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Thermal Imaging in Detection of Fever for Infectious Diseases
Published in U. Snekhalatha, K. Palani Thanaraj, Kurt Ammer, Artificial Intelligence-Based Infrared Thermal Image Processing and Its Applications, 2023
U. Snekhalatha, K. Palani Thanaraj, Kurt Ammer
Prior to the discussion of the normal value of deep body temperature, some basic definitions of the thermoregulation system are provided to foster the understanding of fever. Thermoregulation aims to maintain body core temperature (Tb) within a narrow range. Tb is often considered to be the temperature of inner organs, particularly of the blood in the heart and the brain. However, the core is more of a concept than a practical body site. Measurement of true core temperature can only be obtained by invasive methods, but for convenience, oral, axillary, and rectal sites have become standard for clinical contact thermometry.
Thermal Physiology and Thermoregulation
Published in James Stewart Campbell, M. Nathaniel Mead, Human Medical Thermography, 2023
James Stewart Campbell, M. Nathaniel Mead
Increased core temperature or heatstroke, is common among those who work in hot, humid environments. Exposure to “wet-bulb” temperatures exceeding 35°C (95°F) for prolonged periods may be fatal even in the shade and with forced-air convection. A wet-bulb thermometer measures the ambient temperature minus the heat loss from water evaporation. Hyperthermia results when the body's core temperature rises above 40°C (104°F). If this temperature continues to rise and exceeds 42°C (107.6°F), cellular damage occurs.6 This manifests as progressive organ and neuronal dysfunction, eventually causing multi-organ failure.7 Active cooling is paramount for averting death in this situation.
Injuries Due to Burns and Cold
Published in Ian Greaves, Keith Porter, Jeff Garner, Trauma Care Manual, 2021
Ian Greaves, Keith Porter, Jeff Garner
In the UK, injuries due to cold are uncommon and, when seen, are normally associated with social deprivation or neglect. They are manifested as: Hypothermia, the systemic effects of a reduced core temperatureLocal tissue damage
A mathematical model to study thermoregulation and heat-transfer processes in hypothermic neonates under variable physiological parameters
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Hypothermia is a decrease in the body core temperature. It has negative effects for both term and preterm neonates. Due to insufficient and premature body defence system, neonates cannot resist hypothermic situation. Term-babies have several protective factors which prevent this abnormal decay in their body temperature. They develop brown fat in the last few weeks of gestation. This brown fat burns in order to produce heat in their bodies. They also have protection of more subcutaneous fat which helps them to insulate from the cold around them. But term-babies are still prone to hypothermia because they cannot shiver, as no neonate is capable of shivering. So term-babies can become hypothermic if they are exposed to too much cold or they are sick. During sickness, their brain does not work properly to regulate the body’s physiological processes. So term-babies become hypothermic without any apparent cause. Moreover, if the neonates are septic, their body temperature is usually low instead of high. Other factors by which they become hypothermic are through the problems with their brain such as asphyxia or meningitis and exposure to cold. When the baby is severely septic, the temperature can fluctuate up and down (see Guyton 2000; Keener and Sneyd 2009).
Hemodynamic response to thermal stress varies with sex and age: a murine MRI study
Published in International Journal of Hyperthermia, 2022
A. Colleen Crouch, Aditi Batra, Joan M. Greve
Core temperature impacts human performance and health. Humans maintain core temperature via the process of thermoregulation [1–5]. Thermoregulation is affected by changes in: convective heat transfer from skin to environment, autonomic nervous system and metabolic processes, and cardiovascular (CV) system. The CV system influences heat transfer via forced convection and conduction by changes in blood distribution (conduction and convection), proximity of vessels/tissues (conduction), and blood velocity (convection) [6]. Cardiac output, vessel size, blood flow velocity, and pressure all influence these parameters. In addition, sex and age influence the body’s ability to perceive and respond to changes in temperature [5,7–10] and affect the function of the CV system [11–13]. Therefore, the effect of body temperature on each parameter must be quantified, ideally across age and sex, to fully understand the CV system’s role in thermoregulation.
Non-contact infrared assessment of human body temperature: The journal Temperature toolbox
Published in Temperature, 2021
Josh Foster, Alex Bruce Lloyd, George Havenith
The threshold temperature is the temperature setting above which the target is potentially febrile [ISO13154, 14]. The ISO standard does not stipulate a precise threshold temperature and instead states that “the responsible organization should consult their medical advisor on the setting of the threshold temperature”. One difficulty with advising a threshold temperature is that a single temperature will yield different performance characteristics. If the threshold temperature is too low, it will result in many false positives. If it is set too high, it may result in many false negatives, contributing to the spread of infections. In a clinical setting, a forehead temperature threshold of 35.1°C provides a good balance of false positive and false negatives [5]. For the inner canthus temperature, a threshold temperature of 37.5°C is recommended in a clinical setting [25]. Given the limited accuracy of many NCIT devices in use in the field, a fixed threshold may represent quite different temperatures in reality. Some devices operate in an “adjusted mode”, which means the Tskin is converted to an internal body temperature with a proprietary algorithm. In that case, fever is defined as a core temperature exceeding 38°C.