Abstract: A method and apparatus for directly counting the number of doses expended from a Metered Dose Inhaler (MDI) medicinal delivery system. A miniature pressure sensor and microprocessor is used to detect the pressure pulse in the transfer channel of the mouthpiece of the MDI through which the inhaler dose (the prescribed mixture of aerosol propellant and medicinal drug) is released. The microprocessor processes data reflecting the dynamics of the pressure pulse and counts the number of doses administered. The microprocessor displays the counted doses (or doses remaining) on a miniature digital display. Additional information also may be provided to a user from the display or via an audible signal.

Abstract: A method and apparatus for directly counting the number of doses expended from a Metered Dose Inhaler (MDI) medicinal delivery system. A miniature pressure sensor and microprocessor is used to detect the pressure pulse in the transfer channel of the mouthpiece of the MDI through which the inhaler dose (the prescribed mixture of aerosol propellant and medicinal drug) is released. The microprocessor processes data reflecting the dynamics of the pressure pulse and counts the number of doses administered. The microprocessor displays the counted doses (or doses remaining) on a miniature digital display. Additional information also may be provided to a user from the display or via an audible signal.