scholarly journals Hypercapnia increases core temperature cooling rate during snow burial

2004 ◽  
Vol 96 (4) ◽  
pp. 1365-1370 ◽  
Author(s):  
Colin K. Grissom ◽  
Martin I. Radwin ◽  
Mary Beth Scholand ◽  
Chris H. Harmston ◽  
Mark C. Muetterties ◽  
...  
Keyword(s):  
Body Temperature ◽  
Cooling Rate ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Minute Ventilation ◽  
Clothing Insulation ◽  
Prehospital Treatment ◽  
Core Body ◽  
Snow Temperature ◽  
Burial Time

Previous retrospective studies report a core body temperature cooling rate of 3°C/h during avalanche burial. Hypercapnia occurs during avalanche burial secondary to rebreathing expired air, and the effect of hypercapnia on hypothermia during avalanche burial is unknown. The objective of this study was to determine the core temperature cooling rate during snow burial under normocapnic and hypercapnic conditions. We measured rectal core body temperature (Tre) in 12 subjects buried in compacted snow dressed in a lightweight clothing insulation system during two different study burials. In one burial, subjects breathed with a device (AvaLung 2, Black Diamond Equipment) that resulted in hypercapnia over 30-60 min. In a control burial, subjects were buried under identical conditions with a modified breathing device that maintained normocapnia. Mean snow temperature was -2.5 ± 2.0°C. Burial time was 49 ± 14 min in the hypercapnic study and 60 min in the normocapnic study ( P = 0.02). Rate of decrease in Tre was greater with hypercapnia (1.2°C/h by multiple regression analysis, 95% confidence limits of 1.1-1.3°C/h) than with normocapnia (0.7°C/h, 95% confidence limit of 0.6-0.8°C/h). In the hypercapnic study, the fraction of inspired carbon dioxide increased from 1.4 ± 1.0 to 7.0 ± 1.4%, minute ventilation increased from 15 ± 7 to 40 ± 12 l/min, and oxygen saturation decreased from 97 ± 1 to 90 ± 6% ( P < 0.01). During the normocapnic study, these parameters remained unchanged. In this study, Tre cooling rate during snow burial was less than previously reported and was increased by hypercapnia. This may have important implications for prehospital treatment of avalanche burial victims.

scholarly journals Temperature Monitoring and Perioperative Thermoregulation

2008 ◽  
Vol 109 (2) ◽  
pp. 318-338 ◽  
Author(s):  
Daniel I. Sessler ◽  
David S. Warner ◽  
Mark A. Warner
Keyword(s):  
Body Temperature ◽  
General Anesthesia ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Neuraxial Anesthesia ◽  
General Anesthetics ◽  
The Core ◽  
Core Body ◽  
Dose Dependent ◽  
Body Heat

Most clinically available thermometers accurately report the temperature of whatever tissue is being measured. The difficulty is that no reliably core-temperature-measuring sites are completely noninvasive and easy to use-especially in patients not undergoing general anesthesia. Nonetheless, temperature can be reliably measured in most patients. Body temperature should be measured in patients undergoing general anesthesia exceeding 30 min in duration and in patients undergoing major operations during neuraxial anesthesia. Core body temperature is normally tightly regulated. All general anesthetics produce a profound dose-dependent reduction in the core temperature, triggering cold defenses, including arteriovenous shunt vasoconstriction and shivering. Anesthetic-induced impairment of normal thermoregulatory control, with the resulting core-to-peripheral redistribution of body heat, is the primary cause of hypothermia in most patients. Neuraxial anesthesia also impairs thermoregulatory control, although to a lesser extent than does general anesthesia. Prolonged epidural analgesia is associated with hyperthermia whose cause remains unknown.

scholarly journals The Effects of Hyperbaric Exposure on Immediate and Delayed Changes in Core Temperature and Its Circadian Fluctuations

2017 ◽  
Vol 60 (3) ◽  
pp. 19-25
Author(s):  
Sławomir Kujawski ◽  
Joanna Słomko ◽  
Monika Zawadka-Kunikowska ◽  
Mariusz Kozakiewicz ◽  
Jacek J. Klawe ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Temperature ◽  
Core Body Temperature ◽  
The Body ◽  
Physiological Adaptation ◽  
Deep Body Temperature ◽  
Delayed Effects ◽  
Hyperbaric Exposure ◽  
Core Body ◽  
Deep Body

Abstract Changes observed in the core body temperature of divers are the result of a multifaceted response from the body to the change of the external environment. In response to repeated activities, there may be a chronic, physiological adaptation of the body’s response system. This is observed in the physiology of experienced divers while diving. The purpose of this study is to determine the immediate and delayed effects of hyperbaric exposure on core temperature, as well as its circadian changes in a group of three experienced divers. During compression at 30 and 60 meters, deep body temperature values tended to increase. Subsequently, deep body temperature values showed a tendency to decrease during decompression. All differences in core temperature values obtained by the group of divers at individual time points in this study were not statistically significant.

scholarly journals Is Oral Temperature an Accurate Measurement of Deep Body Temperature? A Systematic Review

2011 ◽  
Vol 46 (5) ◽  
pp. 566-573 ◽  
Author(s):  
Stephanie M. Mazerolle ◽  
Matthew S. Ganio ◽  
Douglas J. Casa ◽  
Jakob Vingren ◽  
Jennifer Klau
Keyword(s):  
Body Temperature ◽  
Key Words ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Ambient Air ◽  
Controlled Vocabulary ◽  
Cochrane Library ◽  
Original Research ◽  
Oral Temperature ◽  
Core Body

Context: Oral temperature might not be a valid method to assess core body temperature. However, many clinicians, including athletic trainers, use it rather than criterion standard methods, such as rectal thermometry. Objective: To critically evaluate original research addressing the validity of using oral temperature as a measurement of core body temperature during periods of rest and changing core temperature. Data Sources: In July 2010, we searched the electronic databases PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), SPORTDiscus, Academic Search Premier, and the Cochrane Library for the following concepts: core body temperature, oral, and thermometers. Controlled vocabulary was used, when available, as well as key words and variations of those key words. The search was limited to articles focusing on temperature readings and studies involving human participants. Data Synthesis: Original research was reviewed using the Physiotherapy Evidence Database (PEDro). Sixteen studies met the inclusion criteria and subsequently were evaluated by 2 independent reviewers. All 16 were included in the review because they met the minimal PEDro score of 4 points (of 10 possible points), with all but 2 scoring 5 points. A critical review of these studies indicated a disparity between oral and criterion standard temperature methods (eg, rectal and esophageal) specifically as the temperature increased. The difference was −0.50°C ± 0.31°C at rest and −0.58°C ± 0.75°C during a nonsteady state. Conclusions: Evidence suggests that, regardless of whether the assessment is recorded at rest or during periods of changing core temperature, oral temperature is an unsuitable diagnostic tool for determining body temperature because many measures demonstrated differences greater than the predetermined validity threshold of 0.27°C (0.5°F). In addition, the differences were greatest at the highest rectal temperatures. Oral temperature cannot accurately reflect core body temperature, probably because it is influenced by factors such as ambient air temperature, probe placement, and ingestion of fluids. Any reliance on oral temperature in an emergency, such as exertional heat stroke, might grossly underestimate temperature and delay proper diagnosis and treatment.

scholarly journals Thermoregulatory inversion: a novel thermoregulatory paradigm

2017 ◽  
Vol 312 (5) ◽  
pp. R779-R786 ◽  
Author(s):  
Domenico Tupone ◽  
Georgina Cano ◽  
Shaun F. Morrison
Keyword(s):  
Body Temperature ◽  
Core Temperature ◽  
Neural Circuit ◽  
Core Body Temperature ◽  
Normal Body Temperature ◽  
Dorsomedial Hypothalamus ◽  
Pharmacological Mechanism ◽  
Brown Adipose ◽  
Skin Cooling ◽  
Core Body

To maintain core body temperature in mammals, the normal central nervous system (CNS) thermoregulatory reflex networks produce an increase in brown adipose tissue (BAT) thermogenesis in response to skin cooling and an inhibition of the sympathetic outflow to BAT during skin rewarming. In contrast, these normal thermoregulatory reflexes appear to be inverted in hibernation/torpor; thermogenesis is inhibited during exposure to a cold environment, allowing dramatic reductions in core temperature and metabolism, and thermogenesis is activated during skin rewarming, contributing to a return of normal body temperature. Here, we describe two unrelated experimental paradigms in which rats, a nonhibernating/torpid species, exhibit a “thermoregulatory inversion,” which is characterized by an inhibition of BAT thermogenesis in response to skin cooling, and a switch in the gain of the skin cooling reflex transfer function from negative to positive values. Either transection of the neuraxis immediately rostral to the dorsomedial hypothalamus in anesthetized rats or activation of A1 adenosine receptors within the CNS of free-behaving rats produces a state of thermoregulatory inversion in which skin cooling inhibits BAT thermogenesis, leading to hypothermia, and skin warming activates BAT, supporting an increase in core temperature. These results reflect the existence of a novel neural circuit that mediates inverted thermoregulatory reflexes and suggests a pharmacological mechanism through which a deeply hypothermic state can be achieved in nonhibernating/torpid mammals, possibly including humans.

scholarly journals Diagnosis and treatment of post-traumatic hypothermia in hospitals – a pilot study

2019 ◽  
Vol 91 (2) ◽  
pp. 25-29
Author(s):  
Paweł Podsiadło ◽  
Sylweriusz Kosiński ◽  
Tomasz Darocha ◽  
Katherine Zerebiec ◽  
Przemysław Wolak ◽  
...  
Keyword(s):  
Intensive Care ◽  
Pilot Study ◽  
Body Temperature ◽  
Core Temperature ◽  
Thermal Insulation ◽  
Core Body Temperature ◽  
Post Traumatic ◽  
Trauma Victims ◽  
Warming Devices ◽  
Core Body

Background: An unintentional drop in core body temperature of trauma victims is associated with increased mortality. Thermoregulation is impaired in these patients, especially when treated with opioids or anesthetics. Careful thermal insulation and active warming are necessary to maintain normothermia. The aim of the study was to assess the equipment and procedures for diagnosing and managing post-traumatic hypothermia in Polish hospitals. Methods: Survey forms regarding equipment and procedures on monitoring of core temperature (Tc) and active warming were distributed to every hospital that admits trauma victims in the Holy Cross Province. Questionnaires were addressed to surgery departments, intensive care units (ICUs) and operating rooms (ORs). Results: 92% of surgery departments did not have equipment to measure core body temperature and 85% did not have equipment to rewarm patients. Every ICU had equipment to measure Tc and 83% had active warming devices. In 50% of ICUs, there were no rewarming protocols based on Tc and the initiation of rewarming was left to the physician’s discretion. In 58% of ORs Tc was not monitored and in 33% the patients were not actively warmed. Conclusions: The majority of surveyed ICUs and ORs are adequately equipped to identify and treat hypothermia, however the criteria for initiating Tc monitoring and rewarming remain unstandardized. Surgery departments are not prepared to manage post-traumatic hypothermia.

Lowest core body temperature and adverse outcomes associated with coronary artery bypass surgery

Perfusion ◽  
2003 ◽  
Vol 18 (2) ◽  
pp. 127-133 ◽  
Author(s):  
Gordon R DeFoe ◽  
Charles F Krumholz ◽  
Christian P DioDato ◽  
Cathy S Ross ◽  
Elaine M Olmstead ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Body Temperature ◽  
Hospital Mortality ◽  
Coronary Artery Bypass ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Artery Bypass ◽  
Mortality Rates ◽  
Adverse Outcomes ◽  
Core Body

To examine the effect of lowest core body temperature on adverse outcomes associated with coronary artery bypass graft (CABG) surgery, data were collected on 7134 isolated CABG procedures carried out in New England from 1997 to 2000. Excluded from the analysis were patients with pump times <60 and >120 min and those operated upon using continuous warm cardioplegia. Data for lowest core temperature were divided into quartiles for analysis (≤31.4°C, 31.5-33.1°C, 33.2-34.3°C, and ≥34.4°C). Patients with lower core body temperature on cardio-pulmonary bypass (CPB) had higher in-hospital mortality rates. Crude mortality rates were 2.9% in the ≤31.4°C group, 2.1% in the 31.5 - 33.1°C group, 1.3% in the 33.2 - 34.3°C group and 1.2% in the ≥34.4°C group. The trend toward higher mortality as core temperature decreased was statistically significant (ptrend<0.001). Adjustment for differences in patient and disease characteristics did not significantly change the results and the test of trend remained significant ( p<0.001). Rates of perioperative stroke were somewhat lower in the colder groups. Rates in the two colder groups were0.9% compared with 1.6% and 1.4% in the warmer groups (ptrend = 0.082). This remained a marginal but significant trend after adjustment for possible confounding factors (p=0.044). Low core body temperatures on CPB are associated with higher rates of in-hospital mortality among isolated CABG patients. Rates of intra- or postoperative use of an intra-aortic balloon pump are also higher with lower core temperatures. We concluded that temperature management strategy during CABG surgery has an important effect on patient outcomes.

Relationship between ventilatory response and body temperature during prolonged submaximal exercise

2006 ◽  
Vol 100 (2) ◽  
pp. 414-420 ◽  
Author(s):  
Keiji Hayashi ◽  
Yasushi Honda ◽  
Takeshi Ogawa ◽  
Narihiko Kondo ◽  
Takeshi Nishiyasu
Keyword(s):  
Body Temperature ◽  
Oxygen Uptake ◽  
Skin Temperature ◽  
Blood Lactate ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Minute Ventilation ◽  
Submaximal Exercise ◽  
Rate Of Increase ◽  
The Relationship

We examined whether an increase in skin temperature or the rate of increase in core body temperature influences the relationship between minute ventilation (V̇e) and core temperature during prolonged exercise in the heat. Thirteen subjects exercised for 60 min on a cycle ergometer at 50% of peak oxygen uptake while wearing a suit perfused with water at 10°C (T10), 35°C (T35), or 45°C (T45). During the exercise, esophageal temperature (Tes), skin temperature, heart rate (HR), V̇e, tidal volume, respiratory frequency (f), respiratory gases, blood pressure (BP), and blood lactate were all measured. We found that oxygen uptake, carbon dioxide output, BP, and blood lactate did not differ among the sessions. Tes, HR, V̇e, and f remained nearly constant from minute 10 onward in the T10 session, but all of these parameters progressively increased in the T35 and T45 sessions, and significantly higher levels were seen in the T45 than the T35 session. For all but two subjects in the T35 and T45 sessions, plotting V̇e as a function of Tes revealed no threshold for hyperventilation; instead, increases in V̇e were linearly related to Tes, and there were no significant differences in the slopes or intercepts between the T35 and T45 sessions. Thus, during prolonged submaximal exercise in the heat, V̇e increases with core temperature, and the influences of skin temperature and the rate of increase in Tes on the relationship between V̇e and Tes are apparently small.

scholarly journals Association of core body temperature and peripheral blood flow of the hands with pain intensity, pressure pain hypersensitivity, central sensitization, and fibromyalgia symptoms

2021 ◽  
Vol 12 ◽  
pp. 204062232199725
Author(s):  
Antonio Casas-Barragán ◽  
Francisco Molina ◽  
Rosa María Tapia-Haro ◽  
María Carmen García-Ríos ◽  
María Correa-Rodríguez ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Temperature ◽  
Clinical Symptoms ◽  
Core Body Temperature ◽  
Body Core Temperature ◽  
Peripheral Blood Flow ◽  
Greater Trochanter ◽  
Body Core ◽  
Hypothenar Eminence ◽  
Core Body

Our aim was to analyse body core temperature and peripheral vascular microcirculation at skin hypothenar eminence of the hands and its relationship to symptoms in fibromyalgia syndrome (FMS). A total of 80 FMS women and 80 healthy women, matched on weight, were enrolled in this case–control study. Thermography and infrared thermometer were used for evaluating the hypothenar regions and core body temperature, respectively. The main outcome measures were pain pressure thresholds (PPTs) and clinical questionnaires. Significant associations were observed between overall impact [ β = 0.033; 95% confidence interval (95%CI) = 0.003, 0.062; p = 0.030], daytime dysfunction ( β = 0.203; 95%CI = 0.011, 0.395; p = 0.039) and reduced activity ( β = 0.045; 95%CI = 0.005, 0.085; p = 0.029) and core body temperature in FMS women. PPTs including greater trochanter dominant ( β = 0.254; 95%CI = 0.003, 0.504; p = 0.047), greater trochanter non-dominant ( β = 0.650; 95%CI = 0.141, 1.159; p = 0.013), as well as sleeping medication ( β = −0.242; 95%CI = −0.471, −0.013; p = 0.039) were also associated with hypothenar eminence temperature. Data highlighted that FMS women showed correlations among body core temperature and hand temperature with the clinical symptoms.

scholarly journals Comparative Analysis of Temperature Measurement Methods based on Degree of Agreement

2021 ◽  
Vol 3 (3) ◽  
pp. 209-223
Author(s):  
Nayana Shetty
Keyword(s):  
Body Temperature ◽  
Temperature Measurement ◽  
Core Temperature ◽  
Temperature Control ◽  
Core Body Temperature ◽  
Spontaneous Circulation ◽  
Body Core Temperature ◽  
Invasive Approach ◽  
Non Invasive ◽  
Core Body

Many sports have a high risk of climatic ailments, such as hypothermia, hyperthermia, and heatstroke. The measurement of a sportsperson's body core temperature (Tc) may have an impact on their performances and it assists them to avoid injuries as well. To avoid complications like electrolyte imbalances or infections, it's essential to precisely measure the core body temperature during targeted temperature control when spontaneous circulation has returned. Previous approaches on the other hand, are intrusive and difficult to use. The usual technique, an oesophageal thermometer, was compared to a disposable non-invasive temperature sensor that used the heat flux methodology. This research indicates that, non-invasive disposable sensors used to measure core body temperature are very reliable when used for targeted temperature control after overcoming a cardiac arrest successfully. The non-invasive method of temperature measurement has somewhat greater accuracy than the invasive approach. The results of this study must be confirmed by more clinical research with various sensor types to figure out if the bounds of agreement could be increased. This will ensure that the findings are accurate based on core temperature.

scholarly journals Do Alternative Cooling Methods Have Effective Cooling Rates for Hyperthermia Compared With Previously Established CWI Cooling Rates?

2020 ◽  
Vol 29 (3) ◽  
pp. 367-372 ◽  
Author(s):  
Kailin C. Parker ◽  
Rachel R. Shelton ◽  
Rebecca M. Lopez
Keyword(s):  
Body Temperature ◽  
Cooling Rate ◽  
Cold Water ◽  
Core Body Temperature ◽  
Ice Sheet ◽  
Clinical Question ◽  
Cooling Rates ◽  
Cooling Method ◽  
Core Body ◽  
Cooling Methods

Clinical Scenario: In the last few years, there have been several studies examining alternative cooling strategies in the treatment of exertional heat stroke (EHS). Morbidity and mortality with EHS are associated with how long the patient’s core body temperature remains above the critical threshold of 40.5°C. Although cold-water immersion (CWI) is the gold standard of treatment when cooling a patient with EHS, more recent alternative cooling techniques have been examined for use in settings where CWI may not be feasible (ie, remote locations). Clinical Question: Do alternative cooling methods have effective core body temperature cooling rates for hyperthermia compared with previously established CWI cooling rates? Summary of Key Findings: The authors searched for studies using alternative cooling methods to cool hyperthermic individuals. To be included, the studies needed a PEDro score ≥6 and a level of evidence ≥2. They found 9 studies related to our focused clinical question; of these, 5 studies met the inclusion criteria. The cooling rates for hand cooling, cold-water shower, and ice-sheet cooling were 0.03°C/min, 0.08°C/min, and 0.06°C/min, respectively, whereas the tarp-assisted cooling with oscillation (TACO) method was the only method that had an acceptable cooling rate (range 0.14–0.17°C/min). Clinical Bottom Line: When treating EHS, if CWI is not available, the tarp-assisted cooling method may be a reasonable alternative. Clinicians should not use cold shower, hand cooling, or ice-sheet cooling if better cooling methods are available. Clinicians should always use CWI when available. Strength of Recommendation: Five level 2 studies with PEDro scores ≥6 suggest the TACO method is the only alternative cooling method that decreases core body temperature at a similar, though slower, rate of CWI. Hand cooling, cold showering, and ice-sheet cooling do not decrease core body temperature at an appropriate rate and should not be used in EHS situations if a modality with a better cooling rate is available.

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