Hypothermia-Related Mortality,
1979--2002
During 1979--2002, a total of 16,555 deaths in
the United States, an average of 689 per year, were attributed to
exposure to excessive natural cold (International Classification of
Diseases, Ninth and Tenth Revision ICD-9 codes E901.0, E901.8, and
E901.9; ICD-10 code X31)
In 2002, a total of 646 hypothermia-related
deaths were reported, with an annual death rate of 0.2 per 100,000
population. The majority of reported hypothermia-related deaths (66%)
occurred in males, but the overall death rate (0.5) was the same for
both males and females.
States with the greatest overall death rates for
hypothermia in 2002 were Alaska (3.0), New Mexico (0.9), North Dakota
(0.9), and Montana (0.8). In addition, hypothermia-related deaths were
reported by states with characteristically milder climates that
experience rapid temperature changes (e.g., North Carolina [0.4] and
South Carolina [0.4]) and by western states that have high elevations
and experience considerable changes in nighttime temperatures (e.g.,
Arizona [0.3]).
Reported by: F Fallico, MD, Alaska Dept of Health
and Social Svcs. K Nolte, MD, Office of the Medical Investigator, Univ
of New Mexico School of Medicine, Albuquerque, New Mexico. L Siciliano,
Vermont Dept of Health. Div of Environmental Hazards and Health Effects,
National Center for Environmental Health; F Yip, PhD, EIS Officer, CDC.
Editorial Note:
( Most hypothermia-related deaths are preventable.
Early recognition of the signs and symptoms of hypothermia and awareness
of key risk factors can help minimize morbidity and mortality from
exposure to extreme cold.
Active rewarming,
especially among persons with moderate to severe hypothermia, typically
involves rewarming
of the airways. - 
RES-Q-AIR
-
or
administration of warmed intravenous fluids
-
IV WARMER - )
Hypothermia can be classified as mild (core
body temperature: 90.0°F to <95.0°F [32.2°C to <35.0°C]),
moderate (82.5°F to <90.0°F [28.0°C to <32.2°C]), or severe
(<82.5°F [<28.0°C]) . Onset of hypothermia is not always
evident, although shivering, numbness, lethargy, poor coordination, and
slurred speech are typical early manifestations. Among infants, warning
signs also include bright red skin and low energy. When body temperature
is <90.0°F [<32.2°C], shivering might not be evident, and the
victim might not feel cold. In severe hypothermia, the victim loses
consciousness, and a pulse might not be apparent.
Understanding the risk factors for hypothermia
can help identify populations at risk. This report highlights three risk
factors for hypothermia-related deaths: advanced age (>65 years),
mental impairment, and substance abuse.
Additional contributing factors can include
homelessness, dehydration, and serious medical conditions. Older persons
are at particular risk because their lower metabolic rate might prevent
their maintaining normal body temperatures when indoor or outdoor
temperatures fall below 64.4°F (18.0°C). Older persons also might not
perceive cold as well as younger persons and might be slow to compensate
for the cold.
Hypothyroidism and diabetes can contribute
to hypothermia risk through decreased metabolic rate and hypoglycemia,
respectively. Substance abuse is another potential contributor to
hypothermia; alcohol and drug use (e.g., sedatives or phenothiazines)
can suppress vasoconstriction and the shivering response through
cutaneous vasodilation, alter decision-making, and decrease awareness of
and response to hazardous environmental conditions.
To prevent hypothermia-related deaths,
public health strategies should target health departments in states
characterized by milder winter climates but rapid temperature changes
should identify groups at high risk for hypothermia, ensure that proper
resources are available to them.
Educating public safety personnel and hospital
staff to better recognize hypothermia victims and to familiarize
themselves with initial treatments also can help prevent
hypothermia-related morbidity and mortality. Because certain signs of
hypothermia, such as confusion and loss of coordination, can resemble
alcohol intoxication, hypothermia victims might be sent to
detoxification centers before they are sent to hospitals. Workers at
detoxification centers should be aware of signs and risk factors for
hypothermia and be instructed to take the temperature of potential
hypothermia victims on admission.
References
1. Kilbourne EM. Illness due to thermal extremes.
In: Last JM, Wallace RB, eds. Public health and preventative medicine.
13th ed. Norwalk, CT: Appleton and Lange; 1992:63--8.
2. CDC. Extreme cold: a prevention guide to
promote your personal health and safety. Atlanta, GA: US Department of
Health and Human Services, CDC; 2004. Available at http://www.bt.cdc.gov/disasters/winter/guide.asp.
3. Weinberg AD. Hypothermia. Ann Emerg Med
1993;22:370--7.
4. National Center for Health Statistics.
Compressed mortality file. Hyattsville, MD: US Department of Health and
Human Services, CDC, National Center for Health Statistics; 2004.
5. Lazar HL. The treatment of hypothermia. N Engl
J Med 1997; 337:1545--7.
6. Abramowicz M. Treatment of hypothermia. Med
Lett Drugs Ther 1994;36(938):116--7.
7. CDC. Exposure-related hypothermia
deaths---District of Columbia, 1972--1982. MMWR 1982;31:669--71
Alaskan Protocol