Forced Air Warming System: Evaluation of Internal System Contamination.

Abstract

Despite the indisputable need to prevent peri-operative hypothermia, some evidence in the literature questions the possible role of forced air warming systems as a risk factor for the occurrence of surgical site infection. The objective of the study is to evaluate the micro-biologic safety of a forced air warming systems (FAW) in relation to the risk of emission of micro-organisms in the surgical environment. A quantitative, descriptive-exploratory laboratory study performed in a large hospital. An evaluation of possible internal contamination was performed by collecting air from the hose onto plates containing Trypticase Soy Agar. The experiment was performed in triplicate two months after replacing the filter and again after six months using a random sample of 50% of the FAW in use, which corresponded to 13 FAW and a total of 75 samples. Among the 39 samples analyzed in the first stage, only nine (23.1%) plates presented microbial growth of one or two colonies, while only six (16.7%) plates of the 36 evaluated samples in the second phase had growth of one or two colonies. This study showed small microbial growth of culture after 48 hours after filter replacement. New investigations that correlate the findings of micro-biology analysis and the occurrence of surgical site infection should be conducted.