. Similarly, the LIF PPG signal amplitudes have reduced by 47.52% and 46.8% respectively. In contrast, no significant changes were seen in the red and infrared EC PPG amplitude measurements, which changed by +2.5% and -1.2% respectively. The RIF and LIF pulse oximeters have failed to estimate accurate SpO2 in seven and four volunteers respectively, while the EC pulse oximeter has only failed in one volunteer. These results suggest that the EC may be a suitable site for reliable monitoring of PPGs and SpO2s even in the presence of peripheral vasoconstriction.

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The human ear canal: investigation of its suitability for monitoring photoplethysmographs and arterial oxygen saturation

The suitability of different methods of finding the foot point of a pulse as measured using earlobe photoplethysmography during stationary conditions was investigated. Instantaneous pulse period (PP) values from PPG signals recorded from the ear in healthy volunteer subjects were compared with simultaneous ECG-derived cardiac periods (RR interval). Six methods of deriving pulse period were used, each based on a different method of finding specific landmark points on the PPG waveform. These methods included maximum and minimum value, maximum first and second derivative, ‘intersecting tangents’ and ‘diastole patching’ methods. Selected time domain HRV variables were also calculated from the PPG signals obtained using multiple methods and compared with ECG-derived HRV variables. The correlation between PPG and ECG was greatest for the intersecting tangents method compared to the other methods (RMSE = 5.69 ms, r2 = 0.997). No significant differences between PP and RR were seen for all PPG methods, however the PRV variables derived using all methods showed significant differences to HRV, attributable to the sensitivity of PRV parameters to pulse transients and artifacts. The results suggest that the intersecting tangents method shows the most promise for extracting accurate pulse rate variability data from PPG datasets. This work has applications in other areas where pulse arrival time is a key measurement including pulse wave velocity assessment.

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Comparison of foot finding methods for deriving instantaneous pulse rates from photoplethysmographic signals

Objectives: The purpose of this study was to review history and trends of personal health record research in PubMed and to provide accurate understanding and categorical analysis of expert opinions. Methods: For the search strategy, PubMed was queried for ‘personal health record, personal record, and PHR’ in the title and abstract fields. Those containing different definitions of the word were removed by one-by-one analysis from the results, 695 articles. In the end, total of 229 articles were analyzed in this research. Results: The results show that the changes in terms over the years and the shift to patient centeredness and mixed usage. And we identified history and trend of PHR research in some category that the number of publications by year, topic, methodologies and target diseases. Also from analysis of MeSH terms, we can show the focal interest in regards the PHR boundaries and related subjects. Conclusions: For PHRs to be efficiently used by general public, initial understanding of the history and trends of PHR research may be helpful. Simultaneously, accurate understanding and categorical analysis of expert opinions that can lead to the development and growth of PHRs will be valuable to their adoption and expansion.

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History and Trends of "Personal Health Record" Research in PubMed.

Photoplethysmography (PPG) is a non-invasive optical technique used in detecting blood volume changes in vascular tissue. In recent years, photoplethysmography has generated renewed interest among researchers, particularly due to its potential for widespread clinical applications beyond estimating heart rate and arterial oxygen saturation. Progress in these areas of research is dependent on PPG systems with the ability to record raw photoplethysmographic signals with high signal-to-noise ratio, ideally from more than one channel and one wavelength, for real-time or retrospective analysis. In this work we present the design, development and validation of such a modular PPG system. “Zen PPG” - a portable (16.0 × 10.3 × 5.4 cm) battery operated dual channel, dual wavelength system with the capability to operate with commercial sensors was developed and calibrated using a FLUKE Index 2 SpO2 simulator. A brief study has been conducted on a small group of healthy volunteers to demonstrate the functionality of the system. Red and Infrared PPG signals obtained from volunteers were used to estimate SpO2 and heart rate. These results were compared with simultaneously acquired data from a commercial pulse oximeter (Masimo Radical 7). The SpO2 values showed close correlation between commercial and custom made system (Channel 1: r2 = 0.978; channel 2: r2= 0.708).

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Design and development of a novel multi-channel photoplethysmographic research system

Photoplethysmography (PPG) is a technique that uses light to noninvasively obtain a volumetric measurement of an organ with each cardiac cycle. A PPG-based system emits monochromatic light through the skin and measures the fraction of the light power which is transmitted through a vascular tissue and detected by a photodetector. Part of thereby transmitted light power is modulated by the vascular tissue volume changes due to the blood circulation induced by the heart beating. This modulated light power plotted against time is called the PPG signal. Pulse Oximetry is an empirical technique which allows the arterial blood oxygen saturation (SpO2 – molar fraction) evaluation from the PPG signals. There have been many reports in the literature suggesting that other arterial blood chemical components molar fractions and concentrations can be evaluated from the PPG signals. Most attempts to perform such evaluation on empirical bases have failed, especially for components concentrations. This paper introduces a non-empirical physical model which can be used to analytically investigate the phenomena of PPG signal. Such investigation would result in simplified engineering models, which can be used to design validating experiments and new types of spectroscopic devices with the potential to assess venous and arterial blood chemical composition in both molar fractions and concentrations non-invasively.

http://iopscience.iop.org/article/10.1088/1742-6596/238/1/012061/pdf

Beer-lambert law along non-linear mean light pathways for the rational analysis of Photoplethysmography

In most emergency situations, health professionals rely on patients to provide information about their medical history. However, in some cases patients might not be able to communicate this information, and in most countries an online integrated patient record system has not been adopted yet. Therefore, in order to address this issue the ongoing project MyCare Card (MyC2, www.myc2.org) has been established. The aim of this project is to design, implement, and evaluate a prototype patient held electronic health record device. Due to the wide range of user requirements, the device, its communication interface, and its software have to be compatible with many common platforms and operating systems. Thus, this paper is addressing one of the software compatibility matters-the cross-platform GUI implementation. It introduces a portable object-oriented GUI framework, suitable for a declarative layout definition, components customization, and fine model-view code separation. It also rationalizes the hardware and software solutions selected for this project implementation.

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MyCare Card Development: Portable GUI Framework for the Personal Electronic Health Record Device

In most emergency situations, health professionals rely on patients to provide information about their medical history. However, in some cases patients might not be able to communicate this information, and in most countries, including the UK an on-line integrated patient record system has not been adopted. Therefore, in order to address this issue the ongoing project MyCare Card (MyC2, www.myc2.org) has been established. The aim of this project is to design, implement and evaluate a prototype patient held electronic health record card. One of the tasks involved in the project was to develop a Graphical User Interface (GUI) software, which provides access to the data stored on the card. The requirements for this software had to be established via questionnaire surveys and end user evaluations, conducted simultaneously with the software development. This paper is addressing development of the MyCare Card GUI software. It also overviews the hardware and open-source software solutions selected for the MyCare Card implementation.

/pdf/development-of-a-personal-electronic-health-record-card-in-1ejd0pkfm6.pdf

Development of a personal electronic health record card in the United Kingdom

Photoplethysmography (PPG) is a technique that uses light to non-invasively obtain a volumetric measurement of an organ with each cardiac cycle. Pulse Oximetry (PO) is an empirical technique which allows the arterial blood oxygen saturation (SpO2) evaluation from the PPG signals. There have been many reports in the literature suggesting that other arterial blood chemical components can be evaluated from the PPG signals. Most attempts to perform such evaluation on empirical bases have failed, especially for components concentrations. This paper introduces a non-empirical rational theory called Dynamic Pulsatile Spectroscopy (DPS) which can be used to analytically investigate the phenomena of PPG. The DPS theory provides the mathematically rigid method of how PPG signals can be used for arterial blood analysis to evaluate its chemical component concentrations and molar fractions spectroscopically and transcutaneously. It also highlights what other signals might be required for such evaluation. DPS opens the possibility of extending PPG application for blood analysis beyond conventional PO. The DPS basic principles are introduced in this paper.

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V O Rybynok

Papers

Design and development of a novel multi-channel photoplethysmographic research system

Beer-lambert law along non-linear mean light pathways for the rational analysis of Photoplethysmography

MyCare Card Development: Portable GUI Framework for the Personal Electronic Health Record Device

Development of a personal electronic health record card in the United Kingdom

Theory of Dynamic Pulsatile Spectroscopy for photoplethysmographic signals analysis