WO2020185419A1

WO2020185419A1 - Finger cuff including a bladder heat set to shape

Info

Publication number: WO2020185419A1
Application number: PCT/US2020/020298
Authority: WO
Inventors: Jeong Soo Lee
Original assignee: Edwards Lifesciences Corporation
Priority date: 2019-03-14
Filing date: 2020-02-28
Publication date: 2020-09-17

Abstract

Disclosed is a finger cuff connectable to a patient's finger to be used in measuring the patient's blood pressure utilizing the volume clamp method. The finger cuff may comprise: a bladder mountable within the finger cavity, wherein the patient's finger received in the finger cavity abuts against the bladder; and control circuitry to control pressure applied by the bladder to the patient's finger based upon measuring a pleth signal received from an optical source and sensor pair to keep the pleth signal approximately constant to replicate the patient's blood pressure to implement the volume clamp method. The bladder may be formed from a heat set material, the heat set material being heat set at a predetermined temperature within a predetermined temperature range for a predetermined time, such that the bladder formed by the heat set material is set to a desired band shape.

Description

FINGER CUFF INCLUDING A BLADDER HEAT SET TO SHAPE

BACKGROUND

Field

[0001] Embodiments of the invention relate generally to non-invasive blood pressure measurement. More particularly, embodiments relate to a finger cuff to be used in measuring the patient’s blood pressure by a blood pressure measurement system utilizing the volume clamp method, in which, the finger cuff utilizes a bladder that is heat set to shape.

Relevant Background

[0002] Volume clamping is a technique for non-invasively measuring blood pressure in which pressure is applied to a patient’s finger in such a manner that arterial pressure may be balanced by a time varying pressure to maintain a constant arterial volume. In a properly fitted and calibrated system, the applied time varying pressure is approximately equal to the arterial blood pressure in the finger. The applied time varying pressure may be measured to provide a reading of the patient’s blood pressure.

[0003] This may be accomplished by a finger cuff that is arranged or wrapped around a finger of a patient. The finger cuff may include an optical source, an optical sensor, and an inflatable bladder. The light may be sent from the optical source through the finger in which a finger artery is present. The optical sensor picks up the light and the amount of light registered by the sensor may be inversely proportional to the artery diameter and indicative of the pressure in the artery.

[0004] In the finger cuff implementation, by inflating the bladder in the finger cuff, a pressure is exerted on the finger and finger artery. If the pressure is high enough, it will compress the artery causing the artery diameter to become smaller and the amount of light registered by the sensor will decrease. The amount of pressure necessary in the inflatable bladder to compress the artery is dependent on the blood pressure. By controlling the pressure of the inflatable bladder such that the diameter of the finger artery is kept constant, the blood pressure may be monitored in very precise detail as the pressure in the inflatable bladder is directly linked to the patient’s blood pressure.

[0005] In a typical present day finger cuff implementation, a volume clamp system is used with the finger cuff. The volume clamp system typically includes a pressure generating system and a regulating system that includes: a pump, a valve, a controller, and a pressure sensor in a closed loop feedback system that is used in the measurement of the arterial volume. To accurately measure blood pressure, the feedback loop provides sufficient pressure generating and releasing capabilities to match the pressure oscillations of the patient’s blood pressure.

[0006] As has been described, a finger cuff, as part of a volume clamp system, is used to measure the patient’s blood pressure at their finger (e.g., the finger cuff being wrapped around the patient’s finger). As an example, a controller may control the pneumatic pressure applied to the finger cuff by the pump as well as many other functions. In one example, the pneumatic pressure applied by the pump to the bladder of the finger cuff to replicate the patient’s blood pressure may be calculated by the controller and may be based upon measuring the plethysmograph/plethysmogram (pleth) signal received from the optical source and sensor pair of the finger cuff (e.g., to keep the pleth signal constant) and further the controller may measure the patient’s blood pressure by monitoring the pressure of the bladder from a pressure sensor.

[0007] In efforts to expand and broaden the market for finger cuffs, it is desirable to improve the design, efficiency, accuracy, and ease of use of the finger cuff. In presently utilized commercial finger cuffs, certain components of the bladder may be improved. Typical commercial finger cuffs utilize a tube to deliver pneumatic pressure to a bladder that may comprise a non-plasticized polymer, such as, polyurethane, bonded to a plasticized PVC material. For a typical finger cuff, in addition to the bladder, a polycarbonate or co polyester, i.e. HYTREL®“band”, is inserted into the bladder to maintain a cylindrical shape. The cylindrical bladder shape provides more efficient usage and a more accurate blood pressure reading. However, because of the addition of the polycarbonate or HYTREL® band, the manufacturing process is more tedious and slowed down significantly. Therefore, it would be beneficial to eliminate the additional“band”, thus simplifying the manufacturing process.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. l is a diagram of an example of a blood pressure measurement system, according to one example.

[0009] FIG. 2 is a block diagram of a finger cuff system to measure the blood pressure of a patient, according to one example.

[0010] FIG. 3 is flow diagram illustrating a method to heat set an inflatable bladder, according to one example.

[0011] FIG. 4 is diagram illustrating an exploded view of an inflatable bladder, according to one example.

[0012] FIG. 5 is diagram illustrating a perspective view of a finger cuff including the inflatable

bladder, according to one example.

DETAILED DESCRIPTION

[0013] As will be described in more detail hereafter, one example of a finger cuff may relate to a finger cuff that is connectable to a patient’s finger to be used in measuring the patient’s blood pressure by a blood pressure measurement system utilizing the volume clamp method. The finger cuff may comprise: a finger cavity to receive the patient’s finger; an optical source and optical sensor pair to generate a pleth signal; and a bladder mountable within the finger cavity, in which, the patient’s finger received in the finger cavity abuts against the bladder. Further, control circuitry may be used to control pressure applied by the bladder to the patient’s finger based upon measuring the pleth signal received from the optical source and sensor pair to keep the pleth signal approximately constant to replicate the patient’s blood pressure to implement the volume clamp method and to measure the patient’s blood pressure. The bladder may be formed from a heat set material. The heat set material may be heat set at a predetermined temperature within a predetermined temperature range for a predetermined time, such that the bladder formed by the heat set material is set to a desired band shape.

Also a tube may be connected to the bladder, such that the tube provides pneumatic pressure to the bladder to provide pressure by the bladder to the patient’s finger to implement the volume clamp method.

[0014] By utilizing a bladder that utilizes a heat settable material, the previously described problem associated with the use of an additional“band” that slows down the manufacturing process and makes the manufacturing process more tedious, may be avoided.

[0015] In one optional example, the optical source and the optical sensor pair may include an LED- PD pair. In one optional example, the heat set material of the bladder comprises at least one of polyethylene terephthalate (PET), polyester, co-polyester, Nylon, polyurethane, or co polyamide. In another optional example, the bladder may comprise a top foil and a bottom foil. In one optional example, one or both of the top and bottom foil may comprise a heat set material of at least one of polyethylene terephthalate (PET), polyester, co-polyester, Nylon, polyurethane, or co-polyamide. As another optional example, the heat set material may be heat set to the desired band shape in a predetermined temperature range of 80°C~100°C for a predetermined time period of approximately 3 hours. Also, in one optional example, the co polyamide may be a high durometer co-polyamide.

[0016] As an example, with reference to FIG. 1, which illustrates an example of a blood pressure measurement system according to one example, a blood pressure measurement system 102 that includes a finger cuff 104 that may be attached to a patient’s finger and a blood pressure measurement controller 120, which may be attached to the patient’s body (e.g., a patient’s wrist or hand), is shown.

[0017] The blood pressure measurement system 102 may further be connected to a patient

monitoring device 130, and, in some embodiments, a pump 134. The finger cuff 104 may be formed from a flexible material that is wrapped around the patient’s finger such that the patient’s finger is received in a finger cavity of the finger cuff. Further, the finger cuff 104 may include a bladder (not shown) and an optical source and optical sensor pair (e.g., an LED-PD pair) (not shown), which are conventional for finger cuffs, that are located in the finger cavity of the finger cuff.

[0018] In one embodiment, the blood pressure measurement system 102 may include a pressure measurement controller 120 that includes: a small internal pump, a small internal valve, a pressure sensor, and control circuitry. In this embodiment, the control circuitry may be configured to: control the pneumatic pressure applied by the internal pump to the bladder of the finger cuff 104 to replicate the patient’s blood pressure based upon measuring the pleth signal received from the LED-PD pair of the finger cuff 104. Further, the control circuitry may be configured to: control the opening of the internal valve to release pneumatic pressure from the bladder; or the internal valve may simply be an orifice that is not controlled.

Additionally, the control circuitry may be configured to: measure the patient’s blood pressure by monitoring the pressure of the bladder based upon the input from a pressure sensor, which should correspond to or be the same as patient’s blood pressure, and may display the patient’s blood pressure on the patient monitoring device 130.

[0019] In another example, a conventional pressure generating and regulating system may be

utilized, in which, a pump 134 is located remotely from the body of the patient. In this embodiment, the blood pressure measurement controller 120 receives pneumatic pressure from remote pump 134 through tube 136 and passes on the pneumatic pressure through tube 123 to the bladder of finger cuff 104. Blood pressure measurement device controller 120 may also control the pneumatic pressure (e.g., utilizing a controllable valve) applied to the finger cuff 104 as well as other functions. In this example, the pneumatic pressure applied by the pump 134 to the bladder of finger cuff 104 to replicate the patient’s blood pressure based upon measuring the pleth signal received from the LED-PD pair of the finger cuff 104 (e.g., to keep the pleth signal constant) and measuring the patient’s blood pressure by monitoring the pressure of the bladder may be controlled by the blood pressure measurement controller 120 and/or a remote computing device and/or the pump 134 and/or the patient monitoring device 130 to implement the volume clamping method. In some embodiments, a blood pressure measurement controller 120 is not used at all and there is simply a connection from tube 136 from a remote pump 134 including a remote pressure regulatory system to finger cuff 104, and all processing for the pressure generating and regulatory system, data processing, and display is performed by a remote computing device.

[0020] Continuing with this example, as shown in FIG. 1, a patient’s hand may be placed on the face 110 of an arm rest 112 for measuring a patient’s blood pressure with the blood pressure measurement system 102. The blood pressure measurement controller 120 of the blood pressure measurement system 102 may be coupled to a bladder of the finger cuff 104 in order to provide pneumatic pressure to the bladder for use in blood pressure measurement. Blood pressure measurement controller 120 may be coupled to the patient monitoring device 130 through a power/data cable 132. Also, in one example, as previously described, in a remote implementation, blood pressure measurement controller 120 may be coupled to a remote pump 134 through tube 136 to receive pneumatic pressure for the bladder of the finger cuff 104. The patient monitoring device 130 may be any type of medical electronic device that may read, collect, process, display, etc., physiological readings/data of a patient including blood pressure, as well as any other suitable physiological patient readings. Accordingly, power/data cable 132 may transmit data to and from patient monitoring device 130 and also may provide power from the patient monitoring device 130 to the blood pressure

measurement controller 120 and finger cuff 104. In an optional example, the patient monitoring device 130 may be in wireless communication with the blood pressure measurement controller 120 and finger cuff 104 without the use of a wire.

[0021] As can be seen in FIG. 1, in one example, the finger cuff 104 may be attached to a patient’s finger and the blood pressure measurement controller 120 may be attached on the patient’s hand or wrist with an attachment bracelet 121 that wraps around the patient’s wrist or hand. The attachment bracelet 121 may be metal, plastic, Velcro, etc. It should be appreciated that this is just one example of attaching a blood pressure measurement controller 120 and that any suitable way of attaching a blood pressure measurement controller to a patient’s body or in close proximity to a patient’s body may be utilized and that, in some examples, a blood pressure measurement controller 120 may not be used at all. It should further be appreciated that the finger cuff 104 may be connected to a blood pressure measurement controller described herein, or a pressure generating and regulating system of any other kind, such as a pressure generating and regulating system that is located remotely from the body of the patient. Any kind of pressure generating and regulating system can be used, including but not limited to the blood pressure measurement controller, and may be described simply as a pressure generating and regulating system that may be used with a finger cuff 104 including an LED-PD pair and a bladder to implement the volume clamping method. In one optional example, the blood pressure measurement controller 120 and finger cuff 104 are a wearable device that may be in wireless communication with the patient monitoring device 130, as previously described. [0022] With additional reference to FIG. 2, FIG. 2 is a block diagram of a blood pressure measurement system 200 to measure the blood pressure of a patient. As an example, finger cuff 104 may be connectable to a patient’s finger to be used in measuring the patient’s blood pressure by the blood pressure measurement system utilizing the volume clamp method. As has been described, finger cuff 104 may be wrapped around a patient’s finger and may include a finger cavity to receive the patient’s finger. Further, finger cuff 104 may include an optical source and an optical sensor pair to measure a pleth signal. As an example, the optical source and an optical sensor pair may be an LED-PD pair 214, as they will be hereafter referred to, but may be any type of optical source and sensor pair to measure a pleth signal. Moreover, finger cuff 104 may include an inflatable bladder 212 mountable within the finger cavity of the finger cuff, in which, the patient’s finger received in the finger cavity abuts against the inflatable bladder 212 such that the inflatable bladder 212 and the LED-PD pair 214 are used in measuring the patient’s blood pressure information utilizing the volume clamp method.

[0023] Control circuitry 230 of the finger cuff 104 may be configured to: control pressure applied by the inflatable bladder 212 to the patient’s finger by the pressure generating and regulating system 220 to replicate the patient’s blood pressure based upon measuring the pleth signal by the LED-PD pair 214 (e.g., to keep the pleth signal approximately constant) to implement the volume clamp method.

[0024] The finger cuff 104 may be a finger cuff, as previously described, in which, the inflatable bladder 212 may be pneumatically connected to the pressure generating and regulating system 220. The LED may be used to illuminate the finger skin and light absorption or reflection may be detected with the PD. The pressure generating and regulating system 220 and control circuitry (e.g., including a processor) 230 may generate, measure, and regulate pneumatic pressure that inflates or deflates the inflatable bladder 212, and may further comprise such elements as a pump, a valve, a pressure sensor, and/or other suitable elements, as previously described. In particular, pressure generating and regulating system 220 in cooperation with control circuitry 230 may be configured to implement a volume clamp method with the finger cuff 104 by: applying pneumatic pressure to the inflatable bladder 212 of the finger cuff 104 to replicate the patient’s blood pressure based upon measuring the pleth signal received from the LED-PD pair 214 of the finger cuff 104 (e.g., to keep the pleth signal approximately constant); and measuring the patient’s blood pressure by monitoring the pressure of the inflatable bladder 212 based upon input from a blood pressure sensor 211, which should correspond to or be the same as patient’s blood pressure, and may further command the display of the patient’s blood pressure on the patient monitoring device 130 via wired or wireless communication. As previously described, in one optional example, the finger cuff 104, pressure generating and regulating system 220, and control circuitry 230 may be a wearable device that may be in wireless communication with the patient monitoring device 130.

[0025] Optional examples relate to utilizing an inflatable bladder 212 of a finger cuff 104 that

utilizes a heat settable material. For example, polyethylene terephthalate (PET or polyester), co-polyester, Nylon, polyurethane, or high durometer co-polyamide can be heat set to any shape desired. As an example, these materials are commonly used for an angioplasty balloon. An angioplasty balloon may be made by deforming extruded tubing under pressure at an elevated temperature. Such a balloon may be“frozen” in the deformed state to room temperature and thus“heat set” as a balloon. In optional examples to be hereafter described, the inflatable bladder 212 may be made out of one or more of these materials (e.g., PET, polyester, co-polyester, Nylon, polyurethane, or co-polyamide), and the inflatable bladder can be heat set to the desired“band” shape without the use of an additional polycarbonate band or HYTREL® band. As one optional example, heat setting can be achieved in an 80°C~100°C oven for about 3 hours or longer depending upon the type of bladder material utilized. It should be appreciated that these are only examples of heat settable materials that may be used, and that any suitable heat settable material for an inflatable bladder may be utilized.

[0026] With brief reference to FIG. 3, a process 201 may be performed. The process may include a first operation 203 in which a heat set material (e.g., PET, polyester, co-polyester, Nylon, polyurethane, or co-polyamide) is selected for forming an inflatable bladder 212. Next, in a second operation 204, the inflatable bladder 212 is formed from the heat set material. As an optional example, as shown in operation 205, the heat set material of the inflatable bladder 212 may heat set at a predetermined temperature within a predetermined temperature range for a predetermined time, such that the inflatable bladder 212 formed by the heat set material is set to a desired band shape.

[0027] With further additional reference to FIGs. 4 and 5, particular examples of an inflatable

bladder 212 will be described. As has been described, the finger cuff 104 is connected to a patient’s finger to be used in measuring the patient’s blood pressure by a blood pressure measurement system utilizing the volume clamp method, which includes the use of an inflatable bladder 212. The finger cuff 104 may comprise: a finger cavity to receive the patient’s finger; an optical source and optical sensor pair (e.g., LED-PD pair 214) to generate a pleth signal; and an inflatable bladder 212 mountable within the finger cavity, in which, the patient’s finger received in the finger cavity abuts against the inflatable bladder 212. Further, control circuitry 230 may be used to control pressure applied by the inflatable bladder 212 to the patient’s finger based upon measuring the pleth signal received from the optical source and sensor pair 214 to keep the pleth signal approximately constant to replicate the patient’s blood pressure to implement the volume clamp method and to measure the patient’s blood pressure, as has been described. [0028] As has been described, in one optional example, the inflatable bladder 212 may be formed from a heat set material. The heat set material may be heat set at a predetermined

temperature within a predetermined temperature range for a predetermined time, such that the inflatable bladder 212 formed by the heat set material is set to a desired band shape.

[0029] As one optional example, the inflatable bladder 212 may be balloon formed and assume the combined balloon shape of top portion 252 and bottom portion 254 combined together (shown in exploded form in FIG. 4). In one optional example, inflatable bladder 212 may be balloon formed by deforming extruded tubing of a selected material (e.g., via a free-blowing procedure) and may be put under pressure at an elevated temperature for a predetermined time. The balloon formed inflatable bladder 212 may then be“frozen” in the deformed state to room temperature and thus“heat set” to a desired band shape.

[0030] As another optional example, the inflatable bladder 212 may be formed from a separate top portion 252 (e.g., referred to as a top foil 252) and a separate bottom portion 254 (e.g., referred to as a bottom foil 254) that are welded together to create the inflatable bladder 212. After welding, inflatable bladder 212 may be balloon formed (e.g., via a free-blowing procedure) and may be put under pressure at an elevated temperature for a predetermined time. The balloon formed inflatable bladder 212 may then be“frozen” in the deformed state to room temperature and thus“heat set” to a desired band shape.

[0031] In either of the optional examples of the formation of the balloon shaped inflatable bladder 212 (e.g., via welding or extrusion), the inflatable bladder 212 may be made out of one or more of heat settable materials (e.g., PET, polyester, co-polyester, Nylon, polyurethane, or co-polyamide), and the inflatable bladder 212 can be heat set to the desired“band” shape without the use of an additional polycarbonate band or HYTREL® band. As one optional example, heat setting can be achieved in an 80°C~100°C oven for about 3 hours or longer depending upon the bladder material. Further, under any of these optional examples, the tube 123 may be connected to the inflatable bladder 112 by welding or by other suitable connection procedures. Moreover, it should be appreciated that these are only examples of heat setting procedures and that any suitable heat setting procedure to create a desired band shape may be utilized.

[0032] Examples of co-polyester and nylon with their deformation point temperatures and distortion temperatures that are suitable for balloon shaping and heat setting of the inflatable bladder 212 are shown in the table below:

[0033] It should be noted that the top portion 252 of the heat set shaped inflatable bladder 212 abuts the patient’s finger. Further, the tube 123 may be welded or connected by other suitable procedures to the heat set shaped inflatable bladder 212 during the formation of the inflatable bladder 212 or after the formation of the inflatable bladder 212. As an optional example, tube 123 may have a mating portion 261 that is connected within an extended portion of inflatable bladder 212. As has been described, the tube 123 provides pneumatic pressure to the heat set shaped inflatable bladder 212 to provide pressure by the inflatable bladder 212 to the patient’s finger to implement the volume clamp method, as has been described. In particular, the top portion 252 of the inflatable bladder 212 applies pressure directly to the patient’s finger when inflated with air. The inflatable bladder 212 should be able to follow quick pressure/volume changes without losing too much energy during the inflation and deflation process. The inflatable bladder 212, when assembled into the finger cuff 104, transfers the pressure directly to the finger. As can be seen, the top portion 252 and bottom portion 254 of the heat set shaped inflatable bladder 212 may be approximately rectangular shaped.

[0034] As an example of the assembly process of the heat set shaped inflatable bladder 212, holes 251 may be punched into the top portion 252. A print pattern 270 may be hot stamped onto the top portion 252. The use of the print pattern 270 will be discussed in more detail hereafter. Also, holes (not shown) may be punched into the bottom portion 254. In particular, the top portion 252, the bottom portion 254, and the mating portion 261 of the tube 123 may be positioned relative to one another and may be connected together, as previously described.

[0035] Further, as can be particularly seen in FIG. 5, the heat set shaped inflatable bladder 212 may be properly secured to a flexible finger wrapping portion 280 of the finger cuff 104. The inflatable bladder 212 may be properly secured to the flexible finger wrapping portion 280 by suitable securing mechanisms (e.g., adhesive, mechanical fastening mechanisms, welding, etc.). The flexible finger wrapping portion 280 may be approximately rectangular shaped and may be used such that the finger cuff 104 can be properly wrapped around the patient’s finger such that the finger cuff 104 may operate properly. Examples of flexible materials for the flexible finger wrapping portion 280 may include suitably flexible polymers (natural or synthetic), plastics, metals, combinations thereof, or any suitable flexible material. Further, the flexible finger wrapping portion 280 of the finger cuff 104 may include a proper fastening mechanism (e.g., VELCRO, reusable adhesive, mechanical clip, tape, etc.) to secure the finger cuff 104 to the patient’s finger. As an example, the internal side of the flexible wrapping portion 280 outside of the inflatable bladder 212 may include a fastening mechanism (e.g., VELCRO) that mates with a fastening mechanism (e.g., VELCRO) on the opposite exterior side of flexible wrapping portion 280 to secure the finger cuff 104 to a patient’s finger. [0036] Therefore, the finger cuff 104 being formed from a flexible material that is wrapped around the patient’s finger creates a finger cavity, such that the patient’s finger is received in the finger cavity of the finger cuff 104, and the finger cuff 104 is secured to the patient’s finger by suitable securing mechanisms, and the patient’s finger is secured in the finger cavity.

With this configuration, the heat set shaped inflatable bladder 212 is mounted within the finger cavity of the finger cuff 104, such that the patient’s finger received in the finger cavity abuts against the inflatable bladder 212. Further, the LED-PD pair 214 similarly located within the finger cavity of the finger cuff 104 in conjunction with the inflatable bladder 212 are used in measuring the patient’s blood pressure utilizing the volume clamp method, as previously described.

[0037] As can be seen in FIG. 5, the print pattern 270 may be used to guide the patient’s finger on the finger cuff 104 for proper mounting. The print pattern 270 may include a first rectangular colored section 276 located above the LED-PD pair 214 and a second section 274 for aligning with the patient’s finger that is rectangular shaped with two opposed arrows on opposite sides. The patient’s finger can be properly aligned within the finger cuff by being placed on the second rectangular shaped section 274 between the two arrows. Also, finger marking 272 may be located on the print pattern 270 to show the proper finger direction. In some examples, the finger cuff 104 may be sized as small, medium, or large for different patient’s finger sizes. However, any suitable sizing configuration may be utilized. By utilizing the previously described print pattern 270, the patient’s finger may be properly located within the finger cuff 104 and then secured to the patient’s finger with one of the previously described fastening mechanisms. The patient’s finger is secured within the finger cuff 104 between the LED-PD pair 214 (extending through holes) and within the inflatable bladder assembly 212 such that the heat set shaped inflatable bladder 212 provides pneumatic pressure to the patient’s finger to implement the volume clamp method, as has been described.

[0038] As has been described, the finger cuff 104 of FIGs. 1-5 may be connectable to a patient’s finger to be used in measuring the patient’s blood pressure by the blood pressure

measurement system utilizing the volume clamp method. Further, the finger cuff 104 may include an optical source and an optical sensor pair to measure a pleth signal. Typically, the optical source and an optical sensor pair may be an LED-PD pair 214, but may be any type of optical source and sensor pair to measure a pleth signal. Furthermore, finger cuff 104 may include the heat set shaped inflatable bladder 212 that is mounted within the finger cavity of the finger cuff 104 when the cuff is wrapped around the finger, in which, the patient’s finger received in the finger cavity abuts against the inflatable bladder 212 such that the inflatable bladder 212 and the LED-PD pair 214 are used in measuring the patient’s blood pressure information utilizing the volume clamp method. The patient’s finger may properly fitted within the finger cuff 104, utilizing the print pattern 270, as previously described. In particular, as has been described, a pressure generating and regulating system 220 in cooperation with control circuitry 230 may be configured to implement a volume clamp method with the finger cuff 104 by: applying pneumatic pressure to the inflatable bladder 212 of the finger cuff 104 to replicate the patient’s blood pressure based upon measuring the pleth signal received from the LED-PD pair 214 of the finger cuff 202 (e.g., to keep the pleth signal approximately constant); and measuring the patient’s blood pressure by monitoring the pressure of the inflatable bladder assembly 212 based upon input from a pressure sensor, which should correspond to or be the same as patient’s blood pressure, and may further command the display of the patient’s blood pressure on the patient monitoring device 130.

[0039] In particular, as has been described, an example of finger cuff may relate to a finger cuff 104 that is connectable to a patient’s finger to be used in measuring the patient’s blood pressure by a blood pressure measurement system utilizing the volume clamp method. The finger cuff 104 may comprise: a finger cavity to receive the patient’s finger; an optical source and optical sensor pair 214 to generate a pleth signal; and a bladder 212 mountable within the finger cavity, in which, the patient’s finger received in the finger cavity abuts against the bladder 212. Further, control circuitry 230 may be used to control pressure applied by the bladder 212 to the patient’s finger based upon measuring the pleth signal received from the optical source and sensor pair 214 to keep the pleth signal approximately constant to replicate the patient’s blood pressure to implement the volume clamp method and to measure the patient’s blood pressure. The bladder 212 may be formed from a heat set material. The heat set material may be heat set at a predetermined temperature within a predetermined temperature range for a predetermined time, such that the bladder 212 formed by the heat set material is set to a desired band shape. Also a tube 123 may be connected to the bladder 212, such that the tube provides pneumatic pressure to the bladder to provide pressure by the bladder to the patient’s finger to implement the volume clamp method.

[0040] As has been described, the inflatable bladder 212 may be formed from a heat set material.

The heat set material may be heat set at a predetermined temperature within a predetermined temperature range for a predetermined time, such that the inflatable bladder 212 formed by the heat set material is set to a desired band shape. The inflatable bladder may comprise a heat set material of at least one of polyethylene terephthalate (PET or polyester), co polyester, Nylon, polyurethane, or high durometer co-polyamide. As an optional example, the heat set material may be heat set to the desired band shape in a predetermined temperature range of 80°C~100°C for a predetermined time period of approximately 3 hours. Therefore, as an optional example, the inflatable bladder 212 may be made out of one or more of these materials (e.g., PET, polyester, co-polyester, Nylon, polyurethane, or co-polyamide), and the bladder can be heat set to the desired“band” shape utilizing a ballooning procedure without the use of an additional polycarbonate band or HYTREL® band. This greatly simplifies the time and complexity existing manufacturing processes.

[0041] It should be appreciated that Figure 2 illustrates a non-limiting example of a control circuitry 230 implementation. As an example, control circuitry may comprise a processor, a memory, and an input/output connected with a bus. Under the control of the processor, data may be received from an external source through the input/output interface and stored in the memory, and/or may be transmitted from the memory to an external destination through the

input/output interface. The processor may process, add, remove, change, or otherwise manipulate data stored in the memory. Further, code may be stored in the memory. The code, when executed by the processor, may cause the processor to perform operations relating to data manipulation and/or transmission and/or any other possible operations.

[0042] It should be appreciated that aspects of the invention previously described may be

implemented in conjunction with the execution of instructions by control circuitry, processors, circuitry, controllers, etc. As an example, control circuitry may operate under the control of a program, algorithm, routine, or the execution of instructions to execute methods or processes in accordance with embodiments of the invention previously described. For example, such a program may be implemented in firmware or software (e.g. stored in memory and/or other locations) and may be implemented by control circuitry, processors, and/or other circuitry, these terms being utilized interchangeably. Further, it should be appreciated that the terms processor, microprocessor, circuitry, control circuitry, circuit board, controller, microcontroller, etc., refer to any type of logic or circuitry capable of executing logic, commands, instructions, software, firmware, functionality, etc., which may be utilized to execute embodiments of the invention.

[0043] The various illustrative blocks, processors, modules, and circuitry described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a specialized processor, circuitry, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor may be a microprocessor or any conventional processor, controller, microcontroller, circuitry, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0044] The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module/firmware executed by a processor, or any combination thereof. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.

[0045] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

WHAT IS CLAIMED IS:

1. A finger cuff connectable to a patient’s finger to be used in measuring the patient’s blood pressure by a blood pressure measurement system utilizing the volume clamp method, the finger cuff comprising:

a finger cavity to receive the patient’s finger;

an optical source and optical sensor pair to generate a pleth signal;

a bladder mountable within the finger cavity, wherein the patient’s finger received in the finger cavity abuts against the bladder; and

control circuitry to control pressure applied by the bladder to the patient’s finger based upon measuring the pleth signal received from the optical source and sensor pair to keep the pleth signal approximately constant to replicate the patient’s blood pressure to implement the volume clamp method and to measure the patient’s blood pressure;

wherein, the bladder is formed from a heat set material, the heat set material being heat set at a predetermined temperature within a predetermined temperature range for a predetermined time, such that the bladder formed by the heat set material is set to a desired band shape, wherein a tube is connected to the bladder, such that the tube provides pneumatic pressure to the bladder to provide pressure by the bladder to the patient’s finger to implement the volume clamp method.

2. The finger cuff of claim 1, wherein the optical source and the optical sensor pair includes an LED-PD pair.

3. The finger cuff of claim 1, wherein the heat set material of the bladder comprises at least one of polyethylene terephthalate, polyester, co-polyester, Nylon, polyurethane, or co polyamide.

4. The finger cuff of claim 1, wherein the bladder comprises a top foil and a bottom foil.

5. The finger cuff of claim 4, wherein one or both of the top and bottom foil comprise a heat set material of at least one of polyethylene terephthalate, polyester, co-polyester,

Nylon, polyurethane, or co-polyamide.

6. The finger cuff of claim 1 or 5, wherein the heat set material is heat set to the desired band shape in a predetermined temperature range of 80°C~100°C for a predetermined time period of approximately 3 hours.

7. A system to measure a patient’s blood pressure, the system comprising:

a finger cuff connectable to a patient’ s finger to be used in measuring the patient’ s blood pressure by a blood pressure measurement system utilizing the volume clamp method, the finger cuff comprising:

a finger cavity to receive the patient’s finger;

an optical source and optical sensor pair to generate a pleth signal;

control circuitry to control pressure applied by the bladder to the patient’s finger based upon measuring the pleth signal received from the optical source and sensor pair to keep the pleth signal approximately constant to replicate the patient’s blood pressure to implement the volume clamp method and to measure the patient’s blood pressure; wherein the bladder is formed from a heat set material, the heat set material being heat set at a predetermined temperature within a predetermined temperature range for a predetermined time, such that the bladder formed by the heat set material is set to a desired band shape, wherein a tube is connected to the bladder, such that the tube provides pneumatic pressure to the bladder to provide pressure by the bladder to the patient’s finger to implement the volume clamp method.

8. The system of claim 7, wherein the optical source and the optical sensor pair includes an LED-PD pair.

9. The system of claim 7, wherein the heat set material of the bladder comprises at least one of polyethylene terephthalate, polyester, co-polyester, Nylon, polyurethane, or co polyamide.

10. The system of claim 7, wherein the bladder comprises a top foil and a bottom foil.

11. The system of claim 10, wherein one or both of the top and bottom foil comprise a heat set material of at least one of polyethylene terephthalate, polyester, co-polyester, Nylon, polyurethane, or co-polyamide.

12. The system of claim 7 or 11, wherein the heat set material is heat set to the desired band shape in a predetermined temperature range of 80°C~100°C for a predetermined time period of approximately 3 hours.

13. A method to measure a patient’s blood pressure by a finger cuff connectable to a patient’s finger with a blood pressure measurement system utilizing the volume clamp method, the method comprising:

attaching the finger cuff to the patient’s finger, wherein the patient’s finger received in a finger cavity of the finger cuff abuts against a bladder mounted within the finger cavity; and controlling pressure applied by the bladder to the patient’ s finger based upon measuring a pleth signal received from an optical source and optical sensor pair of the finger cuff to keep the pleth signal approximately constant to replicate the patient’s blood pressure to implement the volume clamp method and to measure the patient’s blood pressure, wherein, the bladder is formed from a heat set material, the heat set material being heat set at a predetermined temperature within a predetermined temperature range for a predetermined time, such that the bladder formed by the heat set material is set to a desired band shape, wherein a tube is connected to the bladder, such that the tube provides pneumatic pressure to the bladder to provide pressure by the bladder to the patient’s finger to implement the volume clamp method.

14. The method of claim 13, wherein the optical source and the optical sensor pair includes an LED-PD pair.

15. The method of claim 13, wherein the heat set material of the bladder comprises at least one of polyethylene terephthalate, polyester, co-polyester, Nylon, polyurethane, or co polyamide.

16. The method of claim 13, wherein, the bladder comprises a top foil and a bottom foil.

17. The method of claim 16, wherein one or both of the top and bottom foil comprise a heat set material of at least one of polyethylene terephthalate, polyester, co-polyester, Nylon, polyurethane, or co-polyamide.

18. The method of claim 13 or 16, wherein the heat set material is heat set to the desired band shape in a predetermined temperature range of 80°C~100°C for a predetermined time period of approximately 3 hours.