Closed-loop infusion system, both method and apparatus, based on real time urine measurement
First Claim
1. A closed loop system for controlled infusion of fluids, medication and diagnostic substances based on real time measurement of urine output of a patient, comprising:
- (a) a urine drop counter including(i) a drop chamber,(ii) means for successively sensing occurrences of drops of urine within said drop chamber,(iii) inlet means having an opening size and configuration adapted to form drops of substantially uniform volume,(iv) means to compensate for drop volume variation with variation in urine flow rate; and
(v) outlet means adapted for conducting urine from said chamber to a collection site;
(b) a small diameter tube connected at one end to said inlet means and adapted in length and configuration for connection at the other end to a bladder catheter to be associated with the patient, the catheter/tube combination including means to prevent rate of urine flow within said tube from exceeding rate of urine production by a patient'"'"'s renal system;
(c) comparator means coupled to said drop sensing means to provide monitoring of real time flow rate of said urine based on frequency of drop occurrence and to compare said real time flow rate with a predetermined flow rate selected for the patient, said comparator means including means to provide an error signal output corresponding to a variance detected between the real time and predetermined flow rates;
(d) regulated infusion means adapted for automatically introducing said fluids, medications and diagnostic substances within said patient at variable infusion rates; and
(e) computer means coupled to (i) the error signal output of the comparator means and (ii) the regulated infusion means, for processing said error signal and for providing an appropriate correction signal to said infusion means for adjusting infusion rates to thereby increase or decrease patient fluid levels or concentrations of medication or diagnostic substances until a null reading is obtained at the comparator based on changes in urine output.
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Accused Products
Abstract
A closed loop system for controlled infusion of fluids, medication or diagnostic substances into a patient based on real time measurement of urine output. Proper urine flow techniques and a self compensating drop count apparatus provide accurate representation as to cumulative number of drops and flow rate, with drop volume variations being compensated by a control algorithm which corrects computer parameters reflecting drop volume to correspond with urine volume measured. This real time urine flow rate is compared with a preset, desired flow rate to develop an error signal which is processed by a computer. Such processing includes modification by a PID control algorithm which governs infusion of fluids into the patient to effect the proper fluid resuscitation, medication or diagnostic treatment.
146 Citations
22 Claims
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1. A closed loop system for controlled infusion of fluids, medication and diagnostic substances based on real time measurement of urine output of a patient, comprising:
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(a) a urine drop counter including (i) a drop chamber, (ii) means for successively sensing occurrences of drops of urine within said drop chamber, (iii) inlet means having an opening size and configuration adapted to form drops of substantially uniform volume, (iv) means to compensate for drop volume variation with variation in urine flow rate; and (v) outlet means adapted for conducting urine from said chamber to a collection site; (b) a small diameter tube connected at one end to said inlet means and adapted in length and configuration for connection at the other end to a bladder catheter to be associated with the patient, the catheter/tube combination including means to prevent rate of urine flow within said tube from exceeding rate of urine production by a patient'"'"'s renal system; (c) comparator means coupled to said drop sensing means to provide monitoring of real time flow rate of said urine based on frequency of drop occurrence and to compare said real time flow rate with a predetermined flow rate selected for the patient, said comparator means including means to provide an error signal output corresponding to a variance detected between the real time and predetermined flow rates; (d) regulated infusion means adapted for automatically introducing said fluids, medications and diagnostic substances within said patient at variable infusion rates; and (e) computer means coupled to (i) the error signal output of the comparator means and (ii) the regulated infusion means, for processing said error signal and for providing an appropriate correction signal to said infusion means for adjusting infusion rates to thereby increase or decrease patient fluid levels or concentrations of medication or diagnostic substances until a null reading is obtained at the comparator based on changes in urine output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for closed loop regulation of infusion based on real time measurement of urine production and composition comprising the steps of:
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(a) attaching one end of a fluid filled tube to a patient'"'"'s bladder catheter and the other end to a self compensating, optical drop count apparatus to thereby maintain siphon forces useful to develop uniform urine flow therein in accordance with urine production and to develop a signal representing real time urine flow rate; (b) comparing said signal with a predetermined flow rate to develop an error signal corresponding to any variance between real time flow rate and said predetermined flow rate; (c) processing said error signal through a computer means having a control algorithm to develop a compensating signal; (d) applying said compensating signal to a regulated infusion means coupled to said patient to adjust infusion flow rate to correct error signal; and (e) repeating the previous steps to maintain a continuous closed loop control for adjusting infusion rates in response to real time need for increase and decrease in fluid, medication or diagnostic substance levels within the patient. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification