saline or lactated Ringer solution, warmed to about 43°C (109.4°F) in a bloodwarming coil, is appropriate initially Electrolyte determinations should guide further replacement If clotting abnormalities occur, fresh-frozen plasma (10 mL/kg) is a useful choice for volume expansion (see Chapter 93 Hematologic Emergencies ) As temperature rises and peripheral vasoconstriction diminishes, hypovolemia is expected Fluid volume should be sufficient to maintain an adequate arterial BP Hypoglycemia, if present, is treated with glucose (0.5 to g/kg by IV) Hyperglycemia, which may result from impaired insulin release in the hypothermic pancreas, should be tolerated to avoid severe hypoglycemia with rewarming FIGURE 90.8 Algorithm for rewarming (Adapted from Danzl DF, Pozos RS Accidental hypothermia N Engl J Med 1994;331(26):1756–1760.) A number of rewarming strategies exist ( Fig 90.8 ) Passive rewarming implies removal of the patient from a cold environment and use of blankets to maximize the effect of basal heat production For patients with mild hypothermia (temperature higher than 32°C [89.6°F]), this may be adequate As shown in the algorithm, the adequacy of perfusion and the degree of hypothermia are the major factors in the selection of rewarming strategies For patients with an adequate pulse, passive rewarming is used as the initial strategy if the temperature is greater than 32°C and active core rewarming if the temperature is less than 32°C Those with poor perfusion require active rewarming with a temperature greater than 32°C and ECMO, if available, with temperature less than 32°C Active rewarming is divided into external and core rewarming techniques Electric blankets, hot-water bottles, overhead warmers, and thermal mattresses are simple, easily available sources of external heat Immersion in warm-water