118 - Effect of Patient Warming Device on Cleanliness of Surgical Field
Description: [Background] Patient warming devices play an important role in the prevention of perioperative hypothermia. However, increased particle counts have been confirmed while using forced air warming devices(FAW) and there is a concern that the surgical field may be contaminated because of this. Therefore, it is necessary to study a safe intraoperative patient temperature management method that does not contaminate the surgical field with particles while not disturbing the laminar flow in the operating room. [Purpose] By measuring particle counts and overall cleanliness of the operating room, examine a patient warming system that safely warms the patient while minimizing potentially infectious particles over the surgical field. [Method] We simulated a lower limb surgery by preparing a mannequin and drapes on an operating table in an operating room of ISO cleanliness class 5.A particle counter that takes in 28.3l/min was installed near the thigh and particle counts in the surgical field were measured.Measurements were taken for three groups.Group A:No heating device,Group B:forced-air warming device(FAW),upper body blanket set at 43 degrees,Group C:Conductive fabric heating device,Multi-position blanket set at 43 degrees. [Results] The average number of particles(/ft3) at the operative field in each group was as follows.Group A(without heating device)?0.3µm3.2(SD1.7),?0.5µm0.2(SD0.4),?1µm0(SD0),?2µm0(SD0),Group B(FAW)?0.3µm78(SD47.1),?0.5µm40.8(SD24.5),?1µm14(SD10.9),?2µm3.6(SD2.9),Group C(conductive fabric type)?0.3µm0.4(SD0.8),?0.5µm0(SD0),?1µm0(SD0),?2µm0(SD0).Compared with Group A, the number of particles of?0.3µm,?0.5µm,?1µm,?2µm was significantly higher in Group B(p?0.05).In addition, compared with group A, group C was significantly lower at ?0.3µm and there was no significant difference at ?0.5µm•?1µm•?2µm. [Discussion] We believe the reason high particle counts were detected in Group B(FAW) is that the warm air generated by the device created an upward airflow, and particles are believed to be carried over the surgical field and around the surgical drape.Since we were able to confirm the particle sizes, we know that they are capable of carrying bacteria so there is a possibility that the surgical field is contaminated by bacteria laden particles.On the other hand, particle counts in the conductive fabric device group were low because the device uses conduction to generate heat and thus does not generate warm air that can interfere with the operating room’s airflow.Based on our findings, we believe that much care should be taken if airborne contamination is a concern when using FAW, or perhaps alternative warming methods should be considered [Conclusion] Forced-air patient warming devices may contaminate the surgical field.The conductive fabric type patient heating device can safely warm the patient without affecting the cleanliness of the surgical field.