6 4 S U P P L E M E N T T O O U T P A T I E N T S U R G E R Y M A G A Z I N E M A Y 2 0 1 5
duration of action for anesthetic and neuromuscular
blocking agents, as it also inhibits drug metaboliza-
tion, which may extend a patient's stay in post-anes-
thesia recovery; and even delayed wound healing.
Since general and regional anesthesia both impair
the body's normal thermoregulatory responses, and
since the perioperative environment is oftentimes a
chilly one for skin-exposed patients, most patients
who undergo surgery will become hypothermic,
unless effective, evidence-based practices are used.
Numerous clinical trials have demonstrated that
the use of convective (or forced-air) warming blan-
kets or garments are an effective intervention for
preventing perioperative hypothermia, and much
more effective than cabinet-warmed cotton blankets.
Despite the feeling of comfort they offer patients,
warmed cloth blankets are actually ineffective at
maintaining normothermia.
A range of other patient warming systems are
available, of course, including conductive fabric
blankets, thermal mattresses and under-body pads,
but generally speaking there has been a greater
amount of clinical research conducted on forced-air
warming devices than on these other methods.
Studies have also shown that effective warming
depends on timing. In order to prevent hypothermia,
active warming should be initiated before anesthesia
induction, and the body's subsequent redistribution
of heat. Additionally, though, warming patients for
20 or 30 minutes pre-operatively, before their arrival
