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Critical Care

, 4:P204 | Cite as

Accidental hypothermia and active rewarming: the metabolic changes observed above and below 32°C

  • JJ McInerney
  • B Breakell
  • W Madira
  • T Davies
  • PA Evans
Meeting abstract

Keywords

Magnesium Parathyroid Hormone Tissue Injury Full Text Metabolic Change 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Full text

Background

In accidental hypothermia the underlying physiological mechanisms responsible for poor outcome during rewarming through 32°C remain obscure. Deleterious changes in plasma calcium (Ca2+), magnesium (Mg2+), and acid-base concentrations have been reported in other forms of tissue injury, whilst parathyroid hormone (PTH) and interleukin 6 (IL-6) levels are elevated. Accordingly this study investigated the changes which occur in Ca2+, Mg2+, pH, PTH and IL-6 during rewarming.

Methods

Eight patients, 4 males and 4 females, age 45 to 85 years, admitted with core temperatures <35°C were included in the study. Patients were rewarmed with dry warm blankets and fluid replaced by crystalloid at 40°C. Blood for Ca2+ and Mg2+, pH, PTH and IL-6 were collected at presentation, during rewarming, and at 24 h.

Results

Four patients were admitted with mild hypothermia (32–35°C) and four with moderate (28–32°C) hypothermia. All patient clinical parameters responded favourably to rewarming. Rewarming to 32°C had no significant effect on the presenting acidosis (P=0.1740), although above 32°C pH increased with temperature (P<0.0001). There was a negative correlation between pH and both Ca2+ (P=0.0005) and Mg2+(P=0.0488) below 32°C; above this temperature the relationship was significant only for Ca2+ (P=0.0494). PTH and Ca2+correlated positively (P=0.0041) and negatively (P=0.0039) in moderate and mild hypothermia respectively. IL-6 and Ca2+ also correlated positively (P=0.0039) and negatively (P=0.0018) when presentation temperature was below and above 32°C respectively.

Conclusions

During rewarming pH remains unchanged until patient temperature reaches 32°C. Ca2+ and Mg2+ decline is associated with this pH change. Poor outcome is associated with presentation temperature (<32°C), nonphysiological correlation between PTH and Ca2+, and age (≥ 84 years). IL-6 levels mirror this PTH change but further study is required to explain these findings.

Copyright information

© Current Science Ltd 2000

Authors and Affiliations

  • JJ McInerney
    • 1
  • B Breakell
    • 1
  • W Madira
    • 1
  • T Davies
    • 1
  • PA Evans
    • 1
  1. 1.Accident and Emergency departmentThe Leicester Royal InfirmaryLeicesterUK

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