A heat and moisture exchanger (HME) adaptor for a closed suction catheter assembly having one end in communication with a closed suction catheter assembly and another end configured to rotationally engage and releasably hold the HME is disclosed herein. The adaptor may include a retainer having an aperture that engages projections on the HME to releasably secure the adaptor to the HME. The adaptor may include a retaining ring that may be deformed or rotated to engage or disengage projections on the HME. The adaptor may be used with extended use closed suction catheter assemblies.