US Patent 7404329 Pressure gauge for use with an airway lumen

A pressure gauge for use in combination with an airway lumen having an inflatable cuff, the pressure gauge including a housing and a flexible diaphragm within the housing defining a fluid tight chamber with the chamber in fluid communication with the cuff. In use a surface of the diaphragm moves along an axis in response to a fluid pressure change in the cuff. The pressure gauge also includes a radial indicator attached to the housing extending transverse the surface of the diaphragm and a linear to radial linkage operatively associated between the surface of the diaphragm and the radial indicator to cause radial movement of the indicator. In one embodiment the linear to radial linkage includes a gear tooth rack associated with the surface of the diaphragm and a pinion gear mating with the rack. In such an embodiment the radial indicator may further include a pointer operatively associated with the pinion gear. This embodiment will also include a scale having select markings which in conjunction with the pointer allow a user to read the fluid pressure within the cuff.