Provoxweb

This device consists of a disposable HME cassette as its indispensable core with a reusable multi-magnet automatic speaking valve on top. The HME can be secured to the bottom of the speaking valve to ensure proper retention in the housing of the adhesive attached to the peristomal skin and is removed by ‘cracking’ the cassette when it needs changing (at least every 24 hours). The HME is deliberately placed underneath the valve to ensure protection of the valve against mucus contamination in case the patient coughs up phlegm. The reusable automatic speaking valve contains a silicone membrane, which can occlude the side opening of the device and has a magnet at its tip. The valve has two positions. In the ‘talk’ position the membrane can move freely; in the ‘walk’ position (achieved by rotating the device 750 in the housing) the membrane magnet locks against an eccentrically placed pin, preventing closure of the membrane during physical exertion. This membrane magnet, in combination with a second magnet near the side opening, keeps the membrane closed during speech, facilitating voicing with a low trachea pressure. Furthermore, on top of the device there is a cough-relief valve, which is hinged with elastic silicone bands. This valve opens during coughing, to release the pressure built up in the trachea and to diminish the possibility of the adhesive coming loose. The cough-relief valve is closed by means of magnets, which allow adjustment of its opening pressure by varying the distance between the magnets. Preferably, the Speech-Language Pathologist (SLP) makes this adjustment for the patient (using the special screwdriver that comes with the system), to achieve a sufficiently high gradient between the pressures needed for closure of the speaking valve and for opening of the cough-relief valve. For adhesion to the skin, patients can use the adhesives for the Provox HME system, or a special cannula (LaryTube; Atos Medical AB, Sweden). Three types of easily exchangeable, color-coded membranes are available: white (most flexible), green (least flexible), and blue (intermediate flexibility). Together with the SLP, the patient selects the most comfortable and efficient membrane for voicing. In our development study group, 6 patients chose the white membrane, 9 the blue one, and none selected the green version.1

The airflow resistance of the HME is adapted to its combination with the automatic valve, which has some airflow resistance of its own. A special container is provided for cleaning the device (overnight) with a standard denture cleanser.