Medical infusion controller and user interface

A medical infusion system for controlling the flow of fluid from a reservoir through a drip chamber via a flow tube and valve arrangement to a patient, such system comprising:

• data entry means for permitting a user to enter desired dose data;
• data cumulation means, for storing data entered by the user, for receiving drip detection signals derived from a drip detector, and for cumulating such signals to provide a measure of total delivered volume, the data cumulation means further comrising queue means, in communication with the timing means, for cumulating data signals representative of the time of occurrence of a predetermined number of consecutive drip detection signals, such predetermined number being a variable increasing function of the magnitude of the drip rate;
• timing means for providing clock signal pulses;
• drip rate analysis means, in communication with the timing means, for receiving drip detection signals derived from a drip detector and determining the current drip rate therefrom, the drip rate analysis means further including means in communication with the queue means for determining the average drip rate of the predetermined number of drops from the data signals in the queue;
• so that a stable measure of drip rate is provided, irrespective of changes in the relative magnitude of the drip rate;
• target rate means, in communication with the timing means and the data cumulation means for repeatedly deriving a target rate to correct the delivered volume at a given time to a volume corresponding to the user-entered data;
• and
• valve control means, in communication with the the drip rate analysis means and the target rate means, for adjusting the valve so that the current drip rate approaches the target rate.

A medical infusion system for controlling the flow of fluid from a reservoir through a drip chamber via a flow tube and valve arrangement to a patient, such system comprising:

• data entry means for permitting a user to enter desired dose data;
• data cumulation means, for storing data entered by the user, for receiving drip detection signals derived from a drip detector, and for cumulating such signals to provide a measure of total delivered volume;
• timing means for providing clock signal pulses;
• drip rate analysis means, in communication with the timing means, for receiving drip detection signals derived from a drip detector and determining the current drip rate therefrom;
• target rate means, in communication with the timing means and the data cumulation means for repeatedly deriving a target rate to correct the delivered volume at a given time to a volume corresponding to the user-entered data;
• valve control means, in communication with the the drip rate analysis means and the target rate means, for adjusting the valve so that the current drip rate approaches the target rate;
• occlusion number means in communication with the drip rate analysis means for repeatedly determining an occlusion number as a function of the current drip rate;
• and
• resettable occlusion time counter means, in communication with the occlusion number means and the timing means, for decrementing the occlusion number upon each clock signal pulse and for providing an alarm signal when the occlusion number has been decremented to a threshold, such means being reset to a new occlusion number on receipt of a drip detection signal if the alarm signal has not been provided.