GI motility decreases at less than 34°C (93.2°F) The liver’s capacity for detoxification or conjugation of drugs and products of metabolism is poor Insulin release abates, and serum glucose rises Frank pancreatic necrosis may also occur, producing clinical evidence of pancreatitis Clinical Recognition Elevated body temperature is a routine concern for most physicians, especially pediatricians However, hypothermia is often overlooked Reduced body temperature may be a consequence or cause of many disorders but is diagnosed only if healthcare providers maintain a high index of suspicion Special thermometers may be required to detect hypothermia Triage Considerations A history of sudden immersion in icy water or prolonged exposure to low environmental temperatures provides the obvious clue, but significantly low core temperatures may occur under much less suggestive circumstances Examples include trauma victims found unconscious or immobile on a wet, windy, summer day; infants who are from inadequately heated homes or who are left exposed during prolonged medical evaluation; adolescents with anorexia nervosa; and patients with sepsis or burns Severe hypothermia, coma, and cardiac arrest may present as the sudden infant death syndrome Hypothermia may go undetected if the patient’s temperature falls below the lower limit of the thermometer in use or if a manual thermometer is not shaken down adequately Low-recording thermometers should be available in EDs and ICUs This diagnosis should be kept in mind for any patient with a suggestive history or coma of uncertain cause Initial Assessment Physical examination reveals a pale or cyanotic patient At mild levels of hypothermia, mental status may be normal, but CNS function is progressively impaired with falling temperature until frank coma occurs at approximately 27°C (80.6°F) BP also falls steadily at less than 33°C (91.4°F) and may be undetectable Heart rate slows gradually unless atrial or ventricular fibrillation occurs Intense peripheral vasoconstriction and bradycardia may render the pulse unapparent or absent At less than 32°C (89.6°F), shivering ceases, but muscle rigidity may mimic rigor mortis Pupils may be dilated and may not react Deep tendon reflexes are depressed or absent Evidence of head trauma or other injury, drug ingestion, and frostbite should be sought ( Figs 90.6 and 90.7 ) FIGURE 90.6 Frostbite of toes Note the line of demarcation and ulcerative lesion Severe hypothermia mimics death However, the significant decrease in oxygen consumption may allow life to be sustained for long periods, even after cessation of cardiac function Signs usually associated with certain death (i.e., dilated pupils or rigor mortis) have little prognostic value If the patient’s history suggests that hypothermia is the primary event and not a consequence of death, resuscitation and active rewarming should be attempted, and death should be redefined as failure to revive with rewarming Initial laboratory tests should include CBC, platelet count, clotting studies, electrolytes, BUN and creatinine, glucose, serum amylase/lipase, and ABGs corrected for temperature ( Table 90.6 ) Urine should be sent for drug screening FIGURE 90.7 Swollen fingers of a child with cold exposure TABLE 90.6 EFFECT OF BODY TEMPERATURE ON ARTERIAL BLOOD GASES MEASURED AT 37°C (98.6°F) pH Paco2 (mm Hg) For each elevation of °C −0.015 +4.4% For each depression of °C +0.015 −4.4% Pao2 (mm Hg) +7.2% −7.2% Management and Diagnostic Studies Therapy for hypothermia can be divided into two parts: general supportive measures and specific rewarming techniques ( Table 90.7 ) Once hypothermia is diagnosed, temperature must be monitored continuously as treatment progresses Defibrillation is less effective when body temperature is below 30°C (86°F), and pacing is generally ineffective Several case reports suggest that the use of vasopressors and/or defibrillation may sometimes be effective in hypothermic patients, although the effectiveness of antiarrhythmics is less clear Pending further research, it is recommended administering vasopressors and attempting defibrillation as indicated, while aggressively rewarming the patient