Estimation of Mean Body Temperature from Mean Skin and Core Temperature

Background Mean body temperature (MBT) is the mass-weighted average temperature of body tissues. Core temperature is easy to measure, but direct measurement of peripheral tissue temperature is painful and risky and requires complex calculations. Alternatively MBT can be estimated from core and mean skin temperatures with a formula proposed by Burton in 1935: MBT = 0.64 x TCore + 0.36 x TSkin. This formula remains widely used, but has not been validated in the perioperative period and seems unlikely to remain accurate in dynamic perioperative conditions such as cardiopulmonary bypass. Therefore, the authors tested the hypothesis that MBT, as estimated with Burton's formula, poorly estimates measured MBT at a temperature range between 18 degrees and 36.5 degrees C. Methods The authors reevaluated four of their previously published studies in which core and mass-weighted mean peripheral tissue temperatures were measured in patients undergoing substantial thermal perturbations. Peripheral compartment temperatures were estimated using fourth-order regression and integration over volume from 18 intramuscular needle thermocouples, 9 skin temperatures, and "deep" hand and foot temperature. MBT was determined from mass-weighted average of core and peripheral tissue temperatures and estimated from core temperature and mean skin temperature (15 area-weighted sites) using Burton's formula. Results Nine hundred thirteen data pairs from 44 study subjects were included in the analysis. Measured MBT ranged from 18 degrees to 36.5 degrees C. There was a remarkably good relation between measured and estimated MBT: MBTmeasured = 0.94 x MBTestimated + 2.15, r = 0.98. Differences between the estimated and measured values averaged -0.09 degrees +/- 0.42 degrees C. Conclusions The authors concluded that estimation of MBT from mean skin and core temperatures is generally accurate and precise.

Download Full-text

Tissue Heat Content and Distribution during and after Cardiopulmonary Bypass at 31 [degree sign]C and 27 [degree sign]C

Anesthesiology ◽

10.1097/00000542-199806000-00015 ◽

1998 ◽

Vol 88 (6) ◽

pp. 1511-1518 ◽

Cited By ~ 46

Author(s):

Angela Rajek ◽

Rainer Lenhardt ◽

Daniel I. Sessler ◽

Andrea Kurz ◽

Gunther Laufer ◽

...

Keyword(s):

Cardiopulmonary Bypass ◽

Temperature Gradient ◽

Heat Content ◽

Peripheral Tissue ◽

Tissue Temperature ◽

Peripheral Compartment ◽

Peripheral Tissues ◽

The Core ◽

Total Body ◽

Body Heat

Background Afterdrop following cardiopulmonary bypass results from redistribution of body heat to inadequately warmed peripheral tissues. However, the distribution of heat between the thermal compartments and the extent to which core-to-peripheral redistribution contributes to post-bypass hypothermia remains unknown. Methods Patients were cooled during cardiopulmonary bypass to nasopharyngeal temperatures near 31 degrees C (n=8) or 27 degrees C (n=8) and subsequently rewarmed by the bypass heat exchanger to approximately 37.5 degrees C. A nasopharyngeal probe evaluated core (trunk and head) temperature and heat content. Peripheral compartment (arm and leg) temperature and heat content were estimated using fourth-order regressions and integration over volume from 19 intramuscular needle thermocouples, 10 skin temperatures, and "deep" foot temperature. Results In the 31 degrees C group, the average peripheral tissue temperature decreased to 31.9+/-1.4 degrees C (means+/-SD) and subsequently increased to 34+/-1.4 degrees C at the end of bypass. The core-to-peripheral tissue temperature gradient was 3.5+/-1.8 degrees C at the end of rewarming, and the afterdrop was 1.5+/-0.4 degrees C. Total body heat content decreased 231+/-93 kcal. During pump rewarming, the peripheral heat content increased to 7+/-27 kcal below precooling values, whereas the core heat content increased to 94+/-33 kcal above precooling values. Body heat content at the end of rewarming was thus 87+/-42 kcal more than at the onset of cooling. In the 27 degrees C group, the average peripheral tissue temperature decreased to a minimum of 29.8 +/-1.7 degrees C and subsequently increased to 32.8+/-2.1 degrees C at the end of bypass. The core-to-peripheral tissue temperature gradient was 4.6+/-1.9 degrees C at the end of rewarming, and the afterdrop was 2.3+/-0.9 degrees C. Total body heat content decreased 419+/-49 kcal. During pump rewarming, core heat content increased to 66+/-23 kcal above precooling values, whereas peripheral heat content remained 70+/-42 kcal below precooling values. Body heat content at the end of rewarming was thus 4+/-52 kcal less than at the onset of cooling. Conclusions Peripheral tissues failed to fully rewarm by the end of bypass in the patients in the 27 degrees C group, and the afterdrop was 2.3+/-0.9 degrees C. Peripheral tissues rewarmed better in the patients in the 31 degrees C group, and the afterdrop was only 1.5+/-0.4 degrees C.

Download Full-text

Effect of food intake on the ventilatory response to increasing core temperature during exercise

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2018-0069 ◽

2019 ◽

Vol 44 (1) ◽

pp. 22-30 ◽

Cited By ~ 2

Author(s):

Keiji Hayashi ◽

Nozomi Ito ◽

Yoko Ichikawa ◽

Yuichi Suzuki

Keyword(s):

Food Intake ◽

Body Temperature ◽

Skin Temperature ◽

Core Temperature ◽

Mean Skin Temperature ◽

Carbon Dioxide Elimination ◽

Transient Effect ◽

Mean Body Temperature ◽

Ventilatory Parameters ◽

Effect Of Food

Food intake increases metabolism and body temperature, which may in turn influence ventilatory responses. Our aim was to assess the effect of food intake on ventilatory sensitivity to rising core temperature during exercise. Nine healthy male subjects exercised on a cycle ergometer at 50% of peak oxygen uptake in sessions with and without prior food intake. Ventilatory sensitivity to rising core temperature was defined by the slopes of regression lines relating ventilatory parameters to core temperature. Mean skin temperature, mean body temperature (calculated from esophageal temperature and mean skin temperature), oxygen uptake, carbon dioxide elimination, minute ventilation, alveolar ventilation, and tidal volume (VT) were all significantly higher at baseline in sessions with food intake than without food intake. During exercise, esophageal temperature, mean skin temperature, mean body temperature, carbon dioxide elimination, and end-tidal CO2 pressure were all significantly higher in sessions with food intake than without it. By contrast, ventilatory parameters did not differ between sessions with and without food intake, with the exception of VT during the first 5 min of exercise. The ventilatory sensitivities to rising core temperature also did not differ, with the exception of an early transient effect on VT. Food intake increases body temperature before and during exercise. Other than during the first 5 min of exercise, food intake does not affect ventilatory parameters during exercise, despite elevation of both body temperature and metabolism. Thus, with the exception of an early transient effect on VT, ventilatory sensitivity to rising core temperature is not affected by food intake.

Download Full-text

Circadian variations in the sweating mechanism

Journal of Applied Physiology ◽

10.1152/jappl.1975.39.2.226 ◽

1975 ◽

Vol 39 (2) ◽

pp. 226-230 ◽

Cited By ~ 21

Author(s):

J. Timbal ◽

J. Colin ◽

C. Boutelier

Keyword(s):

Body Temperature ◽

Human Subjects ◽

Heat Exposure ◽

The Body ◽

Circadian Variations ◽

Mean Body Temperature ◽

Two Temperatures ◽

The Difference ◽

Gains And Losses ◽

Skin Temperatures

Sweat rates and body temperatures of human subjects were measured at 0200, 1000, and 1800 h during a heat exposure of 90 min. The latent period of sweating was not significantly altered in the evening but significantly shortened during the night. Mean body temperature corresponding to the onset of sweating was nearer to the basal body temperature during the night, while during the day the difference between these two temperatures became larger. This phenomenon seems related to the circadian cycle of vasomotor adjustment, since during the night body conductance was higher than during the day and corresponded to a state of a vasodilatation similar to that observed at the onset of sweating. During the day, this situation was reversed. During steady state, the following changes were observed: sweating rate, night less than morning less than evening; skin temperatures, night less than morning less than evening; and rectal temperature increase, morning less than evening less than night. It is hypothesized that these changes are due to either different metabolic rates or an imbalance between heat gains and losses which preserve the circadian rhythm of the body temperature, even under thermal loads.

Download Full-text

Prewarming: Preventing Intraoperative Hypothermia

British Journal of Perioperative Nursing (United Kingdom) ◽

10.1177/175045890501501004 ◽

2005 ◽

Vol 15 (10) ◽

pp. 444-451 ◽

Cited By ~ 9

Author(s):

Panagiotis Kiekkas ◽

Maria Karga

Keyword(s):

Temperature Gradient ◽

Core Temperature ◽

Peripheral Tissue ◽

Tissue Temperature ◽

Temperature Decrease ◽

Perioperative Hypothermia ◽

Normal Limits ◽

Normal Core ◽

Short Period ◽

Peripheral Temperature

Perioperative hypothermia can be followed by severe complications. The greatest proportion of temperature decrease is attributed to heat redistribution, which mainly occurs during the first hour of anaesthesia and is difficult to treat intraoperatively. Prewarming, based on active warming techniques, has been proposed. Even a short period of prewarming may significantly increase peripheral tissue temperature, minimise normal core-to-peripheral temperature gradient, and keep core temperature within normal limits.

Download Full-text

Evaluation of the accuracy of body temperature measurement using external radio transmitters

Canadian Journal of Zoology ◽

10.1139/z96-196 ◽

1996 ◽

Vol 74 (9) ◽

pp. 1778-1781 ◽

Cited By ~ 59

Author(s):

Doris Audet ◽

Donald W. Thomas

Keyword(s):

Body Temperature ◽

Core Temperature ◽

Field Conditions ◽

Temperature Sensitive ◽

External Temperature ◽

Ambient Temperatures ◽

Body Temperature Measurement ◽

Radio Transmitters ◽

The Difference ◽

Skin Temperatures

The facultative depression of body temperature represents an important energy strategy for small homeotherms. However, measuring body temperature under field conditions by means other than externally attached temperature-sensitive radio transmitters is problematical. We show that skin temperatures measured by external radio transmitters can accurately reflect core temperature for the bat Carollia perspicillata. We compared body and skin temperatures at three ambient temperatures (Ta; 21, 26, and 31 °C). The difference between skin and body temperature (ΔT) was linearly correlated with Ta and can be predicted by ΔT = 4.396 − 0.118Ta. We argue that external temperature-sensitive radio transmitters can provide a reliable index of core temperature and so permit the study of torpor or facultative hypothermia under field conditions.

Download Full-text

Some aspects of body temperature regulation in sheep

The Journal of Agricultural Science ◽

10.1017/s002185960006559x ◽

1968 ◽

Vol 71 (1) ◽

pp. 61-66 ◽

Cited By ~ 3

Author(s):

M. E. D. Webster ◽

K. G. Johnson

Keyword(s):

Body Temperature ◽

Surface Area ◽

Cold Water ◽

The Body ◽

Body Temperatures ◽

Mean Body Temperature ◽

Merino Sheep ◽

Infra Red ◽

Heat Increment ◽

Skin Temperatures

SummarySkin temperatures, deep body temperatures and respiratory rates have been measured in Southdown and Merino sheep following feeding, and during infra-red irradiation, rumen infusions of hot and cold water, and cold exposure induced by shearing. The increases in respiratory rate and skin temperatures induced by infra-red heating and the heat increment of feeding were reversed by addition of iced water to the rumen and were suppressed by shearing. These responses could not be systematically related to particular body temperatures in the sheep and appeared to be continuously variable rather than ‘all-or-none’ phenomena. Considerable overlap was observed between respiratory and vasomotor mechanisms of thermoregulation. Measurements of the surface area and weight of ears and legs showed that these regions contribute approximately 23% of the surface area and 8% of the body weight in Merino sheep. Calculations suggested that up to 70% of the additional heat produced in the 2 h after feeding in sheep may be stored in the tissues through increase in mean body temperature. Sheep kept in short wool throughout the winter appeared to establish a new thermoregulatory ‘set-point’ associated with lower rectal temperatures than those in sheep with a full fleece.

Download Full-text

Effects of a Circulating-water Garment and Forced-air Warming on Body Heat Content and Core Temperature

Anesthesiology ◽

10.1097/00000542-200405000-00005 ◽

2004 ◽

Vol 100 (5) ◽

pp. 1058-1064 ◽

Cited By ~ 69

Author(s):

Akiko Taguchi ◽

Jebadurai Ratnaraj ◽

Barbara Kabon ◽

Neeru Sharma ◽

Rainer Lenhardt ◽

...

Keyword(s):

Heat Transfer ◽

Core Temperature ◽

Thermal Flux ◽

Heat Content ◽

Skin Surface ◽

Peripheral Tissue ◽

Tissue Temperature ◽

Circulating Water ◽

Forced Air Warming ◽

Forced Air

Background Forced-air warming is sometimes unable to maintain perioperative normothermia. Therefore, the authors compared heat transfer, regional heat distribution, and core rewarming of forced-air warming with a novel circulating-water garment. Methods Nine volunteers were each evaluated on two randomly ordered study days. They were anesthetized and cooled to a core temperature near 34 degrees C. The volunteers were subsequently warmed for 2.5 h with either a circulating-water garment or a forced-air cover. Overall, heat balance was determined from the difference between cutaneous heat loss (thermal flux transducers) and metabolic heat production (oxygen consumption). Average arm and leg (peripheral) tissue temperatures were determined from 18 intramuscular needle thermocouples, 15 skin thermal flux transducers, and "deep" hand and foot thermometers. Results Heat production (approximately 60 kcal/h) and loss (approximately 45 kcal/h) were similar with each treatment before warming. The increases in heat transfer across anterior portions of the skin surface were similar with each warming system (approximately 65 kcal/h). Forced-air warming had no effect on posterior heat transfer, whereas circulating-water transferred 21+/-9 kcal/h through the posterior skin surface after a half hour of warming. Over 2.5 h, circulating water thus increased body heat content 56% more than forced air. Core temperatures thus increased faster than with circulating water than forced air, especially during the first hour, with the result that core temperature was 1.1 degrees +/- 0.7 degrees C greater after 2.5 h (P < 0.001). Peripheral tissue heat content increased twice as much as core heat content with each device, but the core-to-peripheral tissue temperature gradient remained positive throughout the study. Conclusions The circulating-water system transferred more heat than forced air, with the difference resulting largely from posterior heating. Circulating water rewarmed patients 0.4 degrees C/h faster than forced air. A substantial peripheral-to-core tissue temperature gradient with each device indicated that peripheral tissues insulated the core, thus slowing heat transfer.

Download Full-text

A Rapid Increase in Foot Tissue Temperature Predicts Cardiovascular Collapse during Anaphylactic and Anaphylactoid Reactions

Anesthesiology ◽

10.1097/00000542-199709000-00016 ◽

1997 ◽

Vol 87 (3) ◽

pp. 559-568 ◽

Cited By ~ 5

Author(s):

Naoki Kotani ◽

Tetsuya Kushikata ◽

Takashi Matsukawa ◽

Daniel I. Sessler ◽

Masatoshi Muraoka ◽

...

Keyword(s):

Core Temperature ◽

Drug Administration ◽

Clinical Severity ◽

Peripheral Tissue ◽

Tissue Temperature ◽

Cardiovascular Collapse ◽

Positive Skin ◽

Test Reactions ◽

Anaphylactoid Reactions

Background Cardiovascular collapse during anaphylactic and anaphylactoid reactions results from release of histamine and other vasoactive substances. Intense arteriolar vasodilation associated with severe allergic reactions is likely to increase convective transfer of heat and peripheral tissue temperature, and finally to provoke cardiovascular collapse. Therefore the authors tested the hypothesis that during anaphylactic and anaphylactoid reactions, an acute increase in peripheral tissue temperature precedes cardiovascular collapse and that the magnitude of the increase correlates with the severity of the reaction. Methods During a 13-yr period, approximately 120,000 patients were screened for clinical evidence of intraoperative anaphylactic and anaphylactoid reactions. Core temperature was measured in the distal esophagus, and "deep" foot tissue temperature was measured on the sole of one foot in all these patients. Otherwise unexplained cardiovascular collapse accompanied by bronchospasm and/or cutaneous signs such as urticaria, flushing, or angioedema occurred in 32 patients who were entered into a prospective diagnostic protocol. Among these, 15 met laboratory criteria for anaphylactic or anaphylactoid reactions. Anaphylaxis was confirmed in nine of them by a positive skin test to the suspected agent, the in vitro leukocyte histamine-release test, or the Praunitz-Küstner test. Reactions were considered anaphylactoid in six others when laboratory evidence did not support anaphylaxis, but plasma histamine or tryptase concentrations were much greater during episodes than 6 weeks later. Results Development of anaphylactic and anaphylactoid reactions followed a characteristic pattern: (1) Foot temperature, which was initially 3.3 +/- 1.7 degrees C less than core temperature, increased to within 0.3 degrees C of core temperature 3.2 +/- 1.4 min after drug administration; (2) onset of cardiovascular collapse ensued 1.8 +/- 0.8 min later; and (3) core temperature increased from 34.7 +/- 1.0 degrees C to peak values 37.1 +/- 0.6 degrees C 13 +/- 5 min after drug administration. The most severe reactions were associated with shorter times to comparable core and foot temperatures, faster onset of cardiovascular collapse, and higher maximum core temperatures. Conclusions The normal core-to-peripheral tissue temperature gradient was obliterated several minutes before hemodynamic consequences associated with anaphylactic and anaphylactoid reactions. Further, a rapid increase in deep foot temperature and maximum core temperature correlated with clinical severity.

Download Full-text

Determination of heat debt in the cold: partitional calorimetry vs. conventional methods

Journal of Applied Physiology ◽

10.1152/jappl.1992.72.4.1380 ◽

1992 ◽

Vol 72 (4) ◽

pp. 1380-1385 ◽

Cited By ~ 24

Author(s):

A. L. Vallerand ◽

G. Savourey ◽

J. H. Bittel

Keyword(s):

Body Temperature ◽

Core Temperature ◽

Cold Exposure ◽

Cooling Curves ◽

Mean Body Temperature ◽

Heat Gain ◽

Conventional Methods ◽

Partitional Calorimetry

Measurements of core temperature (Tc) at different sites produce on some occasions different cooling curves in cold-exposed humans, suggesting that the corresponding thermometric heat debts (HD) could be equally different when calculated by conventional methods [via the change in either Tc or mean body temperature (Tb)]. The present study also compared these thermometric HD values with the calorimetric HD obtained by partitional calorimetry (S). Nine subjects who showed similar initial but different final Tc [rectal (Tre) and auditory canal temperatures (Tac)] during nude cold exposure (2 h at 1 degrees C at rest) were used. Tc-derived HD corresponded to a heat gain of 12 +/- 21 kJ and an HD of 78 +/- 20 kJ with use of Tre and Tac, respectively, whereas the Tb-derived HD varied from 266 +/- 35 to less than or equal to 1,479 +/- 71 kJ with the use of various well-known Tb weighing coefficients. In contrast, S corresponded to 504 +/- 79 kJ, a level that could have been obtained only if the thermoneutral/cold Tb weighing coefficients had been 0.818/0.818 for Tre and 0.865/0.865 for Tac. The results demonstrate that calculation by conventional methods can markedly overestimate or underestimate HD. These differences could not be explained by the site chosen to represent Tc, inasmuch as about the same effect was observed with use of either Tre or Tac. It is concluded that the thermometric value of HD in the cold is not, at least under the present conditions, as accurate and reliable as S.

Download Full-text