Device with needle for administering fluid in the target location
Patent Information
- Application Number
- BR112021022589
- Authority / Receiving Office
- BR · BR
- Patent Type
- Patents
- Current Assignee / Owner
- Publication Date
- 2026-08-11
Smart Images
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Abstract
Description
1 / 40 Needle-based device for administering fluid to the target location. RELATED ORDERS
[0001] This application claims the benefit of priority of the Application No. US 16 / 414,499, filed May 16, 2019, the contents of which application(s) are incorporated by reference herein. FIELD OF TECHNIQUE
[0002] The present invention relates generally to methods and apparatus for use in locating a target region situated in the body of an individual, for example, for the delivery of drugs. BACKGROUND
[0003] Locating a target region in a body, for example, an anatomical cavity in a patient's body, is important, among other things, for anesthetics, or biopsy or aspiration of material from the cavity.
[0004] For example, a regional anesthesia block of the epidural tissue space is considered to produce effective transient anesthesia of the lower extremities of the body. It can be used effectively for a vast number of invasive body procedures, including, but not limited to, childbirth, hip replacement, and a variety of other surgical procedures where anesthesia below the waist is required. It can also be used effectively for the treatment of chronic and acute pain, including, for example, back pain, vertebral diseases, and compression of the accessory nerves of the spinal column. To obtain effective regional anesthesia and block nerve transmission to the central nervous system, an adequate volume of a local anesthetic solution must be deposited in the vicinity of the spinal cord in a Petition 870260039818, dated 04 / 29 / 2026, page 5 / 99 2 / 40 a specific level of the spinal column within the anatomical location known as the epidural space.
[0005] The epidural space is the part of the vertebral canal not occupied by the dura mater and its contents. It is situated between the dura mater and the periosteum that lines the interior of the vertebral canal. It extends from the foramen magnum to the sacral hiatus. The anterior and posterior nerve roots in the dural membrane pass through the epidural space to unite in the intervertebral bodies and intervertebral discs. Laterally, the epidural space is surrounded by the periosteum of the vertebral pedicles and the intervertebral foramen. Posteriorly, the bordering structures are the periosteum of the anterior surface of the laminae, the articular processes and their connecting ligaments, the periosteum of the spinal roots, and the interlaminar spaces filled by the ligamentum flavum. The space contains venous plexuses and fatty tissue that is continuous with the fat in the paravertebral space.
[0006] The epidural fluid-filled space (posterior epidural space) is a limited anatomical area with an irregular shape measuring several square millimeters in relation to the cross-section of the vertebrae and spinal column. The fluid-filled space is very narrow and is closely associated with the dura mater of the spinal column with the ligamentum flavum closely adjacent. The fluid-filled space must therefore be clearly identified when the bevel or tip of the needle exits the ligamentum flavum, as the dura mater will be punctured if the needle continues to penetrate. The standard technique for locating the epidural fluid-filled space employs the loss-of-resistance (LOR) technique. This technique uses a low-friction syringe made of plastic or glass connected to a Touhy epidural needle (16 to 18 gauge). Additionally, other pump-driven systems have been developed to identify the epidural space, using Petition 870260039818, dated 04 / 29 / 2026, page 6 / 99 3 / 40 pressure monitoring with visual and acoustic representation of fluid pressure within the system or at the needle tip.
[0007] When using a LOR technique, the syringe needle is advanced until the clinician's subjective sensation of resistance results in a distinct backpressure on the plunger. The clinician must subjectively differentiate the backpressure or resistance encountered to identify the location of the anatomical structure of the ligamentum flavum. The space filled with epidural fluid is inserted through the needle tip after passing through the ligamentum flavum, thus identifying a true LOR.
[0008] During needle advancement into tissues, it is common for the operator to identify a pressure drop or a false-LOR. A false-LOR can be attributed to the needle tip entering a low-density tissue structure, such as a vacuole (adipose tissue), or an anatomical structure with high tissue compliance, such as interspinous tissues. Needle repositioning (forward and backward) often occurs when the needle makes contact with bony vertebrae while attempting to find the correct trajectory to the epidural space. Any backward movement (retraction) of the needle along a path during repositioning creates a drop in fluid pressure, which can result in a false-LOR that further complicates the detection of a true-LOR.
[0009] Several conditions can create a false LOR. False LORs can lead to many problems. For example, excess fluid can be injected indiscriminately when attempting to determine the location of the epidural space. The additional fluid released into these tissues can further complicate the identification of the epidural space. Additionally, if the physician has difficulty distinguishing between a false-LOR and a true-LOR, the Touhy needle can be moved. Petition 870260039818, dated 04 / 29 / 2026, page 7 / 99 4 / 40 beyond the contour of the epidural space and inadvertently advanced into and through the dura mater of the spinal cord, producing what is termed a wet puncture, which can have dangerous long-term consequences for the patient.
[0010] Therefore, it is desirable to provide a system that supplements or overcomes the loss of resistance information to accurately guide a needle during insertion. SUMMARY OF THE INVENTION
[0011] The present invention provides a method and apparatus or device that enables medical professionals to more easily identify anatomical target regions, such as the epidural space.
[0012] The present invention provides a novel system for guiding a needle to an anatomical target region. The system provides software logic and an apparatus that can simplify the discrimination between a false-LOR and true-LOR when performing operations such as epidural space detection, thereby improving the reliability and safety of such injections.
[0013] According to a first aspect, the present invention provides a needle-based apparatus for administering fluid into an anatomical space of a mammalian individual. The apparatus includes a fluid reservoir for storing fluid to be delivered to the needle, an ejection element displaceable relative to the fluid reservoir for expelling fluid from the reservoir, and a drive element configured to engage the ejection element to control the displacement of the ejection element. A controller is provided to control the drive element to control the flow of fluid from the reservoir to the needle. Additionally, the apparatus includes a sensor to detect a characteristic indicative of fluid pressure in the needle. The sensor is configured to detect Petition 870260039818, dated 04 / 29 / 2026, page 8 / 99 5 / 40 continuously monitors the characteristic as the needle-equipped device is inserted into the individual. A flexible conduit is in fluid communication with the fluid reservoir and the sensor; and the conduit is substantially radially rigid. The controller periodically interrupts the movement of the drive element and processes data from the sensor to detect one or more characteristics indicative of a pulsatile waveform. Additionally, the conduit, reservoir, ejection element, and drive element are configured so that the fluid volume between the needle and the fluid reservoir is substantially constant, so that the sensor is able to accurately detect the pulsatile waveform that passes through the residual fluid in the needle when the movement of the drive element has been interrupted. Optionally, the fluid reservoir can be a syringe cylinder.Furthermore, the ejection element can be moved in a sliding manner within the fluid reservoir.
[0014] According to another aspect, the invention relates to a controller configured to analyze sensor data to detect one or more characteristics indicative of a loss of resistance.
[0015] According to yet another aspect, the invention provides a system in which, in response to the detection of one or more characteristics, the controller interrupts the movement of the drive element and processes the sensor data to detect one or more characteristics indicative of a pulsed waveform. Optionally, the controller can be configured to provide a verification signal that the needle is properly placed adjacent to a target tissue after receiving a signal indicating a loss of resistance and after receiving a signal indicating the presence of a pulsed waveform in the needle. Petition 870260039818, dated 04 / 29 / 2026, page 9 / 99 6 / 40
[0016] Yet another aspect of the invention provides a display that includes a first output section configured to display the fluid pressure at the needle as a function of time in a manner consistent with a resistance loss orientation procedure. Furthermore, the controller can be configured to process data from the sensor to isolate indicative data from a pulsed waveform. The display may comprise a second output section configured to display the indicative data from a pulsed waveform, while the first section displays the fluid pressure data as a function of time in the first section.
[0017] The present invention also provides a method for locating a target region situated on the body of an individual using a needle communicating with a fluid reservoir. The method includes the steps of providing a reservoir containing injection fluid, tubing communicating at one end with the reservoir and connected at the other end to the needle to be inserted into the individual's body, and the step of acquiring data on a resistance measurement of the injection fluid as the fluid is pumped into the individual's body through the needle. The method further includes the steps of advancing the needle into the patient. Additionally, the method may include the step of pumping injection fluid into the patient during the needle advancement step. Furthermore, the method may include the step of intermittently interrupting the needle advancement step and the injection fluid pumping step.The method may also include the step of acquiring data regarding fluid pressure in the needle during the intermittent interruption step and processing the data acquired during the intermittent interruption step to detect one or more characteristics indicative of a pulsatile waveform in the needle. Petition 870260039818, dated 04 / 29 / 2026, page 10 / 99 7 / 40
[0018] Optionally, another aspect of the invention comprises restarting the needle advance and injection fluid pumping steps after the intermittent interruption step.
[0019] Additionally, another aspect includes the data processing step regarding fluid pressure at the needle, removing noise related to fluid flow when the fluid is pumped into the body. The pump may be operable to pump fluid during the fluid injection pumping step, and the noise removal step may include pump operation steps before inserting the needle into the individual's body and acquiring noise-related data during the pump operation step. Furthermore, the noise removal step may involve modifying the fluid pressure data in response to the acquired noise-related data.
[0020] According to another aspect, the invention provides a method that includes the step of selectively varying an amplitude range for processed fluid pressure data in order to attempt to identify a pulsatile waveform.
[0021] Another aspect of the invention provides a method for inserting a needle into a patient. The method includes the step of performing a loss-of-resistance procedure to attempt to place a needle at a target location in the patient, wherein the step of performing a loss-of-resistance procedure comprises the steps of: inserting the needle into the patient, injecting fluid through the needle during the insertion step, detecting fluid pressure in the needle during the injection step, and guiding the needle in response to the fluid pressure detection step. The presence of a pulsatile waveform in the needle is detected, which may include the steps of detecting fluid pressure in the needle when the needle is substantially stationary in the patient and injecting a bolus of Petition 870260039818, dated 04 / 29 / 2026, page 11 / 99 8 / 40 medication in the patient after the step of performing a loss of resistance procedure indicates that the needle is in the target location and after the step of detecting the presence of a pulsatile wave indicates the presence of a pulsatile waveform.
[0022] Optionally, the method may include the step of intermittently switching between the step of performing a resistance loss procedure and the step of detecting the presence of a pulsed waveform. Additionally, the fluid injection step comprises electronically controlling a drive unit to dispense fluid from a fluid reservoir. Furthermore, the injection step comprises electronically controlling the drive unit in response to the fluid pressure detection step.
[0023] Yet another aspect of the present invention is an apparatus for locating a target region which is an anatomical space situated in an individual's body. The apparatus includes a reservoir for receiving an injection fluid, a needle communicating with the reservoir, and an operable sensor to detect a characteristic indicative of fluid pressure in the needle. A pump is configured to pump fluid to the needle from the reservoir, and an operable controller processes sensor data regarding fluid pressure in the needle. The controller is configured to process data from the sensor when the needle is stationary to identify a pulsatile waveform. Additionally, the controller is configured to provide signals to guide needle insertion, wherein the signals are provided in response to data from the sensor.Furthermore, the system comprises an input mechanism to selectively vary an amplitude range for the processed data in order to identify a pulsed waveform.
[0024] These and other modalities are described in more Petition 870260039818, dated 04 / 29 / 2026, page 12 / 99 9 / 40 details hereinafter in this document. The various innovative features that characterize the invention are pointed out in particular in the appended claims and which form part of this disclosure. For a better understanding of the invention, its operational advantages and specific objectives achieved by its uses, reference is made to the appended drawings and the descriptive material in which a preferred embodiment of the invention is illustrated. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 is a top view of a computer-controlled drug delivery system;
[0026] Figure 2 is a top view of the drug delivery system illustrated in Figure 1 with a disposable injection set connected to the system;
[0027] Figure 3 is a schematic representation of the computer-controlled drug delivery system illustrated in Figure 1;
[0028] Figure 4A is a view of a display screen of the system illustrated in Figure 1, which shows fluid pressure measurements detected by the system;
[0029] Figure 4B is a view of a display screen of the Figure 4A illustrated with a different amplitude range;
[0030] Figure 4C is a view of a display screen of the Figure 4B illustrated with a different amplitude band;
[0031] Figure 4D is a view of a display screen of the Figure 4C illustrated with a different amplitude range;
[0032] Figure 5A is a view of the system display screen illustrated in Figure 1; and
[0033] Figure 5B is a view of the display screen shown in Figure 5A illustrates a band with a different amplitude. DETAILED DESCRIPTION OF PREFERRED OPTIONS Petition 870260039818, dated 04 / 29 / 2026, page 13 / 99 10 / 40
[0034] Although the methods and apparatus described herein are by way of example for various embodiments and illustrative drawings, persons skilled in the art will recognize that the inventive methods and apparatus for classifying items using a dynamically reconfigurable classification matrix are not limited to the embodiments or drawings described. It should be understood that the drawings and the detailed description thereof are not intended to limit the embodiments to the particular form disclosed. Rather, the intention is to cover all modifications, equivalents, and alternatives within the spirit and scope of the methods and apparatus for detecting a pulsed waveform and using the detection of a pulsed waveform to guide or verify the placement of a needle or other conduit. Any heading used herein is for organizational purposes only and is not intended to limit the scope of the description or the claims.As used in this document, the word may is used in a permissive sense (that is, meaning to have the potential to), rather than in the obligatory sense (that is, meaning must). Similarly, the words include, which includes, and include mean including, but without limitation.
[0035] With reference now to the drawings, in general and to the Figures Specifically, a drug infusion system is generally designated 10. The system 10 includes an injection assembly 20 and a computer-controlled drug delivery instrument 50, referred to as the drive unit. The injection assembly 20 includes an insertion needle 24 configured for insertion into a mammalian subject. The injection assembly 20 is connected to the drive unit 50, which controls the fluid flow to the injection assembly during use. The system 10 also includes one or more output mechanisms that provide data to the medical professional during a procedure to assist in proper placement. Petition 870260039818, dated 04 / 29 / 2026, page 14 / 99 11 / 40 of the needle in the individual.
[0036] System 10 allows a medical professional to precisely identify a target tissue. In particular, the system can be adapted for use in identifying the injection site for a drug, while limiting the placement of drugs in non-targeted tissues. This can be performed for both diagnostic and therapeutic procedures. System 10 utilizes the pressure of a fluid as it flows from a needle or catheter after the needle / catheter has been placed within the tissue, in order to identify the accuracy of the placement and monitor the placement during an injection or aspiration. System 10 can utilize a continuous flow of fluid at what is considered a slow flow rate. In this case, a slow flow rate is defined as a constant flow rate between 0.01 ml / sec and 0.20 ml / sec.
[0037] Continuous fluid flow maintains a constant fluid column that can allow for a virtually instantaneous reaction time to pressure changes within the tissues to be detected. Generally, a flow rate between 0.005 cm3 / sec and 0.20 cm3 / sec will be appropriate for the individual and the intervention, although 0.01 to 0.15 cm3 / sec may be preferable.
[0038] As discussed further below, the system is adapted to identify the proper placement of a needle according to several criteria. For example, the system can identify a space such as the epidural space using a loss-of-resistance technique. Additionally, the system 10 can be adapted to identify the target tissue based on the identification of a pulsed waveform. In this way, the system can identify the proper placement of the needle in relation to a target tissue using a first search criterion and the system can verify or validate the proper placement of the needle in relation to the target tissue using a Petition 870260039818, dated 04 / 29 / 2026, page 15 / 99 12 / 40 according to research criteria, such as the identification of a pulsatile waveform.
[0039] The flow rate range provided by the drive unit 50 during needle placement is capable of providing a response to a change in pressure that can be detected quickly. Additionally, the system 10 includes one or more output mechanisms to provide audible and / or visual feedback of the fluid pressure detected at the insertion needle. The operator uses the feedback as guidance during needle placement. As shown in Figure 2, the first output mechanism may be a video display screen, such as an LCD display, to display data to assist the operator. Furthermore, a second output mechanism may also be provided. For example, the second output mechanism may be a loudspeaker 84 to provide an output signal. INJECTION ASSEMBLY
[0040] With reference to Figure 2, the system 10 includes an injection assembly 20 that cooperates with a drive unit 50 during a drug infusion procedure. The injection assembly includes a syringe 18, a handpiece or needle 24, and a fluid line 22 that connects the syringe to the handpiece.
[0041] Several elements of the injection set may be disposable, such as syringe 18, fluid line 22, and / or needle 24. Alternatively, the elements may be reusable. Consequently, several elements of the injection set may be removablely connectable. For example, fluid line 22 may include a fluid connector at each end. Fluid-tight connectors may be any of a variety of connectors. One such connector is a Luer connector. At the first end, the fluid connector connects in a way Petition 870260039818, dated 04 / 29 / 2026, page 16 / 99 13 / 40 sealed with the syringe and at the second end the fluid line connects in a sealed manner with the needle 24. Alternatively, the fluid line 22 can be fixedly connected to the rear end of the needle 24. In either embodiment, the needle 24 and the syringe are in fluid communication to provide a flow of fluid from the syringe to the needle.
[0042] Syringe 18 can be any of a variety of hypodermic syringes, and the size can vary depending on the intended use. Syringe 18 includes a barrel to hold a volume of medication and a plunger 19 that slides inside the barrel to draw fluid into or eject fluid from the barrel. Syringe 18 also preferably includes flanges that project outward from the barrel. The flanges operate as finger flanges to facilitate the movement of the plunger into the barrel.
[0043] The injection assembly 20 also includes a pressure sensor 20 to detect fluid pressure in the injection assembly. The pressure sensor may be arranged in one of several locations to measure a pressure that correlates with the fluid pressure at the needle tip 24. Alternatively, instead of or in addition to an in-line pressure sensor, the pressure sensor may be a force sensor located within or connected to the thumb plate that actuates the syringe plunger 58 or a force sensor that is internal to the drive unit 50 that measures the force applied to the syringe plunger. Such a force sensor detects the force required to inject the fluid, which is related to the fluid pressure, the fluid pressure at the needle. Using such a sensor, the detected force is converted into a pressure value by a calculation through the processor. In the present case, the pressure sensor 20 is an in-line fluid pressure sensor attached to the syringe 18 between the syringe and the tubing 22.In this way, pressure sensor 20 detects fluid pressure. Petition 870260039818, dated 04 / 29 / 2026, page 17 / 99 14 / 40 when the fluid exits the syringe and enters tubing 22 to which the insertion needle 24 is connected. Similarly, the in-line pressure sensor can be interposed between the tubing and the needle. As shown in Figure 2, the insertion needle 24 is connected to the front end of the handpiece and tubing 22 is connected to the rear end of the handpiece.
[0044] The tubing 22 comprises an elongated polymer tube that is sufficiently flexible longitudinally to allow the tube to bend during use, but substantially does not expand radially with a rigid wall thickness. In particular, the tube is a polymer tube that remains radially rigid without any radial expansion at pressures below 500 mm / Hg.
[0045] The injection assembly 20 can be operated manually to inject fluid. However, in the present case, a computer-controlled drug delivery system 50 controls the fluid flow from the injection assembly, as discussed further below. An electrical cable connects the pressure sensor 20 to the drug delivery system 50 so that the drug delivery system can monitor and, if desired, vary the fluid flow from the syringe in response to the pressure sensor 20 data. The pressure transducer 20 can be connected in-line between the front end of the syringe barrel 18 and the first tubing end 22. One such connection is a Luer connection to connect the pressure transducer 20 to the syringe tip, although other connections may be used. The connection may be secured by a threaded connection and / or an irreversible threaded connection, such as a Luer-Lock.Alternatively, the pressure transducer 20 can be permanently attached to the syringe by plastic welding or chemical bonding, such as adhesive. In this way, the actual instantaneous fluid pressure in the drug delivery line 22 is detected and... Petition 870260039818, dated 04 / 29 / 2026, page 18 / 99 15 / 40 used by the instrument, thus providing a close approximation to the actual and instantaneous fluid pressure at the point or tip of the needle 24 and therefore at the location on the patient's body where the needle tip is located. The electronic pressure transducer 20 provides pressure data via an electronic data cable that is connected directly to the central unit 50 to collect the pressure measurements.
[0046] The electronic pressure transducer 20 can be any of several pressure sensors. One type of sensor is a piezoelectric pressure sensor, such as the sensors available from Merit Medical Systems, Inc., such as the Meritrans® Pressure Transducer item MER212. AUTOMATED FLUID DISTRIBUTION SYSTEM
[0047] As described above, the system 10 may include a fluid delivery system 50 to provide a controlled flow of medication to the injection assembly 20. Preferably, the fluid delivery system is an automated system and, in the present case, it is a computer-controlled fluid delivery system referred to as the drive unit 50.
[0048] With reference to Figures 1-3, the drive unit 50 is designed to work in connection with an injection element, such as the syringe 18. The drive unit 50 may include a cradle 56 configured to receive the syringe 18 and a clamp to retain the syringe in the cradle. The drive unit 50 includes an operable drive element 58 to actuate the plunger in the syringe to expel fluid from the syringe. The drive unit 50 controls the displacement of the drive element 58, thus controlling the ejection of fluid from the syringe. In the present case, the drive element may include a motor 70 that drives an arm 58 which has a clamp with a plurality Petition 870260039818, dated 04 / 29 / 2026, page 19 / 99 16 / 40 of fingers 60 that removablely engage the plunger 19. The cradle 56 includes a recess to receive the syringe configured to restrict the syringe against longitudinal movement. For example, the cradle 56 may include a slot to receive the flange that projects radially outward from the surface of the syringe cylinder. Consequently, actuating the motor in a first direction drives the arm 58 forward to advance the plunger 19. Since the syringe cylinder is held in a relatively fixed axial position, the displacement of the plunger moves the plunger relative to the cylinder, thus expelling the fluid. The CPU 82 of the drive unit provides signals to the motor to control the motor operation.
[0049] The drive unit 50 is operable to provide constant or variable fluid flow. In the present case, the drive unit can provide continuous fluid in response to signals received from the electronic pressure transducer 20, which continuously detects fluid pressure during an insertion / injection procedure. Based on a predetermined pressure, the drive unit 50 can stop the fluid flow when the detected pressure exceeds a predefined threshold. The predefined threshold can be set by the medical professional and stored in a memory 80 of a microprocessor or computer 82 of the electronic components in the drive unit 50. Similarly, based on a predetermined pressure, the fluid flow will resume when the fluid pressure falls below a predetermined pressure and will continue to flow as long as the pressure remains below the threshold.The same predetermined pressure can be used to control the stopping and restarting of fluid flow. In this case, as the fluid initially enters the tissue, the pressure will increase to a predetermined level and then stop until the pressure once again drops below that predetermined level. A. Petition 870260039818, dated 04 / 29 / 2026, page 20 / 99 17 / 40 Once the fluid pressure drops below the predetermined level, the fluid flow will resume and be maintained on a continuous basis. In this way, the fluid flow can start and stop during the procedure, creating an interruption of the fluid flow once a specific predetermined pressure is detected.
[0050] The system may include predefined pressure thresholds used to control the flow of medication from syringe 18 during the procedure. This allows a clinician to selectively inject drugs into specific sites and tissues intended for diagnostic and therapeutic procedures. Pre-selected maximum permissible pressure limits and / or flow rates are stored in memory 80 and define the recommended maximum pressures or other criteria. As the pressure approaches this limit, a visual and / or audible alarm is generated for the clinician, i.e., on screen 62 and through the speaker 84, which is activated by data from the microprocessor 82. In addition, descriptive data of the entire injection process are stored for future analysis in memory 80.
[0051] System 10 can directly measure the fluid pressure in the injection assembly 20, or the system can measure a characteristic indicative of the fluid pressure in the injection assembly. For example, pressure can be measured by detecting the pressure resistance measured during infusion. The measured pressure resistance is converted into a continuous baseline visual signal during the insertion procedure. The medication flow rate during the procedure can be based on the fluid pressure detected in real time during the procedure. Therefore, the medication flow rate can be variable and can depend on the pressure in the system. In this way, fluid pressure can be the primary control variable of the system.
[0052] One feature of the present system is the ability to Petition 870260039818, dated 04 / 29 / 2026, page 21 / 99 The 18 / 40 system detects minute changes in pressure at the needle tip while a needle is being placed within the patient's tissue. A feature that facilitates the detection of minute pressure changes is the constant movement of fluid within the tissues under controlled conditions, thus allowing the identification and / or avoidance of undesirable locations based on the pressure within the tissue. The system detects these minute pressure changes in real time and dynamically when a continuous fluid flow is used. This continuous flow can be coordinated with a predetermined maximum pressure used by the system to stop the fluid flow at a predetermined pressure limit to prevent damage to the tissues. With a constant fluid flow, the loading pressure provides the necessary resistance within the tissues to allow subtle changes in tissue density and compliance to be detected on a virtually instantaneous basis.
[0053] Another aspect that facilitates the detection of minimal pressure changes is the precise volume control of the injection assembly 18. Specifically, the tubing 22 of the injection assembly 20 is substantially radially rigid so that the tubing does not expand radially under pressures below 500 mmHg. Therefore, under any backpressure that the injection assembly 20 could reasonably expect during use, the tubing will not expand or swell so that the tubing volume will not expand from any backpressure that the injection assembly may encounter. Additionally, the drive unit 50 rigidly controls the position of the plunger relative to the syringe cylinder to precisely control the volume within the cylinder. Specifically, the drive unit controls the position of the plunger so that when the drive unit motor stops, the drive unit maintains the plunger in a position Petition 870260039818, dated 04 / 29 / 2026, p. 22 / 99 19 / 40 fixed against forward or backward displacement. In this way, the drive unit prevents or avoids piston movement in response to fluid backpressure. Under normal system operating conditions, the drive unit maintains the piston in a fixed position against any backpressure the system may encounter during use. Thus, when the drive unit motor stops, the drive unit acts as a stop, preventing the relative displacement of the piston in relation to the cylinder. These mechanical elements, combined with the rigidity of the materials used in assembly 20, prevent deformation at pressures below 500 mmHg, which could prevent the detection of subtle pressure changes within the fluid detected by sensor 20. In particular, when the drive unit is stopped, the configuration of the injection assembly 20 and the drive unit prevent a change in fluid volume that affects the detection of the pulsatile waveform.
[0054] The flow rate, therefore, becomes another variable that can be modulated within a predetermined range to maintain the desired fluid flow. In one specific embodiment, the fluid flow is stopped when the pressure exceeds a predetermined threshold (maximum pressure). The flow rate, as a second variable, can be limited so that fluid injections are not unduly rapid under low-pressure conditions. It is contemplated that the relationship between pressure and fluid flow rate can be binary or continuous. A binary relationship exists when the injection device is configured to supply fluid at a single predetermined flow rate for any pressure below the predefined maximum. Thus, the fluid flow is switched on or off based on whether or not the pressure exceeds the threshold. Alternatively, the flow rate can be modulated as a function of pressure. In this case, the flow rate Petition 870260039818, dated 04 / 29 / 2026, page 23 / 99 20 / 40 will be reduced as the maximum pressure approaches and increased as the pressure drops. Optionally, the flow rate can be limited to a first predefined maximum pressure and a continuous flow rate at a second distinct predefined pressure.
[0055] As mentioned above, the system 10 may include a mechanism for displaying relevant injection data, which includes, for example, instantaneous flow rates, pressures, and injection quantities on a screen 30 of the drive unit 50. Similarly, the system may include a mechanism for recording such information for subsequent analysis after the procedure is performed. For example, the system may include a non-volatile electronic storage medium, such as a hard disk, flash drive, optical drive, or other media for storing electronic data.
[0056] All measurements and information may be presented to the clinician in real time so that the clinician can determine whether the injection is being applied to the intended location and / or correct tissues and may, consequently, modify the injection technique. Additionally, measurements may be recorded for later review and documentation of the clinical event.
[0057] It is also contemplated that several syringes actuated by separate syringe plungers may be used to allow multiple drugs to be injected, as well as a second syringe actuation that does not require a predetermined pressure to be reached for any said purpose. The second actuation may be programmed at a specific flow rate to allow the infusion of a drug, such as local anesthetic and other therapeutic drugs, into a variety of tissues.
[0058] In yet another embodiment, the device may contain two distinct syringe actuators, both of which are capable of modulation based on fluid pressure, as described. Petition 870260039818, dated 04 / 29 / 2026, page 24 / 99 21 / 40 previously in this document. CALCULATION OF FLUID PRESSURE AT THE NEEDLE OUTLET
[0059] As discussed above, fluid pressure can be used to control the operation of the system 10. For example, the system can provide a signal to the operator when the fluid pressure exceeds a threshold, thus indicating that the needle may be located against or in dense tissue, such as the dura mater. There are several methodologies for calculating the fluid pressure at the needle outlet.
[0060] A pressure sensor can detect fluid pressure in the injection assembly 20. For example, as discussed above, the pressure sensor can be an in-line pressure sensor. Alternatively, a pressure sensor internal to the drive unit 50 can detect fluid pressure between a conduit, such as tubing 22, and a fluid reservoir, such as a syringe 18, fluid-filled cartridge, or other fluid reservoir. Similarly, the pressure sensor can be interposed between the syringe tubing 22 and the needle 24. Furthermore, the in-line sensor can be embedded in a barrel connected to the needle or between tubing 22 and the barrel. Another alternative is to use a thumb force sensor to detect the force driving the plunger 19 to calculate the pressure inside the syringe 18. A command signal from the pressure sensor sends pressure data to the CPU for calculation to determine the output pressure.The output pressure value is used to control motor 70, which controls the fluid flow from syringe 18.
[0061] The system can be configured to provide one or more visual cues for the user to observe and / or analyze the detected pressure signals. For example, referring to Figures 1-4A, the system 10 may include a display screen 30 to display data related to the operation of the system, which includes, but is not limited to, Petition 870260039818, dated 04 / 29 / 2026, page 25 / 99 22 / 40 pressure data and fluid flow data. For example, as shown in Figures 4A-4C, the system includes a primary pressure graph 32 on the display 30. The primary pressure graph 32 plots fluid pressure against time, so the graph represents variations in fluid pressure detected over a period of time. This graph represents general pressure trend information and, in the present case, the controller processes the signal received from the pressure sensing element to remove variations that are not created by fluid pressure. For example, the controller 30 can be programmed to process the pressure data to remove variations in pressure signals caused by motor operation, static friction of the syringe, and general pressure variations caused by tubing bending and needle tip elevation changes.Higher frequency variations and noise are removed through the use of a low-pass filter, either electrically or in software. As shown in Figures 1 and 2, the display may also include a current pressure display 38 that shows the most recently detected fluid pressure.
[0062] Additionally, display 30 also includes a pulse wave detection display 34. As discussed below, it may be desirable to analyze fluid pressure data to detect the presence of a pulse waveform. The controller is configured to process the data in a way that isolates a pulse wave from the underlying fluid pressure in the needle environment, as described below. The pulse wave display 34 shows this processed data so that the operator can determine if the data are indicative of the presence of a pulse waveform. As discussed below, the pulse wave display 34 includes an amplitude range identified as element 36. This range of Petition 870260039818, dated 04 / 29 / 2026, page 26 / 99 The 23 / 40 amplitude 36 can be varied in order to display the pulsed waveform more clearly, depending on the amplitude of the waveform.
[0063] As noted above, it may be desirable to analyze fluid pressure data to detect the presence of a pulsatile waveform in the pressure data detected by a pressure sensor, such as sensor 20. In fluid dynamics, a flow with periodic variations is known as pulsatile flow. Pulsatile flow is an intrinsic property of the cardiovascular system. In other words, the basic operation of the cardiovascular system generates pulsatile flow as follows: when the ventricle contracts and creates the necessary pressure gradient, a volume of blood is rapidly ejected into the arterial vessels. The aorta and arteries have less resistance to blood flow compared to smaller blood vessels such as arterioles and capillaries. Due to the slower flow into the arteriole, the arteries are inflated to accommodate the extra blood volume. During diastole, the elastic recoil of the arteries forces blood out into the arterioles.In this way, the elasticity of the arteries helps to convert the pulsatile flow of blood from the heart into a more continuous flow throughout the rest of the circulation.
[0064] The pulsatile waveform produced intravascularly by the cardiovascular system also creates a corresponding extravascular pulsatile waveform, caused by the movement of blood vessels, such as arteries. For example, the arteries of the spinal cord nerve bundle create a pulsatile waveform that is observed in the spinal fluid in the epidural space. The frequency of the extravascular pulsatile waveform is similar to the intravascular pulsatile waveform; however, the magnitude of the extravascular waveform is significantly smaller than the magnitude of the intravascular pulsatile waveform. Specifically, the intravascular pulsatile waveform is created directly by blood pressure, while the Petition 870260039818, dated 04 / 29 / 2026, page 27 / 99 The 24 / 40 extravascular pulsed waveform is created by the movement of blood vessels in response to blood pressure.
[0065] In order to identify the pulsed waveform, the data can be processed to isolate the representative data of the pulsed waveform. The pulsed waveform can be difficult to identify due to the magnitude of the background fluid pressure. For example, the amplitude of the pulsed waveform may be an order of magnitude smaller than the background fluid pressure. For example, if the needle is located in dense tissue, the detected fluid pressure may exceed 100 mmHg, while the amplitude of the resulting pressure variations from the pulsed wave may be only 10 mmHg. In this case, the pressure may fluctuate only from 95 mmHg to 105 mmHg, which may be imperceptible in a pressure versus time plot. Therefore, it is desirable to isolate the pulsed wave pressure from the underlying pressure, where the underlying pressure or background pressure is the pressure that results primarily from the density of the tissue in which the needle tip is located.
[0066] To isolate the representative data of a pulse wave, the controller may include a self-centering filter to keep the waveform centered on the pulse wave detection display graph 34. Several filter types can be implemented to remove the average value. These filters can be constructed using mechanical, electrical, or software designs. In the present case, a working average filter is designed in software programmed into the controller to generate an average value for the pressure that is subtracted from the current pressure reading for graphical purposes. This keeps the pulse waveform data centered on the graph. For example, the data can be processed so that the data are generally centered on a baseline between the Petition 870260039818, dated 04 / 29 / 2026, page 28 / 99 25 / 40 upper limit of the pulse waveform and the lower limit of the pulse waveform. In one embodiment, the pressure data can be processed as follows: first, an average pressure value is calculated based on the pressure values detected by the sensor during the most recent time period, such as a time period ranging from 2 to 10 seconds. The calculated average is then subtracted from the current pressure value. The system displays the resulting value on the pulse detection display 34. Large transient pressures will cause the plot to be cut off on the pulse detection display 34; however, the average will remain in the center of the detection display 34.
[0067] The amplitude of the pulsating waveform can vary from situation to situation. Additionally, the fluid pressure at which the pulsating waveform becomes perceptible can also vary. As described above, the controller can be configured to process the pressure sensor data to isolate the pulsating waveform. Additionally, the controller can be configured to process the data from the pressure sensor to attempt to center the waveform on the pulsation detection display 34. Although the process of attempting to center the waveform can improve the probability of identifying the pulsating waveform, it is still possible to miss the waveform in many situations. For example, Figures 4A-4D show how the amplitude scale of the pulsation detection display can determine whether pulsating motion is detected.Specifically, in Figure 4A, the display illustrates the processed pressure data with an amplitude scale of 5 mm Hg (2.5 above the baseline and 2.5 below the baseline). As can be seen in Figure 4A, the pulsed waveform is readily identified using this scale. With reference to Figure 4B, the amplitude range 36 is twice that of Figure 4A. Petition 870260039818, dated 04 / 29 / 2026, page 29 / 99 26 / 40 As such, the oscillations are significantly diminished, but still perceptible. In Figure 4C, the amplitude range is doubled again. The oscillations are subtle, but identifiable. In Figure 4D, the amplitude range is doubled again. At the scale of Figure 4D, the pulsed waveform is not discernible. Consequently, if the operator had to start with a large amplitude range of 36, as in Figure 4D, it would appear that sensor 20 did not detect a pulsed waveform.
[0068] In contrast, Figures 5A and 5B illustrate the opposite problem. In Figure 5A, the data are plotted with an amplitude range of 10 mm Hg. However, the range of the pressure data is greater than 10 mm Hg, therefore many of the data points are out of scale. With reference to Figure 5A, the same data are plotted with an amplitude range of 40 mm Hg. Since the amplitude range is large enough to accommodate all the pressure data, the pulsatile waveform is identifiable in Figure 5B.
[0069] Since the amplitude range for a given set of pressure data is highly variable, the system can include the option to easily scale the data to change the amplitude range. Specifically, the system 10 includes the ability to readily re-graph the processed pressure data in response to the operator selecting or entering a change in the amplitude range. The request can be entered using any of a number of input mechanisms, which includes, but is not limited to, a mouse, a foot switch, voice activation, a keyboard, a button on the drive unit 50, or a touchscreen button, as well as automatic rotation through different amplitude ranges via software. In the present case, the display 30 is a touchscreen that includes a button that allows the operator to switch between any of a variety of Petition 870260039818, dated 04 / 29 / 2026, page 30 / 99 27 / 40 amplitude ranges. When the user selects a different amplitude range, the system redraws the data graph. In this way, the operator can manipulate the pressure data display to identify if a pulsatile waveform is present. NOISE COMPENSATION
[0070] As discussed above, system 10 can be configured to continue injecting fluid through the needle while the system or operator analyzes pressure data to detect the presence of a pulsatile waveform. However, fluid injection can cause disturbances that affect the detection of the pulsatile waveform. For example, turbulence from the fluid flow and static friction from the rubber / elastomeric piston in the syringe are two variables that can adversely affect the detection of the pulsatile waveform. To overcome the potential problems created by such disturbances, the system can be configured to isolate the pulsatile waveform from the effects of the disturbances.
[0071] To isolate the pulsatile waveform, the system may include a process to evaluate disturbances caused by the system configuration and fluid injection. In one particular embodiment, the system includes a noise cancellation mode. Before inserting the needle into the patient, the user selects the noise cancellation mode. The system then operates the drive unit to inject fluid through the needle. The system monitors any pressure changes that occur during the noise cancellation mode. When the presence of a pulsatile waveform is assessed, the system modifies the detected pressure data based on the data collected during the noise cancellation mode. SYSTEM CONTROL
[0072] The system includes a user-operable input mechanism, which allows the operator to provide input signals to Petition 870260039818, dated 04 / 29 / 2026, page 31 / 99 28 / 40 control the system. The input mechanism can be any of a variety of devices, such as a touchscreen, buttons on the drive unit, or a foot-operated control that provides a means for the operator to start, stop, and change the flow rate from a single flow rate to a distinct second or third predefined flow rate. Alternatively, the input element can be a mouse, keyboard, or microphone to provide audible input commands. Additionally, the system may include a plurality of input mechanisms to allow the operator to input a variety of inputs for various stages of a procedure. For example, the system may include a first input mechanism, such as a foot pedal, that controls the flow of fluid through the device.When the foot pedal switch is activated (i.e., pressing the switch), it sends a signal to the drive unit's CPU, which in turn sends a signal to the motor to start the motor so that fluid flows from the syringe to the needle 24 while the pedal is actuated. Alternatively, actuating the pedal once can operate a start signal to initiate fluid flow, and the fluid can continue to flow until the operator actuates the pedal again. In this way, the second actuation operates as a stop signal to interrupt the fluid flow.
[0073] As described above, the system is operable to control fluid flow during a procedure. In addition to using an actuator to control the on / off switch, the system can provide two or more flow rate settings. In particular, the control unit 50 can incorporate a multi-speed pump that provides a variable flow rate. Similarly, the pump can include two or more predefined flow rates. In the present case, the control unit 50 includes an electric motor 70 that controls the speed at which the control unit moves the plunger in the syringe. Petition 870260039818, dated 04 / 29 / 2026, page 32 / 99 29 / 40 18. The control unit 50 can control the speed of the motor 70 so that the motor is driven at one of multiple preset speeds to provide multiple preset flow rates. The different flow rates can be used in conjunction with different pressure settings and / or other characteristics during different portions of a procedure.
[0074] Switching between presets can be manual or automatic. For example, the operator can manipulate an input device, such as a keyboard, touch-sensitive device, or other, as noted above. Alternatively, the system can automatically switch to the second preset based on detected criteria, such as fluid pressure. METHOD OF OPERATION
[0075] An exemplary method for guiding a needle to a target location using the system described above will now be described. It should be understood that the present system is not limited to use in guiding a needle for drug infusion. Consequently, it should be understood that the principles and methods described below can be easily adapted for needle insertion into tissues and anatomical areas in a variety of applications and procedures.
[0076] When the needle is in an adjacent fluid or vessel that produces a pulsatile waveform, the processed pressure data forms an oscillatory wave, such as a sine wave. Detection of the pulsatile waveform can act as a primary indication that the needle is positioned in or adjacent to the target tissue. Alternatively, detection of the pulsatile waveform can operate as a validation or verification that an alternative method for identifying a target tissue (such as by a resistance loss technique) was accurate. In this way, the detection of a waveform of Petition 870260039818, dated 04 / 29 / 2026, p. 33 / 99 30 / 40 pulsed wave can operate in combination with other research methodologies in order to increase the likelihood of proper needle placement and reduce the likelihood of inadvertent needle / anesthesia injuries. In the following example, the system is used in combination with a loss-of-resistance technique to identify a target tissue.
[0077] First, the operator determines that the target tissue is one in which the target tissue will generate a pulsatile waveform. After making or confirming such a determination, the operator advances the needle 24 into the patient, preferably as the fluid flows through the needle at a defined flow rate. In a method where the drive unit is used, the fluid reservoir, such as a syringe, is loaded into the drive unit 50. The drive unit then precisely controls the position of the drive element 58 to precisely control the fluid flow from the syringe. The pressure sensor 20 detects the fluid pressure in the needle and, as shown in Figure 4A, the fluid pressure varies as the needle advances through different types of tissue. When searching for a target tissue, the change in fluid pressure can guide the needle advancement. For example, the system can provide a perceptible output that guides the operator.In one example, the system can provide an audible tone representative of the pressure. For example, the tone of the audible signal can increase as the pressure increases and decrease as the pressure decreases. Similarly, the system can provide a visual signal indicating the change in pressure. For example, as illustrated in Figure 4A, a graph 32 provides a visual indication of fluid pressure. Graph 32 plots the pressure as it varies over time. In Figure 4A, an apparent loss of resistance appears to occur at approximately 2840 seconds. However, a... Petition 870260039818, dated 04 / 29 / 2026, page 34 / 99 31 / 40 true loss of resistance occurs in approximately 2860 seconds. The present system can be used to confirm when an apparent loss of resistance is a real loss of resistance, as discussed further below.
[0078] As noted above, when the needle 24 is being advanced or withdrawn, the fluid pressure changes as the needle passes through different types of tissue. Conversely, when the needle is held in a specific location, the fluid pressure tends to stabilize and remain at a generally constant value. However, if the needle tip is held in a substantially constant location, the sensor can detect pressure variations due to a pulsatile wave. Specifically, if the needle is held in a specific location relative to a target area, and if that specific location is adjacent to an artery, the system will then detect periodic variations in the detected fluid pressure. Furthermore, the detected magnitude of fluid pressure can also guide the user, in addition to detecting periodic variations.For example, if the system detects a pressure profile with periodic pressure variations, the needle may then be adjacent to an artery. However, if the fluid pressure is high and the amplitude of the pressure variation is above a threshold, the system may determine that the needle is inside the artery, rather than near the artery. For example, a pressure curve indicating periodic variations between 80 mmHg and 120 mmHg would indicate that the needle is inside an artery, rather than near the artery.
[0079] In this way, the system can combine the detection of periodic variations in fluid pressure with a second fluid pressure characteristic, such as resistance loss, as described above. For example, the system can monitor the Petition 870260039818, dated 04 / 29 / 2026, page 35 / 99 32 / 40 fluid pressure as the operator advances the needle to guide the operator toward a target tissue, such as the epidural space. Once the system detects a pressure drop indicative of a loss of resistance, the system can indicate that the needle is in the epidural space. In response to this determination, the system provides a signal to the user indicating that the needle is located in the target tissue, so that the user maintains the needle in the specific location. To verify that the needle is in the epidural space, the system can monitor the fluid pressure to determine the presence of periodic variations in the detected fluid pressure. If the system detects periodic variations in fluid pressure indicative of a pulsatile waveform, this detection is validation that the needle is located in the epidural space.Having validated that the needle is adjacent to or located within the target tissue, the medication can be safely injected through the needle and into the patient at the target tissue site.
[0080] It should be understood that in the preceding description the system is described as automatically detecting the presence of a pulsatile waveform to validate the needle placement determination. However, it should be understood that, in addition to the system 10 being configured to automatically detect the presence of a pulsatile waveform, alternatively, the system can be configured to display fluid pressure data in a way that facilitates the operator determining that the needle detects a pulsatile waveform.
[0081] In the previous method, an operator locates a needle adjacent to a target tissue, using constant feedback with respect to the fluid pressure detected in the needle to guide the needle. One such method for guiding the needle is a loss-of-resistance process to identify a target tissue location that is adjacent to a dense barrier tissue. Once the tissue of Petition 870260039818, dated 04 / 29 / 2026, page 36 / 99 When the 33 / 40 barrier is penetrated, the fluid pressure drops rapidly, providing an indication that the needle is correctly positioned in the target space. The system then validates the needle placement by processing the pressure data to attempt to detect a pulsatile wave. The detection of the pulsatile wave acts as a validation of the needle placement.
[0082] Although the previous example illustrates the use of the system in connection with a loss-of-resistance process to position a needle at a specific location, it should be understood that any number of processes can be used to place the needle at the target location, provided that the target location is an adjacent tissue that is likely to provide a pulsed waveform. For example, as described below, the system can operate in combination with a peripheral nerve block system to verify or validate that the needle is correctly placed.
[0083] In a peripheral nerve block procedure, the target tissue is nerves associated with a neurovascular bundle. When an anesthetic is injected adjacent to the nerve, the anesthetic can then provide appropriate anesthesia. However, if the needle is placed inside the nerve, the anesthetic can cause nerve damage. Consequently, a peripheral nerve block procedure can use electrical stimulation to guide the needle. The level of stimulation can be varied to guide the needle toward the target location. The operator advances the needle and applies electrical stimulation to the tissue at the needle tip. If a response to the electrical stimulation is observed, the needle may be adjacent to the target nerve. Furthermore, as described in International Patent Application No. PCT / US18 / 31096 published as Publication No.WO 2018 / 204789, dated November 8, 2018, states that fluid pressure adjacent to the needle tip can be monitored during a peripheral nerve block procedure. Petition 870260039818, dated 04 / 29 / 2026, p. 37 / 99 34 / 40 All disclosure in International Patent Application No. PCT / US18 / 31096 published as Publication No. WO 2018 / 204789 is incorporated herein by reference. In such a process, the combination of fluid pressure and electrical stimulation can be used to guide the needle to the target location. Once the peripheral nerve block process is used to position the needle tip at the target location, pulse wave detection is then used to verify or validate needle placement. In particular, once the needle is positioned at the proposed location, the needle positioning is maintained without significant movement. While the needle is held in position, the system continues to monitor the pressure signal from sensor 20. The pressure data is processed to isolate the pressure data from the background pressure to identify the presence of a pulse waveform.If such a pulsed waveform is present, the needle placement decision is verified. The operator then performs the next step for the target tissue. The next step may be a medical procedure on the target tissue, or the next step may be the injection of medication or anesthesia. Alternatively, if the peripheral nerve block procedure positions the needle in a location thought to be the target tissue, but a pulsed waveform is not detected, then the operator determines that the needle is not correctly positioned adjacent to the target tissue, and the process for locating the needle is restarted.
[0084] From the foregoing, it should be understood that the present invention may incorporate one or more of a variety of research techniques that are configured to identify or validate that a needle is positioned in or within a target tissue. For example, in the following discussion, the system is used to validate needle placement. However, it should be understood that the system may be Petition 870260039818, dated 04 / 29 / 2026, page 38 / 99 35 / 40 is used to verify or validate the placement of a conduit other than a needle. An example is the placement of a catheter. Frequently, a catheter can be inserted using any of a variety of techniques, such as the loss-of-resistance technique described above. Once the needle is correctly placed, a catheter can be inserted into the patient so that the catheter is located in or within the target tissue. The catheter may need to remain positioned within the patient for an extended period. During this extended period, the catheter may be moved, accidentally moving the catheter in the opposite direction from the target tissue. Currently, the method for verifying catheter placement is to inject a fluid, such as a medication, and monitor the patient to determine if the medication had the intended effect.If the medication has affected the patient in the intended manner, then it is determined that the catheter is correctly placed; otherwise, the investigation is restarted. However, the present system can be used to verify or validate catheter placement. Instead of a 24-gauge needle, the system may include a cannon configured to form a fluid-tight seal with the catheter cannon. The system cannon is interconnected with the catheter cannon to form a fluid-tight seal. The drive unit is then initiated to inject fluid from the syringe into the cannon and then into the catheter until the catheter is substantially filled with fluid. The system then detects the fluid in the catheter. If the pressure signal includes a pulsatile waveform, the operator verifies or validates that the catheter is still correctly placed so that fluid can be injected into the target tissue through the catheter.On the other hand, if a pulsed waveform is not detected through the catheter, the operator determines that the catheter is not correctly positioned and the catheter can be repositioned. Petition 870260039818, dated 04 / 29 / 2026, p. 39 / 99 36 / 40
[0085] In the above examples, pulse wave detection is used as a signal to validate or verify a needle or other conduit after the conduit has been placed. Additionally, it should be noted that pulse waveform detection can be used as the primary data to guide the placement of a needle or other conduit. According to one example, a needle is inserted into a patient towards a target tissue. As the needle advances towards the target tissue, the amplitude of the pulse waveform may increase. Consequently, by first monitoring the presence of a pulse waveform, the operator determines that the needle is within the general area of the target tissue. As the needle is moved closer to the target tissue, the amplitude of the pulse waveform increases. In this way, the variation of the pulse waveform is used to guide the needle towards the target tissue.
[0086] In particular, the system can be configured to provide guidance for placing a needle or other conduit based on two characteristics. The first characteristic is a pressure range determined by the tissue resistance to a constant flow rate, thus producing a first characteristic response to said flow rate. In other words, a constant flow of fluid is injected through a needle, and a sensor detects the fluid pressure range in the needle while the needle is in a specific tissue. A second characteristic is determined based on pressure data received by the sensor while the needle is held in a stationary position with no fluid being injected through the needle from a fluid reservoir. The second characteristic is based on the presence of a pulsed waveform. In particular, the second characteristic can be the amplitude of the pulsed waveform.The system is configured to allow the operator to switch between a) translational movement of the needle during needle insertion. Petition 870260039818, dated 04 / 29 / 2026, page 40 / 99 37 / 40 during which fluid flows through the needle and b) stationary positioning of the needle without fluid flow. A comparison of the amplitude of the pulsatile pressure waveform between two or more different locations provides the relative distance of the needle tip to the target. When the needle translation is interrupted so that the needle is held in a stationary position, the second characteristic is observed again. The comparison of the height of the pulsatile waveform amplitude between two or more time points can be aided by modifying and varying the scale 36 of the pulsatile pressure waveform graph 34 to allow visualization of the height of the oscillating waveform amplitude. Comparing the height of the pressure waveform amplitude between two or more different time points provides information to determine the relative position of the needle tip with respect to the target tissue.For example, if the amplitude of the subsequent pressure waveform is decreasing compared to the previous waveform, the needle then moves in the opposite direction to the target tissue. Conversely, if the amplitude of the subsequent pressure waveform is increasing compared to the previous waveform, the needle then moves towards the target. And, if the amplitude of the pressure waveform does not change significantly between two time points, then the relative distance of the needle tip to the target tissue has not changed. It is understood that the device is capable of varying the amplitude scale to identify pressure waveforms of varying intensity during this process.Thus, relying on a primary feature to identify a specific space or tissue, and subsequently using a secondary feature with variable amplitude, provides objective data regarding the directional movement of the needle within the tissues and forms the basis for using these two different features to determine the... Petition 870260039818, dated 04 / 29 / 2026, page 41 / 99 38 / 40 needle orientation to the target tissue.
[0087] An example of using pulsed waveform amplitude as feedback for a needle placement procedure is a dental application. The method involves setting a specific scale for the pulsed waveform graph 34 and observing the amplitude of the pulsed waveform from the center of graph 34 at a given distance. As the operator advances the needle closer to the intended target, an increase in amplitude is observed during intermittent stops of needle advancement and drug injection. This provides guidance for needle tip movement, allowing the anesthetic solution to be deposited close to the neurovascular bundle of the Inferior Alveolar Nerve Plexus. This system is used in conjunction with the dental instrument with an LED screen displaying a pulsed waveform graph, such as the display 34. Furthermore, instead of using a single-use in-line sensor, the system can incorporate a reusable, non-in-line sensor.For example, the injection set may include a fluid line that has a flexible sidewall. A shell-shaped sensor engages with the outer wall of the tubing so that the flexible sidewall is between the halves of the shell sensor. The sensor detects the radial pressure of the fluid by pressing radially outward, which is indicative of the fluid pressure in the tubing and, consequently, the fluid pressure within the needle. In this way, the shell sensor functions as an alternative to an in-line pressure sensor currently described for the epidural system. The piezoelectric shell sensor allows the tubing to be placed inside the shell to detect the in-line fluid pressure.
[0088] System 10 can also be incorporated into a process for placing a needle or other conduit to confirm the Petition 870260039818, dated 04 / 29 / 2026, page 42 / 99 39 / 40 placement of a spinal needle into cerebrospinal fluid. The system can be used in combination with a previously discussed loss-of-resistance technique to guide the needle into the appropriate position, and the needle will then be stopped in the determined position. The system processes fluid pressure data while the needle movement is stopped. If a pulsatile waveform is detected, the operator determines that the needle is properly placed in the cerebrospinal fluid.
[0089] In addition, the system can be incorporated into other procedures to identify whether a needle or other element is properly placed. One such application is a cardiac vascular application. In a cardiac vascular application, the system is used to determine the placement of a needle or catheter in the lumen of a vessel by measuring the absolute pressure, as well as detecting the presence of a pulsatile waveform to determine the unblocking of the vessel during the placement of a vascular stent and / or during the use of cardiac ablation where a therapeutic drug or diagnostic procedure is performed to determine the unblocking of said vessel of the cardiovascular system. The detection of a pulsatile waveform in conjunction with the absolute pressure values provides diagnostic information when performing these procedures.
[0090] Yet another application of system 10 is directed to an infusion pump. In the embodiments described above, the system uses a syringe pump to deliver fluid to the patient. However, the present improvements can be incorporated for use in an infusion pump system that includes a peristaltic pump system with a closed drug delivery system consisting of a drive unit, tubing, and a permanent catheter in a patient's vein. The system would operate by intermittently stopping. Petition 870260039818, dated 04 / 29 / 2026, page 43 / 99 The 40 / 40 motor allows for the detection of a pulsatile waveform to confirm that the catheter has not migrated from its position in the patient. In this way, the system provides a process for determining the catheter's position and its relative unobstructed position during use.
[0091] It will be recognized by those skilled in the art that changes or modifications may be made to the embodiments described above without departing from the broad inventive concepts of the invention. For example, in the preceding description, the system is described in the context of fluid infusion delivery. However, it should be understood that the system can be used for needle placement to aspirate fluid-filled tissue or a sample of a target tissue, such as performing a biopsy. It should therefore be understood that this invention is not limited to the particular embodiments described herein, but is intended to include all changes and modifications that are within the scope and spirit of the invention as set forth in the claims. Petition 870260039818, dated 04 / 29 / 2026, page 44 / 99
Claims
1 / 3 CLAIMS 1. Needle apparatus for administering fluid to the target location in a patient, comprising an injection assembly (20) comprising: (a) a fluid reservoir which is a syringe cylinder (18) for storing fluid to be supplied to the needle (24); (b) an ejection element which is a plunger (19) displaceable relative to the fluid reservoir for expelling fluid from the reservoir; (c) a sensor (20) for detecting a characteristic indicative of fluid pressure in the needle (24), wherein the sensor (20) is configured to continuously detect the characteristic as the needle apparatus (24) is inserted into the individual; (d) a flexible fluid conduit (22) communicating with the fluid reservoir and the sensor (20),wherein the conduit (22) is radially rigid so that the tube does not expand radially under pressures below 500 mmHg; wherein the apparatus further comprises: (e) a display screen (62) for displaying data relating to the operation of the system, which includes, but is not limited to, fluid pressure at the needle outlet (24) and also displays a pulsed waveform, characterized in that the apparatus further comprises: (f) a drive unit (50) comprising: i) a drive element (58) including a motor (70), wherein the drive element (58) is configured to engage the ejection element to control the displacement of the ejection element; and ii) an operable controller (30) for controlling the Petition 870260039818, dated 29 / 04 / 2026,pg. 45 / 99 2 / 3 drive element (58) to control the fluid flow from the reservoir to the needle (24); wherein the controller (30) is configured to periodically interrupt the movement of the drive element (58) and process sensor data (20) to detect one or more indicative characteristics of said pulsatile waveform, and wherein, during use, the apparatus is configured so that the fluid volume between the needle (24) and the fluid reservoir is constant, so that the sensor (20) is able to accurately detect said pulsatile waveform passing through the residual fluid in the needle (24) when the movement of the drive element (58) is interrupted, and wherein the drive unit (50) rigidly controls the position of the plunger (19) relative to the syringe cylinder (18) to accurately control the volume inside the cylinder, so that, when the motor of the drive unit (50) stops,The drive unit (50) maintains the piston (19) in a fixed position against forward or backward movement, preventing or hindering the movement of the piston (19) in response to the back pressure of the fluid and thus acting as a stop that prevents the relative displacement of the piston (19) in relation to the cylinder, so that the configuration of the injection assembly (20) and the drive unit (50) prevents a change in the fluid volume that could affect the detection of the pulsed waveform.
2. Needle apparatus (24), according to claim 1, characterized in that the controller (30) is configured to analyze the data from the sensor (20) to detect one or more characteristics indicative of a loss of resistance.
3. Needle apparatus (24), according to Petition 870260039818, dated 04 / 29 / 2026, page 46 / 99 3 / 3 claim 2, characterized in that in response to the controller (30) detecting one or more features, the controller (30) is configured to interrupt the movement of the drive element (58) and process data from the sensor (20) to detect one or more features indicative of a pulsed waveform.
4. Needle device (24), according to claim 3, characterized in that the controller (30) is configured to provide a verification signal that the needle (24) is properly placed adjacent to a target tissue after receiving a signal indicating a loss of resistance and after receiving a signal indicating the presence of a pulsed waveform in the needle (24).
5. Needle apparatus (24), according to any one of claims 1 to 4, characterized in that the display includes a first output section configured to display the fluid pressure at the needle (24) as a function of time in a manner consistent with a resistance loss guidance procedure, and optionally in that the controller (30) is configured to process data from the sensor (20) to isolate indicative data of a pulsed waveform, wherein the display comprises a second output section configured to display the indicative data of a pulsed waveform while the first section displays the fluid pressure data as a function of time in the first section. Petition 870260039818, dated 29 / 04 / 2026, p. 47 / 99