The Risks and Disadvantages of Forced Air Warming

Posted by Lauren Burke on

Hypothermia is a known risk of surgery, making thermoregulation a priority during procedures. An estimated 50 to 90 percent of patients will experience inadvertent perioperative hypothermia unless the surgical staff applies preventative measures.

Studies indicate that inadvertent hypothermia can increase postoperative discomfort, prolong the patient’s hospital stay and increase the risk of infection, morbid cardiac events, coagulation disorders and blood loss.

There are several perioperative temperature regulating resources available including somewhat controversial forced-air warming blankets. Are forced-air warming blankets worth the potential risks that come with their use?

Forced-Air Warming Blankets

Forced-air warming promotes convective heat transfer by moving warm air across the skin, so the blanket provides thermoregulation at a lower temperature. Forced-air warming is available in hospitals because it does offer benefits but risks, as well.

Risks Associated With Forced Air Systems

Often overlooked is the effect a forced-air system has on laminar airflow in the operating room. Laminar indicates the ventilation system moves the airflow in one direction, essentially sweeping over all surfaces including the patient. One of the top concerns regarding forced-air warming blankets is the disruption of that unidirectional flow and the increase of surgical site infections (SSIs).

The goal of unidirectional airflow is to remove dust, debris and microorganisms from the air over the patient to reduce the risk of surgical site infections. SSIs are the leading complication with orthopedic implant surgeries. Using forced air works against this effort by interfering with the structured flow.

Other disadvantages of using a forced-air warming system include basic design issues. It is necessary to manually turn the forced air heater on, which can be overlooked in a busy surgical environment leaving the patient with no thermoregulation.

There have been cases of thermal burns when the forced-air system is set up incorrectly. In one case, the nozzle was not connected to baffles meant to protect the patient so the hot air hit her skin for 30 minutes leading to significant burns. Units must be plugged into an electrical socket in the operating theater, as well. The cord running across the floor represents a hazard to the surgical staff.

The question becomes is the forced-air method better than conductive warming options?

Conductive vs. Convective

Convection is transferring heat through direct matter. Conduction is the transfer of heat through contact. Put simply, putting a warm blanket or using warm fluid is a form of conduction heat transfer.

Studies show that conductive heat through blankets is a more effective way to warm patients and prevent hypothermia. A blanket warmer can store blankets and sterile fluids for irrigation or intravenous therapy and sits in the background out of the way.

Although both convective and conductive heat can work to prevent inadvertent perioperative hypothermia, forced-air warming blankets may increase the risk of infection and come with other significant disadvantages.

Source:

  1. http://www2.aaos.org/bulletin/jun06/fline7.asp
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