A forced air warming system uses heated air to warm patients through convection-the transfer of heat by the actual movement of warmed air. These systems are routinely used during surgery to keep patients warm and prevent complications of hypothermia.1 The system consists of a heater, a hose, and an inflatable, disposable blanket that covers all or part of the patient.2,3 When used correctly, the unit delivers heated air through the hose into the disposable blanket, which distributes the heat evenly over the patient.3 These systems are considered safe and effective when used according to the manufacturer's operating instructions.3

Beware of hosing

Complications are rare with these systems and usually occur when the hose isn't attached to the disposable blanket when in use. Using the forced air warming system without attaching the blanket to the hose is called hosing or free hosing.4 According to the Center for Devices and Radiological Health (CDRH), hosing has caused first-, second-, and third-degree burns in surgical patients.2-4 The most severe injury reported from hosing resulted in an above-the-knee amputation.2,3

There are two ways that hosing can cause thermal injuries. The first occurs when the hose is placed under the surgical drapes or sheets and warm air flows directly on one area of the patient's body for a period of time. The second method of thermal injury can occur when the hose isn't attached to the blanket and the nozzle of the hose heats up and comes in direct contact with the patient's body.4

Steps to prevention

Educate the OR staff about the dangers encountered if the manufacturer's recommendations aren't followed. Be sure there's a written policy in place explaining the dangers of hosing and review the policy annually. Also, explain the purpose of the disposable blanket and the potential for burns.3

Preventing patient injuries from the misuse of forced air warming systems is the responsibility of the entire surgical team. Users must understand the manufacturer's operating instructions, techniques, precautions, warnings, and associated risks to specific patient populations. Preventing thermal injuries and preventing the untoward effects of hypothermia can be accomplished by following the operator's manual for safe, proper, and effective management of the forced air warming system.

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