In a recent study, researchers compare the efficacy of resistant-polymer and forced-air warming devices in maintaining normothermia in orthopedic patients.

May 4, 2010

According to a study published in the March 2010 issue of Anesthesia & Analgesia, several adverse consequences can be caused by mild perioperative hypothermia.

Today, maintaining normothermia in the OR is done with patient warming systems, mostly with forced air (FA). Thus, FA has become a standard procedure during anesthesia. Recently, a polymer-based resistive patient warming system was developed. The researchers, including Brandt S, Oguz R, Hüttner H, Waglechner G, Chiari A, Greif R, Kurz A, Kimberger O., compared the efficacy of a widely distributed FA system with the resistive-polymer (RP) system in a prospective, randomized clinical study.

Eighty patients scheduled for orthopedic surgery were randomized to either FA warming (Bair Hugger warming blanket #522 and blower #750, Arizant, Eden Prairie, MN) or RP warming (Hot Dog Multi-Position Blanket and Hot Dog controller, Augustine Biomedical, Eden Prairie, MN). Core temperature, skin temperature (head, upper and lower arm, chest, abdomen, back, thigh, and calf), and room temperature (general and near the patient) were recorded continuously.

The researchers found after an initial decrease, core temperatures increased in both groups at comparable rates (FA: 0.33 degrees C/h +/- 0.34 degrees C/h; RP: 0.29 degrees C/h +/- 0.35 degrees C/h; P = 0.6). There was also no difference in the course of mean skin and mean body (core) temperature. FA warming increased the environment close to the patient (the workplace of anesthesiologists and surgeons) more than RP warming (24.4 degrees C +/- 5.2 degrees C for FA vs 22.6 degrees C +/- 1.9 degrees C for RP at 30 minutes; P(AUC) <0.01).

Overall, the researchers concluded that RP warming performed as efficiently as FA warming in patients undergoing orthopedic surgery.