If you’ve ever had an operation, and remember the shivers afterwards, you will be glad to hear of a new form of blanket coverage.

Operating rooms are cold places. The doctors and nurses don’t notice it so much because they are covered from head to toe in surgical garb, and are working intently. For the patient, however, the cool ambiance can significantly lower the body temperature for a couple of reasons. First, by being put to sleep, albeit artificially with the help of an anesthetist, the body’s metabolism slows down. That’s why we can fall asleep on a Chesterfield after a late movie, and then wake up in search of a blanket a couple of hours later, even though the room temperature is unchanged.

For another reason, the operation often exposes significant areas of our insides to evaporation, making the patient colder than the doctors. About half of all people undergoing surgery become hypothermic during the procedure, sometimes by as much as three degrees Celsius or five degrees Fahrenheit, according to Dr. Daniel Sessler, a professor at the University of California at San Francisco. More than just a nuisance, such cooling disrupts drug metabolism, may impair blood clotting, inhibit wound healing, increase wound infections, and delay recovery from anesthesia.

Researchers have tested a lot of devices to solve the problem, but seem to have favored a forced air blanket to prevent heat loss. The device is much like a giant hair dryer which blows warm air through an empty quilt. The air fills the channels and there are slits on the inner side of the quilt which allow the warm air to diffuse over the patient. Because it delivers heat by all three mechanisms, namely conduction, convection, and radiation, it seems to work much better than radiant heat lamps and thermal ceiling devices.

Here’s an action tip:
If you are going to undergo major surgery, ask your anesthetist for extra warmth during the procedure. If they don’t have one of the latest forced air quilts, you should at least demand the best blanket coverage you can get.