Background: Generally, a heat and moisture exchanger filter [HMEF] is being single used at the Y-piece of breathing systems. However, it is common to reuse the corrugated tubes for multiple patients in Thailand. Reusing corrugated tubes among patients could be a cause of bacterial contamination and cross infection. Therefore, sharing of the corrugated tubes and breathing systems is a concern amongst clinicians.

Objective: To evaluate the bacterial contamination and nosocomial pneumonia from using corrugated tubes on multiple patients.

Materials and Methods: This experimental observational study was performed with 30 corrugated tubes in each group and consisted of seven groups of corrugated tubes. Microbiological samples were obtained by swabbing at Y-piece every day. The corrugated tubes were also washed with normal saline, which was sent for bacterial culture. The corrugated tubes were changed according to seven different schedules at 24, 48, 72, 96, 120, 144, and 168 hours.

Results: One hundred sixty-eight breathing systems comprising of 891 microbiological samples from both Y-piece and corrugated tubes were tested for bacterial contamination. The Chi-square test and McNemar’s test revealed no statistical significant differences among those groups in bacterial contamination and transmission of nosocomial pneumonia (p<0.001).

Conclusion: The long-term use and sharing of corrugated tubes during 24 hours with single used of HMEF at the Y-piece of breathing systems did not increase significantly the risk of bacterial contamination and infection. For economical and environmental reasons, to reuse breathing systems within 24 hours is recommended as the patient safety is not reduced.

Keywords: Bacterial contamination, Heat and moisture exchanger filter, Corrugated tubes, Reusing