EP0802813A1 — Dosimetric spacer

USPTO Abstract

An apparatus for administering a fluid medicament to a patient in a gas for inhalation and for calculating the dosage administered to the patient comprising a holding member (1) for temporarily holding the medicament and gas prior to inhalation, means for introducing a quantity of the medicament into the holding chamber (1), a sensor (4) for detecting the introduction of the medicament into the holding chamber (1), detector means for detecting the rate of flow of gas inhaled by a patient from the holding chamber (1) and calculation means (25, 27, 29, 30, 31) operably connected to the sensor (4) and to the detector means for calculating the amount of medicament received by a patient. The calculating means (25, 27, 29, 30, 31) makes its calculation on the basis of the quantity of medicament released into the holding chamber (1), the volume of the holding chamber (1), the time elapsed from the detection of the introduction of the medicament, and the detected rate of flow of gas inhaled from the holding chamber (1). The calculation being made by assessing the concentration of the medicament in the holding chamber (1) on a time basis during reduction of the said concentration within the holding chamber (1), and by determining the volume of the gas received by the patient during inhalation, and the time elapsed from the detected introduction of medicament to the inhalation by the patient.