transfer of heat to the skin. This situation, however, is rapidly reversed
in the postoperative period when anesthetically induced vasodilation
dissipates. The peripheral vasoconstriction that results makes forced-
air warming least effective in the post-operative period. Post-op patients
under regional anesthesia will warm faster than patients who have had
general anesthesia due to the residual vasodilation produced by region-
al anesthetics.
13. Which of the following is least effective in preventing hypothermia in adults
during anesthesia?
a. prewarming patients via forced-air systems
b. prewarming IV fluids
c. maintaining warm room temperature during induction
d. heating and humidifying anesthetic gases
d. Less than 10% of metabolic heat production is lost via the respira-
tory tract. Because so little heat is lost via this modality, both heat-
ing and humidifying gases have little effect on raising core tempera-
ture. This is especially true during long open surgeries, when far
more heat is lost via evaporation from the surgical wound. Airway
heating and humidification is more effective in decreasing heat loss
in infants and children, compared with adults, but cutaneous warm-
ing still transfers 10 times as much heat.
14. One liter of room temperature crystalloid will decrease mean core body tem-
perature by __________ .
a. 0.10°C
b. 0.25°C
c. 0.50°C
d. 1.00°C
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J U N E 2 0 1 5 | O U T P A T I E N TS U R G E R Y. N E T
