Method and apparatus for pressure infusion and temperature control of infused liquids

• US 6,824,528 B1
• Filed: 04/24/2000
• Issued: 11/30/2004
• Est. Priority Date: 03/03/1997
• Status: Expired due to Term

• Current Assignee: Medical Solutions Incorporated
• Original Assignee: Medical Solutions Incorporated
• Inventors: DuBose, George T. Jr., Heymann, Bruce, Faries, Durward I. Jr., Blankenship, Calvin
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US09/380,507
• Time in Patent Office: 1,681 Days
• Field of Search: 604/113, 604/114, 604/141, 604/142, 604/246, 604/251, 604/253
• US Class Current: 604/113
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/3653 by Joule effect, i.e. electric resistance
• CPC Class Codes: A61M 2209/04 Tools for specific apparatus
• CPC Class Codes: A61M 5/1424 Manually operated pumps
• CPC Class Codes: A61M 5/148 flexible, e.g. independent bagsA61M5/155 takes precedence
• CPC Class Codes: A61M 5/1483 using flexible bags externally pressurised by fluid pressure
• CPC Class Codes: A61M 5/1689 Drip counters
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: A61M 5/44 having means for cooling or heating the devices or media
• CPC Class Codes: A61M 5/445 the media being heated in the reservoir, e.g. warming bloodbags

Abstract

A method and apparatus for pressure infusion and temperature control of infused liquids includes a receptacle for receiving a liquid-filled bag containing intravenous solution or other liquid and an inflatable pressure device. The inflatable pressure device is disposed within a pressure device bag and is positioned proximate the liquid-filled bag in the receptacle. The inflatable pressure device expands within the pressure device bag upon inflation and exerts pressure on the liquid-filled bag. A heating element may be disposed on the inflatable pressure device bag to heat the liquid-filled bag to a desired temperature. The liquid may alternatively be maintained at a desired temperature, while flowing to a patient via a heating assembly disposed along a tube. The heating assembly includes a sleeve having a slot for receiving the tube and a plurality of individually controlled heaters. An infrared sensing device is mounted proximate a drip chamber to ascertain a drip count, while a temperature sensor is disposed within a holder that is positioned toward the entry site on a patient. A heat controller controls the heaters based on a drip count, while a safety controller disables heater operation in response to liquid temperature exceeding the desired temperature. Thus, the safety controller and heat controller, in combination, control the heating assembly heaters based on liquid temperature and flow rate, respectively. Alternatively, the liquid-filled bag may be heated to a desired temperature whereby the heating assembly includes a single heater controlled by a controller to maintain the liquid at the desired temperature during infusion of the liquid into a patient.

Claims

1. An apparatus for facilitating pressurized infusion of liquid from a liquid-filled container through a tube into a patient, wherein said liquid-filled container includes proximal and distal portions and permits liquid to flow from said container at a container distal end, and wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and an infusion site on said patient, said apparatus comprising:

an inflatable pressure device for applying pressure to and compressing said liquid-filled container to facilitate a desired flow rate of liquid from said liquid-filled container through said tube to the infusion site, wherein said inflatable pressure device includes a tapered portion;

a receptacle for receiving said liquid-filled container and said inflatable pressure device and engaging said support, wherein said inflatable pressure device is placeable within said receptacle adjacent said liquid-filled container such that the tapered portion engages the liquid filled containter to facilitate greater compression of said container proximal portion than of said container distal portion; and

a pressure controller for regulating fluid pressure within and expansion of said inflatable pressure device to control liquid flow rate through said tube, wherein manipulation of said pressure controller regulates pressure applied by said inflatable pressure device to said liquid-filled container to generate said desired liquid flow rate through said tube from said liquid-filled container to the infusion site.

2. The apparatus of claim 1 wherein said inflatable pressure device includes a bellows.

3. The apparatus of claim 1 wherein said pressure controller includes a bulb having a valve to regulate fluid pressure within said inflatable pressure device, wherein manipulation of said bulb facilitates increased fluid pressure within said inflatable pressure device and manipulation of said valve facilitates reduced fluid pressure within said inflatable pressure device.

4. The apparatus of claim 1 further including a pressure device bag for containing said pressure device within said receptacle.

5. The apparatus of claim 1 wherein said inflatable pressure device includes pressure means for distributing pressure along said liquid-filled container such that said distributed pressure is greatest toward said container proximal portion and decreases gradually therefrom along said liquid-filled container toward said container distal portion.

6. An apparatus for facilitating pressurized infusion of liquid from a liquid-filled container through a tube into a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and said patient, said apparatus comprising:

an inflatable pressure device for applying pressure to said liquid-filled container to facilitate flow of liquid from said liquid-filled container through the tube to the patient;

a receptacle for engaging said support and receiving said liquid-filled container and said inflatable pressure device, wherein said inflatable pressure device is placeable within said receptacle adjacent said liquid-filled container;

a pressure controller for regulating fluid pressure within and expansion of said inflatable pressure device to control pressure applied by said inflatable pressure device to said liquid-filled container to generate a desired liquid flow rate from said liquid-filled container to the patient;

a pressure device bag for containing said pressure device within said receptacle;

a heating element to heat said liquid-filled container; and

a conductive plate to apply heat from said heating element to said liquid-filled container;

wherein said pressure device bag includes a pocket for receiving said heating element and said conductive plate such that said conductive plate is disposed between said liquid-filled container and said heating element to apply heat from said heating element to said liquid-filled container.

7. The apparatus of claim 6 further including a control circuit to control said heating element to maintain said liquid-filled container at a desired temperature, said control circuit including:

a power switch to enable power to said control circuit;

a power supply connected to said power switch to supply power to said heating element; and

a controller connected to said power supply and said heating element to measure temperature of said heating element and regulate power to said heating element based on said measured temperature to maintain said liquid-filled container at said desired temperature.

8. The apparatus of claim 7 wherein said controller includes:

a sensor to measure resistance of said heating element to provide an indication of heating element temperature; and

control means for regulating power to said heating element based on said measured resistance to maintain said liquid-filled container at said desired temperature.

9. An apparatus for controlling temperature of infused liquids as liquid flows from a liquid-filled container through a drip chamber and tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said drip chamber is coupled to said liquid-filled container with said tube extending from said drip chamber to said entry site, said apparatus comprising:

a drip detector placeable about said drip chamber to detect drips within said drip chamber and produce a drip count;

a heating assembly removably attachable to said tube and having a plurality of heaters to heat a portion of said tube, wherein each said heater is independently controlled;

a temperature sensor placeable proximate said tube toward said entry site to measure temperature of liquid within said tube;

a holder to maintain said temperature sensor adjacent said tube in a proper position to measure temperature of said liquid within said tube;

a controller to control each said heater based on said drip count and said measured liquid temperature; and

a control panel to enable entry of a desired liquid temperature and to display temperature of said liquid measured by said temperature sensor, said desired liquid temperature and said drip count produced by said drip detector.

10. The apparatus of claim 9 wherein said control panel includes:

a power switch to control power to said apparatus;

a counter display to display said drip count produced by said drip detector;

a temperature display to display said temperature of said liquid measured by said temperature sensor;

a set point display to display said desired liquid temperature; and

a plurality of heater indicators each corresponding to a heater to indicate activation of that heater.

16. The apparatus of claim 9 wherein said temperature sensor includes an infrared temperature sensor.

11. An apparatus for controlling temperature of infused liquids as liquid flows from a liquid-filled container through a drip chamber and tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said drip chamber is coupled to said liquid-filled container with said tube extending from said drip chamber to said entry site, said apparatus comprising:

a drip detector placeable about said drip chamber to detect drips within said drip chamber;

a temperature sensor placeable proximate said tube toward said entry site to measure temperature of liquid within said tube;

a heating assembly placeable along said tube and having a plurality of individually controlled heaters to heat a portion of said tube, wherein said heating assembly further includes;

an elongated sleeve having a slot defined in the upper portion of the sleeve to receive a portion of said tube; and

at least one channel disposed through said sleeve to accommodate wiring from said temperature sensor and said heaters;

wherein said plurality of heaters are placeable within said sleeve proximate said tube portion, and are individually controlled to maintain liquid flowing within said tube at a desired liquid temperature;

a holder to maintain said temperature sensor adjacent said tube in a proper position to measure temperature of said liquid within said tube; and

a control panel to enable entry of said desired liquid temperature and to display temperature of said liquid measured by said temperature sensor, said desired liquid temperature and a count of drips detected within said drip chamber by said drip detector.

12. The apparatus of claim 11 wherein said heating assembly further includes a jacket to cover said sleeve to prevent injury to the patient.

13. An apparatus for controlling temperature of infused liquids as liquid flows from a liquid-filled container through a drip chamber and tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said drip chamber is coupled to said liquid-filled container with said tube extending from said drip chamber to said entry site, said apparatus comprising:

a drip detector placeable about said drip chamber to detect drips within said drip chamber, wherein said drip detector includes;

a first block having an emitter to transmit signals through said drip chamber; and

a second block having at least one detector wherein each detector detects said signals transmitted by said emitter and modified by drips within said drip chamber;

wherein said first and second blocks are placeable about said drip chamber such that the detectors detect said modified signals to sense drips within said drip chamber;

a heating assembly placeable along said tube and having a plurality of individually controlled heaters to heat a portion of said tube;

a temperature sensor placeable proximate said tube toward said entry site to measure temperature of liquid within said tube;

a holder to maintain said temperature sensor adjacent said tube in a proper position to measure temperature of said liquid within said tube; and

a control panel to enable entry of a desired liquid temperature and to display temperature of said liquid measured by said temperature sensor, said desired liquid temperature and a count of drips detected within said drip chamber by said drip detector.

14. The apparatus of claim 13 wherein said emitter is an infrared emitter and each said detector is an infrared detector.

15. An apparatus for controlling temperature of infused liquids as liquid flows from a liquid-filled container through a drip chamber and tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said drip chamber is coupled to said liquid-filled container with said tube extending from said drip chamber to said entry site, said apparatus comprising:

a drip detector placeable about said drip chamber to detect drips within said drip chamber;

a heating assembly placeable along said tube and having a plurality of individually controlled heaters to heat a portion of said tube;

a temperature sensor placeable proximate said tube toward said entry site to measure temperature of liquid within said tube;

a holder to maintain said temperature sensor adjacent said tube in a proper position to measure temperature of said liquid within said tube, wherein said holder includes;

a platform for interfacing the patient;

a pair of prongs extending from said platform to receive and maintain said temperature sensor in a proper position for measuring temperature of said liquid within said tube;

a recess disposed adjacent said platform between said prongs for receiving said tube and placing said tube proximate said temperature sensor; and

a safety circuit for disabling operation of said apparatus when said safety circuit is in an open state; and

a control panel to enable entry of a desired liquid temperature and to display temperature of said liquid measured by said temperature sensor, said desired liquid temperature and a count of drips detected within said drip chamber by said drip detector.

17. An apparatus for controlling temperature of infused liquids as liquid flows from a liquid-filled container through a drip chamber and tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said drip chamber is coupled to said liquid-filled container with said tube extending from said drip chamber to said entry site, said apparatus comprising:

a drip detector placeable about said drip chamber to detect drips within said drip chamber;

a heating assembly placeable along said tube and having a plurality of individually controlled heaters to heat a portion of said tube;

a temperature sensor placeable proximate said tube toward said entry site to measure temperature of liquid within said tube;

a holder to maintain said temperature sensor adjacent said tube in a proper position to measure temperature of said liquid within said tube; and

a control panel to enable entry of a desired liquid temperature and to display temperature of said liquid measured by said temperature sensor, said desired liquid temperature and a count of drips detected within said drip chamber by said drip detector, wherein said control panel includes;

a safety controller to disable power to said heaters in response to said temperature sensor measuring a temperature of said liquid equal to or in excess of said desired liquid temperature;

a drip counting circuit to count drips detected within said drip chamber by said drip detector and generate a drip count; and

a heat controller to individually control each said heater within said heating assembly based on said drip count generated by said drip counting circuit;

wherein disablement of said heaters by said safety controller overrides control of said heaters by said heat controller.

18. The apparatus of claim 17 wherein said drip counting circuit includes:

an opticoupler circuit to receive signals from said drip detector and determine the presence of a drip within said drip chamber; and

a counting circuit to maintain and increment said drip count based on said determination by said opticoupler circuit.

19. An apparatus for maintaining temperature of infused liquids as liquid flows from a heated liquid-filled container through a tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and said entry site, said apparatus comprising:

a receptacle for receiving a liquid filled container;

a heating element placeable in said receptacle and positionable proximate said liquid-filled container to heat said liquid-filled container to a desired temperature;

a tube;

a heating assembly, removably attachable to said tube and including a heater, to maintain liquid flowing from said heated liquid-filled container through said tube at said desired temperature; and

a control unit coupled to said heating element and said heater to control heating of said liquid, wherein said heating element is controlled based on a measured heating element temperature, and said heater is controlled independently of said heating element based on a measured heater temperature.

20. The apparatus of claim 19 further including a control circuit to control said heating element and heater to maintain said liquid at said desired temperature, said control circuit including:

a power switch to enable power to said control circuit;

a power supply connected to said power switch to supply power to said heating element and heater; and

said control unit, wherein the control unit includes;

a heating element controller connected to said power supply and said heating element to measure temperature of said heating element and regulate power to said heating element based on said measured heating element temperature to maintain said liquid-filled container at said desired temperature; and

a heater controller connected to said power supply and said heater to measure temperature of said heater and regulate power to said heater based on said measured heater temperature to maintain said liquid at said desired temperature.

21. The apparatus of claim 20 wherein said heating element controller includes:

a sensor to measure resistance of said heating element to provide an indication of heating element temperature; and

control means for regulating power to said heating element based on said measured resistance to maintain said liquid-filled container at said desired temperature.

22. The apparatus of claim 20 wherein said heater controller includes:

a sensor to measure resistance of said heater to provide an indication of heater temperature; and

control means for regulating power to said heater based on said measured resistance to maintain said liquid flowing through said tube at said desired temperature.

23. An apparatus for maintaining temperature of infused liquids as liquid flows from a heated liquid-filled container through a tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and said entry site, said apparatus comprising:

a heating element placeable proximate said liquid-filled container to heat said liquid-filled container to a desired temperature; and

a heating assembly placeable along said tube having a heater to maintain liquid flowing within said tube at said desired temperature, wherein said heating assembly further includes;

an elongated sleeve having a slot defined in the upper portion of the sleeve to receive a portion of said tube; and

at least one channel disposed through said sleeve to accommodate wiring from said heater;

wherein said heater is placeable within said sleeve proximate said tube portion to maintain said liquid flowing through said tube at said desired temperature.

24. A tool for use in an apparatus for controlling temperature of infused liquids said tool to dispose a portion of said tube within a heating assembly sleeve disposed along said tube to heat liquid within said tube, wherein said heating assembly sleeve includes at least one heater to heat said liquid and a slot for receiving said tube, said tool comprising:

a handle; and

a tube interface disposed toward a handle distal end to engage said tube and insert said tube into said slot of said heating assembly sleeve;

wherein said tube interface includes legs having curved portions that form an opening between said curved portions to receive said tube, and sections that extend transversely outward from said curved portions and are configured to penetrate said slot of said heating assembly sleeve and insert said tube within said slot.

25. An apparatus for controlling temperature of infused liquids as liquid flows from a liquid-filled container through a tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and said entry site, wherein said apparatus comprises:

a heating assembly placeable along said tube to heat a portion of said tube;

a temperature sensor to measure temperature of liquid within said tube;

a safety controller to intermittently disable power to said heating assembly, wherein said safety controller includes power means for disabling power to said heating assembly during time intervals where said measured liquid temperature is equal to or exceeds a desired liquid temperature;

a flow rate sensor to measure liquid flow rate of liquid within said tube; and

a heat controller, independent of said safety controller, to control said heating assembly based on said measured liquid flow rate;

wherein said safety and heat controllers concurrently control said heating assembly such that disablement of power to said heating assembly by said safety controller overrides and modulates control of said heating assembly by said heat controller to control temperature of said liquid.

26. A method for controlling temperature of infused liquids as liquid flows from a liquid-filled container through a tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and said entry site, wherein said method comprises the steps of:

(a) heating a portion of said tube via a heating assembly disposed along said tube;

(b) measuring temperature of liquid within said tube via a temperature sensor;

(c) intermittently disabling power to said heating assembly, via a safety controller, wherein power is disabled to said heating assembly during time intervals where said measured liquid temperature is equal to or exceeds a desired liquid temperature;

(d) measuring liquid flow rate of liquid within said tube via a flow rate sensor; and

(e) controlling said heating assembly, via a heat controller, based on said measured liquid flow rate;

wherein said safety and heat controllers concurrently control said heating assembly such that disablement of power to said heating assembly by said safety controller overrides and modulates control of said heating assembly by said heat controller to control temperature of said liquid.

27. An apparatus for facilitating pressurized infusion of liquid from a heated liquid-filled container through a tube into a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and an infusion site on said patient, said apparatus comprising:

an inflatable pressure device for applying pressure to said liquid-filled container to facilitate a desired flow rate of liquid through said tube from said liquid-filled container to the infusion site;

a heater to heat liquid contained within said liquid-filled container;

a receptacle for receiving said liquid-filled container, said inflatable pressure device and said heater and engaging said support, wherein said heater is disposed within said receptacle between said inflatable pressure device and said liquid-filled container;

a pressure controller for regulating fluid pressure within and expansion of said inflatable pressure device to apply said heater to said liquid-filled container and to control liquid flow rate through said tube from said liquid-filled container to the infusion site.

28. A method for facilitating pressurized infusion of liquid from a heated liquid-filled container through a tube into a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and an infusion site on said patient, said method comprising the steps of:

(a) applying pressure to said liquid-filled container, via an inflatable pressure device, to facilitate a desired flow rate of liquid through said tube from said liquid-filled container to the infusion site;

(b) engaging said support, via a receptacle, and disposing said liquid-filled container, said inflatable pressure device and a heater in said receptacle such that said heater is disposed within said receptacle between said inflatable pressure device and said liquid-filled container;

(c) regulating fluid pressure within and expansion of said inflatable pressure device, via a pressure controller, to apply said heater to said liquid-filled container and to control liquid flow rate through said tube from said liquid-filled container to the infusion site.

29. A method for facilitating pressurized infusion of liquid from a liquid-filled container through a tube into a patient, wherein said liquid-filled container includes proximal and distal portions and permits liquid to flow from said container at a container distal end, and wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and an infusion site on said patient, said method comprising the steps of:

(a) compressing said liquid-filled container such that said container proximal portion is compressed more than said container distal portion to facilitate a desired flow rate of liquid through said tube from said liquid-filled container to the infusion site;

(b) engaging said support, via a receptacle, and disposing said liquid-filled container within said receptacle such that said container is compressed in accordance with step (a); and

(c) controlling liquid flow rate through said tube by variably selectively compressing said liquid-filled container to generate the desired liquid flow rate through the tube from said liquid-filled container to the infusion site.

30. A method for facilitating pressurized infusion of liquid from a liquid-filled container through a tube into a patient, wherein said liquid-filled container includes proximal and distal portions and permits liquid to flow from said container at a container distal end, and wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and an infusion site on said patient, said method comprising the steps of:

(a) applying pressure to and compressing said liquid-filled container, via an inflatable pressure device, such that said container proximal portion is compressed more than said container distal portion to facilitate a desired flow rate of liquid through said tube from said liquid-filled container to the infusion site;

(b) engaging said support, via a receptacle, and disposing said liquid-filled container and said inflatable pressure device within said receptacle such that said inflatable pressure device is disposed within said receptacle adjacent said liquid-filled container; and

(c) regulating fluid pressure within and expansion of said inflatable pressure device, via a pressure controller, to control liquid flow rate through said tube by selectively manipulating said pressure controller to regulate pressure applied by said inflatable pressure device to said liquid-filled container to generate the desired liquid flow rate through the tube from said liquid-filled container to the infusion site.

31. The method of claim 30 wherein said pressure controller includes a bulb having a valve to regulate fluid pressure within said inflatable pressure device, and step (c) further includes:

(c.1) manipulating said bulb to increase fluid pressure within said inflatable pressure device to exert increased pressure on said liquid-filled container; and

(c.2) manipulating said valve to reduce fluid pressure within said inflatable pressure device to exert reduced pressure on said liquid-filled container.

32. The method of claim 30 wherein step (b) further includes:

(b.1) disposing said inflatable pressure device within a pressure device bag in said receptacle.

33. The method of claim 30 wherein step (a) further includes:

(a.1) distributing pressure along said liquid-filled container such that said distributed pressure is greatest toward said container proximal portion and decreases therefrom gradually along said liquid-filled container toward said container distal portion.

34. A method for facilitating pressurized infusion of liquid from a liquid-filled container through a tube into a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and said patient, said method comprising the steps of:

(a) applying pressure to said liquid-filled container, via an inflatable pressure device, to facilitate flow of liquid from said liquid-filled container through the tube to the patient;

(b) engaging said support, via a receptacle, and disposing said liquid-filled container and said inflatable pressure device within said receptacle, wherein said inflatable pressure device is disposed within said receptacle adjacent said liquid-filled container, and

step (b) further includes;

(b.1) disposing said inflatable pressure device within a pressure device bag in said receptacle; and

(b.2) disposing a heating element and a conductive plate in a pocket of said pressure device bag such that said conductive plate is disposed between said liquid-filled container and said heating element;

(c) regulating fluid pressure within and expansion of said inflatable pressure device, via a pressure controller, to control pressure applied by said inflatable pressure device to said liquid-filled container to generate a desired liquid flow rate from said liquid-filled container to the patient; and

(d) applying heat from said heating element through said conductive plate to said liquid-filled container.

35. The method of claim 34 wherein step (d) further includes:

(d.1) measuring temperature of said heating element and regulating power to said heating element based on said measured temperature to maintain said liquid-filled container at said desired temperature.

36. The method of claim 35 wherein step (d.1) further includes:

(d.1.1) measuring resistance of said heating element to provide an indication of heating element temperature; and

(d.1.2) regulating power to said heating element based on said measured resistance to maintain said liquid-filled container at said desired temperature.

37. A method for controlling temperature of infused liquids as liquid flows from a liquid-filled container through a drip chamber and tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said drip chamber is coupled to said liquid-filled container with said tube extending from said drip chamber to said entry site, said method comprising the steps of:

(a) detecting drips within said drip chamber, via a drip detector disposed about said drip chamber, and providing a drip count;

(b) removably attaching a heating assembly having multiple heaters to said tube to heat a portion of said tube, wherein each said heater is independently controlled;

(c) measuring temperature of liquid within the tube via a temperature sensor disposed proximate said tube toward said entry site;

(d) maintaining said temperature sensor adjacent said tube in a proper position, via a holder, to measure temperature of said liquid within said tube;

(e) controlling each said heater based on said drip count and said measured liquid temperature; and

(f) facilitating entry of a desired liquid temperature and displaying temperature of said liquid measured by said temperature sensor, said desired liquid temperature and said drip count produced by said drip detector.

38. The method of claim 37 wherein step (a) further includes:

(a.1) transmitting signals, via an emitter, through said drip chamber; and

(a.2) detecting said signals transmitted by said emitter and modified by drips within said drip chamber via detectors;

wherein said emitter and detectors are disposed about said drip chamber such that the detectors detect said modified signals to sense drips within said drip chamber.

39. The method of claim 37 wherein step (a) further includes:

(a.1) counting drips detected within said drip chamber by said drip detector and generating a drip count via a drip counting circuit; and

step (e) further includes;

(e.1) disabling power to said heaters, via a safety controller, in response to said temperature sensor measuring a temperature of said liquid equal to or in excess of said desired liquid temperature; and

(e.2) individually controlling each said heater within said heating assembly, via a heat controller, based on said drip count generated by said drip counting circuit;

wherein disablement of said heaters by said safety controller overrides control of said heaters by said heat controller.

40. A method for maintaining temperature of infused liquids as liquid flows from a heated liquid-filled container through a tube to an entry site on a patient, wherein said liquid-filled container is suspended from a support and said tube extends between said liquid-filled container and said entry site, said method comprising the steps of:

(a) heating said liquid-filled container to a desired temperature via a heating element disposed proximate said liquid-filled container, and controlling said heating element based on a measured heating element temperature; and

(b) maintaining said liquid flowing from said heated liquid-filled container through said tube at said desired temperature via a heating assembly removably attached to said tube and including a heater, and controlling said heater independently of said heating element based on a measured heater temperature.

41. The method of claim 40 wherein step (a) further includes:

(a.1) measuring temperature of said heating element and regulating power to said heating element, via a heating element controller, based on said measured heating element temperature to maintain said liquid-filled container at said desired temperature; and

step (b) further includes;

(b.1) measuring temperature of said heater and regulating power to said heater based on said measured heater temperature to maintain said liquid at said desired temperature.

42. The method of claim 41 wherein step (a.1) further includes:

(a.1.1) measuring resistance of said heating element, via a sensor, to provide an indication of heating element temperature; and

(a.1.2) regulating power to said heating element based on said measured resistance to maintain said liquid-filled container at said desired temperature.

43. The method of claim 41 wherein step (b.1) further includes:

(b.1.1) measuring resistance of said heater, via a sensor, to provide an indication of heater temperature; and

(b.1.2) regulating power to said heater based on said measured resistance to maintain said liquid flowing through said tube at said desired temperature.