Rationale:

• Alcohol and other drugs, such as meperidine and phenothiazines, interfere with the body's capacity to generate heat by shivering.
• Decreases in the level of physical exercise (related to drug-induced sedation or physical immobility) will decrease heat production.
• Compromised mental faculties related to drugs, alcohol ingestion, senile dementia, or cerebral vascular accident can cloud judgment and increase the patient's risk for prolonged exposure.
• Malnutrition characterized by decreased body fat may compromise thermal homeostasis by significantly reducing the body's energy supply and thermal insulation.
• Elderly persons often have a lower core temperature, which is related to decreased basic metabolic rate, malnutrition, impaired circulation, decreased sensitivity to cold temperatures, and impaired neuroendocrine and autonomic system function, with diminished responses to cold, including vasoconstriction, norepinephrine release, and vasomotor response.

Evidence:

• Several studies of mentally impaired patients found that the severity of hypothermia is often related to the severity of impaired judgment and the type of antipsychotic drug administered (19; 20; 21).
  • All classes of antipsychotic medication, including the atypical antipsychotics, have been associated with hypothermia (19; 20; 21; 22; 23; 24; 25).
  • The hypothermic effects of antipsychotic medication appear to be regulated by CNS dopamine receptors (26; 27).
• Several studies have looked at impaired thermo-production in elderly patients requiring additional warming (28; 29; 30; 31).

Comments:

• None.