Hemofiltration system and method based on monitored patient parameters, supervisory control of hemofiltration, and adaptive control of pumps for hemofiltration

Abstract

A multipurpose hemofiltration system and method are disclosed for the removal of fluid and / or soluble waste from the blood of a patient. The system continuously monitors the flow rates of drained fluid, blood, and infusate. When necessary, the pumping rates of the infusate, drained fluid and blood are adjusted to remove a preselected amount of fluid from the blood in a preselected time period. A supervisory controller can monitor patient parameters, such as heart rate and blood pressure, and adjust the pumping rates accordingly. The supervisory controller uses fuzzy logic to make expert decisions, based upon a set of supervisory rules, to control each pumping rate to achieve a desired flow rate and to respond to fault conditions. An adaptive controller corrects temporal variations in the flow rate based upon an adaptive law and a control law.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of patent application Ser. No. 10 / 030,011, which is the National Stage of International Application No. PCT / US00 / 11620, filed Apr. 28, 2000, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 60 / 131,995, filed Apr. 30, 1999, each disclosure of which is hereby expressly incorporated by reference herein in its entirety.FIELD OF THE INVENTION [0002] The present invention is directed to a system and method of blood filtration, and more particularly supervisory control systems and methods and an adaptive control systems and methods for controlling the continuous filtration of fluid and / or soluble waste from the blood of a patient based on one or more monitored patient parameters and fluid flow rates. BACKGROUND OF THE INVENTION [0003] For various reasons, including illness, injury or surgery, patients may require replacement or supplementation of their natural renal functio...

AI Technical Summary

Benefits of technology

[0013] The present invention is directed to a multipurpose system and method for removal of fluid and / or soluble waste from the blood of a patient: ultrafiltration only, hemodiafiltration, hemodiafiltration and ultrafiltration, hemodialysis, and plasmapheresis with or without fluid replacement. The system and method of the present invention can provide reliable, long term operation (5-10 days) with a great degree of accuracy (on the order of ±2 grams regardless of the total volume of fluid passing through the system). The system and method of the invention are advantageous because of the multipurpose nature thereof, the repeatability and accuracy of the processes, and the simultaneous, continuous flow of fluids in an extracorporeal blood circuit, while being equally applicable to adult, pediatric and neonatal patients.

[0022] In yet another alternative embodiment, the computer controller receives data signals from one or more patient infusion pumps that are otherwise independent of the hemofiltration system. These infusion pumps are used for infusion to the patient of intravenous fluids, medications, parenteral nutrition and / or blood products. By monitoring the data output from the independent infusion pumps, the extraneous total fluid volume per unit time may be ascertained. The controller will then, as required, change the pumping rates of the system infusate, drained fluid and blood pumps, as necessary, so as to alter the ultrafiltration rate and / or infusate fluid rate automatically in response to changes in intravenous fluid therapy. This facilitates independent patient management while hemofiltration is being performed. Proper coordination of the controller with the independent infusion pumps allows the desired or targeted fluid removal goals by hemofiltration to be achieved automatically in concordance with ongoing intravenous fluid therapy.

Problems solved by technology

This system is not driven by a weight measuring device and does not offer precise control of the amount of liquids used in the procedure.

This system does not utilize circulating dialysate fluid in the blood filtration.

In general, current systems for monitoring and controlling renal replacement procedures lack the flexibility and accuracy required to perform such procedures on neonates.

This is mainly due to the absence of a satisfactory automatic control of the pumps employed.

The continuing need to monitor the fluid removed leads to a significant increase in nursing care and thus increases the cost of the therapy.

If the hemofilter clots while the pumps are de-energized, the tubing and hemofilter must be replaced with a concomitant increase in the chance of infection for the patient.

Furthermore, the hemofiltration procedure is delayed with a possibly negative impact upon the patient's health.

Furthermore, the replacement of a tubing set requires a rapid change adjustment of the pumping rates that may be difficult to initially establish as a relatively constant value due to short-term transient variations.

Current systems for monitoring and controlling renal replacement procedures lack the ability to autonomously correct these time-dependent flow rate variations with high accuracy, rapid response, and minimal overshoot or transient variations following correction.

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