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Adaptive low-power wrist SpO2 monitoring system design using a multi-filtering scheme. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2022.104432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Badiola I, Blazek V, Jagadeesh Kumar V, George B, Leonhardt S, Hoog Antink C. Accuracy enhancement in reflective pulse oximetry by considering wavelength-dependent pathlengths. Physiol Meas 2022; 43. [PMID: 35959652 DOI: 10.1088/1361-6579/ac890c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/11/2022] [Indexed: 11/11/2022]
Abstract
Objective. Noninvasive measurement of oxygen saturation (SpO2) using pulse oximetry based on transmissive photoplethysmography (tPPG) is clinically accepted and widely employed. However, reflective photoplethysmography (rPPG) - present in smartwatches - has not become equally accepted, partially because the pathlengths of the red and infrared PPGs are patient-dependent. Thus, even the most popular "Ratio of Modulation" (R) method requires patient-dependent calibration to reduce the errors in the measurement of SpO2 using rPPGs.Approach. In this paper, a correction factor or "pathlength ratio" β is introduced in an existing calibration-free algorithm that compensates the patient-dependent pathlength variations, and improved accuracy is obtained in the measurement of SpO2 using rPPGs. The proposed β is derived through the analytical model of a rPPG signal. Using the new expression and data obtained from a human hypoxia study wherein arterial oxygen saturation values acquired through Blood Gas Analysis were employed as a reference, β is determined.Main results. The results of the analysis show that a specific combination of the β and the measurements on the pulsating part of the natural logarithm of the red and infrared PPG signals yields a reduced root-mean-square error (RMSE). It is shown that the average RMSE in measuring SpO2 values reduces to 1 %.Significance. The human hypoxia study data used for this work, obtained in a previous study, coversSpO2values in the range from 70 % to 100 %, and thus shows that the pathlength ratio β proposed here works well in the range of clinical interest. This work demonstrates that the calibration-free method applicable for transmission type PPGs can be extended to determineSpO2using reflective PPGs with the incorporation of the correction factor β. Our algorithm significantly reduces the number of parameters needed for the estimation, while keeping the RMSE below the clinically accepted 2 %.
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Affiliation(s)
- Idoia Badiola
- Medical Information Technology (MedIT), RWTH Aachen University, Schurzelter Strasse 570, Aachen, 52074, GERMANY
| | - Vladimir Blazek
- Medical Information Technology (MedIT), RWTH Aachen University, Pauwelsstrasse 20, Aachen, 52074, GERMANY
| | - V Jagadeesh Kumar
- Department of Electrical Engineering, Indian Institute of Technology Madras, Madras, Chennai, Tamil Nadu, 600036, INDIA
| | - Boby George
- Department of Electrical Engineering, Indian Institute of Technology Madras, Madras, Chennai, Tamil Nadu, 600036, INDIA
| | - Steffen Leonhardt
- Medical Information Technology (MedIT), RWTH Aachen University, Pauwelsstr 20, Aachen, 52074, GERMANY
| | - Christoph Hoog Antink
- Künstlich intelligente Systeme der Medizin (KISMED), TU Darmstadt, Magdalenenstraße 4, Darmstadt, Hessen, 64289, GERMANY
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Mainard N, Tsiakaka O, Li S, Denoulet J, Messaoudene K, Vialle R, Feruglio S. Intraoperative Optical Monitoring of Spinal Cord Hemodynamics Using Multiwavelength Imaging System. SENSORS (BASEL, SWITZERLAND) 2022; 22:3840. [PMID: 35632249 PMCID: PMC9146887 DOI: 10.3390/s22103840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 12/10/2022]
Abstract
The spinal cord is a major structure of the central nervous system allowing, among other things, the transmission of afferent sensory and efferent motor information. During spinal surgery, such as scoliosis correction, this structure can be damaged, resulting in major neurological damage to the patient. To date, there is no direct way to monitor the oxygenation of the spinal cord intraoperatively to reflect its vitality. This is essential information that would allow surgeons to adapt their procedure in case of ischemic suffering of the spinal cord. We report the development of a specific device to monitor the functional status of biological tissues with high resolution. The device, operating with multiple wavelengths, uses Near-InfraRed Spectroscopy (NIRS) in combination with other additional sensors, including ElectroNeuroGraphy (ENG). In this paper, we focused primarily on aspects of the PhotoPlethysmoGram (PPG), emanating from four different light sources to show in real time and record biological signals from the spinal cord in transmission and reflection modes. This multispectral system was successfully tested in in vivo experiments on the spinal cord of a pig for specific medical applications.
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Affiliation(s)
- Nicolas Mainard
- Department of Pediatric Surgery, Jeanne-de-Flandre Hospital, CHU Lille, Avenue Eugène-Avinée, 59000 Lille, France
- Laboratoire D’Informatique de Paris 6 (LIP6), CNRS UMR7606, Sorbonne Université, 4 Place Jussieu, CEDEX 05, 75252 Paris, France; (S.L.); (J.D.); (K.M.); (S.F.)
| | - Olivier Tsiakaka
- CERVO, Biomedical Microsystems Laboratory, Université Laval, Quebec, QC G1V 0A6, Canada;
| | - Songlin Li
- Laboratoire D’Informatique de Paris 6 (LIP6), CNRS UMR7606, Sorbonne Université, 4 Place Jussieu, CEDEX 05, 75252 Paris, France; (S.L.); (J.D.); (K.M.); (S.F.)
| | - Julien Denoulet
- Laboratoire D’Informatique de Paris 6 (LIP6), CNRS UMR7606, Sorbonne Université, 4 Place Jussieu, CEDEX 05, 75252 Paris, France; (S.L.); (J.D.); (K.M.); (S.F.)
| | - Karim Messaoudene
- Laboratoire D’Informatique de Paris 6 (LIP6), CNRS UMR7606, Sorbonne Université, 4 Place Jussieu, CEDEX 05, 75252 Paris, France; (S.L.); (J.D.); (K.M.); (S.F.)
| | - Raphael Vialle
- Clinical Research Group “RIC” Robotics and Surgical Innovations, GRC-33 Sorbonne University, 26 Avenue du Dr. Arnold Netter, 75012 Paris, France;
| | - Sylvain Feruglio
- Laboratoire D’Informatique de Paris 6 (LIP6), CNRS UMR7606, Sorbonne Université, 4 Place Jussieu, CEDEX 05, 75252 Paris, France; (S.L.); (J.D.); (K.M.); (S.F.)
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Mohammad U, Awan MA, Bermak A, Tang F. State-of-the-Art Light to Digital Converter Circuits Applicable in Non-Invasive Health Monitoring Devices to Combat COVID-19 and Other Respiratory Illnesses: A Review. IEEE SENSORS JOURNAL 2022; 22:9189-9197. [PMID: 35939263 PMCID: PMC9280809 DOI: 10.1109/jsen.2022.3164148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/28/2022] [Indexed: 05/08/2023]
Abstract
In the past few years, a tremendous advancement in the outcome of biomedical circuits and systems has been reported. Unfortunately, at the time of the sudden outbreak of COVID-19, the electronic engineering researchers felt dearth on their side to combat the pandemic, as no such immediate cutting-edge solutions were ready to recognize the virus with some standard and smart electronic devices. Likely, in this paper, a detailed comparative and comprehensive study on circuit architectures of the biomedical devices is presented. Mostly, this study relates the industry standard circuit schemes applicable in non-invasive health monitoring to combat respiratory illnesses. The trending circuit architectural schemes casted-off to tapeout non-invasive health-care devices available in the past literature are meticulously and broadly discussed in this study. Further, the comprehensive comparison of the state of art of the device performance in terms of supply voltage, chip area, sensitivity, dynamic range, etc. is also shown in this paper. The inclusive design processes of the health monitoring devices from Lab to Industry is thoroughly discussed for the readers. The authors think, that this critical review summarising all the trending and most cited health-care devices in a single paper will alternately help the industrialists to adapt and modify the circuit architectures of the health monitoring devices more precisely and straightforwardly. Finally, the demand for health monitoring devices particularly responsible to detect respiratory illnesses, measuring blood pressure and heart-rate is growing widely in the market after the the incident of COVID-19 and other respiratory diseases.
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Affiliation(s)
- Umar Mohammad
- Chongqing Engineering Laboratory of High Performance Integrated CircuitsDepartment of Information and Communication EngineeringChongqing University Chongqing 400044 China
| | - M Asfandyar Awan
- College of Science and EngineeringHamad Bin Khalifa University Doha Qatar
- The Hong Kong University of Science and Technology Hong Kong
| | - Amine Bermak
- College of Science and EngineeringHamad Bin Khalifa University Doha Qatar
- The Hong Kong University of Science and Technology Hong Kong
| | - Fang Tang
- Chongqing Engineering Laboratory of High Performance Integrated CircuitsDepartment of Information and Communication EngineeringChongqing University Chongqing 400044 China
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