Dosimetric spacer for calculating dosage administered

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 chamber for holding the medicament and gas prior to inhalation;
• means for introducing a quantity of the medicament into the holding chamber;
• a sensor for sensing introduction of the medicament into the holding chamber;
• detector means for detecting the rate of flow of gas inhaled by a patient from the holding chamber;
• and
• calculation means operably connected to the sensor and to the detector means for calculating the amount of medicament received by a patient, the calculation means including
• a timing means for indicating the time elapsed since the sensor senses the introduction of medicament into the holding chamber;
• means for supplying the initial concentration of medicament in the holding chamber immediately after the introduction of medicament therein;
• means for determining the concentration of medicament in the holding chamber during inhalation by the patient, the concentration of medicament reducing with time due at least in part to deposition of the medicament within the holding chamber, the determination being made on the basis of the initial concentration supplied by the means for supplying initial concentration, and of the time elapsed since the sensor sensed the introduction of medicament into the holding chamber;
• and
• means for determining the amount of medicament received by the patient by calculating the volume of gas inhaled by the patient from the holding chamber by integrating the rate of flow detected by the detector means, and by multiplying the calculated volume of gas by the concentration of medicament in the holding chamber at that time determined by the means for determining the concentration of medicament.

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 chamber for temporarily holding the medicament and gas prior to inhalation;
• means for introducing a quantity of the medicament into the holding chamber;
• a sensor for sensing the introduction of the medicament into the holding chamber;
• detector means for detecting the rate of flow of gas inhaled by a patient from the holding chamber;
• and
• calculation means operably connected to the sensor and to the detector means for calculating the amount of medicament received by a patient on the basis of:
• the preset quantity of medicament released into the holding chamber;
• of the preset volume of the holding chamber;
• the time elapsed from the sensing of the introduction of the medicament, of the detected rate of flow of gas inhaled from the holding chamber;
• the calculation being made by assessing the concentration of the medicament in the holding chamber on the basis of the detected inhaled volume during reduction of the said concentration within the holding chamber due at least in part to dilution of the medicament within the holding chamber, and by determining the volume of the gas received by the patient during inhalation.

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 chamber for holding the medicament and gas prior to inhalation;
• means for introducing a quantity of the medicament into the holding chamber;
• a sensor for sensing introduction of the medicament into the holding chamber;
• detector means for detecting the rate of flow of gas inhaled by a patient from the holding chamber;
• and
• calculation means operably connected to the sensor and to the detector means for calculating the amount of medicament received by a patient, the calculation means including
• a timing means for indicating the time elapsed since the sensor senses the introduction of medicament into the holding chamber;
• means for supplying the initial concentration of medicament into the holding chamber immediately after the introduction of medicament therein;
• means for determining the concentration of medicament in the holding chamber during inhalation by the patient, the concentration of medicament reducing with the volume of gas inhaled due at least in part to dilution of the medicament within the holding chamber, the determination being made on the basis of the initial concentration supplied by the means for supplying initial concentration, and of the volume of gas inhaled, calculated from the rate of flow of gas detected by the detector since the sensor sensed the introduction of medicament into the holding chamber;
• and
• means for determining the amount of medicament received by the patient by calculating the volume of gas inhaled by the patient from the holding chamber by integrating the rate of flow detected by the detector means, and by multiplying the calculated volume of gas by the concentration of medicament in the holding chamber at that time determined by the means for determining the concentration of medicament.

A method for administering a measured dosage of a fluid medicament to a patient in a gas for inhalation using an apparatus comprising:

• a holding chamber for holding the medicament and gas prior to inhalation;
• means for introducing a quantity of medicament into the holding chamber;
• a sensor for sensing the introduction of medicament into the holding chamber;
• detector means for detecting the rate of flow of gas inhaled by a patient from the holding chamber;
• and
• calculation means operably connected to the sensor and to the detector means for calculating the amount of medicament received by a patient;
• the method comprising:
• sensing the introduction of medicament into the holding chamber, the sensing being made by the sensor;
• monitoring the time elapsed since the introduction of the medicament is sensed, the monitoring being made by the calculation means;
• supplying the value of the initial concentration of medicament in the holding chamber;
• determining the concentration of medicament in the holding chamber during inhalation by the patient, the concentration of medicament reducing with time due at least in part to deposition of the medicament within the holding chamber, the determination being made on the basis of the supplied initial concentration and of the time elapsed since the sensor senses the introduction of medicament into the holding chamber;
• and
• determining the amount of medicament received by the patient by calculating the volume of gas inhaled by the patient from the holding chamber by integration of the rate of flow detected by the detector means, and by multiplying the calculated volume of gas by the determined concentration of medicament in the holding chamber at that time.

A method of administering a fluid medicament to a patient in a gas for inhalation and for calculating the dosage administered to the patient comprising

• sensing the introduction of a quantity of medicament into a holding chamber;
• detecting the rate of flow of gas inhaled by a patient from the holding chamber;
• monitoring the time elapsed from the sensing of the introduction of the quantity of medicament into the holding chamber;
• determining the concentration of medicament in the holding chamber during inhalation by the patient, the concentration of medicament reducing with time due at least in part to deposition of the medicament within the holding chamber, the determination being made on the basis of the predetermined initial concentration of medicament within the holding chamber immediately after the introduction of medicament therein, and on the basis of the monitored time elapsed since the sensing of the introduction of medicament;
• and
• calculating the amount of medicament received by the patient by calculating the volume of gas inhaled by the patient from the holding chamber by integrating the detected rate of flow, and by multiplying the calculated volume of gas inhaled by the determined concentration of medicament in the holding chamber.