BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic drawing of the first embodiment of a portable IV infusion monitoring system for the present invention.
FIG. 2 is the schematic drawing of an alternative first embodiment of the present invention.
FIG. 3 is a schematic drawing of an alternative liquid level sensor for the present invention.
FIG. 3A is a schematic drawing of an exemplary coaxial cable, shielding plate and assembly box for removing the environmental interference in the present invention.
FIG. 4 is a block diagram of an exemplary microprocessor for the present invention.
FIG. 4A is a block diagram of an alternative microprocessor for the present invention.
FIG. 4B is a block diagram of three alternative embodiments of the interference filtering means in the microprocessor for the present invention.
FIG. 5 is a block diagram of an exemplary monitor terminal for the present invention.
FIG. 5A-5C are block diagrams of exemplary and alternative alarm means for the present invention.
FIG. 5D is a block diagram of an alternative monitor terminal for the present invention.
FIG. 6 is a schematic drawing of the second embodiment of a portable IV infusion monitoring system for the present invention.
FIG. 7 is a schematic drawing of the third embodiment of a portable IV infusion monitoring for the present invention.
FIG. 8 is a block diagram of an exemplary signal processor for the third embodiment of the present invention.
FIG. 9 is a block diagram of an exemplary alarm device for the third embodiment of the present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
In describing preferred embodiment of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.
FIG. 1 is a schematic drawing of the first embodiment of a portable IV infusion monitoring system that is capable of detecting the liquid level of the medical liquid 10 inside an IV bottle 11, and giving alarm when the medical liquid 10 in the IV bottle 11 drops to a predetermined low level.
The IV infusion system comprises the IV bottle 11 containing the medical liquid 10 and air 12 above the medical liquid 10. A liquid needle 13 and an air needle 14 are inserted into the IV bottle 11. A liquid tube 15 is connected at the end of the liquid needle 13. An air tube 16 is connected at the end of the air needle 14. The IV bottle 11 can be made of stiff materials such as glass or harden plastics, or it can be made of flexible plastic bags.
The IV infusion monitoring system comprises a liquid level sensor 20 including at least two electrodes 20A, 20B, a microprocessor 30, and a monitor terminal 40. The power is provided preferably by a battery 50 or by an external power source as an option to user. The at least two electrodes 20A, 20B are located at two sides of the IV bottle 11 in opposite direction with each other, and are capable of conducting an alternating current between them. The microprocessor 30 acting as a mini computer is capable of detecting the electric parameters of the alternating current, analyzing the electric parameters to obtain the liquid level data inside the IV bottle 11, and sending all the liquid level data to the monitor terminal 40. The electric parameters related to the liquid level include at least one of voltage, current, impedance, phase and frequency etc. The liquid level data includes the liquid level inside the IV bottle 11 at any time moment, the liquid flow rate during infusion process, and the comparison with the predetermined low level. The monitor terminal 40 includes an alarm means for sending out an alarm signal to activate an alarm to patient and nurses if the medical liquid 10 has dropped to the predetermined low level.
In a typical electric environment, at least one shielding plate 20C, 20D made of conductive materials is placed on the outer surface of each electrode 20A, 20B, and is insulated from the electrodes 20A, 20B. The at least one shielding plate 20C, 20D is connected to a reference point with zero potential, e.g., the negative pole of a battery 50. Alternatively, the interference signal in the at least one shielding plate is passed over to the microprocessor 30, and it is then filtered out in signal processing. Meanwhile, at least two coaxial cables 20E, 20F consist of a center conductor surrounded by a concentric outer shielding layer made of conductive materials. The center conductor is insulated with the outer shielding layer. The center conductors of the at least two coaxial cables 20E, 20F connect the at least two electrodes 20A, 20B to the microprocessor 30 for transmitting the signal. The outer shielding layers of the at least two coaxial cables 20E, 20F are connected to the reference point with zero potential, e.g., the negative pole of a battery 50. Alternatively, the outer shielding layers are connected to the microprocessor 30 for interference filtering process. However, if the electric environment is very noisy, and the interference becomes too strong to perform a normal operation of this monitoring system, the signal interference from the environment can be removed by special signal processing methods described in FIG. 4B. Further alternatively, two pairs of electrodes can be positioned in parallel outside the IV bottle 11. By differentiation of the signal or electric parameters, the environmental interference will be removed too. Hereby there is no need of grounding in order to avoid the environmental interference since this monitoring system is designed as a portable device.
FIG. 2 is the schematic drawing of an alternative embodiment of the present invention. It is similar to the embodiment of FIG. 1, but the liquid level sensor 20 includes at least two electrodes 20G, 20H, which are positioned at one side of the IV bottle 11 in parallel location.
Again, for removing the interference from the environment, at least one shielding plate 201 made of conductive materials is placed on the outer surface of each electrode 20G, 20H. The at least one shielding plate 201 is connected to a reference point with zero potential, e.g., the negative pole of a battery 50. Alternatively, the interference signal in the at least one shielding plate 201 is passed over to the microprocessor 30, and it is then filtered out in signal processing. Meanwhile, at least two coaxial cables 20J, 20K consist of a center conductor surrounded by a concentric outer shielding layer made of conductive materials. The center conductors of the at least two coaxial cables 20J, 20K connect the at least two electrodes 20G, 20H to the microprocessor 30 for transmitting the signal. The outer shielding layers of the at least two coaxial cables 20J, 20K are connected to the reference point with zero potential, e.g., the negative pole of a battery 50. Alternatively, the outer shielding layers are connected to the microprocessor 30 for interference filtering process. However, if the electric environment is too noisy to perform the normal operation of this monitoring system, the signal processing methods described in FIG. 4B can be applied to remove most environmental interference. Further alternatively, two pairs of electrodes can be positioned in parallel outside the IV bottle. By differentiation of the signal or electric parameters, the environmental interference will be removed too.
FIG. 3 is a schematic drawing of an alternative liquid level sensor 20L. The liquid level sensor 20L uses an electric bridge 20M to detect the electric signal of the alternating current. The electric bridge 20M contains the at least two electrodes 20A, 20B in FIG. 1, or 20G, 20H in FIG. 2.
FIG. 3A is a schematic drawing of an exemplary coaxial cable, shielding plate and assembly box for removing the environmental interference. The at least one shielding plate 20C, 20D, 201 is connected to a reference point with zero potential 51, e.g., the negative pole of a battery 50. The at least one shielding plate 20C, 20D, 201 is insulated from the electrodes 20A, 20B, 20G, 20H. Alternatively, the interference signal in the at least one shielding plate 20C, 20D, 201 is passed over to the microprocessor 30, 30A and it is then filtered out in signal processing. Meanwhile, at least two coaxial cables 20E, 20F, 20J, 20K consist of a center conductor 20E′, 20F′, 20J′, 20K′ surrounded by a concentric outer shielding layer 20E″, 20F″, 20J″, 20K″ made of conductive materials. The center conductors 20E′, 20F′, 20J′, 20K′ are insulated from the outer shielding layers 20E″, 20F″, 20J″, 20K″. The center conductors 20E′, 20F′, 20J′, 20K′ of the at least two coaxial cables 20E, 20F, 20J, 20K connect the at least two electrodes 20A, 20B, 20G, 20H to the microprocessor 30, 30A for transmitting the signal. The outer shielding layers 20E″, 20F″, 20J″, 20K″ of the at least two coaxial cables 20E, 20F, 20J, 20K are connected to the reference point with zero potential 51, e.g., the negative pole of a battery 50. Alternatively, the outer shielding layers 20E″, 20F″, 20J″, 20K″ are connected to the microprocessor 30, 30A for interference filtering process. The at least two coaxial cables 20E, 20F, 20J, 20K are in a form of wire, or string, or strip, or twisted-pair, or cable. The center conductor 20E′, 20F′, 20J′, 20K′ is made of solid conductor, e.g., copper in a form of single wire, stranded wires or twist-pair (i.e, two insulated strands of conductive wire twisted around each other). The outer shielding layer 20E″, 20F″, 20J″, 20K″ is made of at least one foil insulation and braided metal, for example, it could be dual shielding (i.e., one layer of foil insulation and one layer of braided metal shielding), or quad shielding (i.e., two layers of foil insulation and two layers of braided metal shielding) if the environmental interference is strong. The coaxial cable 20E, 20F, 20J, 20K has high resistance not only to noise interference, but also to attenuation. The microprocessor 30, 30A, part of the monitor terminal 40 and the battery 50 are contained in an assembly box 60. To shielding the microprocessor 30, 30A and other parts inside the assembly box 60 from the environmental interference, either the assembly box 60 is made of metal or the assembly box 60 is coated with conductive materials. The coated methods include chemical coating, physical coating, mechanical coating, or a simple metal lining etc. Similar to the shielding plate 20C, 20D, 201, the conductive part of the assembly box 60 is connected to a reference point with zero potential 51, e.g., the negative pole of the battery 50. Alternatively, the environmental noise in the assembly box 60 is passed over to the microprocessor 30, 30A for interference filtering.
FIG. 4 is a block diagram of an exemplary microprocessor 30. The microprocessor 30 acting as a mini computer includes a control means 31 for applying the alternating current to the at least two electrodes 20A, 20B in FIG. 1 and 20E, 20F in FIG. 2, receiver means 32 for receiving the electric signal of the alternating current, detector means 33 for detecting the electric parameters of the electric signal, process means 34 for analyzing the electric parameters and obtaining the liquid level data inside the IV bottle 11, and transmission means 35 for sending out the liquid level data. Each of above elements may be built together in one chip, or they can stand alone as individual circuit or chip. The control means 31 includes at least one of an oscillator, an oscillator circuit, a logic circuit etc. The receiver means 32 includes at least one of an input port, an amplifier, a filter etc. The detector means 33 includes at least one of a C/V converter (capacitance to voltage converter), a differential circuit, or a voltage meter etc. The process means 34 includes at least one of signal interface, A/D converter, digital register, processor, or logic circuit etc. The transmission means 35 includes at least one of output port, conductive wire or antenna etc.
FIG. 4A is a block diagram of an alternative microprocessor 30A. The microprocessor 30A comprises receiver 32A for receiving the electric signal of the alternating current, detector 33A for detecting the voltage signal from the electric signal, signal interface 34A for storing the voltage signal, A/D converter 34B for converting the voltage signal into digital data, digital register 34C for storing the digital data, processor 34D for analyzing the digital data and obtaining the liquid level data, output port 35A for transmitting the liquid level data. All the functions of each element are controlled by program controller 36, which is programmed with unique software code for administrating the operation of all above elements. Each of above elements may be built together in one chip, or they can stand alone as individual circuit or chip.
FIG. 4B is a block diagram of three alternative embodiments of the interference filtering means 37, 37A, 37B, which are included in microprocessor 30B, 30C, 30D respectively. The control means 31 in microprocessor 30, 30A of FIGS. 4 and 4A generates the alternating current, which is in various forms including narrow band signal 38, multi-frequency signal 38A or an encode signal 38B. These signals are passed over to the liquid level sensor 20, and then received by microprocessor 30, 30A, 30B, 30C, 30D. For a narrow band signal 38, the interference filtering means 37 includes a narrow band filter 39, which can filter out the signal within this narrow band, and removing all random interference outside the narrow band. For a multi-frequency signal 38A, the interference filtering means 37A includes a Fourier analyzer 39A, which can perform Fourier analysis to pick up the right signal, and remove the noise interference. For an encode signal 38B, the interference filtering means 37B includes a decoder 39B, which can perform decoding to pick up the right signal, and remove the noise interference. The form of signal includes single frequency signal, continuous wave, pulse signal, impulse signal, digital signal, spread spectrum signal and encoded signal etc. The way of encoding includes frequency modulation, angle modulation, phase modulation, pulse modulation, pulse code modulation, FDMA and CDMA modulations etc. All the above interference filtering methods are more effective in digital format.
In addition to the environmental interference, the signal deformation may also reduce the reliability of the monitoring system, e.g., in the case of flexible IV bag, the bag may deform during infusion process and therefore lead to the deformation of the electrical signal and related electrical parameters. However, such signal deformation can be analyzed by the microprocessor 30, and the corrected electric parameters can be picked up by the analysis. Therefore, it would be impossible to obtain high accuracy and high reliability without the microprocessor 30.
FIG. 5 is a block diagram of an exemplary monitor terminal 40. The monitor terminal 40 includes alarm means 41 for providing an alarm, and display means 42 for displaying the liquid level data in a terminal screen.
FIG. 5A is a block diagram of an exemplary alarm means 41A. The alarm means 41A includes a sound generator 43 for giving a loud sound when the medical liquid level inside the IV bottle 11 in FIGS. 1, 2 drops to the predetermined low level.
FIG. 5B is a block diagram of an alternative alarm means 41B. The alarm means 41B includes a switch means 44 for cutting off the feeding of medical liquid 45 when the medical liquid level inside the IV bottle 11 in FIGS. 1, 2 drops to the predetermined low level.
FIG. 5C is a block diagram of another alternative alarm means 41C. The alarm means 41C including a signal network 46 for sending the liquid level data by the signal network 46 to either a nurse station 47 wirelessly from an antenna 46′ to an antenna 47″, or a nurse station 47A by wire.
FIG. 5D is a block diagram of an alternative monitor terminal 40A. The monitor terminal 40A comprises a rate controller 48 for controlling the infusion rate according to a predetermined rate value. The rate controller 48 includes an input port 48A for inputting the desired infusion rate 48B of the medical liquid 10 inside the IV bottle 11, a comparator 48C for comparing the desired infusion rate 48B and the detected infusion rate 48D, and an electric switch means 48E for adjusting the infusion rate according to the results from the comparator.
FIG. 6 is a schematic drawing of the second embodiment of a portable IV infusion monitoring system that is capable of detecting the liquid level of the medical liquid 10 inside an IV bottle 11, and giving alarm when the medical liquid 10 in the IV bottle 11 drops to a predetermined low level.
The second embodiment is similar to the first embodiment in FIG. 1, but only at least one electrode 20P is positioned outside the IV bottle 11. Meanwhile, a conductive wire 20Q is connected to either the liquid needle 13 or the air needle 14. This embodiment is especially usable for an old IV infusion system, where both the liquid needle 13 and air needle 14 are made of metal. When an alternating current is applied between the electrode 20P and the conductive wire 20Q, the electric parameters (e.g., impedance) between the medical liquid 10 and the electrode 20P is detected since the alternating current goes through the conductive wire 20Q to the metallic needle 13 or 14 to the medical liquid 10 and finally to the electrode 20P.
For removing the environmental interference, similar to the first embodiment, at least one shielding plate 20R made of conductive materials is placed on the outer surface of the electrode 20P. Meanwhile, at least one coaxial cable 20S connects the at least one electrode 20P to the microprocessor 30 for transmitting the signal, and the conductive wire 20Q is made of coaxial cable. The outer shielding layers of the coaxial cable 20Q, 20S are connected to the battery 50 or/and the microprocessor 30. The assembly box 60 in FIG. 3A containing the microprocessor 30, the battery 50 and part of the monitor terminal 40 also provides shielding function. However, if the electric environment is too noisy to perform the normal operation of this monitoring system, the signal processing described in FIG. 4B is performed to remove most environmental interference.
FIG. 7 is a schematic drawing of the third embodiment of a portable IV infusion monitoring system that is capable of giving alarm when the medical liquid 10 in the IV bottle 11 drops to a predetermined low level.
The third embodiment of the present invention comprises a liquid level sensor 20T including a first conductive wire 20U connected to the air needle 14, a second conductive wire 20V connected to the liquid needle 13, a signal processor 30E, and an alarm device 40B. All the monitoring system is powered preferably by a battery 50 or an external source as an option to user. The signal processor 30E comprising electronic circuits is capable of applying an electric current (preferably a direct current, but an alternating current as an option) between the two conductive wires 20U and 20V, detecting the electric parameters of the electric current, analyzing the electric parameters related to the liquid level inside the IV bottle 11, and sending an alarm signal when the medical liquid 10 in the IV bottle 11 drops to a predetermined low level. As the electric current is applied between the two conductive wires 20U and 20V, the electric parameters (e.g., impedance) between the two needles 13 and 14 are detected. The alarm device 40B is capable of giving alarm to patient and nurses after receiving the alarm signal from the signal processor 30E. To remove the environmental interference, the two conductive wires 20U and 20V are made of coaxial cables while the outer shielding layers of the coaxial cables are connected to a reference point with zero potential, e.g., the negative pole of a battery 50. The assembly box 60 in FIG. 3A containing the signal processor 30E, the battery 50 and part of the alarm device 40B also provides shielding function.
FIG. 8 is a block diagram of an exemplary signal processor 30E. the signal processor 30E comprises control means 31A for applying an electric current between the two conductive wires 20U and 20V in FIG. 7, receiver means 32B for receiving the electric parameters of the electric current, process means 34E for analyzing the received electric parameter and judging if the medical liquid 10 inside the IV bottle 11 has dropped below the predetermined low level, transmission means 35B for sending an alarm signal if the liquid level has dropped to the predetermined low level.
FIG. 9 is a block diagram of an exemplary alarm device 40B. The alarm device 40B includes alarm means 41 for giving alarm after receiving the alarm signal from the transmission means 35B in signal processor 30E of FIG. 8. The detailed alarm means is similar to that in the first embodiment described in FIG. 5A-5C.
Patent Application
20070293817
