Mechanism of afterdrop after cold water immersion

1988 ◽  
Vol 65 (4) ◽  
pp. 1535-1538 ◽  
Author(s):  
T. T. Romet
Keyword(s):  
Body Temperature ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Deep Body Temperature ◽  
Convective Component ◽  
Rate Of Cooling ◽  
Humidified Air ◽  
Male Subjects ◽  
Deep Body

It was hypothesized that if afterdrop is a purely conductive phenomenon, the afterdrop during rewarming should proceed initially at a rate equal to the rate of cooling. Eight male subjects were cooled on three occasions in 22 degrees C water and rewarmed once by each of three procedures: spontaneous shivering, inhalation of heated (45 degrees C) and humidified air, and immersion up to the neck in 40 degrees C water. Deep body temperature was recorded at three sites: esophagus, auditory canal, and rectum. During spontaneous and inhalation rewarming, there were no significant differences between the cooling (final 30 min) and afterdrop (initial 10 min) rates as calculated for each deep body temperature site, thus supporting the hypothesis. During rapid rewarming, the afterdrop rate was significantly greater than during the preceding cooling, suggesting a convective component contributing to the increased rate of fall. The rapid reversal of the afterdrop also indicates that a convective component contributes to the rewarming process as well.

Effect of occluded venous return on core temperature during cold water immersion

1988 ◽  
Vol 65 (6) ◽  
pp. 2709-2713 ◽  
Author(s):  
K. D. Mittleman ◽  
I. B. Mekjavic
Keyword(s):  
Blood Flow ◽  
Cold Water ◽  
Water Immersion ◽  
Peripheral Circulation ◽  
Cold Water Immersion ◽  
Esophageal Temperature ◽  
Complete Neglect ◽  
Rate Of Cooling ◽  
Physical Laws ◽  
Male Subjects

Recent studies using inanimate and animal models suggest that the afterdrop observed upon rewarming from hypothermia is based entirely on physical laws of heat flow without involvement of the returning cooled blood from the limbs. During the investigation of thermoregulatory responses to cold water immersion (15 degrees C), blood flow to the limbs (minimized by the effects of hydrostatic pressure and vasoconstriction) was occluded in 17 male subjects (age, 29.0 +/- 3.3 yr). Comparisons of rectal (Tre) and esophageal temperature (Tes) responses were made during the 5 min before occlusion, during the 10-min occlusion period, and for 5 min immediately after the release of the cuffs (postocclusion). In the preocclusion phase, Tre and Tes showed similar cooling rates. The occlusion of blood flow to the extremities significantly arrested the cooling of Tes (P less than 0.05) with little effect on Tre. Upon release of the pressure cuffs, the returning extremity blood flow resulted in an increased rate of cooling, that was three times greater at the esophageal site (-0:149 +/- 0.052 vs. -0.050 +/- 0.026 degrees C.min-1). These results suggest that the cooled peripheral circulation, minimized during cold water immersion, may dramatically affect esophageal temperature and the complete neglect of the circulatory component to the afterdrop phenomenon is not warranted.

A second postcooling afterdrop: more evidence for a convective mechanism

1992 ◽  
Vol 73 (4) ◽  
pp. 1253-1258 ◽  
Author(s):  
G. G. Giesbrecht ◽  
G. K. Bristow
Keyword(s):  
Core Temperature ◽  
Initial Rate ◽  
Treadmill Exercise ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Probable Mechanism ◽  
Warm Bath ◽  
Male Subjects ◽  
Shivering Thermogenesis

An attempt was made to demonstrate the importance of increased perfusion of cold tissue in core temperature afterdrop. Five male subjects were cooled twice in water (8 degrees C) for 53–80 min. They were then rewarmed by one of two methods (shivering thermogenesis or treadmill exercise) for another 40–65 min, after which they entered a warm bath (40 degrees C). Esophageal temperature (Tes) as well as thigh and calf muscle temperatures at three depths (1.5, 3.0, and 4.5 cm) were measured. Cold water immersion was terminated at Tes varying between 33.0 and 34.5 degrees C. For each subject this temperature was similar in both trials. The initial core temperature afterdrop was 58% greater during exercise (mean +/- SE, 0.65 +/- 0.10 degrees C) than shivering (0.41 +/- 0.06 degrees C) (P < 0.005). Within the first 5 min after subjects entered the warm bath the initial rate of rewarming (previously established during shivering or exercise, approximately 0.07 degrees C/min) decreased. The attenuation was 0.088 +/- 0.03 degrees C/min (P < 0.025) after shivering and 0.062 +/- 0.022 degrees C/min (P < 0.025) after exercise. In 4 of 10 trials (2 after shivering and 2 after exercise) a second afterdrop occurred during this period. We suggest that increased perfusion of cold tissue is one probable mechanism responsible for attenuation or reversal of the initial rewarming rate. These results have important implications for treatment of hypothermia victims, even when treatment commences long after removal from cold water.

Respiratory responses to cold water immersion: neural pathways, interactions, and clinical consequences awake and asleep

2006 ◽  
Vol 100 (6) ◽  
pp. 2057-2064 ◽  
Author(s):  
Avijit Datta ◽  
Michael Tipton
Keyword(s):  
Cold Water ◽  
Water Immersion ◽  
Respiratory Rhythm ◽  
Respiratory Arrest ◽  
Cold Water Immersion ◽  
Neural Pathways ◽  
Metabolic Demand ◽  
Deep Body Temperature ◽  
Clinical Consequences ◽  
Respiratory Responses

The ventilatory responses to immersion and changes in temperature are reviewed. A fall in skin temperature elicits a powerful cardiorespiratory response, termed “cold shock,” comprising an initial gasp, hypertension, and hyperventilation despite a profound hypocapnia. The physiology and neural pathways of this are examined with data from original studies. The respiratory responses to skin cooling override both conscious and other autonomic respiratory controls and may act as a precursor to drowning. There is emerging evidence that the combination of the reestablishment of respiratory rhythm following apnea, hypoxemia, and coincident sympathetic nervous and cyclic vagal stimulation appears to be an arrhythmogenic trigger. The potential clinical implications of this during wakefulness and sleep are discussed in relation to sudden death during immersion, underwater birth, and sleep apnea. A drop in deep body temperature leads to a slowing of respiration, which is more profound than the reduced metabolic demand seen with hypothermia, leading to hypercapnia and hypoxia. The control of respiration is abnormal during hypothermia, and correction of the hypoxia by inhalation of oxygen may lead to a further depression of ventilation and even respiratory arrest. The immediate care of patients with hypothermia needs to take these factors into account to maximize the chances of a favorable outcome for the rescued casualty.

Free fatty acid availability and temperature regulation in cold water

1989 ◽  
Vol 67 (6) ◽  
pp. 2466-2472 ◽  
Author(s):  
L. Martineau ◽  
I. Jacobs
Keyword(s):  
Cold Exposure ◽  
Temperature Regulation ◽  
Cold Water ◽  
Vastus Lateralis ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Glucose Levels ◽  
Plasma Ffa ◽  
Glycogen Utilization ◽  
Male Subjects

The purpose of this study was to investigate whether a reduced availability of plasma free fatty acids (FFA) would impair human temperature regulation during cold exposure. Seven seminude male subjects were immersed on two occasions in 18 degrees C water for 90 min or until their rectal temperature (Tre) decreased to 35.5 degrees C. The immersion occurred after 2 h of intermittent oral ingestion of either nicotinic acid (NIC) or a placebo (PLAC). Plasma FFA levels immediately before the immersion were significantly lower in NIC (87 +/- 15 mumol/l) than in PLAC (655 +/- 116 mumol/l, P less than 0.05). Although FFA levels increased by 73% in NIC during the immersion (P less than 0.05), they remained significantly lower than in PLAC (151 +/- 19 vs. 716 +/- 74 mumol/l, P less than 0.05) throughout the immersion. Muscle glycogen concentrations in the vastus lateralis decreased after cold water immersion in both trials (P less than 0.05), but the rate of glycogen utilization was similar, averaging 1.00 +/- 0.27 mmol glucose unit.kg dry muscle-1.min-1). Plasma glucose levels were significantly reduced after immersion in both trials (P less than 0.05), this decrease being greater in NIC (1.3 +/- 0.2 mmol/l) than in PLAC (0.7 +/- 0.1 mmol/l, P less than 0.05). O2 uptake increased to 3.8 +/- 0.3 times preimmersion values in both trials (P less than 0.05). Mean respiratory exchange ratio (RER) immediately before the immersion was greater in NIC (0.87 +/- 0.02) than in PLAC (0.77 +/- 0.01, P less than 0.05). Cold exposure increased RER in PLAC but not in NIC.(ABSTRACT TRUNCATED AT 250 WORDS)

Human temperature regulation during subanesthetic levels of nitrous oxide-induced narcosis

1995 ◽  
Vol 78 (6) ◽  
pp. 2301-2308 ◽  
Author(s):  
S. S. Cheung ◽  
I. B. Mekjavic
Keyword(s):  
Nitrous Oxide ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Dependent Manner ◽  
Significant Difference ◽  
Dose Dependent ◽  
Male Subjects ◽  
Dose Dependent Effect ◽  
Shivering Thermogenesis

The present study investigated whether nitrous oxide (N2O) attenuates shivering thermogenesis during cold water immersion in a dose-dependent manner. Seven male subjects were immersed to the neck for 60 min in 20 degrees C water on five separate occasions while breathing either air (AIR) or a normoxic mixture of 10, 15, 20, or 25% N2O balanced with N2. All N2O concentrations investigated caused a significant (P < 0.02) reduction in shivering thermogenesis compared with AIR. Despite similar heat flux from the skin, the relative changes in esophageal temperature from resting preimmersion levels were significantly greater (P < 0.05) during the N2O trials compared with AIR, with no significant difference among the N2O conditions. A dose-dependent trend in the perception of thermal comfort was observed for the N2O conditions. It is concluded that shivering thermogenesis, and thus thermal balance, is affected to the same degree for the range of inspired N2O concentrations investigated, with no discernable dose-dependent effect.

Accidental Hypothermia and Rewarming in Dogs

1979 ◽  
Vol 56 (6) ◽  
pp. 601-606 ◽  
Author(s):  
C. D. Auld ◽  
I. M. Light ◽  
J. N. Norman
Keyword(s):  
Core Temperature ◽  
Muscle Relaxant ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Hot Water ◽  
Control Group ◽  
Normal Core ◽  
Humidified Air ◽  
Respiratory Heat Exchange

1. Twenty lightly anaesthetized dogs were cooled to 29°C by cold-water immersion. Ventilation was spontaneous and the animals were allowed to shiver freely. Metabolic heat production and respiratory heat exchange were measured during rewarming. 2. The animals were divided into four groups each of five dogs and each group was rewarmed by a different technique. The control group was allowed to rewarm spontaneously; a second group was given warm (45–50°C) fully humidified air to breathe in addition; a third group was rewarmed in a hot-water bath (42–44°C) and the remaining group was given a muscle relaxant to abolish shivering and rewarmed by warm inspired air only. 3. The group rewarmed in hot water achieved normal core temperature most rapidly but there was no difference in the rewarming rates of the group rewarmed spontaneously and of the group given warm air to breathe in addition. 4. The group given a muscle relaxant and rewarmed with warm inspired air required 12 h to achieve the same core temperature as the shivering groups achieved in 2 h. Compared with the heat produced by shivering the amount of heat which it was possible to transfer across the respiratory tract was so small that it did not materially influence the rate of rewarming.

Respiratory and other responses in subjects immersed in cold water

1976 ◽  
Vol 40 (6) ◽  
pp. 903-910 ◽  
Author(s):  
K. E. Cooper ◽  
S. Martin ◽  
P. Riben
Keyword(s):  
Body Temperature ◽  
Respiratory Rate ◽  
Cold Water ◽  
Water Immersion ◽  
Oxygen Demand ◽  
Cold Water Immersion ◽  
Minimal Change ◽  
Moderate Rate ◽  
The Subject ◽  
End Tidal

Subjects have been immersed in water at 27 degrees C and 10 degrees C and while immersed their respiratory rates, minute volumes, and end-tidal PCO2 levels were measured. Measurements were made with the subjects at rest, exercising at approximately 0.8 liter oxygen-min-1, and very vigorously at 1.8–2.0 liters oxygen-min-1. Immersion in the cold water caused an increase in respiratory rate and a fall in end-tidal PCO2. At the moderate rate of exercise the hyperventilation persisted in relation to the oxygen demand and there was still a significant reduction in end-tidal PCO2. At the greatest rates of exercise, the end-tidal PCO2 did not differ from that obtained in similar rates of exercise in warm water. Preheating the subject in a sauna so as to increase skin temperature, with minimal change in body temperature, greatly attenuated the ventilatory and end-tidal PCO2 responses to cold water immersion. The significance of these findings is discussed.

scholarly journals Physiology Of Drowning: A Review

Physiology ◽  
2016 ◽  
Vol 31 (2) ◽  
pp. 147-166 ◽  
Author(s):  
Joost J. L. M. Bierens ◽  
Philippe Lunetta ◽  
Mike Tipton ◽  
David S. Warner
Keyword(s):  
Body Temperature ◽  
Cold Shock ◽  
Water Immersion ◽  
Upper Airway ◽  
Hot Water ◽  
Neurological Injury ◽  
Diving Response ◽  
Electrolyte Disorders ◽  
Deep Body Temperature ◽  
Deep Body

Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning.

Effect of cold-water immersion duration on body temperature and muscle function

2009 ◽  
Vol 27 (10) ◽  
pp. 987-993 ◽  
Author(s):  
Jeremiah J. Peiffer ◽  
Chris R. Abbiss ◽  
Greig Watson ◽  
Ken Nosaka ◽  
Paul B. Laursen
Keyword(s):  
Body Temperature ◽  
Muscle Function ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion

Patient Involvement in Treatment Decision Making Can Help or Hinder Placebo Analgesia

2014 ◽  
Vol 222 (3) ◽  
pp. 165-170 ◽  
Author(s):  
Andrew L. Geers ◽  
Jason P. Rose ◽  
Stephanie L. Fowler ◽  
Jill A. Brown
Keyword(s):  
Patient Involvement ◽  
Cold Water ◽  
Prior Experience ◽  
Water Immersion ◽  
Treatment Decision ◽  
Cold Water Immersion ◽  
Not Given ◽  
Placebo Analgesia ◽  
Treatment Decision Making ◽  
Immersion Experience

Experiments have found that choosing between placebo analgesics can reduce pain more than being assigned a placebo analgesic. Because earlier research has shown prior experience moderates choice effects in other contexts, we tested whether prior experience with a pain stimulus moderates this placebo-choice association. Before a cold water pain task, participants were either told that an inert cream would reduce their pain or they were not told this information. Additionally, participants chose between one of two inert creams for the task or they were not given choice. Importantly, we also measured prior experience with cold water immersion. Individuals with prior cold water immersion experience tended to display greater placebo analgesia when given choice, whereas participants without this experience tended to display greater placebo analgesia without choice. Prior stimulus experience appears to moderate the effect of choice on placebo analgesia.

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