Abstract: An ultrasound waveguide that is attachable to an ultrasound probe so as to identify a target area on a target object. The ultrasound waveguide has an ultrasound transducer coupling signal to be transmitted through a guide means. The ultrasound waveguide also has a positioning means for positioning the guide means in relation to the target area on the target object. The guide means is provided with a channel that provides a discontinuity within the guide means that causes a discontinuity in the ultrasound signal emitted by the probe. The presence of this discontinuity allow for proper alignment of the ultrasound waveguide with the target object.

Abstract: Method for making a filter cartridge that is suitable for attachment to a respiratory mask. The method comprises the steps of (a) providing a mass of filter material; (b) providing a filter cartridge housing that has an inlet and outlet and a sidewall that includes sheet material; and (c) thermoforming the sheet material of the housing sidewall around at least part of the mass of filter material to place the housing sidewall in direct contact with the mass of filter material to encapsulate the filter material so that fluid is prevented from passing through the filter cartridge from the inlet to the outlet without being filtered by the mass of filter material.