Method and apparatus for wetting internal fluid path surfaces of a fluid port to enhance transmission of ultrasound signals

Abstract

A method for preparing a fluid sensor associated with a medical device includes attaching a flow restrictor to a fluid outlet of the fluid sensor. The fluid sensor includes a fluid channel, a fluid inlet at a first end of the fluid channel, and a fluid outlet at a second end of the fluid channel, wherein the fluid inlet is configured to be coupled to an outlet of an applicable fluid source. Fluid is delivered from the applicable fluid source through the fluid inlet to the fluid channel. A syringe actuation device including a force-limiting device can be used to deliver the fluid. The fluid is pressurized in the fluid channel between the fluid inlet and the flow restrictor to wet the inner surface of the fluid channel with fluid. The flow restrictor is removed from the fluid outlet.

Description

[0001] Case Analysis

[0002] This application is a divisional application.

[0003] The original parent application of this divisional application is a patent application filed on June 19, 2017 (PCT International Application No. PCT / US2017 / 038115), with Chinese National Application No. 201780034495.1, entitled "Method and apparatus for wetting the internal fluid path surface of a fluid port to improve ultrasonic signal transmission" (file number IIM183559).

[0004] The direct parent application of this divisional application is the first-generation divisional application of the aforementioned most original parent application. The first-generation divisional application was filed on October 11, 2021, with the divisional application number "202111179844.3", the invention title "Method and Apparatus for Wetting the Internal Fluid Path Surface of a Fluid Port to Enhance Ultrasonic Signal Transmission", and the firm's file number is IIM212819.

[0005] On February 17, 2023, the State Intellectual Property Office issued a First Examination Opinion (hereinafter referred to as "Opinion") regarding the first-generation divisional application, pointing out that several claims of the first-generation divisional application lacked unity of claim. The applicant deleted these claims in its response to the Opinion. The Opinion is the direct basis for this (second) divisional application.

[0006] Cross-references to related applications

[0007] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 351,459, filed June 17, 2016, the entire disclosure of which is incorporated herein by reference. Technical Field

[0008] This disclosure generally relates to flow sensor systems. More specifically, this disclosure relates to a flow sensor system and a method for preparing a flow sensor for the flow sensor system to characterize at least one property of a fluid detected by the flow sensor. Background Technology

[0009] The volumetric accuracy of bolus delivery using medical devices needs improvement. A flow sensor system that provides a flow sensor with improved flow measurement characteristics would be advantageous.

[0010] Signal strength is a function of acoustic energy propagating from the sound source through an air (and / or contaminant) boundary layer, which attenuates this propagation. The boundary initially forms when the sensor is first subjected to a fluid. Over time, this layer begins to break down, leaving microbubbles on the sensor surface. Microbubbles remain on the surface as a function of two theories: i) the partial pressure of air dissolved in the fluid and ii) the surface energy or capillary force of the microbubbles relative to the surface. Lower pressure fluids contain smaller partial pressures of air and can allow air to be absorbed into the fluid. Higher pressures applied to the fluid both contract the bubbles and allow more surface area to contact the fluid, and upon release, allow the microbubbles to separate and be absorbed into the fluid. Based on the surface topology or unevenness density, microbubbles enter the cavities of the surface through capillary action or surface tension, which is higher than the buoyancy force within the fluid itself.

[0011] Therefore, there is a need in the art for an improved method and apparatus for wetting the internal fluid path surface of a fluid port to improve ultrasonic signal transmission. Summary of the Invention

[0012] This disclosure provides a system for sensing fluid drug flow. The system includes a smart injection port that can be attached to an injection site (e.g., a "Y-site" or stopcock) for manual IV injection. The system includes two main sub-components: a disposable flow sensor and a reusable base unit, which are assembled together before use. The disposable flow sensor includes a flow tube assembly. This disclosure provides a method for preparing the flow sensor to characterize at least one property of the fluid flowing through the flow tube assembly.

[0013] According to a non-limiting embodiment or aspect, a method for preparing a fluid sensor associated with a medical device is provided, the method comprising: attaching a flow restrictor to a fluid outlet of the fluid sensor, the fluid sensor including a fluid channel, a fluid inlet at a first end of the fluid channel, and a fluid outlet at a second end of the fluid channel, wherein the fluid inlet is configured to be coupled to an outlet of an applicable fluid source; delivering fluid from the applicable fluid source through the fluid inlet to the fluid channel; pressurizing the fluid in the fluid channel between the fluid inlet and the flow restrictor to wet an inner surface of the fluid channel with fluid; and removing the flow restrictor from the fluid outlet.

[0014] In a non-limiting embodiment or aspect, the method further includes applying pressure to the fluid in the fluid passage between the fluid inlet and the flow restrictor during a first time period.

[0015] In one non-limiting embodiment or aspect, the applicable fluid source includes a syringe with a plunger, wherein the method further includes: attaching a syringe actuation device to the syringe; and applying a force to the plunger of the syringe using the syringe actuation device.

[0016] In a non-limiting embodiment or aspect, the method further includes adjusting the syringe actuation device to a first position, wherein, when in the first position, the syringe actuation device applies force to the plunger of the syringe.

[0017] In one non-limiting embodiment or aspect, the pressure is a constant positive pressure.

[0018] In one non-limiting embodiment or aspect, the pressure is a constant negative pressure.

[0019] In a non-limiting embodiment or aspect, the method further includes applying a constant pressure to fluid in a fluid passage between a fluid inlet and a flow restrictor during a second time period, the second time period being a time period before and after the first time period.

[0020] In one non-limiting embodiment or aspect, the applicable fluid source includes a syringe with a plunger, and the method further includes: attaching a syringe actuation device to the syringe; adjusting the syringe actuation device to a first position, wherein, when in the first position, the syringe actuation device applies a first constant force to the plunger of the syringe, the first constant force applying a constant negative pressure to the fluid in the fluid passage for a first time period; and adjusting the syringe actuation device to a second position, wherein, when in the second position, the syringe actuation device applies a second constant force to the plunger of the syringe, the second constant force applying a constant positive pressure to the fluid in the fluid passage for a second time period.

[0021] In a non-limiting embodiment or aspect, the method further includes generating bidirectional flow of fluid in a fluid passage between the fluid inlet and the flow restrictor.

[0022] In a non-limiting embodiment or aspect, the method further includes applying varying pressure to the fluid in the fluid passage between the fluid inlet and the flow restrictor.

[0023] In one non-limiting embodiment or aspect, the flow restrictor includes an outlet whose inner diameter changes in response to varying pressure applied to the fluid in the fluid passage, thereby creating a turbulent flow of fluid in the fluid passage.

[0024] In one non-limiting embodiment or aspect, the current limiter includes an elastomeric material.

[0025] In one non-limiting embodiment or aspect, the applicable fluid source includes a syringe with a plunger, wherein the method further includes: vertically mounting the syringe in a syringe holder; and applying a load to the plunger of the syringe.

[0026] In one non-limiting embodiment or aspect, the method further includes shaking or vibrating the fluid sensor when the fluid is within the fluid channel.

[0027] In one non-limiting embodiment or aspect, the fluid sensor further includes at least one piezoelectric element, wherein the method further includes: stimulating at least one piezoelectric element when fluid is within a fluid channel, thereby expelling microbubbles from the inner wall of the fluid channel.

[0028] In one non-limiting embodiment or aspect, the method further includes wetting the fluid channel with at least one surfactant.

[0029] In one non-limiting embodiment or aspect, the method further includes processing at least one component of the fluid sensor using at least one of plasma etching, grinding and polishing, reaming, or any combination thereof to reduce the surface roughness of the at least one component.

[0030] In one non-limiting embodiment or aspect, the method further includes applying a negative pressure to the fluid in the applicable fluid source before delivering the fluid from the applicable fluid source through a fluid inlet to the fluid channel, thereby removing gas from the fluid.

[0031] In one non-limiting embodiment or aspect, the method further includes attaching a suction cup to a fluid inlet; and actuating the suction cup to apply negative pressure to fluid in an applicable fluid source.

[0032] In a non-limiting embodiment or aspect, the method further includes connecting a flow guide between a fluid inlet at a first end of the fluid channel and an outlet of an applicable fluid source, wherein the flow guide generates a helical fluid flow in the fluid delivered from the applicable fluid source through the fluid inlet to the fluid channel.

[0033] In one non-limiting embodiment or aspect, the method further includes heating the fluid while it is within the fluid channel.

[0034] In one non-limiting embodiment or aspect, the method further includes changing the flow rate of fluid delivered from an applicable fluid source through a fluid inlet to a fluid channel.

[0035] In one non-limiting embodiment or aspect, delivering fluid from an applicable fluid source to a fluid channel via a fluid inlet includes delivering a spurt of fluid from an applicable fluid source to a fluid channel via a fluid inlet.

[0036] In one non-limiting embodiment or aspect, the bolus is periodically delivered to the fluid channel.

[0037] In a non-limiting embodiment or aspect, the method further includes changing at least one of the following options: the volume of the bolus, the pressure applied to the fluid of the bolus, the duration of pressure applied to the fluid of the bolus, or any combination thereof.

[0038] In one non-limiting embodiment or aspect, the applicable fluid source includes a syringe with a plunger, and the method further includes: attaching a force limiting device to the syringe; and using the force limiting device to prevent pressure that violates a threshold pressure from being applied to the fluid in the fluid passage.

[0039] In one non-limiting embodiment or aspect, the force limiting device prevents movement of the syringe plunger in response to applying a pressure that violates a pressure threshold to the fluid in the fluid channel.

[0040] In one non-limiting embodiment or aspect, the applicable fluid source includes a syringe with a plunger, and the method further includes: attaching a force limiting device to the syringe, the force limiting device including at least one pressure indicator; and using at least the pressure indicator to indicate the current pressure of the fluid applied to the fluid passage.

[0041] In one non-limiting embodiment or aspect, the current limiter also includes an outlet of approximately 34G (0.0826mm inner diameter).

[0042] According to a non-limiting embodiment or aspect, a method for preparing a fluid conduit associated with a medical device is provided, the method comprising: attaching a flow restrictor to a fluid outlet of the fluid conduit, the fluid conduit including a fluid channel, a fluid inlet at a first end of the fluid channel, and a fluid outlet at a second end of the fluid channel, the fluid inlet being configured to be coupled to an outlet of an applicable fluid source; delivering fluid from the applicable fluid source through the fluid inlet to the fluid channel; pressurizing the fluid in the fluid channel between the fluid inlet and the flow restrictor to wet an inner surface of the fluid channel with fluid, thereby removing air bubbles from the pressurized fluid in the fluid conduit; and removing the flow restrictor from the fluid outlet.

[0043] According to a non-limiting embodiment or aspect, a method for preparing a fluid sensor associated with a medical device is provided, comprising: generating a first signal via at least one sensor at a fluid port, the first signal characterizing at least one property of a fluid within an applicable fluid source, the fluid port including: a fluid channel, a fluid inlet at a first end of the fluid channel, and a fluid outlet at a second end of the fluid channel having a flow restrictor, wherein the fluid inlet is configured to be coupled to an outlet of the applicable fluid source; removing the flow restrictor; attaching the fluid outlet at the second end of the fluid channel to the inlet, the inlet being configured to deliver fluid from the applicable fluid source to a fluid path providing fluid to the medical device; and generating a second signal of the same type as the first signal, characterizing at least one property of the fluid, by at least one sensor at the fluid port, wherein the second signal is enhanced compared to the first signal.

[0044] According to a non-limiting embodiment or aspect, an apparatus is provided for controlling a plunger of a syringe to deliver fluid from inside the syringe, comprising: an actuator rod extending from a proximal end to a distal end; a plunger engagement portion engaging the distal end of the actuator rod and configured to engage the plunger of the syringe; and a body having a proximal end, a distal end, and an opening at the proximal end, wherein the opening receives the plunger engagement portion, and wherein the plunger engagement portion is threadedly engaged with the body.

[0045] In one non-limiting embodiment or aspect, the plunger engagement is configured to prevent the application of a force that violates a threshold force to the plunger of the syringe.

[0046] In one non-limiting embodiment or aspect, the plunger engagement prevents the plunger of the syringe from moving in response to the plunger reaction force applied by the plunger of the syringe.

[0047] In one non-limiting embodiment or aspect, the device further includes a clutch that engages the distal end of the actuator rod with the plunger engagement.

[0048] In one non-limiting embodiment or aspect, the device further includes a spring extending within the actuator rod.

[0049] In one non-limiting embodiment or aspect, the spring extends within the actuator rod and enters the plunger engagement via an opening in the proximal end of the plunger engagement, wherein the spring engages the inner wall of the distal end of the plunger engagement.

[0050] In one non-limiting embodiment or aspect, the outer wall of the distal end of the plunger engagement engages the plunger.

[0051] In one non-limiting embodiment or aspect, the actuator rod extends into the plunger engagement, wherein a portion of the actuator rod extending into the plunger engagement includes a radially extending flange, and wherein a clutch at the proximal end of the plunger engagement connects the proximal end face of the flange to the inner wall.

[0052] In one non-limiting embodiment or aspect, the clutch disengages the distal end of the actuator rod from the plunger engagement in response to the compression of the spring.

[0053] In one non-limiting embodiment or aspect, the spring is compressed in response to the plunger reaction force applied to the plunger engagement by the plunger of the syringe.

[0054] In one non-limiting embodiment or aspect, the distal end of the body is configured to connect to a syringe, and wherein the plunger of the syringe extends within the body.

[0055] According to a non-limiting embodiment or aspect, an apparatus is provided for controlling a plunger of a syringe to deliver fluid from inside the syringe, the apparatus comprising: a handle and a cooperating trigger, wherein the trigger includes a first portion connected to a second portion via a connector; and a spring connecting the first portion to the second portion; wherein the first portion of the trigger is configured to engage the plunger of the syringe and receive a plunger reaction force applied by the plunger of the syringe, wherein movement of the second portion of the trigger toward the handle applies a tensile force to the spring in response to the plunger reaction force, and wherein the first portion of the trigger disengages the plunger of the syringe in response to the tensile force applied to the spring being greater than a threshold force.

[0056] In one non-limiting embodiment or aspect, the handle and cooperative trigger operate one of the spring-biased grip drive and the ratchet-driven grip drive.

[0057] In a non-limiting embodiment or aspect, a first portion of the trigger engages the plunger of the syringe via at least one of the piston and the drive grip, and wherein the first portion of the trigger disengages from at least one of the piston and the drive grip in response to a tensile force applied to the spring exceeding a threshold force.

[0058] According to a non-limiting embodiment or aspect, an apparatus is provided for controlling a plunger of a syringe to deliver fluid from inside the syringe, the apparatus comprising: an actuator rod extending from a proximal end to a distal end; a spring extending within the actuator rod, wherein the distal end of the spring is configured to engage the plunger of the syringe; a body having a proximal end, a distal end, and an opening at the proximal end, wherein the opening receives the distal end of the actuator rod, and wherein the actuator rod includes at least one indicator indicating a desired amount of compression of the spring.

[0059] In one non-limiting embodiment or aspect, the outer wall of the actuator rod engages with the inner wall of the body in a ratchet-like manner.

[0060] In one non-limiting embodiment or aspect, the distal end of the actuator rod includes a radially extending pawl, and the inner wall of the body includes a plurality of teeth.

[0061] In one non-limiting embodiment or aspect, at least a portion of the actuator rod and at least a portion of the body are transparent, such that the spring and plunger are visible through the actuator rod and body.

[0062] In one non-limiting embodiment or aspect, the position of at least one indicator indicates the desired amount of compression of the spring relative to the position of at least one of the distal end of the spring and the proximal end of the plunger.

[0063] In one non-limiting embodiment or aspect, the actuator rod includes at least two indicators spaced apart from each other, and wherein at least one of the distal end of the spring and the proximal end of the plunger indicates the desired amount of compression of the spring at a position between the at least two indicators.

[0064] In one non-limiting embodiment or aspect, the distal end of the body is configured to connect to a syringe, wherein the plunger of the syringe extends within the body. Attached Figure Description

[0065] The above and other features and advantages of this disclosure, as well as the ways in which they are implemented, will become more apparent from the following description of examples of this disclosure taken in conjunction with the accompanying drawings, in which:

[0066] Figure 1 This is a perspective view of a flow sensor system according to an example of the present invention, viewed from the distal side.

[0067] Figure 2 This is a perspective view of a flow sensor system according to an example of the present invention, viewed from the distal side.

[0068] Figure 3 This is an exploded perspective view of the flow sensor in a flow sensor system according to an example of the present invention.

[0069] Figure 4 This is a perspective view of a flow sensor in a flow sensor system according to an example of the present invention.

[0070] Figure 5 This is a graph showing the signal level of a flow sensor as a function of time for a flow sensor system based on an example case.

[0071] Figure 6 This is a graph showing the signal level of the flow sensor as a function of time in a flow sensor system according to another example case.

[0072] Figure 7 A retainer for a syringe is shown in a flow sensor system according to an example of the present invention.

[0073] Figure 8 An exemplary construction of a force limiting device for a flow sensor system according to an example of the present invention is shown.

[0074] Figure 9 An exemplary construction of a force limiting device for a flow sensor system according to an example of the present invention is shown.

[0075] Figure 10 An exemplary construction of a force limiting device for a flow sensor system according to an example of the present invention is shown.

[0076] In the various views, corresponding reference numerals denote corresponding parts. The examples set forth herein illustrate exemplary cases of this disclosure and should not be construed as limiting the scope of this disclosure in any way. Detailed Implementation

[0077] The following description is provided to enable those skilled in the art to make and use the examples contemplated for carrying out the invention. However, various modifications, equivalents, variations, and alternatives will still be apparent to those skilled in the art. Any and all such modifications, variations, equivalents, and alternatives should fall within the spirit and scope of the invention.

[0078] For the purposes described below, the terms “upper,” “lower,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” “lateral,” “longitudinal,” and their derivatives will refer to the invention as oriented as shown in the accompanying drawings. However, it should be understood that the invention can take various alternative variations unless the opposite is expressly stated.

[0079] As used in the specification and claims, the singular forms of “a,” “an,” and “the” include plural references unless the context clearly specifies otherwise.

[0080] As used herein, "proximal" refers to the part or direction furthest from or away from the patient (upstream), while "distal" refers to the part or direction closest to or towards the patient (downstream). Furthermore, "medicine" is used herein in an illustrative and non-limiting manner to refer to any substance that can be injected into a patient for any purpose. References to "patient" can refer to any living being, person, or animal. References to "clinician" can refer to any person or thing performing the treatment, such as a nurse, doctor, machine intelligence, caregiver, or even self-treatment.

[0081] As used in this article, the phrase “inherent hydrophobicity” refers to a surface that naturally repels water molecules rather than through a drying process, such as drying with hot air.

[0082] Unless otherwise stated, all ranges or ratios disclosed herein shall be construed as including any and all subranges or subratios contained herein. For example, the specified range or ratio “1 to 10” shall be considered to include any and all subranges between the minimum value of 1 and the maximum value of 10 (inclusive); that is, all subranges or subratios begin with a minimum value of 1 or greater and end with a maximum value of 10 or less, such as, but not limited to, 1 to 6.1, 3.5 to 7.8, and 5.5 to 10.

[0083] Unless otherwise stated, all figures indicating quantities used in the specification and / or claims shall be understood to be modified in all cases by the term “approximately”.

[0084] Flow sensor system

[0085] Figure 1-4 An exemplary configuration of the flow sensor system 200 of this disclosure is shown. (Reference) Figure 1-4 The flow sensor system 200 of this disclosure includes two main components assembled together before use: a flow sensor 210 and a base 220. In one example, the flow sensor 210 may be a disposable flow sensor that can engage with a reusable base 220. The flow sensor system 200 is a smart injection port. The flow sensor system 200 may be attached to an injection site (“Y site” or stopcock) for manual IV injection.

[0086] The flow sensor system 200 of this disclosure can reduce bedside medication errors during bolus delivery. The flow sensor system 200 of this disclosure can also provide recording of bolus delivery and electronic measurement of bolus delivery, which allows for monitoring of bolus delivery and automatic registration of bolus delivery as part of the patient's health record. The flow sensor system 200 of this disclosure can also provide an alert when an impending bolus delivery inconsistent with the patient's medical record is about to occur.

[0087] refer to Figure 1-4 In one example, base 220 is a non-sterile, reusable device that houses a battery, scanner (optical, mechanical, inductive, capacitive, proximity, or RFID), electronics, and a wireless transmitter. In some examples, base 220 is battery-powered and rechargeable. In some examples, each base 220 has a unique serial number embossed on or embedded in its surface, which can be sent to a data system before use. The data system can be a local computer or tablet "computer," a cellular phone, another medical device, or a hospital data system.

[0088] refer to Figure 1-4 In one example, the base 220 is removably connected to the flow sensor 210 and includes at least one deflectable vane 280 defining an opening for receiving at least a portion of the flow sensor 210 prior to use and for securing the flow sensor 210 within a portion of the base 220. In one example, a pair of vanes 280 secure the flow sensor 210 within the base 220. The vanes 280 may be flexible, allowing them to deflect outward to allow the flow sensor 210 to pass over them. In one example, the flow sensor 210 is a pre-sterilized disposable device having an injection port 130 and a distal tube connection, such as a Luer tip 109, which may optionally be covered by a Luer cap 108.

[0089] refer to Figure 3The flow sensor 210 may include a flow tube assembly 10 consisting of a flow tube 100 having an outlet end 101 and an inlet end 102. The outlet end 101 may be configured to be in fluid communication with an outlet tube 110 having an outlet connection 105 including a Luer tip 109, which may optionally be covered by a flow restrictor, as described herein. In a preferred example, the outlet connection 105 is a plastic connector with a Luer tip 109; however, any suitable method of injecting a drug into a patient is considered to be within an aspect of the invention. For example, it may be desirable to use a needle instead of the outlet connection 105 and the tube 110 for direct injection / infusion into a patient. In some examples, components of the flow tube assembly 10, such as the flow tube 100 and the sensor connector, may be pre- or post-treated using plasma etching, abrasive polishing, and / or reaming to reduce the surface roughness of the components of the flow tube assembly 10, which may reduce the formation of microbubbles at the inner wall of the flow tube 100.

[0090] The inlet end 102 can be connected to the container of the medication pen or an infusion container. The inlet end 102 of the flow tube 100 can be configured to be in fluid communication with the injection port 130 and may optionally include a connection such as a threaded Luer lock 131 that can engage with a source of fluid to be injected. A puncturable septum (not shown) may be provided with the injection port 130 for maintaining sterility before use. In one example, the flow tube 100 is made of medical-grade stainless steel, approximately 50 mm long, with an inner diameter of 1.0 mm and an outer diameter of 1.6 mm.

[0091] In one example, the flow sensor system 200 supports injection using any Luer lock syringe or liquid medication container. Additionally, the flow sensor system 200 is designed to work with coded syringes, which have a unique barcode identifier, referred to as "coded," on the Luer collar of the syringe. Preferably, the coded syringe includes a commercially available medication pre-filled with a special barcode storing information about the medication contained within the syringe. The coded syringe is off-the-shelf, passive, and disposable. The coded syringe stores the name and concentration of the medication contained within the syringe. Other features may also be included, such as drug origin, container size, drug manufacturer's origin, drug category, color, etc. When the coded syringe is attached to the injection port 130 of the flow sensor 210, the barcode information is read by a scanner in the base 220 and wirelessly transmitted by the flow sensor system 200 to a data system. Preferably, a two-dimensional barcode is added to the syringe during filling. The flow sensor system 200 also accommodates syringes without coding.

[0092] This disclosure provides a flow sensor subassembly for sensing the flow of a fluid pharmaceutical agent. The flow sensor 210 further includes a first piezoelectric element or upstream transducer 150 and a second piezoelectric element or downstream transducer 151. Figure 3 As shown, the first piezoelectric element 150 may be provided with an inlet connector 180 for connection to the injection port 130. Similarly, the second piezoelectric element 151 may be provided with an outlet connector 190 for connection to the outlet tube 110. The first piezoelectric element 150 and the second piezoelectric element 151 are configured to transmit an ultrasonic signal between them representing the flow of a fluid agent in the flow tube 100. In one example, the first piezoelectric element 150 and the second piezoelectric element 151 are annular and surround the flow tube 100 at each respective mounting point. In some examples, the flow sensor 210 may include a measuring instrument disclosed in U.S. Patent No. 7,255,006 to measure the flow of a fluid agent in the flow tube 100, which is incorporated herein by reference in its entirety.

[0093] The flow sensor 210 includes a first spring contact 750a and a second spring contact 750b. In one example, the spring contacts 750a and 750b are fixed to a base 700, which has circuitry for transmitting electrical signals to and from the spring contacts 750a and 750b to a microprocessor. The first spring contact 750a is electrically connected to a first piezoelectric element 150, and the second spring contact 750b is electrically connected to a second piezoelectric element 151. The first spring contact 750a has a first contact force against the first piezoelectric element 150, and the second spring contact 750b has a second contact force against the second piezoelectric element 151. The first contact force may be equal to the second contact force. The first piezoelectric element 150 and the second piezoelectric element 151 vibrate due to fluid flowing through the flow tube 100 of the flow sensor 210. The vibration of the first piezoelectric element 150 and the second piezoelectric element 151 generates an ultrasonic signal, which can be detected and transmitted electronically to a microprocessor. The microprocessor is configured to correlate the ultrasonic signal with the fluid flow rate through the flow tube 100 and provide a fluid flow rate output to the user.

[0094] Methods for preparing flow sensors

[0095] refer to Figure 1-2 The use of the flow sensor system 200 of this disclosure will now be described. In one example, when a drug is injected, the flow sensor system 200 measures the volume of the drug administered ultrasonically. To improve the transmission of the ultrasonic signal in the flow sensor 210, this disclosure proposes various examples of increasing the fluid pressure in the flow sensor 210.

[0096] During manufacturing, the flow sensor 210 can be calibrated on a calibration bench. For example, a fluid such as water is flowed through the flow sensor 210 to calibrate the ultrasonic signal transmission between the first piezoelectric element 150 and the second piezoelectric element 151. Before packaging the flow sensor 210 for shipment, it can be dried, for example using hot air, to eliminate any residual fluid that may remain in the flow sensor 210. Not wanting to be bound by theory, hot air drying of the fluid path surfaces of the flow sensor 210 helps to make these fluid path surfaces exhibit their inherent hydrophobic characteristics. In this way, when the flow sensor 210 is prepared for use by perfusing it with a perfusing fluid, the internal fluid path surfaces of the flow sensor 210 may not be completely wetted by the perfusing fluid. Because the flow sensor 210 is configured to generate an ultrasonic signal corresponding to the fluid flow rate through contact with the internal flow path of the flow sensor 210, the inherent hydrophobic characteristics of the inner surfaces of the fluid path contribute to reducing the ability of the flow sensor 210 to transmit ultrasonic waves. It has been found that wetting the inner surface of the flow path by the flow sensor 210, for example by increasing or maintaining the pressure within the flow path, improves the ultrasonic signal transmission capability of the flow sensor 210.

[0097] refer to Figure 1 A first method for preparing the flow sensor 210 will now be described. In this example, the flow sensor system 200 is prepared for use by attaching the injection port 130 of the flow sensor system 200 to an applicable fluid source, such as a syringe 900 containing fluid. In some examples, the syringe 900 may contain an infusion fluid, such as saline. Before connecting the syringe 900, the injection port 130 is cleaned by wiping the hub according to normal hospital procedures. The syringe 900 is attached to the injection port 130 by rotating the syringe 900 about its longitudinal axis until it stops, i.e., a firm connection is formed between the syringe 900 and the injection port 130. The syringe 900 has a plunger 920 for delivering infusion fluid from inside the syringe 900 when the plunger 920 is pushed in a distal direction.

[0098] In some examples, the flow deflector 999 may be attached between the injection port 130 and the syringe 900. The flow deflector generates a helical fluid flow in the fluid being delivered from the syringe 900 to the fluid sensor 210, which may increase the amount of microbubbles expelled from the inner wall of the flow path of the fluid sensor 210 and / or increase the absorption of microbubbles in the fluid.

[0099] The outlet connection 105 is covered by a flow restrictor (e.g., cap 910). In some examples, cap 910 is configured to mate with the Luer tip 109 of the outlet connection 105. Cap 910 can be attached to the Luer tip 109 by rotating cap 910 about its longitudinal axis until it stops, i.e., a firm connection is formed between cap 910 and Luer tip 109. Once connected to Luer tip 109, cap 910 prevents fluid from flowing out of outlet connection 105.

[0100] In some examples, negative pressure can be applied to the fluid in an applicable fluid source (e.g., syringe 900) before the fluid is delivered from syringe 900 to the flow path of the flow sensor, thereby degassing the fluid in syringe 900. For example, as Figure 3 The vacuum device 996 shown, such as a manual elastomeric suction cup, can be attached to the injection port 130 of the flow sensor 210 before the injection port 130 of the flow sensor system 200 is connected to an applicable fluid source, such as before fluid is delivered to and / or through the flow sensor 210. The vacuum device 996 can be actuated to apply a negative pressure to the fluid in the syringe 900, which can reduce the partial pressure of the syringe 900 before fluid is delivered from the syringe 900 to the flow sensor 200.

[0101] In some examples, one or more surfactants, such as those disclosed in U.S. Patent Nos. 7,264,885 and 7,560,494 (which are incorporated herein by reference in their entirety), are used to wet the inner surface of the flow path of the flow sensor 210 before the fluid is delivered to and / or passes through the flow sensor 210, which can improve the contact between the fluid and the inner surface of the flow path.

[0102] After syringe 900 is attached to injection port 130 and outlet connection 105 is covered by a flow restrictor, plunger 920 of syringe 900 is pushed distally to deliver fluid from syringe 900. Because cap 910 prevents fluid from flowing out of outlet connection 105, the infusion fluid from syringe 900 creates fluid pressure within flow sensor 210. In some examples, the increased fluid pressure of 5-50 psi within flow sensor 210 can be maintained for a predetermined time period. For example, the predetermined time period can be approximately 1-60 seconds. In other examples, a fluid pressure greater than 50 psi within flow sensor 210 can be maintained for a predetermined time period, which can be greater than 60 seconds.

[0103] In some examples, a constant pressure may be applied to the fluid in flow sensor 210 over a period of time. This constant pressure can be a constant positive or a constant negative pressure. A syringe actuator, such as a lever and dilator, may be attached to syringe 900 to apply a constant force to the plunger 920 of syringe 900, resulting in a constant pressure being applied to the fluid in flow sensor 210, which is capped by cap 910. For example, the syringe actuator may be adjusted to a first position in which it applies a constant force to the plunger of the syringe.

[0104] In another example, bidirectional flow of fluid can be generated in the flow path of flow sensor 210. A first constant pressure can be applied to the fluid in flow sensor 210 during a first time period, and a second constant pressure can be applied to the fluid in flow sensor 210 during a second time period, which is a period of time before or after the first time period. The first constant pressure can be a positive or negative constant pressure, and the second constant pressure is the other of positive or negative constant pressure. A syringe actuation device, such as a lever and dilator, can be attached to syringe 900 and adjusted to a first position in which the syringe actuation device applies a first constant force to the plunger 920 of syringe 900, thereby applying a first constant pressure to the fluid in flow sensor 210 during the first time period. Syringe actuation device 944 can be adjusted to a second position in which syringe actuation device 944 applies a second constant force to the plunger 920 of syringe 900, thereby applying a second constant pressure to the fluid in flow sensor 210 during the second time period. For example, the syringe actuator can be adjusted to press down the plunger 920 of the syringe 900 to deliver fluid to and / or through the flow sensor 210 and apply positive pressure to it. The syringe actuator can hold the syringe in the press-down position for a desired or predetermined period of time. After the first period of time, the syringe actuator can be adjusted to a position that pulls the plunger 920 of the syringe in the opposite direction to the press-down direction to apply negative pressure to the fluid in the flow sensor 210, thereby generating fluid flow from the outlet connection 105 toward the injection port 130. The syringe actuator can hold the syringe in the pull-back position for a desired or predetermined period of time. The syringe actuator can alternate between these positions to generate disordered bidirectional flow of fluid in the flow sensor 210.

[0105] In some examples, a pressure sensor may be connected between the syringe 900 and the injection port 130. The pressure sensor may be configured to measure the pressure in the fluid flow sensor 210 and provide the measured pressure output to the user. The user may adjust the syringe actuator based on the measured pressure to obtain the desired pressure in the flow sensor 210. In another example, the pressure sensor may communicate with a controller 930 or another computing device configured to automatically control the electromechanical syringe actuator based on the measured pressure to achieve the desired pressure in the flow sensor 210.

[0106] As described herein, the syringe actuation device may include clamps, such as lever clamps and dilators, adjustable between positions that hold the plunger 920 in various depressed and / or retracted positions. In another example, the syringe actuation device may include a piston or rod configured to engage the plunger 920 of the syringe 900 such that the piston can depress the plunger 920 distally during advance and retract the plunger 920 proximally during retraction. The piston or rod may be provided by a rotary mechanism (e.g., included herein regarding...). Figure 8 The force limiting device 1010 described includes a rotating mechanism and a latching mechanism (e.g., a latching mechanism included in a spring-biased grip drive or a ratchet-driven grip drive, such as the latching mechanism used in well-known caulking guns and / or as described here). Figure 9 The force limiting device 1030 described herein is a latching mechanism or a linear force mechanism that applies a direct linear force to the piston (e.g., as described here regarding...). Figure 10 The force limiting device described herein is driven by a loading spring or ratchet mechanism. In other words, this refers to... Figure 8 , 9 The force limiting devices 1010, 1030 and 1050 described in 10 each include a syringe actuation device according to a non-limiting embodiment or aspect of the invention.

[0107] Regardless of the type of syringe actuation device used to apply force to the plunger, it is conceivable that the syringe actuation device can be configured to be manually driven and controlled based on input from at least one sensor (e.g., a pressure sensor, flow rate sensor, volume sensor, timer, or any combination thereof), or to be automatically driven and controlled by a computing device (e.g., controller 930). For example, controller 930 or another computing device can compare the current pressure of the fluid in the fluid sensor determined by the pressure sensor with the desired pressure and control the operation of the syringe actuation device to adjust the plunger based on the current pressure to obtain the desired pressure.

[0108] In another example, regarding Figure 7The syringe 900 can be vertically mounted in the syringe holder 990. The syringe holder 990 may include an opening 991 configured to receive the syringe 900. A flange of the syringe 900 may be on a laterally extending surface 992 of the syringe holder 990. The distal end of the syringe 900 extends through the opening 991 and is accessible for connection to the injection port 130 of the fluid sensor 210. When the syringe 900 is held vertically in the syringe holder 990, a load 992 may be applied to the plunger 920 of the syringe 900. The load 992 applies a constant force or pressure to the plunger 920, resulting in a constant pressure on the fluid in the flow sensor 210 during the period of application of the load.

[0109] When the flow sensor 210 is pressurized by fluid from the syringe 900, the flow sensor 210 generates at least one first signal to characterize at least one property of the fluid. In various examples, the at least one property may be fluid flow rate and / or fluid pressure. Manually increasing the fluid pressure within the flow sensor 210 while keeping the outlet connection 105 covered helps eliminate any air between the inner surface of the flow path of the flow sensor 210 and the fluid. In this way, the inner surface of the flow path of the flow sensor 210 is fully wetted to allow for enhanced ultrasonic signal transmission from the flow sensor 210.

[0110] The pressure on the plunger 920 of syringe 900 can then be released, and cap 910 is removed from Luer tip 109. Outlet connection 105 is attached to the inlet of a fluid path (not shown) configured to deliver fluid from an applicable fluid source (e.g., syringe 900) to the patient. In some examples, the fluid path may be a catheter configured for connection to a patient. Before connecting the fluid path to the patient, fluid from syringe 900 is first discharged from the fluid path, for example, during infusion of the fluid path. As fluid is delivered from syringe 900, it flows through flow sensor 210 and out of the fluid path. In some examples, 2-7 ml of fluid may be delivered from syringe 900 through the fluid path. Flow sensor 210 may generate at least one second signal of the same type as the first signal to characterize at least one property of the fluid. For example, the second signal may characterize the pressure and / or flow rate of the fluid passing through flow sensor 210. In some examples, the second signal may be stronger than the first signal (i.e., has a higher intensity) because the inner surface of the flow path of flow sensor 210 is fully wetted. For example, the second signal can be 120%, 160%, or 180% stronger than the first signal, including values ​​in between. The flow sensor 210 has now been pre-filled and is ready for use in fluid delivery processes.

[0111] In some examples, the flow sensor 210 can be shaken or vibrated while the fluid is within the fluid channel, thereby dislodging microbubbles from the inner wall of the flow sensor 210. The dislodged microbubbles can be removed from the flow sensor 210 by flushing the fluid from it. In one example, the flow sensor 210 can be shaken or vibrated manually. In another example, as... Figure 2 As shown, the vibrator 997 can be attached to the flow sensor 210 or directly to the flow tube assembly 10 to agitate or vibrate the flow sensor 210. In another example, the first piezoelectric element or upstream transducer 150 and / or the second piezoelectric element or downstream transducer 151 can be actuated to apply ultrasonic transmission to the flow sensor 210 to expel microbubbles from the inner wall of the flow path of the flow sensor 210. The first piezoelectric element 150 and the second piezoelectric element 151 can be actuated before or without measurement. When fluid is delivered from the syringe 900 after vibrating the flow sensor 210 or actuating the first piezoelectric element 150 and the second piezoelectric element 151, the fluid flows through the flow sensor 210 and out of the fluid path, carrying the expelled microbubbles out of the flow sensor 210.

[0112] In another example, the fluid within the flow sensor 210 can be heated, which can expand the fluid's gas-carrying capacity before flushing the fluid out of the flow sensor 210. For example, a heating element 998, such as a variable resistance heating element, can be attached to the flow tube assembly 10 or another element of the flow sensor 210 and apply heat to the flow tube assembly 10, which includes the fluid in the flow sensor 210, before flushing the fluid out of the flow sensor 210. By increasing the fluid's gas-carrying capacity, more microbubbles can be carried out of the flow sensor 210 when the fluid is flushed out of the flow sensor 210.

[0113] In various examples, the flow sensor 210 may communicate with a controller 930. The controller 930 may be configured to receive information from the flow sensor 210, such as receiving at least one first signal and at least one second signal. The controller 930 may be configured to determine, based on data received from the at least one first signal and at least one second signal, that at least one property of the fluid matches at least one condition specified by at least one rule. For example, the controller 930 may be configured to identify the type of fluid flowing through the flow sensor 210 based on the fluid flow rate through the flow sensor 210 at a given fluid temperature and a given fluid pressure. Without being bound by theory, each fluid, such as a liquid pharmaceutical, possesses unique ultrasonic characteristics when flowing through the flow sensor 210. These ultrasonic characteristics may be functions of fluid pressure, temperature, and the composition of the fluid material.

[0114] In various examples, controller 930 may generate at least one operational modification signal in response to at least one attribute of a characterization matching at least one condition specified by at least one rule. For example, controller 930 may perform a flow algorithm based on data representing characteristics or attributes of the fluid flow received from piezoelectric elements 150, 151. In some examples, syringe 900 may have a tag that, when read by a reading device of flow sensor system 200 in operative communication with controller 930, causes controller 930 to initiate a predetermined operational cycle. In some examples, the tag may be a 2D or 3D barcode, QR code, or any other tag capable of storing information that, when read by reading device of flow sensor system 200, is configured to be interpreted as a set of instructions to be executed by controller 930. For example, when the tag is read by the reading device, controller 930 may initiate an infusion cycle for infusing flow sensor 210. In some examples, the infusion cycle may include generating at least one signal, such as the first and second signals discussed herein.

[0115] The controller 930 may transmit an operation modification signal to at least one device via a transmitter (not shown). In some embodiments, if the fluid type is determined to be different from the desired fluid type, or if the flow rate is determined to be different from the desired flow rate, the controller 930 may send an operation modification signal to a display and / or data processing module, causing the module to display an alarm or warning, or causing the module to send a signal back to system 200, which then stops the fluid flow. The controller 930 may also control a wireless transmitter to send injection data representing the drug type, drug dosage, and / or drug dosage time to the display and / or data processing module. In some embodiments, the controller 930 may automatically send data to the module in response to automatic injection.

[0116] refer to Figure 5 An example is shown as a graph depicting the percentage change in signal strength of five flow sensors 210 over time. Each flow sensor 210 was initially calibrated using a standard calibration routine. The signal readings from each of the flow sensors 210 after calibration are shown at point A on the graph. The flow sensors 210 were then dried with hot air and flushed with perfusion fluid without pressurization. The ultrasonic signal transmission readings were then recorded, shown at point B on the graph. Figure 5 As can be easily observed from the graph, the signal strength of each of the flow sensors 210 decreases after being dried with hot air. To increase the signal level, each flow sensor 210 is covered with a cap 910 and pressurized with a perfusion fluid such as brine for 60 seconds. After the pressurization period, another signal reading is obtained. Figure 5Point C in the diagram shows that after pressurizing the flow sensor 210 with the perfusion fluid, the signal level increases from point B.

[0117] refer to Figure 2 The outlet connection 105 can be connected to an exhaust flow restrictor, such as an exhaust cap 940, instead of as described herein. Figure 1 The described cap 910 covers the outlet connection 105. The vent cap 940 includes an orifice or outlet 942 that provides a fluid flow path from the outlet connection 105 through the vent cap 940 to the atmosphere. In some examples, the vent cap 940 may be a needle with a sufficiently small inner diameter to generate back pressure in the flow sensor 210 when fluid is delivered from the syringe 900. For example, the vent cap 940 may be a needle with an outlet having an inner diameter of approximately 30G (0.16 mm inner diameter (ID)). In other examples, the vent cap 940 may have an inner diameter of 0.1-0.2 mm. In yet another example, the vent cap 940 may include a smaller orifice or outlet 942, such as an outlet less than 30G (0.16 mm ID), for example, an outlet of approximately 34G (0.0826 mm ID) or less. The perfusion fluid delivered from the syringe 900 creates back pressure within the flow sensor 210. In some examples, the increased fluid pressure of 5-50 psi or greater within the flow sensor 210 can be maintained for a predetermined period of time. For example, the predetermined period of time could be approximately 1-60 seconds.

[0118] In another example, varying pressure can be applied to the fluid in flow sensor 210. The vent cap 940 can be configured to change the inner diameter of its orifice or outlet 942 according to the fluid pressure within flow sensor 210. For example, vent cap 940 may include an elastomeric material having elasticity that allows outlet 942 to deform in response to applied pressure. When the pressure within flow sensor 210 is sufficient to overcome the elasticity of outlet 942 of vent cap 940, for example, in response to pressure buildup within flow sensor 210 due to infusion fluid delivery, outlet 942 of vent cap 940 deforms in response to the increased pressure to increase its inner diameter. The increased inner diameter of outlet 942 of vent cap 940 results in a higher fluid flow rate from vent cap 940, which can reduce back pressure in flow sensor 210. When the back pressure in flow sensor 210 is no longer sufficient to overcome the elasticity of outlet 942 of vent cap 940, the inner diameter of outlet 942 of vent cap 940 returns to its original or resting diameter. If the infusion fluid continues to be delivered, the back pressure in the flow sensor 210 can begin to increase again until the pressure is once again sufficient to overcome the elasticity of the outlet 942. Therefore, the inner diameter of the outlet 942 of the vent cap 940 can vary over time to generate a turbulent fluid flow within the flow sensor 210 during infusion, which improves the wetting of the inner surface of the flow path of the flow sensor 210 to allow for increased ultrasonic signal transmission of the flow sensor 210.

[0119] In some examples, the flow rate of fluid delivered from an applicable fluid source through a fluid inlet to a fluid channel can be varied. For example, delivering fluid from syringe 900 to fluid sensor 210 may include a flow path that delivers boluses of fluid to fluid sensor 210. Boluses may be delivered to the fluid channel periodically at standard or variable time intervals. These boluses may differ from each other due to at least one of the following factors: the volume of the bolus, the pressure applied to the fluid within the bolus in flow sensor 210, the duration of the pressure applied to the fluid within the bolus in flow sensor 210, or any combination thereof. In one embodiment, the electromechanical device may be configured to automatically deliver boluses to the fluid sensor at periodic time intervals.

[0120] In some examples, the force limiting device is 1010, 1030, or 1050, for example, as described here respectively. Figure 8 , 9As described in 10, it can be attached to syringe 900. Force limiting devices 1010, 1030, or 1050 may include syringe actuation devices as described above. Force limiting devices 1010 or 1030 may prevent pressure exceeding a threshold pressure from being applied to the fluid in the fluid passage of fluid sensor 210. For example, force limiting devices 1010 or 1030 may prevent movement of the plunger 920 of syringe 900 (or the syringe actuation device driving the plunger 920) in response to pressure exceeding a threshold pressure being applied to the fluid in the fluid passage of fluid sensor 210. In another example, force limiting device 1050 may include at least one pressure indicator indicating the current pressure of the fluid applied to the fluid passage.

[0121] When the flow sensor 210 is pressurized by fluid from the syringe 900, the flow sensor 210 generates at least one first signal to characterize at least one property of the fluid. In various examples, the at least one property may be fluid flow rate and / or fluid pressure. Manually increasing the fluid pressure within the flow sensor 210 while keeping the outlet connection 105 covered helps eliminate any air between the inner surface of the flow path of the flow sensor 210 and the fluid. In this way, the inner surface of the flow path of the flow sensor 210 is fully wetted to allow for increased ultrasonic signal transmission from the flow sensor 210.

[0122] Next, the pressure on the plunger 920 of syringe 900 can be released, and the vent cap 940 can be removed from the Luer tip 109. An outlet connection 105 is attached to the inlet of a fluid path (not shown) configured to deliver fluid from an applicable fluid source (e.g., syringe 900) to the patient. In some examples, the fluid path may be a catheter configured for connection to a patient. Before connecting the fluid path to the patient, fluid from syringe 900 is first discharged from the fluid path, for example, during infusion of the fluid path. As fluid is delivered from syringe 900, it flows through flow sensor 210 and out of the fluid path. In some examples, 2-7 ml of fluid may be delivered from syringe 900 through the fluid path. Flow sensor 210 may generate at least one second signal of the same type as the first signal to characterize at least one property of the fluid. For example, the second signal may characterize the pressure and / or flow rate of the fluid passing through flow sensor 210. In some examples, the second signal may be stronger than the first signal (i.e., has a higher intensity) because the inner surface of the flow path of flow sensor 210 is fully wetted. For example, the second signal can be 120%, 160%, or 180% stronger than the first signal, including values ​​in between. The flow sensor 210 has now been pre-filled and is ready for use in fluid transport processes.

[0123] Reference Figure 6Another example shows a graph depicting the signal levels of three flow sensors 210 (labeled 1, 2, and 3) over time. Each flow sensor 210 is provided with a vent cap 940 having a 30G needle. Signal counts (point D) are recorded during the delivery of 2 ml of fluid from a syringe 900. The vent cap 940 is then removed from each flow sensor 210, and signal counts representing pressure drop are recorded (point E). Figure 6 In the graph, it can be easily observed that the signal strength of each of the flow sensors 210 decreases after the exhaust cap 940 is removed from the flow sensor 210. After removing the exhaust cap 940, 7 ml of fluid is delivered from the syringe 900 through each flow sensor 210. In this step, the signal count increases and stabilizes at a high value (point F). The fourth flow sensor 210 (in Figure 6 The signal level marked 4 is shown as a comparison example, where the fourth flow sensor 210 was filled without using the exhaust cap 940. The signal strength of the fourth flow sensor 210 is significantly lower than that of the flow sensor 210 (referenced here). Figure 2 The method described is to prepare using an exhaust cap 940.

[0124] Force limiting device for reading flow sensors

[0125] Figure 8-10 An exemplary construction of the force limiting device of the flow sensor system of this disclosure is shown. (Refer to...) Figure 8 A force limiting device 1010 is used to control the plunger 920 of the syringe 900 to deliver fluid from the interior of the syringe 900. The force limiting device 1010 includes an actuator rod 1012 extending from a proximal end to a distal end. A plunger engagement 1014 engages with the distal end of the actuator rod 1012 and is configured to engage the plunger 920 of the syringe 900. For example, the outer wall of the distal end of the plunger engagement 1014 may engage the plunger 920. A clutch 1020 engages the distal end of the actuator rod 1012 to the plunger engagement 1014. A spring 1018 extends within the actuator rod 1012.

[0126] The force limiting device 1010 also includes a body 1016 having a proximal end, a distal end, and an opening at the proximal end. The opening receives a plunger engagement 1014. The plunger engagement 1014 is threadedly engaged with the body 1016. For example, the inner wall of the body 1016 may include a male or female thread, and the outer wall of the plunger engagement 1014 may include the other of a male or female thread. In one example, the thread is a multi-start high-lead thread. The distal end of the body 1016 is configured to connect to a syringe 900, for example, to a flange on a syringe body, and when the syringe 900 is connected to the body 1016, the plunger 920 of the syringe 900 extends within the body 1016. When the body 1016 is connected to the syringe 900, the body 1016 prevents axial movement of the syringe 900 relative to the body 1016 while allowing axial movement of the plunger 920 within the body 1016. In some examples, the body 1016 may be formed of a first half and a second half, which may be placed together around the syringe and connected by a snap-fit ​​connection to connect the body 1016 to the syringe 900.

[0127] A spring 1018 extends within an actuator rod 1012 and enters a plunger engagement 1014 through an opening in the proximal end of the plunger engagement 1014. The spring 1018 engages the inner wall of the distal end of the plunger engagement 1014. The actuator rod 1012 extends into the plunger engagement 1014. A portion of the actuator rod 1012 extending within the plunger engagement 1014 includes a radially extending flange 1013. A clutch 1020 connects the proximal face of the radially extending flange 1013 to the inner wall at the proximal end of the plunger engagement 1014.

[0128] Clutch 1020 is configured to disengage the distal end of actuator rod 1012 from plunger engagement 1014 in response to compression of spring 1018. For example, the spring constant of spring 1018 determines the force required to disengage clutch 1020. Spring 1018 compresses in response to a plunger reaction force applied to plunger engagement 1014 by plunger 920 of the syringe. Compression of spring 1018 allows actuator rod 1012 to move distally relative to plunger engagement 1014, causing the proximal surface of radially extending flange 1013 to detach from the inner wall at the proximal end of plunger engagement 1014 and separate from the inner wall in the distal direction, thereby disengaging clutch 1020. For example, the plunger reaction force applied to plunger engagement 1014 by plunger 920 is transmitted to spring 1018, causing spring 1018 to compress.

[0129] The plunger engagement 1014 is configured to prevent a force exceeding a threshold force from being applied to the plunger 920 of the syringe 900. For example, the plunger engagement 1014 may partially prevent movement of the plunger 920 of the syringe 900 in response to a plunger reaction force applied by the plunger 920 of the syringe to the outer wall of the distal end of the plunger engagement 1014. When the clutch 1020 is engaged, the rotational force applied to the actuator rod 1012 is transmitted to the plunger engagement 1014, which rotates in a threaded engagement with the body 1016 to move the plunger engagement 1014 axially relative to the body 1016. As the clutch 1020 disengages, the rotational force applied to the actuator rod 1012 is not transmitted to the plunger engagement 1014, thereby preventing further axial movement of the plunger engagement 1014 relative to the body 1016 and preventing a force exceeding the threshold force set by the spring 1018 from being applied to the plunger 920 of the syringe 900.

[0130] refer to Figure 9 A force limiting device 1030 is used to control the plunger 920 of the syringe 900 to deliver fluid from the interior of the syringe 900. The force limiting device 1030 includes a handle 1032 and a cooperating trigger 1034, which can be connected via a first connector 1035. The trigger 1034 includes a first portion 1034a connected to a second portion 1034b via a second connector 1036. A spring 1038 further connects the first portion 1034a to the second portion 1034b.

[0131] The handle 1032 and the cooperating trigger 1034 can be configured to operate a latching mechanism, such as those included in spring-biased grip drives or ratchet-driven grip drives, as is well known in latching mechanisms used in caulking guns. A first portion 1034a of the trigger 1034 is configured to transmit a driving force to the plunger 920 of the syringe 900. The first portion 1034a can be configured to directly engage the plunger 920, or engage the plunger 920 via at least one of the drive grip or plate 1040 and piston 1042, details and operation of which are well known to those skilled in the art and are therefore omitted for brevity. Although not shown in the figures for clarity, the force limiting device 1030 may include a body extending from the handle 1032 configured to keep the syringe 900 stationary relative to the handle 1032 during operation of the plunger 920 by the force limiting device 1030. Such constructions for holding fluid containers during fluid transport are well known to those skilled in the art, and examples of them can be found in U.S. Patent Nos. 4,299,336 and 6,155,463, which are incorporated herein by reference in their entirety.

[0132] Movement of trigger 1034 toward handle 1032 can apply a tensile force to spring 1038. For example, when the first portion 1034a engages and applies a driving force to drive plate 1040, plunger 920 applies a plunger reaction force to the first portion 1034a of trigger 1034 in the opposite direction to the driving force. This can partially or completely prevent movement of the first portion 1034a and the second portion 1034a, thereby transmitting the movement of the second portion 1034a as a tensile force to spring 1018. The first portion 1034a of trigger 1034 disengages from plunger 920 or drive plate 1040 in response to a tensile force applied to spring 1038 exceeding a threshold force. For example, the spring constant of spring 1038 can determine the force required to disengage the first portion 1034a from plunger 920 or drive plate 1040, such that the first portion 1034a cannot provide a driving force in the opposite direction to the plunger reaction force.

[0133] In response to the plunger reaction force applied by the plunger 920 to the first portion 1034a exceeding the threshold force, the tensile force applied to the spring 1038 due to the movement of the trigger 1034 toward the handle 1032 exceeds the spring constant of the spring 1018, thereby stretching the spring and increasing the distance between the first portion 1034a and the second portion 1034b until the first portion 1038 is forced to disengage from the plunger 920 or the drive plate 1040. For example, as Figure 9 As shown, the first part 1034a can be disengaged and its position reversed relative to the connector 1036, thereby preventing any further force from being applied to the plunger 920 by the force limiting device 1030.

[0134] Reference Figure 8 A force limiting device 1050 is used to control the plunger 920 of the syringe 900 to deliver fluid from the interior of the syringe 900. The force limiting device 1050 includes an actuator rod 1052 extending from a proximal end to a distal end. A spring 1054 extends within the actuator rod 1052. The distal end of the spring 1054 is configured to engage the plunger 920 of the syringe 900.

[0135] The force limiting device 1050 also includes a body 1056 having a proximal end, a distal end, and an opening at the proximal end, wherein the opening receives the distal end of an actuator rod 1052, and wherein the actuator rod 1052 includes at least one indicator 1058 indicating a desired amount of compression of the spring 1054. The distal end of the body 1056 is configured to connect to a syringe 900, the plunger 920 of which can extend within the body 1056.

[0136] In some examples, the outer wall of the actuator rod 1052 may engage with the inner wall of the body 1056 in a ratchet-like manner. For example, the distal end of the actuator rod 1052 may include a radially extending pawl, and the inner wall of the body 1056 may include a plurality of teeth.

[0137] At least a portion of the actuator rod 1052 and at least a portion of the body 1056 may be transparent, such that the spring 1054 and the plunger 920 are visible through the actuator rod 1052 and the body 1056. The position of at least one indicator 1058 relative to at least one of the distal end of the spring 1058 and the proximal end of the plunger 920 may indicate the desired amount of compression of the spring 1058, for example, the amount of compression formed during the infusion operation described herein.

[0138] In some examples, actuator rod 1052 may include at least two indicators spaced apart from each other. The position of at least one of the distal end of spring 1058 and the proximal end of plunger 920 between the at least two indicators may indicate the desired amount of compression of spring 1058.

[0139] Methods using flow sensor systems

[0140] To use the infused flow sensor system 200, the user connects the flow sensor 210 to the base 220 by first engaging the flow sensor 210 (tube side) and the front of the base 220, and then fastening them together. Preferably, an audible click is heard to indicate a secure connection between the flow sensor 210 and the base 220. In one example, connecting the flow sensor 210 to the base 220 automatically powers on the flow sensor system 200. In another example, the connection from the flow sensor 210 to the base 220 is verified by a flashing light on the base 220. In other examples, other indicators may be used.

[0141] The flow sensor system 200 is now ready to deliver intravenous medication. In one example, in the event of a malfunction of the flow sensor system 200 (excluding the IV fluid path), the flow sensor system 200 still allows standard medication or fluid to be delivered through the port.

[0142] Next, we will discuss the use of the flow sensor system 200 for injection. First, following standard hospital procedure, the injection port 130 is cleaned by wiping the hub. Next, the syringe 900 is attached to the injection port 130 of the flow sensor 210 by fully rotating the syringe 900 until it stops, i.e., establishing a secure connection between the syringe 800 and the injection port 130. Ideally, before connecting to the injection port 130, the caregiver checks the name and concentration of each medication on the syringe 900 to ensure the correct medication is administered.

[0143] The flow sensor 210 can be discarded after it has been used to sense the flow of at least one fluid agent. The flow sensor base 220 can be used with multiple different flow sensors 210.

[0144] While this disclosure is described as having an exemplary design, it can be further modified within the spirit and scope of this disclosure. Therefore, this application is intended to cover any variations, uses, or modifications of this disclosure using its general principles. Furthermore, this application is intended to cover deviations from this disclosure that are in the known or customary practice in the field to which this disclosure pertains and fall within the limitations of the appended claims.

Claims

1. An apparatus for controlling a plunger of a syringe to deliver fluid from inside the syringe, comprising: an actuator rod extending from a proximal end to a distal end; a spring extending within the actuator rod; a plunger engagement portion engaged with the distal end of the actuator rod and configured to engage the plunger of the syringe; and a body having a proximal end, a distal end, and an opening at the proximal end, wherein the opening receives the plunger engagement portion, and wherein the plunger engagement portion is threadably engaged with the body, wherein the spring extends within the actuator rod and enters the plunger engagement portion via an opening in a proximal end of the plunger engagement portion, and wherein the spring engages an inner wall at a distal end of the plunger engagement portion. The plunger engagement portion resists movement of the plunger of the syringe in response to a plunger reaction force applied by the plunger of the syringe.

2. The apparatus of claim 1, wherein, 3. The apparatus of claim 1, further comprising a clutch that engages the distal end of the actuator rod to the plunger engagement portion. An outer wall at the distal end of the plunger engagement portion engages the plunger.

4. The apparatus of claim 1, wherein, The actuator rod extends into the plunger engagement portion, wherein a portion of the actuator rod extending within the plunger engagement portion includes a radially extending flange, and wherein the clutch connects a proximal face of the flange to the inner wall at the proximal end of the plunger engagement portion.

5. The apparatus of claim 3, wherein, The clutch disengages the distal end of the actuator rod from the plunger engagement portion in response to compression of the spring.

6. The apparatus of claim 5, wherein, The spring compresses in response to a plunger reaction force applied to the plunger engagement portion by the plunger of the syringe.

7. The apparatus of claim 6, wherein, 8. The apparatus of claim 1, wherein the distal end of the body is configured to connect to the syringe, and wherein a plunger of the syringe extends within the body. ​

Images