Apparatus for gravitational IV flow sensing via mass change sensor and droplet counting device

Abstract

An apparatus for gravity IV flow sensing via a mass change sensor and a droplet counting device is disclosed, in particular, an infusion control system capable of controlling and monitoring medical fluid administration of gravity-based medical fluid infusion, where the gravity infusion control system may be coupled with an intravenous administration kit to control the infusion of gravity-based medical fluid. And may include a mass change sensor and a droplet counter.

Description

Background Technology

[0001] This disclosure generally relates to the administration of medical fluids, such as intravenous (IV) medical fluid therapy, and more specifically, to devices and systems for controlling and monitoring gravity-based medical fluid administration. Flow sensing capabilities, such as mass change sensors used in conjunction with droplet counting devices, allow for higher flow accuracy and a wider range of control (e.g., from about 2 mL / hr to over 15,000 mL / hr).

[0002] IV fluid delivery systems are used to deliver or infuse medical fluids to patients at a controlled rate. Several such IV fluid delivery systems exist, including gravity-based systems that use gravity pressure to guide medical fluids from an IV bag through tubing to the patient, and pump-based systems that use a mechanical pump that can be engaged with tubing to guide medical fluids from an IV bag to the patient.

[0003] Gravity-based infusion systems may include an IV administration set comprising an IV bag, infusion chamber, infusion tubing, and flow control device. The flow rate of the medical fluid to the patient is controlled by the flow control device, such as a roller clamp, clamping clamp, or flow valve. Typically, unless flow is interrupted, such as by the patient or caregiver blocking the infusion tubing or disconnecting the tubing from the patient, the patient will receive the full volume of medical fluid from the IV bag. Pump-based infusion systems comprise similar components to gravity-based infusion systems; however, an infusion pump may be used instead of the flow control device used in gravity-based infusion systems to control the flow rate and volume of medication delivered to the patient. Utility Model Content

[0004] While pump-based infusion systems offer the ability to control and monitor the administration of medical fluids, such as by controlling the flow rate and volume of fluids directed to the patient, they can be more complex and expensive than gravity-based systems. Furthermore, both gravity-based and pump-based infusion systems require caregivers or users to assemble and configure the system, including ensuring each component is ready and properly connected, and ensuring infusion and fluid flow parameters are set as intended. Some systems, such as gravity-based infusion systems, may require caregivers or users to prime the fluid pathway and maintain and / or adjust fluid flow parameters throughout the infusion. Additionally, some infusion systems may not provide notification in the event of complications or errors, such as air in the fluid pathway or accidental disconnection from the patient.

[0005] Based on at least some of the embodiments disclosed herein, it is recognized that while gravity-based infusion systems can provide a lower-cost alternative to pump-based infusion systems, both pump-based and gravity-based infusion systems require caregivers to set up, maintain, and monitor several aspects of medical fluid administration. Therefore, using gravity-based infusion systems may expose patients to several potential complications and errors, potentially leading to patient injury or inadequate care.

[0006] Therefore, this disclosure addresses the operational challenges encountered in existing systems for administering medical fluids using gravity-based infusion systems and provides a device for controlling and monitoring the administration of medical fluids that can protect patients from complications during infusion therapy, improve the workflow of clinicians and nurses, maintain patient mobility, reduce medication administration errors, improve drug safety, improve the accuracy and rate stability of drug delivery, reduce costs, and improve documentation efficiency, as well as prevent, detect, and resolve complications such as occlusion, extravasation, and air in the fluid pathway.

[0007] Features of this embodiment can provide a gravity infusion control system that allows control over any aspect, including but not limited to fluid flow rate, dose volume, pre-filling of the IV dosing kit, and automatic stopping and / or starting of infusion. Furthermore, aspects of this disclosure can provide monitoring of fluid pathways of the IV dosing kit, including but not limited to pressure, fluid flow rate, occlusion, air presence, leakage, permeation, and the potential for tampering with the IV dosing kit.

[0008] Embodiments of this disclosure provide a gravity infusion control system comprising: an infusion chamber containing an infusion fluid configured to be fluidly coupled to a patient via an IV tube extending therebetween; a mass change sensor configured to detect either a change in weight or movement of the infusion fluid within the infusion chamber; and a droplet detector configured to detect droplets of the infusion fluid falling from the infusion chamber. In some embodiments, the gravity infusion control system further includes a user interface for controlling the flow rate of the gravity infusion system. In some embodiments, the mass change sensor is a weighing sensor or a weight. In some embodiments, the infusion chamber is coupled to the mass change sensor via an arm, hook, or clamp. In some embodiments, the infusion fluid flow is guided through the IV tube by gravity pressure. In some embodiments, the droplet detector is an infrared light emitter and receiver.

[0009] In some embodiments, the infusion fluid flow is configured to provide a flow rate of approximately 50 mL / h, approximately 100 mL / h, approximately 150 mL / h, approximately 200 mL / h, approximately 250 mL / h, approximately 300 mL / h, approximately 350 mL / h, approximately 400 mL / h, approximately 450 mL / h, or approximately 500 mL / h. In some embodiments, the infusion fluid flow is configured to provide a flow rate of approximately 2 mL / hr, approximately 5 mL / hr, approximately 10 mL / hr, approximately 15 mL / hr, approximately 20 mL / hr, approximately 25 mL / hr, approximately 30 mL / hr, approximately 35 mL / hr, approximately 40 mL / hr, or approximately 55 mL / hr. In some embodiments, the infusion fluid flow is greater than 500 mL / hr. In some embodiments, the gravity infusion control system further includes one or more of the following: an in-line air detector, a leak detector, an external pressure module, a tamper-proof module, an information and control module, and a connection module.

[0010] Embodiments of this disclosure provide a gravity infusion control system comprising an intravenous drug delivery kit coupled to a medical fluid reservoir and a flow sensor coupled to the intravenous drug delivery kit. The gravity infusion control system is configured such that the flow sensor can detect any change in the mass or movement of the medical fluid reservoir. In some embodiments, the flow sensor includes a mass change sensor and a droplet detector. In some embodiments, the flow sensor is configured to detect either a change in the weight or movement of the medical fluid reservoir of the intravenous drug delivery kit. In some embodiments, the mass change sensor is a weighing sensor or a weight. In some embodiments, the droplet detector is an infrared light emitter and receiver.

[0011] Additional features and advantages of this subject matter will be set forth in the following description, and in part will be apparent from the description, or may be learned by practicing the subject matter. The advantages of this subject matter will be realized and obtained through structures particularly pointed out in its written description and embodiments, and in the accompanying drawings.

[0012] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory, and are intended to provide further explanation of the technical subject matter. Attached Figure Description

[0013] Various features of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. The illustrated embodiments are intended to illustrate, but are not limited to, the present invention. The drawings include the following figures:

[0014] Figure 1 A gravity infusion control system for use with an IV delivery kit coupled to a patient is shown, according to various aspects of this disclosure.

[0015] Figure 2A gravity infusion control system for use with an IV drug delivery kit including a mass change sensor, according to various aspects of this disclosure, is shown.

[0016] Figure 3 A gravity infusion control system for use with an IV drug delivery kit including a mass change sensor and a droplet counter, according to various aspects of this disclosure, is shown.

[0017] Figure 4 It is a graph showing a calibration curve that provides the average droplet weight at a specific drop rate.

[0018] Figures 5A-5C The different droplet sizes of the infusion fluid resulting from different drip rates are shown.

[0019] Figure 6 This is a calibration curve showing the normal infusion rate.

[0020] Figure 7 This is a graph showing the signal-to-noise ratio of the sensor during mass change during patency-maintaining (KVO) infusion.

[0021] Figure 8 This is a graph showing the calibration curve for a rapid infusion rate.

[0022] Figure 9 Potential access points for fluid theft are shown. Detailed Implementation

[0023] The following detailed description sets forth numerous specific details to provide a comprehensive understanding of the subject matter. It should be understood that the subject matter can be practiced without some of these specific details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the subject matter.

[0024] Furthermore, while this description sets forth specific details of various embodiments, it should be understood that this description is illustrative only and should not be construed as limiting in any way. Moreover, it is conceivable that although specific embodiments of this disclosure may be disclosed or illustrated in the context of IV drug delivery kits, these embodiments may also be used in other fluid delivery systems. Furthermore, various applications of such embodiments and modifications thereof that may occur to those skilled in the art are also included within the general concepts described herein.

[0025] According to some embodiments, this disclosure discusses various features and advantages of gravity infusion control systems. Gravity infusion control systems can be provided to offer numerous improvements for the control and monitoring of medical fluid administration. Gravity infusion control systems can monitor and control various aspects of medical fluid administration using IV administration kits, and can prevent, detect, and resolve potential or actual complications associated with medical fluid administration.

[0026] The gravity infusion control system includes a user interface, a flow detection interface, and a flow sensing interface. The user interface allows the user to set and / or adjust the operating characteristics of the gravity infusion control system, including but not limited to the dose and / or volume of the medical fluid to be directed to the patient, the flow rate of the drug, the start and / or stop parameters for medical fluid administration, and the pre-filling of the fluid pathway for the medical fluid. In some embodiments of this disclosure, the user interface may include a graphical user interface.

[0027] The flow sensing device described herein is implemented through two input signals. These signals are the mass change of the infusion fluid storage container and the detection of droplets falling from a controlled diameter (e.g., the drip chamber). Flow sensing is critical to the performance of gravity infusion control systems to ensure that an appropriate rate is achieved and that all user-derived parameters are correct (e.g., the estimated time until infusion is complete).

[0028] The flow detection interface allows the gravity infusion control system to couple with a medical fluid reservoir or container and detect the occurrence of flow from or through the medical fluid reservoir.

[0029] The flow detection interface includes an IV drug delivery kit coupler configured to engage or retain part of an IV drug delivery kit, such as an IV bag or infusion chamber, forming a medical fluid reservoir. The flow detection interface also includes a flow sensor configured to detect any change in mass or movement of the medical fluid reservoir to determine the occurrence of flow from or through the medical fluid reservoir. In some embodiments of this disclosure, the flow sensor may include any of a droplet sensor, a weight change sensor, and / or an optical sensor.

[0030] In some embodiments of this disclosure, the flow detection interface is configured with one or more IV dosing kit couplers having a structure for coupling with an IV bag and / or infusion chamber. The IV bag may be configured as an arm, hook, clamp, or another mechanism for suspending the IV bag.

[0031] The flow control interface allows the gravity infusion control system to couple with a portion of the IV drug delivery kit to form an internal channel for fluid flow and to control the flow rate of fluid through the internal channel. The flow control interface includes another IV drug delivery kit coupler configured to engage or retain a portion of the IV drug delivery kit, such as an IV tube, that forms the internal channel.

[0032] refer to Figure 1An embodiment of a gravity infusion control system 100 is shown, which is used in conjunction with an IV administration kit coupled to a patient 1. The gravity infusion control system 100 includes a user interface 110, a flow detection interface, and a flow control interface. The flow detection interface includes a first IV administration kit coupler and a second IV administration kit coupler. Furthermore, the flow control interface includes a third IV administration kit coupler for the gravity infusion control system.

[0033] The gravity infusion control system 100 is coupled to an IV administration kit having an IV bag 12 and an infusion chamber 14, which are fluidly coupled together via an IV tube 16 extending therebetween. A flow control device 20 is coupled to a section of IV tube 18 extending between the infusion chamber 14 and the patient 1. The IV tube is coupled to the patient via a vein through a catheter 22.

[0034] The IV delivery kit and gravity infusion control system 100 are arranged together with an IV bag 12 coupled to a first IV delivery kit coupler, an infusion chamber 14 coupled to a second IV delivery kit coupler, and a flow control device 120 coupled to a third IV delivery kit coupler. After the IV tubing 18 of the IV delivery kit is coupled to the patient, a user interface 110 can be used to initiate the infusion process. Initiating the infusion process may include inputting operating parameters, such as the flow rate of the medical fluid and the volume of the medical fluid to be administered.

[0035] Now for reference Figure 2 An embodiment of a gravity delivery control system 200 is shown, including a mass change sensor 201 as a flow detection interface, a drip chamber 13, a user interface 110, an IV tube 18, and a roller clamp 140. For example, the mass change sensor 201 may be a load cell or a weight. In some embodiments, the mass change sensor 201 is coupled to the drip chamber 13. The structure coupling the mass change sensor 201 to the drip chamber 13 may be formed as an arm, hook, clamp, or another mechanism configured to suspend the drip chamber 13.

[0036] Now for reference Figure 3An embodiment of a gravity delivery control system 300 is shown, including a mass change sensor 201 as a flow detection interface, a droplet detector 301 as a flow sensor, a drip chamber 13, a user interface 110, an IV tube 18, and a roller clamp 140. The gravity delivery control system 300 is similar to the gravity delivery system 200 described above, but with the addition of the droplet detector 301. In some embodiments, the droplet detector 301 is an infrared light emitter and receiver. For example, the mass change sensor 201 can be a weighing sensor or a weight. In some embodiments, the mass change sensor 201 is coupled to the drip chamber 13. The structure coupling the mass change sensor 201 to the drip chamber 13 can be formed as an arm, hook, clamp, or another mechanism configured to suspend the drip chamber 13.

[0037] Flow sensors can include any sensor used to detect movement or weight changes in a medical fluid reservoir. In some embodiments, a flow sensor can be an optical sensor configured to detect changes in the volume of liquid in a medical fluid reservoir.

[0038] The gravity infusion control system disclosed herein can further provide functions that can improve safety and security related to drug administration. In some embodiments, the gravity infusion control system can provide a system or subsystem for identifying and verifying patient identity. Patient identification and verification can be performed using a user interface, scanner, or other devices, such as a smartphone that can communicate with the processor of the gravity infusion control system and / or the patient data system. Patient identification may include capturing a photograph of the patient or scanning a barcode coupled to the patient's identification band.

[0039] Additional features of gravity infusion control systems that can improve the safety and security of drug administration include the ability to detect tampering with the drug associated with the infusion. The gravity infusion control system may include a weight sensor configured to monitor the weight of the fluid reservoir to also detect tampering with medical medications.

[0040] The gravity infusion control system disclosed herein can provide functionality for detecting potential or actual complications related to the infusion process. In some embodiments, the gravity infusion control system can provide a system or subsystem configured to identify potential complications related to the fluid pathway, including but not limited to occlusion, air in the fluid pathway, leakage or extravasation of the fluid pathway, and instability in the flow of medical fluids. To detect potential or actual complications, the gravity infusion control system may include sensors such as in-line air sensors, weight sensors, and / or pressure sensors.

[0041] In some embodiments of this disclosure, the gravity infusion control system is configured to be coupled to one or more subsystems or modules, such as an in-line air subsystem, a tamper-proof subsystem, a permeation subsystem, a leak detection subsystem, a pressurization subsystem, and / or a patient data subsystem.

[0042] Gravity infusion control systems can provide a workflow with higher efficiency and reliability compared to other infusion systems. The workflow associated with a gravity infusion control system may include, but is not limited to, a preparation phase, a pre-charge phase, an infusion phase, an infusion maintenance phase, and an infusion termination phase. It should be understood that one or more phases may occur simultaneously or sequentially.

[0043] During the workflow preparation phase, caregivers can scan the patient's wristband to identify and verify the patient. During the pre-filling phase, caregivers can place the IV delivery kit in the gravity infusion control system and initiate the pre-filling of the fluid pathway. The pre-filling phase may also include indicating the absence of complications, such as air in the fluid pathway, via the gravity infusion control system. During the infusion phase, caregivers can enter the drip rate and initiate or start the infusion process. Documentation or data saving associated with the infusion process can be initiated during the infusion phase or any other phase. During the infusion maintenance phase, the gravity infusion control system can provide one or more notifications, such as the presence of occlusion, air in the tubing, tampering, leakage, and / or seepage. Furthermore, the gravity infusion control system can automatically maintain fluid flow during the infusion maintenance phase. During the infusion termination phase, the gravity infusion control system can automatically clamp or block the IV tubing's fluid pathway to prevent further delivery of medical fluids or accidental leakage of medical fluids while the IV delivery kit is disconnected from the patient.

[0044] Subject matter technology as an explanation of the terms.

[0045] For example, the subject matter technique is illustrated by various aspects described below. For convenience, various examples of the various aspects of the subject matter technique are described as numbered clauses (1, 2, 3, etc.). These are provided by way of example only and do not limit the subject matter technique. It should be noted that any dependent clauses may be combined in any combination and placed in the corresponding independent clauses, such as clause 1 or clause 5. Other clauses may be presented in a similar manner.

[0046] Clause 1: A gravity infusion control system comprising: an infusion chamber containing an infusion fluid configured to be fluidly coupled to a patient via an IV tube extending therethere; a mass change sensor configured to detect either a weight change or movement of the infusion fluid in the infusion chamber; and a droplet detector configured to detect droplets of the infusion fluid falling from the infusion chamber.

[0047] Clause 2: The gravity delivery control system of Clause 1 also includes a user interface for controlling the flow rate of the gravity delivery system.

[0048] Clause 3: The gravity delivery control system of Clause 1, wherein the mass change sensor is a weighing sensor or a weight.

[0049] Clause 4: The gravity infusion control system of Clause 1, wherein the infusion chamber is coupled to a mass change sensor via an arm, hook or clamp.

[0050] Clause 5: The gravity infusion control system of Clause 1, wherein the infusion fluid flow is guided through IV tubing by gravity pressure.

[0051] Clause 6: The gravity delivery control system of Clause 1, wherein the droplet detector is an infrared light emitter and receiver.

[0052] Clause 7: The gravity infusion control system of Clause 5, wherein the infusion fluid flow is configured to provide a flow rate of about 50 mL / h, about 100 mL / h, about 150 mL / h, about 200 mL / h, about 250 mL / h, about 300 mL / h, about 350 mL / h, about 400 mL / h, about 450 mL / h, or about 500 mL / h.

[0053] Clause 8: The gravity infusion control system of Clause 5, wherein the infusion fluid flow is configured to provide a flow rate of about 2 mL / hr, about 5 mL / hr, about 10 mL / h, about 15 mL / hr, about 20 mL / hr, about 25 mL / hr, about 30 mL / hr, about 35 mL / hr, about 40 mL / hr, or about 55 mL / hr.

[0054] Clause 9: The gravity infusion control system of Clause 5, wherein the infusion fluid flow rate is greater than 500 mL / hr.

[0055] Clause 10: The gravity delivery control system of Clause 1 also includes one or more of the following: in-line air detector, leak detector, external pressure module, tamper protection module, information and control module, and connection module.

[0056] Clause 11: A gravity infusion control system comprising an intravenous administration kit coupled to a medical fluid reservoir and a flow sensor coupled to the intravenous administration kit, the gravity infusion control system being configured to enable the flow sensor to detect any change in the mass or movement of the medical fluid reservoir.

[0057] Clause 12: Gravity delivery control system of Clause 11, wherein the flow sensor includes a mass change sensor and a droplet detector.

[0058] Clause 13: The gravity infusion control system of Clause 11, wherein the flow sensor is configured to detect any change in weight or movement of the medical fluid reservoir of the intravenous administration kit.

[0059] Clause 14: Gravity delivery control system of Clause 12, wherein the mass change sensor is a weighing sensor or a weight.

[0060] Clause 15: Gravity delivery control system of Clause 12, wherein the droplet detector is an infrared light emitter and receiver.

[0061] Further consideration

[0062] In some embodiments, any clause herein may be subordinate to any independent clause or any dependent clause. In one aspect, any clause (e.g., a dependent or independent clause) may be combined with any other one or more clauses (e.g., a dependent or independent clause). In one aspect, a claim may include some or all of the words (e.g., steps, operations, means, or components) stated in a clause, sentence, phrase, or paragraph. In one aspect, a claim may include some or all of the words stated in one or more clauses, sentences, phrases, or paragraphs. In one aspect, some words in each of the clauses, sentences, phrases, or paragraphs may be deleted. In one aspect, additional words or elements may be added to the clauses, sentences, phrases, or paragraphs. In one aspect, the subject matter may be implemented without utilizing some of the components, elements, functions, or operations described herein. In one aspect, the subject matter may be implemented using additional components, elements, functions, or operations.

[0063] This disclosure is provided to enable those skilled in the art to practice the various aspects described herein. This disclosure provides various examples of the subject matter, and the subject matter is not limited to these examples. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects.

[0064] Unless otherwise stated, elements submitted in the singular do not indicate "one and only one," but rather "one or more." Unless otherwise stated, the word "some" refers to one or more. Masculine pronouns (e.g., his) include feminine pronouns and neuter pronouns (e.g., her and its), and vice versa. Titles and subtitles (if any) are used for convenience only and do not limit the scope of this invention.

[0065] The term “exemplary” as used herein means “as an example or illustration.” Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or superior to other aspects or designs. In one respect, the various alternative configurations and operations described herein may be considered at least equivalent.

[0066] Phrases such as "aspect" do not imply that the aspect is essential to the present subject matter, nor do they imply that the aspect is applicable to all configurations of the present subject matter. Disclosure relating to an aspect may apply to all configurations, or one or more configurations. An aspect may provide one or more examples. Phrases such as "aspect" may refer to one or more aspects, or vice versa. Phrases such as "embodiment" do not imply that such an embodiment is essential to the present subject matter, nor do they imply that such an embodiment is applicable to all configurations of the present subject matter. Disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. An embodiment may provide one or more examples. Phrases such as "embodiment" may refer to one or more embodiments, or vice versa. Phrases such as "configuration" do not imply that such a configuration is essential to the present subject matter, nor do they imply that such a configuration is applicable to all configurations of the present subject matter. Disclosure relating to a configuration may apply to all configurations, or one or more configurations. A configuration may provide one or more examples. Phrases such as "configuration" may refer to one or more configurations, or vice versa.

[0067] In one respect, unless otherwise stated, all measurements, values, ratings, positions, amplitudes, dimensions, and other specifications set forth in this specification (including the appended claims) are approximate, not precise. In another respect, they are intended to have a reasonable range that is consistent with the functions they address and the conventions of the field to which they belong.

[0068] In one respect, the term "coupling" can refer to direct coupling. In another respect, the term "coupling" can refer to indirect coupling.

[0069] As used in this disclosure, the terms “top,” “bottom,” “front,” and “rear” should be understood to refer to any frame of reference, rather than a conventional gravitational frame of reference. Therefore, the top surface, bottom surface, front surface, and rear surface can extend upward, downward, diagonally, or horizontally in a gravitational frame of reference.

[0070] Various items may be arranged differently (e.g., in different orders or partitioned in different ways), all of which do not depart from the scope of the subject matter. All structural and functional equivalents of elements of the various aspects described throughout this disclosure that are known or will be known hereafter by one of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is expressly recited in the claims. No element of a claim should be interpreted in accordance with paragraph 6 of 35 U.S.SC §112 unless the element is expressly referred to by the phrase “means for…”. Moreover, within the scope of the use of terms such as “include” and “having,” such terms are intended to include in a manner similar to the term “comprise,” since “comprise” is interpreted as including when used as a transition word in a claim.

[0071] The title, background, overview, drawings, brief description, and abstract of this disclosure are hereby incorporated in this disclosure and are provided as illustrative examples rather than limiting descriptions. It should be understood at the time of filing that they are not intended to limit the scope or meaning of the claims. Furthermore, as will be apparent in the detailed description, which provides illustrative examples and, for the sake of simplicity, various features are grouped together in various embodiments. This approach to disclosure should not be construed as reflecting an intention that the claimed subject matter requires more features than expressly recited in each claim. Rather, as reflected in the following claims, the inventive subject matter lies in the fact that a single disclosed configuration or operation has fewer features than all features. The following claims are hereby incorporated in the detailed description, each claim existing independently as a separate claimed subject matter.

[0072] The claims are not intended to be limited to the aspects described herein, but should be given the full scope consistent with the language claims and cover all legal equivalents. Nevertheless, no claim is intended to include subject matter that does not satisfy the requirements of 35 U.S.SC § 101, 102 or 103, nor should they be interpreted in this manner.

[0073] Example

[0074] Example 1: Droplet calibration

[0075] It is known that droplet size (e.g., 20 drops / mL) passing through a normal infusion chamber is affected by droplet rate and fluid properties (e.g., density and surface tension). Therefore, it is desirable to determine droplet size for a specific infusion type and at different rates. The following scheme provides a method for determining the average droplet weight of a given infusion at different rates:

[0076] Step 1: Start the gravity delivery control system from the off position.

[0077] Step 2: The gravity infusion control system opens the flow-limiting subsystem to opening rate 1 for a specified time period or a specified number of drops. Rate 1 is intended for a very slow position (~20 drops per minute). The gravity infusion control system records the drop rate (r1), the number of drops (n1), and the change in mass (dM1).

[0078] Step 3: The gravity infusion control system opens the flow-limiting subsystem to opening rate 2 for a specified time period or a specified number of drops. Rate 2 is designed for faster speeds (~400 drops per minute). The gravity infusion control system records the drop rate (r2), drop count (n2), and mass change (dM2).

[0079] Step 4: Using the data generated in Steps 2 & 3, the gravity infusion control system can create a linear calibration curve for the infusion fluid. The calibration curve provides the average droplet weight at a specific drip rate. This calibration curve is as follows: Figure 4 As shown. Figures 5A-5C The diagram shows three different droplet sizes produced at three different drop rates.

[0080] In principle, the process can be modified to add as many calibration points as needed.

[0081] Example 2: Density Estimation

[0082] This article describes the options for estimating the density of the infusion fluid.

[0083] Option 1: For fluids similar to salt water, assume the fluid density is approximately equal to 0.9% salt water (~1.0049 g / mL).

[0084] Option 2: For fluids like saline solution, assume the volume of one drop is 0.05 mL at low speed (for a dropper chamber with 20 drops per mL). Allow a specified number of droplets to pass through and measure the mass change (as in step 2 or 3 of droplet calibration). Density = (mass change) / [(number of drops) * (0.05 mL)]

[0085] Option 3: Store a fluid density library on the gravity infusion control system. When a nurse scans a medication or enters a medication type, the gravity infusion control system selects the appropriate density value.

[0086] Example 3: Normal infusion

[0087] Normal infusion rate is approximately 50-500 mL / hour. Two options for sensing flow rate during normal infusion are provided below. Figure 6 This is a graph showing an example of an infusion rate of 200 mL / hr.

[0088] Option 1. Mass change as the primary factor: During normal infusion, flow rate can be sensed by dividing the change in mass over time by an assumed or given fluid density.

[0089] Option 2. Calibrated droplets as the primary factor: During normal infusion, flow rate can be sensed by calculating the number of droplets and adjusting their assumed mass based on a linear calibration curve and an assumed or given fluid density.

[0090] Example 4: Maintaining Venous Patency (KVO) Infusion

[0091] KVO infusions are typically 2-50 mL / hr. In principle, KVO infusion control can be similar to the normal infusion described above, except for the following challenges:

[0092] 1. At KVO rates, the time between drops becomes very long (1-2 minutes between drops), which makes the response time for the system to reach the correct flow rate very long if based on the drop rate.

[0093] 2. The signal-to-noise ratio of the mass change sensor becomes very large because the mass change is very small, causing noise effects such as drift to have a more significant impact on the change of total mass over time. For example... Figure 7 As shown.

[0094] To overcome these challenges during KVO infusion, changes in the mass signal are used to create an initial rate setpoint, since changes in mass are detectable during droplet formation. This approach results in a significantly faster response time compared to relying solely on a droplet counter. Furthermore, the droplet counter is used to track the total volume during KVO infusion because it is less susceptible to drift and other potential effects than a mass change sensor.

[0095] In this way, theoretically, the two sensors work together, enabling the gravity infusion control system to reach the required flow rate more quickly and to accurately measure the total volume infused during the KVO infusion process.

[0096] Example 5: Fast Injection

[0097] Rapid infusion is typically greater than 500 mL / hr. Figure 8 This is a graph illustrating an example of a rapid infusion rate. In principle, rapid infusion control can be similar to that of a normal infusion, except for the following challenges:

[0098] The droplets begin to coalesce into a stable flow, and the droplet sensor no longer effectively measures volume changes over time.

[0099] To overcome this challenge during rapid infusion, a mass change sensor was fabricated as the primary sensor for measuring flow rate (Option 1 for normal infusion). At these rates, the mass change will be very large relative to noise effects.

[0100] Example 6: Mechanical noise on the load cell

[0101] Mass change sensors are sensitive to events such as drift, environmental vibration, impact or collision with the IV frame, movement of the IV frame (during transport or walking), potential line tension (e.g., during setup, a clinician may inadvertently connect the IV kit, increasing line tension and creating a stable external force on the mass change sensor), and other similar events.

[0102] If the gravity delivery control system encounters these events, the primary means of detecting flow can be temporarily or permanently switched from Option 1 (mass change as the primary factor) to Option 2 (calibrated droplet count as the primary factor).

[0103] Example 7: Theft or leakage of infusion fluid

[0104] If the flow rate determined by option 1 (with mass change as the primary factor) is significantly greater than the flow rate determined by option 2 (with calibrated droplets as the primary factor), it can be inferred that a serious leak or possible theft of the infusion fluid has occurred. Figure 9 Potential access points for fluid theft are shown.

Claims

1. A gravity delivery control system, characterized in that, The gravity delivery control system includes: An infusion chamber containing an infusion solution configured to be fluidly coupled to a patient via an IV tube extending therebetween; A mass change sensor, configured to detect either a change in weight or movement of the infusion fluid in the infusion chamber; and A droplet detector is configured to detect droplets of the infusion fluid falling from the infusion chamber.

2. The gravity delivery control system according to claim 1, characterized in that, The gravity delivery control system also includes a user interface for controlling the flow rate of the gravity delivery control system.

3. The gravity delivery control system according to claim 1, characterized in that, The mass change sensor is a weighing sensor or a weight.

4. The gravity delivery control system according to claim 1, characterized in that, The drip chamber is coupled to the mass change sensor via an arm, hook, or clamp.

5. The gravity delivery control system according to claim 1, characterized in that, The infusion fluid flow is guided through the IV tube by gravity pressure.

6. The gravity delivery control system according to claim 1, characterized in that, The droplet detector is an infrared light emitter and receiver.

7. The gravity delivery control system according to claim 5, characterized in that, The infusion fluid flow is configured to provide a flow rate of approximately 50 mL / hour, approximately 100 mL / hour, approximately 150 mL / hour, approximately 200 mL / hour, approximately 250 mL / hour, approximately 300 mL / hour, approximately 350 mL / hour, approximately 400 mL / hour, approximately 450 mL / hour, or approximately 500 mL / hour.

8. The gravity delivery control system according to claim 5, characterized in that, The infusion fluid flow is configured to provide a flow rate of about 2 mL / hr, about 5 mL / hr, about 10 mL / hr, about 15 mL / hr, about 20 mL / hr, about 25 mL / hr, about 30 mL / hr, about 35 mL / hr, about 40 mL / hr, or about 55 mL / hr.

9. The gravity delivery control system according to claim 5, characterized in that, The infusion fluid flow rate is greater than 500 mL / hr.

10. The gravity delivery control system according to claim 1, characterized in that, The gravity delivery control system also includes one or more of the following: an in-line air detector, a leak detector, an external pressure module, an anti-tampering module, an information and control module, and a connection module.

11. A gravity delivery control system, characterized in that, The gravity delivery control system includes: An intravenous delivery kit, coupled to a medical fluid reservoir; and A flow sensor is coupled to the intravenous administration kit, and the gravity infusion control system is configured such that the flow sensor can detect any mass change or movement of the medical fluid reservoir.

12. The gravity delivery control system according to claim 11, characterized in that, The flow sensor includes a mass change sensor and a droplet detector.

13. The gravity delivery control system according to claim 11, characterized in that, The flow sensor is configured to detect any change in weight or movement of the medical fluid reservoir in the intravenous administration kit.

14. The gravity delivery control system according to claim 12, characterized in that, The mass change sensor is a weighing sensor or a weight.

15. The gravity delivery control system according to claim 12, characterized in that, The droplet detector is an infrared light emitter and receiver.

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