COMPLICATIONS OF REWARMING
Rewarming complications are common. After-drop describes the phenomenon characterized by a continued decrease in core body temperature after the onset of rewarming. Cold
blood from the body's periphery returns to the core while warmed core blood moves to the periphery.5,8
Rewarming shock is a condition caused by rapid rewarming that induces vasodilation and places great metabolic demands on affected
patients, both of which may readily overwhelm an already compromised circulatory system.5,9
Cats with hypovolemic shock will frequently present with three distinct clinical signs: hypothermia, hypotension, and bradycardia.5 Indeed, this constellation of signs is profound, is indicative of a life-threatening disease, and is anecdotally referred
to as the triad of death. Previous research documented altered adrenergic reactivity in hypothermic cats.10 With effective treatment of hypothermia, adrenergic reactivity and vascular responsiveness are restored; thus, patients
treated with large volumes of crystalloids are at risk for hypervolemia and pulmonary edema. Conservative fluid therapy with
concurrent aggressive rewarming is an essential part of shock resuscitation therapy in hypothermic cats to help avoid the
development of pulmonary edema.
CONCLUSION
Hypothermia is a lowering of the body's temperature. The body's ability to reestablish normothermia lessens and is ultimately
abolished with progressive hypothermia. As body core temperature drops, multiple body systems suffer from the effects of the
reduced temperature.
The primary treatment goal for hypothermic patients is to reestablish a normal core body temperature through passive surface,
active surface, or active core rewarming interventions. To achieve a successful outcome, be prepared to monitor for and treat
complications of both hypothermia and rewarming interventions. For a case example of how to treat hypothermia, see Rewarming a stray kitten.
Christopher G. Byers, DVM, DACVECC, DACVIM (small animal internal medicine)
MidWest Veterinary Specialty Hospital
9706 Mockingbird Drive
Omaha, NE 68127
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