Thermoregulatory model for immersion of humans in cold water

Tikuisis, Peter; Gonzalez, Richard R.; Pandolf, Kent B.

doi:10.1152/jappl.1988.64.2.719

Cited by 52 publications

(29 citation statements)

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“…[6][7][8] Furthermore, it is generally admitted that a physiological response to cold stress is shivering 2 to maintain core temperature. Therefore, in response to external cooling, EE could either vary independently of TЊ or increase with diminution of body temperature.…”

Section: Discussionmentioning

confidence: 99%

Metabolic effects of i.v. propacetamol, metamizol or external cooling in critically ill febrile sedated patients

Poblete¹,

Romand²,

Pichard³

et al. 1997

British Journal of Anaesthesia

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SummaryWe have measured the metabolic response to sequential administration of propacetamol, metamizol and/or external cooling in 20 febrile patients under sedation and analgesia and during mechanical ventilation. There was no change in temperature (TЊ) after propacetamol therapy, whereas after metamizol only a small decrease was noted (from 38.9 (SEM 0.2) to 38.5 (0.3) ЊC; P:0.02). External cooling produced a significant decrease in TЊ (39.1 (0.2) to 37.1 (0.2) ЊC; P:0.0001) accompanied by a decrease in energy expenditure (EE) (2034 (73) to 1791 (88) kcal day 91 ; P:0.004). Heart rate and minute ventilation decreased significantly in parallel. There were no other changes in haemodynamics or pulmonary gas exchanges. We conclude that propacetamol and metamizol did not produce a clinically significant decrease in TЊ in febrile ICU patients whereas external cooling decreased both TЊ and EE. The parallel decrease in body temperature and EE seemed to be related to opioid administration or sedation, or both. (Br. J. Anaesth. 1997; 78: 23-127 Fever in critically ill patients is related frequently to either the systemic inflammatory response syndrome (SIRS) or infection. Usually fever is treated with antipyretic drugs, often paracetamol or metamizol. External cooling by different methods, such as sponging the body surface with ice-cooled water, is also used. 1 Even if reducing fever is still controversial from an immunological point of view, there is little doubt that patient comfort and metabolic demand can be improved by this procedure. 2 Indeed, a previous study in critically ill patients demonstrated diminished oxygen consumption related to decreased body temperature improving the oxygen demand-delivery ratio. 3 However, body cooling in healthy humans results in shivering which increases energy expenditure (EE).The aim of this study was to measure EE as an integrated indicator of body metabolic activity after reduction in temperature. Our hypothesis was that external cooling may induce an increase in EE, in contrast with drugs which, by resetting the thermoregulatory set point, decrease EE. Therefore, we designed a prospective, unblinded, crossover study to evaluate the respective effects of centrally acting drugs (propacetamol or metamizol) or external physical cooling in febrile ICU patients. Patients and methodsThe study was approved by the Ethics Committee of our institution. The requirement for informed consent was waived by the committee who judged that the therapies were applied independently by the attending physician and were accepted in clinical practice, and no invasive measurements were made. We studied 20 patients undergoing mechanical ventilation via a tracheal tube, with a rectal temperature greater than 38.5 ЊC and in whom the physician in charge wished to decrease fever. No patient had an inspired oxygen fraction greater than 0.6, a pneumothorax or a broncho-pleural fistula. Patients' lungs were ventilated with a Veolar-Hamilton (Hamilton Bonaduz, Switzerland) or Engström-Erica ventilator (Engström,...

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Section: Discussionmentioning

confidence: 99%

Metabolic effects of i.v. propacetamol, metamizol or external cooling in critically ill febrile sedated patients

Poblete¹,

Romand²,

Pichard³

et al. 1997

British Journal of Anaesthesia

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“…Hayward developed a simple algorithm using water temperature to predict survival time (122). More sophisticated thermal models using biophysical principles and physiological control systems have also been employed to determine multiple end-points including time to hypothermia (35 • C), swimming muscle failure, and probability of survival (35,229,230,266,269,272). The Cold Exposure Survival Model and the Probability of Survival Decision Aid are two recent thermoregulatory models used by the search and rescue community (226,269).…”

Section: Prolonged Water Immersionmentioning

confidence: 99%

Cold Stress Effects on Exposure Tolerance and Exercise Performance

Castellani

Tipton

2015

Comprehensive Physiology

108

115

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Cold weather can have deleterious effects on health, tolerance, and performance. This paper will review the physiological responses and external factors that impact cold tolerance and physical performance. Tolerance is defined as the ability to withstand cold stress with minimal changes in physiological strain. Physiological and pathophysiological responses to short-term (cold shock) and long-term cold water and air exposure are presented. Factors (habituation, anthropometry, sex, race, and fitness) that influence cold tolerance are also reviewed. The impact of cold exposure on physical performance, especially aerobic performance, has not been thoroughly studied. The few studies that have been done suggest that aerobic performance is degraded in cold environments. Potential physiological mechanisms (decreases in deep body and muscle temperature, cardiovascular, and metabolism) are discussed. Likewise, strength and power are also degraded during cold exposure, primarily through a decline in muscle temperature. The review also discusses the concept of thermoregulatory fatigue, a reduction in the thermal effector responses of shivering and vasoconstriction, as a result of multistressor factors, including exhaustive exercise.

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“…Havenith and Middendorp (1990) presented a relationship between body fat and core temperature in subjects under heat stress. Tikuisis et al (1988) accounted for the impact of body fat on thermal regulation during cold water immersion. Havenith (2001) developed an individualized model including effects of acclimatization.…”

Section: Introductionmentioning

confidence: 99%

Considering individual physiological differences in a human thermal model

Zhang

Huizenga

Arens

et al. 2001

Journal of Thermal Biology

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Physiological differences between individuals can significantly affect human thermal response to the environment. In practice, most thermal models use a single set of physiological data to represent an average person. We have developed a model to translate descriptive data about an individual into a set of physiological parameters which may be used in thermal models. We have incorporated these parameters into a model of human thermoregulation and comfort, which may be used to predict variations in thermal response between individuals. This paper presents this model and examples of its use in thermal simulation. r

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Thermoregulatory model for immersion of humans in cold water

Cited by 52 publications

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Metabolic effects of i.v. propacetamol, metamizol or external cooling in critically ill febrile sedated patients

Metabolic effects of i.v. propacetamol, metamizol or external cooling in critically ill febrile sedated patients

Cold Stress Effects on Exposure Tolerance and Exercise Performance

Considering individual physiological differences in a human thermal model

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