overall health and physiologic reserve and muscle mass. Pediatric
patients are at increased risk of becoming hypothermic because
increased body-surfac-area-to-mass ratio accelerates radiant heat
loss. Young infants are at significant risk of hypothermia as they are
unable to shiver and are dependent on non-shivering thermogenesis
to generate heat. Elderly and cachectic patients have both a
decreased muscle mass and physiologic reserve. Regulatory thresh-
olds in patients 60 to 80 years of age are 1°C less than those in 30- to
50-year-olds. The increased incidences of chronic diseases and the
use of multiple medications such as anti-hypertensives and anti-psy-
chotics, which can impair compensatory responses, increase their
risk further. Obese patients have actually been found to have higher
perioperative core temperatures compared to non-obese patients and
thus do not represent a population at increased risk for developing
hypothermia. It should be noted, however, that obese patients can
still experience perioperative hypothermia and should receive the
same preventive and active treatment methods that other patients
receive.
6. Which statement regarding shivering is false?
a. It is surprisingly ineffective at generating heat compared to exercising
b. It does not occur in infants and is not effective until a child is several years old
c. It consists of fast synchronous muscular activity
d. It can increase metabolic heat production in the adult by 50 to 100%
c. Sustained shivering can increase metabolic heat production by 50 to
100% in adults. By comparison, however, exercise can increase metab-
olism by as much as 500% and is far more effective in increasing meta-
bolic heat production. As noted earlier, infants depend on non-shiver-
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