China
Africa
Explore chapters and articles related to this topic
Liveness Detection in Biometric Devices
Published in Richard C. Dorf, Circuits, Signals, and Speech and Image Processing, 2018
Stephanie A.C. Schuckers, Reza Derakhshani, Sujan T.V. Parthasaradhi, Lawrence Hornak
Liveness falls into three main approaches. The first approach is the utilization of additional hardware in conjunction with the biometric sensor. Examples of this approach include thermal sensing of finger temperature [13], ECG [13], impedance and electrical conductivity of the skin (dielectric response) [14], and pulse oximetry [13,15]. Pulse oximetry is a standard medical monitoring tool, which utilizes the variation over time of the absorption of light due to oxygenated and deoxygenated blood (typically, 660 and 940 nm) [16]. While effective in determining liveness, these methods require additional hardware, which is costly and, unless integrated properly, may be spoofed with an unauthorized live person.
Blood Chemistry Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Pulse oximetry is based on the transmission, absorption, and dispersion of light as it passes through hemoglobin. Beer’s law, as stated in Equation 68.1, determines the transmission of light through a substance. For pulse oximetry, the light illuminates both arterial and venous blood and the light must traverse all tissue between light source and receiver. Figure 68.7 represents the light path and indicates a variable (ac) path length as well as a constant (dc) path length.
Body Systems: The Basics
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
Blood pressure, sometimes called arterial blood pressure, is the pressure of circulating blood on the walls of the arteries. A peak pressure (systolic) is produced when the heart beats. When the heart muscle rests and the heart refills with blood (between beats) a lower, diastolic, pressure is evident. Arterial blood pressure, along with pulse, is a principal vital sign measured to assess both healthy people and people who are ill, under stress, or have experienced trauma. Wearable products have been designed to monitor blood pressure. You may have experienced having your blood pressure taken. The medical professional wraps a band called a cuff around your upper arm. The inflatable cuff expands putting pressure on the brachial artery, the major artery of the arm. As the cuff pressure is released the device (sphygmomanometer) detects the systolic pressure and then the diastolic pressure. The pressures are recorded in millimeters of mercury, for example 120/80 (spoken as “120 over 80”). The normal blood pressure for systolic is 90–119 and for diastolic 60–79. Pressures below those numbers indicate a state of hypotension and numbers above are described in four stages from prehypertension to hypertension (two stages) to hypertensive emergency (American Heart Association, 2016). Heart rhythm, heart muscle contraction strength, and heart rate can be measured simultaneously with electrocardiography (measurement of heart electrical activity), discussed in Chapter 4. Pulse oximetry is a non-invasive method for monitoring oxygen in the blood. Monitoring devices clip on the ear or the finger, or on the foot for infants. The device measures light absorption to determine the oxygen content of the pulsing arterial blood. The device must easily fasten to a part of the body that allows the light to penetrate through one side of the body and be picked up on the other side (Severinghaus & Honda, 1987).
Effective Monitoring for Early Detection of Hypoxia in Fighter Pilots
Published in The International Journal of Aerospace Psychology, 2023
Kosuke Kumagai, Satoshi Maruyama, Takahiro Imamura, Tetsuya Iwamoto, Yoshiki Kanamaru, Masaki Mine, Kunio Takada, Kojiro Wada
Hypoxic-hypoxia is a life-threatening condition for in-flight crew members in both military and civil aviation. Symptoms of hypoxia show individual differences, and may be difficult to recognize, because hypoxia is not accompanied by pain or discomfort (Van der Post et al., 2002). Hypoxia is very important to recognize and correct in the early stage for prevention of aircraft accidents. Pulse oximetry measuring peripheral tissue oxygen saturation (SpO2) is a useful and common tool for detecting hypoxia. However, pulse oximetry has some limitations because poor peripheral perfusion caused by hypothermia or hypotension, or motion artifact cause inaccurate and unreliable pulse oximetry readings. Previous research has investigated noninvasive and neurophysiological parameters to detect early signs of hypoxia in humans (Papadelis et al., 2007; Van der Post et al., 2002), but no method for the early detection of hypoxia on board an aircraft has yet been established.
Importance and use of pulse oximeter in COVID-19 pandemic: general factors affecting the sensitivity of pulse oximeter
Published in Indian Chemical Engineer, 2020
Kirtikumar C. Badgujar, Ashish B. Badgujar, Dipak V. Dhangar, Vivek C. Badgujar
Pulse oximeter is a small non-invasive device which is used to determine the hypoxia in patients [1–4]. The main function of the pulse oximeter is to determine the amount of oxygen saturation (SpO2), which indicates the amount of oxygen in the blood [2–4]. More particularly, it is the % of oxygenated haemoglobin as compared to total amount of haemoglobin (Hb) in the blood [3]. In the case of COVID-19, the major common observed symptoms at the onset of illness are fever, fatigue, dry-cough, myalgia and dyspnoea [5,6]. Patients having trouble in breathing in COVID-19 infection are showing development of pneumonia [5]. In such a case, oxygen exchange capacity of lungs decreases and subsequent hypoxia/dyspnoea is developed which is associated with the abnormal chest CT/X-ray, ground glass opacities, lung auscultation, crackles, multiple patch-like shadows, pleural effusion, ‘white lung-like’ change and consolidation [5–7]. To monitor/manage this situation, two medical instruments are essentially needed: (i) pulse oximeter (to determine the oxygen saturation in blood) and (ii) ventilator (to provide oxygenation therapy) [8,9]. Ventilators (depending on availability) can be available only in the case of well-facilitated hospitals or in medical emergency services; however, portable pocket pulse oximeters are very much available commercially which may play a crucial role in determining the oxygen carrying capacity [7–10].
IoT-Based Remote Diagnosis and Therapeutic Telemedicine Governing System
Published in IETE Journal of Research, 2022
Valeti Sai Deepak, Kolluru Sai Ganapathi Sastrulu, Koppineni Teja Naidu, Vetrivelan Pandu, K. B. Ajeyprasaath
A person with any illness that impacts blood oxygen levels; hence, it is evaluated using pulse oximetry. O2 saturation should be at least 95% normal. In elderly persons, it will be closer to 95%, while in younger ones, it will be closer to 99%. Lower saturations, as low as 89%, are common in people with long-term respiratory diseases like chronic obstructive (COPD) or asthma. Here, in Figure 8, the spo2 values in the first five dates are very low and started increasing to 120–150 percent which is the normal spo2 value. And also, at the end of the month, the spo2 value reached the nearest to the normal which is approximately 80%.