In 1979,* excessive cold was reported as the underlying cause
of
711 deaths among persons of all ages and races and both sexes
(Table
1).
Deaths of males from excessive cold exceeded those of females
(2.8:1 for all ages), especially in the 30- to 44-year age group
(7.8:1). Persons in the 65- to 74-year category, representing 7%
of
the total U.S. population (1), accounted for 18% of these deaths.
Persons 75 years and older, representing 4% of the U.S. population
(1), accounted for 28%. Data for the last few years indicate the
hypothermia death rate among the elderly may be increasing (2).
Hypothermia, defined as a core body temperature lower than 35 C
(95 F), may be classified as acute, subacute, or chronic. Acute
hypothermia is caused by a rapid loss of body heat, usually from
immersion in cold water. Subacute hypothermia often occurs from
exposure to cool weather (below 10 C (50 F)) outdoors, in
combination
with wind chill, wet or inadequate clothing, fatigue, and/or
inadequate nutrition. Chronic hypothermia in predisposed persons
generally occurs from exposure to cold temperatures (below 16 C (60
F)) indoors over a prolonged period. Predisposed persons have an
impaired perception of cold; decreased mobility; and inadequate
nutrition, clothing, and heating systems. This group typically
includes the poor, the elderly, and drug or alcohol abusers.
*The latest year for which data are available for the entire United
States.
Early signs include nonspecific disturbances of mental activity
and judgment, which may be mistaken for other conditions and thus
delay corrective measures (Table 2). Severe and life-threatening
hypothermia occur when core body temperature falls below 30-32 C
(85-90 F). Diagnosing the condition, therefore, requires
recognizing
early signs and symptoms and accurately measuring core body
temperature with low-reading thermometers (below 35 C (95 F)).
Treating patients with severe hypothermia consists of carefully
rewarming them and monitoring their temperatures (3,4). All
hypothermic patients--including those showing no signs of
life--should
be transported quickly and carefully to a medical facility. When
appropriate, rescuers should start cardiopulmonary resuscitation.
Very cold patients, if moved excessively, are susceptible to
ventricular arrhythmias (4).
Reported by Special Studies Br, Chronic Diseases Div, Program Svcs
Br,
Environmental Health Svcs Div, Center for Environmental Health,
CDC.
Editorial Note
Editorial Note: Hypothermic mortality is probably underreported
for
four reasons: 1) its physical signs may not be recognized because
they
resemble other conditions; 2) hospitals may not use low-temperature
thermometers; 3) medical personnel may be unaware of hypothermia's
significance; and 4) even an autopsy cannot prove hypothermia as an
underlying cause of death. Further study and better reporting are
needed to explain the age and sex differences in the hypothermic
death
rates noted in Table 1 and to make such study valid.
Preventing hypothermia involves knowing of the condition and
its
risk factors and taking necessary precautions to avoid excessive
and
prolonged exposure to cold. Anyone who engages in boating,
swimming,
and outdoor winter activities should learn and practice safety
rules
and survival techniques. Everyone, especially the elderly and the
debilitated, should have adequate food, clothing, shelter, and
sources
of heat. Electric blankets may effectively prevent hypothermia,
even
in inadequately heated houses. Additional information on
hypothermia
and safety rules may be obtained from sources listed in references
5-9.
References
National Center for Health Statistics. Current estimates from
the
national health interview survey: United States, 1979, series
10;
no. 141 (computer tape) Hyattsville, Maryland: National Center
for
Health Statistics, 1981.
U.S. Senate. Hearing before the Special Committee on Aging,
November 26, 1979. Washington, D.C.: U.S. Government Printing
Office, 1980.
Martyn JW. Diagnosing and treating hypothermia. Can Med Assoc J
1981;125:1089-96.
Reuler JB. Hypothermia: pathophysiology, clinical settings, and
management. Ann Intern Med 1978;89:519-27.
National Institute on Aging. Accidental hypothermia: a winter
hazard for the old. Bethesda, Maryland: National Institute on
Aging (NIH Publication No. (PHS) 81-1464), 1980.
Select Committee on Aging. Hypothermia: a preventable tragedy.
A
cold weather guide for the elderly. Washington, D.C.: U.S.
Government Printing Office (Comm. Pub. No 97-307), 1981.
CDC. Hypothermia: fact sheet. Atlanta: Centers for Disease
Control, January 1982.
National Safety Council. Public safety fact sheet: hypothermia.
Chicago: National Safety Council.
CDC. Exposure-related hypothermia deaths--District of Columbia,
1972-1982. MMWR 1982;31:669-671.
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