Is oxygen supply a limiting factor for survival during rewarming from profound hypothermia?

@article{Kondratiev2006IsOS,
  title={Is oxygen supply a limiting factor for survival during rewarming from profound hypothermia?},
  author={Timofei V. Kondratiev and Kristina Flemming and Eivind S. P. Myhre and Mikhail A. Sovershaev and Torkjel Tveita},
  journal={American journal of physiology. Heart and circulatory physiology},
  year={2006},
  volume={291 1},
  pages={
          H441-50
        }
}
It has been postulated that unsuccessful resuscitation of victims of accidental hypothermia is caused by insufficient tissue oxygenation. The aim of this study was to test whether inadequate O2 supply and/or malfunctioning O2 extraction occur during rewarming from deep/profound hypothermia of different duration. Three groups of rats (n = 7 each) were used: group 1 served as normothermic control for 5 h; groups 2 and 3 were core cooled to 15 degrees C, kept at 15 degrees C for 1 and 5 h… 
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References

SHOWING 1-10 OF 46 REFERENCES

Cardiovascular effects of epinephrine during rewarming from hypothermia in an intact animal model.

This study shows that, in contrast to normothermic conditions, Epi infused during hypothermia induces vasoconstriction rather than vasodilation combined with lack of CO elevation, which may be related to Hypothermia-induced myocardial failure and changes in temperature-dependent adrenoreceptor affinity.

Oxygen delivery and consumption during hypothermia and rewarming in the dog.

Changes in oxygen consumption (VO2) and oxygen delivery (DO2) were compared in three groups of paralyzed, sedated dogs and found that VO2 and DO2 decreased significantly from control values during the cooling phase, in both the acute and prolonged hypothermia animals.

Myocardial damage caused by keeping pH 7.40 during systemic deep hypothermia.

Oxygen availability during hypothermic cardiopulmonary bypass

A “functional” value of hemoglobin, based upon the effects of the shift of the oxyhemoglobin dissociation curve and, therefore, reflecting the true capacity ofhemoglobin to unload oxygen at the tissue level, was calculated, suggesting that, in spite of reduced metabolic demands, oxygenation reserves are minimal.

Oxygen delivery and utilization in hypothermic dogs.

The overall effect of hypothermia on the ability of the peripheral tissues to extract O2 from blood is determined and hypothermic dogs maintained their base-line VO2's at lower arterial PO2's than control.

Hemodynamics and metabolism during surface-induced hypothermia in the dog: a comparison of pH management strategies.

Changes in Oxygenation Variables During Progressive Hypothermia in Anesthetized Patients

It is concluded that progressive hypothermia in anesthetized patients reduces metabolic rate but does not change DO2, which may partly be related to a leftward shift of the oxyhemoglobin dissociation curve, as evidenced by the decrease in P50.

The Detrimental Effects of Prolonged Hypothermia and Rewarming in the Dog

With rewarming, cardiovascular collapse with severe tissue hypoxia and acidosis developed; CBF became grossly inadequate, resulting in depletion of brain energy stores, and VO2 continued to decrease, and at 24 hours values were 7 and 28 per cent of control, respectively.

Cardiovascular responses in prolonged hypothermia.

In 31 rats cooled to and maintained at a body temperature of 15 C, cardiac output decreased continually during the entire period of hypothermia, having by the end of Hypothermic survival the value of only 25% of output at the beginning of the hypothermic period.

Experimental hypothermia and rewarming: changes in mechanical function and metabolism of rat hearts.

The finding of deteriorated myocardial mechanical function and a shift in energy metabolism shows that the heart could be an important target during hypothermia and rewarming in vivo, thus contributing to the development of a posthypothermic circulatory collapse.