Physiological Impact of Hypothermia: The Good, the Bad and the Ugly

Physiology ◽  
2021 ◽  
Author(s):  
Torkjel Tveita ◽  
Gary C. Sieck
Keyword(s):  
Body Temperature ◽  
Therapeutic Hypothermia ◽  
Clinical Medicine ◽  
Core Body Temperature ◽  
Accidental Hypothermia ◽  
Striking Difference ◽  
Neurosurgical Procedures ◽  
Protective Agent ◽  
Core Body ◽  
The Impact

Hypothermia is defined as a core body temperature of < 35°C, and as body temperature is reduced the impact on physiological processes can be beneficial or detrimental. The beneficial effect of hypothermia enables circulation of cooled experimental animals to be interrupted for 1-2 h without creating harmful effects, while tolerance of circulation arrest in normothermia is between 4 and 5 min. This striking difference has attracted so many investigators, experimental as well as clinical, to this field, and this discovery was fundamental for introducing therapeutic hypothermia in modern clinical medicine in the 1950's. Together with the introduction of cardiopulmonary bypass, therapeutic hypothermia has been the cornerstone in the development of modern cardiac surgery. Therapeutic hypothermia also has an undisputed role as a protective agent in organ transplantation and as a therapeutic adjuvant for cerebral protection in neonatal encephalopathy. However, the introduction of therapeutic hypothermia for organ protection during neurosurgical procedures or as a scavenger after brain and spinal trauma has been less successful. In general, the best neuroprotection seems to be obtained by avoiding hyperthermia in injured patients. Accidental hypothermia occurs when endogenous temperature control mechanisms are incapable of maintaining core body temperature within physiologic limits and core temperature becomes dependent on ambient temperature. During hypothermia spontaneous circulation is considerably reduced and with deep and/or prolonged cooling, circulatory failure may occur, which may limit safe survival of the cooled patient. Challenges that limit safe rewarming of accidental hypothermia patients include cardiac arrhythmias, uncontrolled bleeding, and "rewarming shock".

scholarly journals A novel mouse model of heatstroke accounting for ambient temperature and relative humidity

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kazuyuki Miyamoto ◽  
Keisuke Suzuki ◽  
Hirokazu Ohtaki ◽  
Motoyasu Nakamura ◽  
Hiroki Yamaga ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Temperature ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Organ Damage ◽  
Core Body ◽  
The Impact ◽  
Treatment Water

Abstract Background Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure. Methods Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS. Results The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage. Conclusions We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.

scholarly journals The Impact of Central and Peripheral Cyclooxygenase Enzyme Inhibition on Exercise-Induced Elevations in Core Body Temperature

2017 ◽  
Vol 12 (5) ◽  
pp. 662-667 ◽  
Author(s):  
Matthijs T.W. Veltmeijer ◽  
Dineke Veeneman ◽  
Coen C.C.W. Bongers ◽  
Mihai G. Netea ◽  
Jos W. van der Meer ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Skin Temperature ◽  
Core Body Temperature ◽  
Exercise Tests ◽  
Hypothalamic Temperature ◽  
Set Point ◽  
Exercise Induced ◽  
Core Body ◽  
The Impact

Purpose:Exercise increases core body temperature (TC) due to metabolic heat production. However, the exercise-induced release of inflammatory cytokines including interleukin-6 (IL-6) may also contribute to the rise in TC by increasing the hypothalamic temperature set point. This study investigated whether the exercise-induced increase in TC is partly caused by an altered hypothalamic temperature set point.Methods:Fifteen healthy, active men age 36 ± 14 y were recruited. Subjects performed submaximal treadmill exercise in 3 randomized test conditions: (1) 400 mg ibuprofen and 1000 mg acetaminophen (IBU/APAP), (2) 1000 mg acetaminophen (APAP), and (3) a control condition (CTRL). Acetaminophen and ibuprofen were used to block the effect of IL-6 at a central and peripheral level, respectively. TC, skin temperature, and heart rate were measured continuously during the submaximal exercise tests.Results:Baseline values of TC, skin temperature, and heart rate did not differ across conditions. Serum IL-6 concentrations increased in all 3 conditions. A significantly lower peak TC was observed in IBU/APAP (38.8°C ± 0.4°C) vs CTRL (39.2°C ± 0.5°C, P = .02) but not in APAP (38.9°C ± 0.4°C) vs CTRL. Similarly, a lower ΔTC was observed in IBU/APAP (1.7°C ± 0.3°C) vs CTRL (2.0°C ± 0.5°C, P < .02) but not in APAP (1.7°C ± 0.5°C) vs CTRL. No differences were observed in skin temperature and heart-rate responses across conditions.Conclusions:The combined administration of acetaminophen and ibuprofen resulted in an attenuated increase in TC during exercise compared with a CTRL. This observation suggests that a prostaglandin-E2-induced elevated hypothalamic temperature set point may contribute to the exercise-induced rise in TC.

scholarly journals Impaired Thermogenesis and a Molecular Signature for Brown Adipose Tissue inId2Null Mice

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Peng Zhou ◽  
Maricela Robles-Murguia ◽  
Deepa Mathew ◽  
Giles E. Duffield
Keyword(s):  
Adipose Tissue ◽  
Body Temperature ◽  
Brown Adipose Tissue ◽  
Energy Homeostasis ◽  
Core Body Temperature ◽  
Specific Pattern ◽  
Molecular Signature ◽  
Brown Adipose ◽  
Core Body ◽  
The Impact

Inhibitor of DNA binding 2 (ID2) is a helix-loop-helix transcriptional repressor rhythmically expressed in many adult tissues. Our previous studies have demonstrated thatId2null mice have sex-specific elevated glucose uptake in brown adipose tissue (BAT). Here we further explored the role ofId2in the regulation of core body temperature over the circadian cycle and the impact ofId2deficiency on genes involved in insulin signaling and adipogenesis in BAT. We discovered a reduced core body temperature inId2−/− mice. Moreover, inId2−/− BAT, 30 genes includingIrs1,PPARs, andPGC-1s were identified as differentially expressed in a sex-specific pattern. These data provide valuable insights into the impact ofId2deficiency on energy homeostasis of mice in a sex-specific manner.

scholarly journals Perinatal Infection: A Major Contributor to Efficacy of Cooling in Newborns Following Birth Asphyxia

2021 ◽  
Vol 22 (2) ◽  
pp. 707
Author(s):  
Jibrin Danladi ◽  
Hemmen Sabir
Keyword(s):  
Gene Expression ◽  
Heat Shock ◽  
Body Temperature ◽  
Therapeutic Hypothermia ◽  
Cold Shock ◽  
Core Body Temperature ◽  
Cold Shock Protein ◽  
Perinatal Infection ◽  
Wide Range ◽  
Core Body

Neonatal encephalopathy (NE) is a global burden, as more than 90% of NE occurs in low- and middle-income countries (LMICs). Perinatal infection seems to limit the neuroprotective efficacy of therapeutic hypothermia. Efforts made to use therapeutic hypothermia in LMICs treating NE has led to increased neonatal mortality rates. The heat shock and cold shock protein responses are essential for survival against a wide range of stressors during which organisms raise their core body temperature and temporarily subject themselves to thermal and cold stress in the face of infection. The characteristic increase and decrease in core body temperature activates and utilizes elements of the heat shock and cold shock response pathways to modify cytokine and chemokine gene expression, cellular signaling, and immune cell mobilization to sites of inflammation, infection, and injury. Hypothermia stimulates microglia to secret cold-inducible RNA-binding protein (CIRP), which triggers NF-κB, controlling multiple inflammatory pathways, including nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasomes and cyclooxygenase-2 (COX-2) signaling. Brain responses through changes in heat shock protein and cold shock protein transcription and gene-expression following fever range and hyperthermia may be new promising potential therapeutic targets.

scholarly journals The Effect of Behaviour and Diet on the Rumen Temperature of Holstein Bulls

Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1000
Author(s):  
Rutherford ◽  
Gordon ◽  
Lively ◽  
Arnott
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Rumen Temperature ◽  
Activity Monitors ◽  
Concentrate Supplementation ◽  
Direct Observations ◽  
Healthy Cattle ◽  
Holstein Bulls ◽  
Core Body ◽  
The Impact

Rumen temperature boluses are becoming increasingly used as a means of monitoring core body temperature for the detection of ill health. However, the effect of behavior on rumen temperature is largely unknown. This research investigates the impact of behaviour and diet on the rumen temperature of Holstein bulls, both at grass, and in a housed environment. Rumen temperature was recorded at five-minute intervals using a bolus. Direct observations were conducted on young bulls in two studies (i) at grass (n = 30) and (ii) while housed (n = 32). In addition, activity monitors were attached to bulls at grass (n = 24). Within each study, diet differed by the level of concentrate supplementation. There was no effect of diet on rumen temperature. Significant differences in rumen temperature were observed between behaviour groups for bulls at grass (p < 0.001) and housed (p < 0.001). Furthermore, drinking resulted in the lowest rumen temperature (grass 35.97 °C; housed 36.70 °C). Therefore, rumen temperature is affected by behavior; however, the temperatures recorded were not outside the normal temperature range for healthy cattle.

scholarly journals The impact of exercise-induced core body temperature elevations on coagulation responses

2017 ◽  
Vol 20 (2) ◽  
pp. 202-207 ◽  
Author(s):  
Matthijs T.W. Veltmeijer ◽  
Thijs M.H. Eijsvogels ◽  
Wideke Barteling ◽  
Kitty Verbeek–Knobbe ◽  
Waander L. van Heerde ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Exercise Induced ◽  
Core Body ◽  
The Impact

The Impact of Ambient Temperature Control Across Various Care Settings on Outcomes in Burn Patients: A Review Article

2021 ◽  
pp. 000313482110385
Author(s):  
Kevin Kinter ◽  
Robert Alfaro ◽  
Mason Sutherland ◽  
Mark McKenney ◽  
Adel Elkbuli
Keyword(s):  
Body Temperature ◽  
Temperature Control ◽  
Room Temperature ◽  
Core Body Temperature ◽  
Current Evidence ◽  
Burn Treatment ◽  
Burn Care ◽  
Ambient Room Temperature ◽  
Core Body ◽  
The Impact

Ambient/room temperature settings in burn treatment areas vary greatly due to a lack of evidence-based guidelines to direct care. While it is generally understood that ambient/room temperature impacts patient body temperature and metabolism, the ideal settings for optimizing patient outcomes are unclear. The literature assessing this topic is scarce, with many of the articles having significant limitations. We aim to summarize the current evidence for ambient/room temperature control, to address gaps in current reviews addressing this topic, and to elucidate topics requiring further research. PubMed and Google Scholar databases were queried for studies which evaluated the effect of the ambient/room temperature on burn patient core body temperature, patient metabolism, and outcomes among those treated in trauma bays, burn ICUs, and operating rooms. Although existing literature lacks sufficient patient outcome data regarding specific ambient/room temperatures, we highlight physiological processes that are impacted by changes in room temperatures in an effort to describe strategies that can allow for improved patient core body temperature control and outcomes in burn care settings.

Forced-air pre-warming prevents peri-anaesthetic hypothermia and shortens recovery in adult rats

2017 ◽  
Vol 52 (2) ◽  
pp. 142-151 ◽  
Author(s):  
C J Schuster ◽  
D S J Pang
Keyword(s):  
Body Temperature ◽  
Core Temperature ◽  
Rectal Temperature ◽  
Core Body Temperature ◽  
Temperature Management ◽  
Limits Of Agreement ◽  
Adult Rats ◽  
Air Exposure ◽  
Core Body ◽  
The Impact

General anaesthesia disrupts thermoregulation in mammals, which can cause hypothermia. Decreases in core body temperature of 1℃ cause significant postoperative complications in humans, and peri-anaesthetic hypothermia in mice increases data variability, which can potentially increase animal use. In rats, the impact of different temperature management strategies on the incidence and severity of hypothermia, and the accuracy of different temperature measurement methods, is unknown. Eighteen adult male and female SD rats were block-randomized to one of three treatment groups: no-warming (NW), limited-warming (LW, heat pad during anaesthesia), and pre-warming (PW, warm air exposure before anaesthesia, followed by heat pad). Anaesthesia (isoflurane) duration was for 40 min. Core body temperature (intra-abdominal telemetric temperature capsule) was recorded during anaesthesia and recovery. During anaesthesia, rectal, skin, and tail temperatures were also recorded. In the PW group, core temperature was maintained during anaesthesia and recovery. By contrast, the NW group was hypothermic (11% temperature decrease) during anaesthesia. The LW group showed a decrease in temperature during recovery. Recovery to sternal recumbency was significantly faster in the PW (125 [70–186] s, P = 0.0003) and the LW (188 [169–420] s, P = 0.04) groups than in the NW group (525 [229–652] s). Rectal temperature underestimated core temperature (bias −0.90℃, 95% limits of agreement −0.1 to 1.9℃). Skin and tail temperatures showed wide 95% limits of agreement, spanning 6 to 15℃, respectively. The novel strategy of PW was effective at maintaining core temperature during and after anaesthesia. Rectal temperature provided an acceptable proxy for core body temperature.

scholarly journals Investigation of the Impact of Infrared Sensors on Core Body Temperature Monitoring by Comparing Measurement Sites

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2885 ◽  
Author(s):  
Hsuan-Yu Chen ◽  
Andrew Chen ◽  
Chiachung Chen
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Standard Operating Procedure ◽  
The Body ◽  
Tympanic Temperature ◽  
Good Precision ◽  
Infrared Sensors ◽  
Infrared Thermometer ◽  
Core Body ◽  
The Impact

Many types of thermometers have been developed to measure body temperature. Infrared thermometers (IRT) are fast, convenient and ease to use. Two types of infrared thermometers are uses to measure body temperature: tympanic and forehead. With the spread of COVID-19 coronavirus, forehead temperature measurement is used widely to screen people for the illness. The performance of this type of device and the criteria for screening are worth studying. This study evaluated the performance of two types of tympanic infrared thermometers and an industrial infrared thermometer. The results showed that these infrared thermometers provide good precision. A fixed offset between tympanic and forehead temperature were found. The measurement values for wrist temperature show significant offsets with the tympanic temperature and cannot be used to screen fevers. The standard operating procedure (SOP) for the measurement of body temperature using an infrared thermometer was proposed. The suggestion threshold for the forehead temperature is 36 °C for screening of fever. The body temperature of a person who is possibly ill is then measured using a tympanic infrared thermometer for the purpose of a double check.

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