คำศัพท์ทIf the hypothermia has developed rapidly, many
different processes may contribute to hyperglycaemia,
which can contribute an osmotic component
to the diuresis. Insulin release is inhibited by increased
corticosteroid levels, as well as by a direct cooling
effect on the islets of Langerhans;90 in addition,
peripheral uptake of insulin at the tissues is
impaired. Sympathetic activity is increased, with
raised plasma norepinephrine and free fatty acid
levels,91 and the catecholamine-induced glycogenolysis
and gluconeogenesis contribute to the hyperglycaemia.
The glucagon level is increased, and
plasma cortisol levels correlate with lactate and
glycerol levels, implying active stimulation of glycogenolysis
and lipolysis.92 In cases where hypothermia
has developed more slowly or is long-lasting,
glycogen stores may be depleted, and then it is
likely that hypoglycaemia will develop. Shivering
may also deplete glycogen stores and in the longer
term contribute to hypoglycaemia. With rewarming,
the factors leading to a raised plasma glucose correct,
and so moderate degrees of hyperglycaemia
should be tolerated rather than be treated, in order
to avoid profound hypoglycaemia on rewarming.
Exogenous insulin has little effect in the hypothermic
state, and high doses would be needed for
any apparently beneficial effect. If hyperglycaemia
persists during the process of rewarming, diabetic
ketoacidosis and pancreatitis need to be considered,
and insulin therapy instituted once the temperature
has returned to )30 8C.างการแพทย์