To reuse your circuit: the HME debate

Heat and moisture exchangers (HMEs) have been used for more than 30 years for heat and moisture retention during general anesthesia. Studies about bacteriostatic vs nonbacteriostatic HMEs (BHMEs/NHMEs) have been conducted to assess their role in preventing bacterial transmission to the anesthesia breathing circuit; none have been done on anesthetized patients in the operating room. The present study adds to existing knowledge about the HME's ability to prevent transmission of bacteria, with implications for cost reduction resulting from reuse of anesthesia breathing circuits among patients. The chi 2 test revealed no statistically significant differences between groups in transmission of bacteria from endotracheal tube (ETT) to anesthesia breathing circuit (P = .48). However, both groups showed statistically significant differences between presence of bacteria in ETTs and anesthesia breathing circuits: Group 1, BHME (P < .005) and group 2, NHME (P < .005). Neither HME prevented contamination of the machine side of the circuit. These results support not reusing breathing circuits. Of 53 participants in group 2, 28 had positive ETT cultures with 7 showing transmission to anesthesia breathing circuit. Of 46 participants in group 1, 28 had positive ETT cultures with 9 showing transmission to anesthesia breathing circuit.