Abstract: A low dead space liquid trap includes: a tube, having an inlet, an outlet, and an aperture disposed between the inlet and the outlet at a bottom of the tube, wherein the tube defines a channel extending in a first direction between the inlet and the outlet, the channel having a cross section perpendicular to the first direction; a reservoir disposed beneath the aperture of the tube; and a gas permeable membrane extending across the channel at an angle greater than zero with respect to the cross section of the channel.

Abstract: A removable water trap device (110) removes moisture from a respiratory gas stream from a patient interface assembly (140), enabling monitoring of gas within the respiratory gas stream by an analysis bench (120). The device includes a housing (111), an upstream water trap connector (115), and a filter assembly (360). The housing includes a first portion (210) insertably attachable to a tether assembly receptacle (132) to connect the device to the analysis bench for delivering the gas stream via a tether line (136). The upstream water trap connector is attachable to a downstream patient interface connector (141, 143) in a sample flow line (145, 148) of the patent interface assembly for receiving the gas stream via the sample flow line. The filter assembly is insertably contained within the housing and configured to remove moisture from the gas stream, the filter assembly including a downstream water trap connector (116) attachable with the tether line within the tether assembly receptacle.

Abstract: A system and method are configured to monitor composition of a flow of breathable gas being provided to a subject. A measurement flow of breathable gas is diverted in order to monitor composition of the flow of breathable gas, and then the measurement flow of breathable gas is returned to the flow of breathable gas. This will tend to conserve the constituent gases within the flow of breathable gas, which may be significant in instances where the flow of breathable gas is being used to deliver medicaments or drugs (e.g., relatively expensive anesthetic, and/or other medicaments or drugs). Since the measurement flow of breathable gas will tend to have contaminants (e.g., mucus blood, medications, or other materials), routing the measurement flow of breathable gas back into the flow of breathable gas constitutes a placement solution for the contaminants.