WO2021086497A1

WO2021086497A1 - Finger cuff with de-coupled sensor and bladder and associated method

Info

Publication number: WO2021086497A1
Application number: PCT/US2020/049722
Authority: WO
Inventors: Jeong Soo Lee
Original assignee: Edwards Lifesciences Corporation
Priority date: 2019-10-28
Filing date: 2020-09-08
Publication date: 2021-05-06
Also published as: EP4051101A1; CN114599276A

Abstract

Disclosed is 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 may comprise: a pleth cuff; a bladder cuff; an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient's finger; a bladder mountable within the bladder cuff, wherein the patient's finger abuts against the bladder of the bladder cuff; and a controller. The controller 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.

Description

FINGER CUFF WITH DE-COUPLED SENSOR AND BLADDER AND ASSOCIATED METHOD

BACKGROUND

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62/926,852 filed October 28, 2019, which is incorporated by reference herein in its entirety.

Field

[0002] 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 a patient’s blood pressure by a blood pressure measurement system utilizing the volume clamp method, in which, the finger cuff utilizes a sensor and bladder that are de-coupled from one another.

Relevant Background

[0003] 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.

[0004] This may be accomplished by a finger cuff that is arranged or wrapped around the finger of a patient. The finger cuff may include an optical source and an optical sensor pair (e.g., a light emitting diode - photodiode (LED-PD) pair)) 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.

[0005] 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 increase. 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] One issue that arises with present day finger cuffs is that the bladder and the optical source and sensor pair are structurally connected together, such that, as pressure is applied, and the bladder inflates, the optical source and sensor pair (e.g., the LED-PD pair) is pushed away from the finger, losing close contact with finger, and is changed in position from the initial finger contact positions, and calibration is then required. Because of this, the frequent use of a calibration algorithm (e.g., a Physiocal algorithm) is required to obtain a better plethysmograph signal by the step wise increase of pressure to the bladder and measuring the plethysmograph signal strength, and then applying that optimum pressure to the bladder. Unfortunately, current finger cuff design, with current optical source and sensor pair and bladder design structures, causes instability in the contact between the optical source and sensor pair and the patient’ s finger, requires frequent calibration, and decreases the potential accuracy of the plethysmograph-based blood pressure measurement of the patient. SUMMARY

[0010] In one example, disclosed is a system to measure a patient’s blood pressure and a finger cuff for use in the system, in which, the finger cuff may be 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 pleth cuff to define a pleth cuff finger cavity to receive the patient’ s finger; a bladder cuff to define a bladder cuff finger cavity to receive the patient’s finger; an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient’s finger received in the pleth cuff finger cavity; and a bladder mountable within the bladder cuff, wherein the patient’s finger received in the bladder cuff finger cavity abuts against the bladder of the bladder cuff. Further, a controller 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. In one optional example, the pleth cuff including the optical source and optical sensor pair and the bladder cuff including the bladder are de-coupled from one another. Therefore, as an optional example, two distinct cuffs may be utilized - a bladder cuff including the inflatable bladder and a pleth cuff including the plethysmograph optical source and the optical sensor. The bladder and pleth cuffs may be separated or connected together, but are individually structurally distinctly formed. As an optional example, the pleth cuff and the bladder cuff may be connected together to form a complete integrated housing structure. In another optional example, the pleth cuff and the bladder cuff may be separate from one another and separately connected to the patient’ s finger. In one optional example, the optical source and optical sensor pair of the pleth cuff may include an emitter and detector. As one optional example, the emitter and detector pair of the pleth cuff may include an LED-PD pair. As a further optional example, the pleth cuff may be mounted closer to the patient’s fingertip distal from the bladder cuff. It should be appreciated that the optional examples may be utilized independently from one another or in combination with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a diagram of an example of a blood pressure measurement system, according to one example.

[0012] FIG. 2 is a block diagram of a finger cuff system to measure the blood pressure of a patient, according to one example. [0013] FIG. 3 is diagram illustrating one optional example of a de-coupled finger cuff.

[0014] FIG. 4 is diagram illustrating another optional example of a de-coupled finger cuff.

DETAILED DESCRIPTION

[0015] Examples of the disclosure relate to a finger cuff, in which, the bladder is de coupled from the optical source and sensor pair. As has been described, one issue that arises with present day finger cuffs is that the bladder and the optical source and sensor pair are structurally connected together, such that, as pressure is applied, and the bladder inflates, the optical source and sensor pair (e.g., the LED-PD pair) is pushed away from the finger, losing close contact with finger, and is changed in position from the initial finger contact positions, and calibration is then required. Because of this, the frequent use of a calibration algorithm (e.g., a Physiocal algorithm) is required to obtain a better plethysmograph signal by the step wise increase of pressure to the bladder and measuring the plethysmograph signal strength, and then applying that optimum pressure to the bladder. Unfortunately, current finger cuff design, with current optical source and sensor pair and bladder design structures, causes instability in the contact between the optical source and sensor pair and the patient’s finger, requires frequent calibration, and decreases the potential accuracy of the plethysmograph- based blood pressure measurement of the patient.

[0016] Examples of the disclosure relate to a finger cuff, in which, the bladder is de coupled from the optical source and sensor pair. In particular, in contrast to current implementations, by keeping the optical source and sensor pair (e.g., an LED- PD pair) position at a fixed location, away from the inflatable bladder, with a good intimate contact against the finger, finger movement may not cause instability and the accuracy of the non- invasive plethysmograph-based blood pressure measurement of the patient may be improved. As a particular example, the inflatable bladder may be de-coupled from the optical source and sensor pair, such as, a plethysmograph emitter and detector (e.g., an LED-PD pair). As one optional example, two distinct cuffs may be utilized - a bladder cuff including the inflatable bladder and a pleth cuff including the plethysmograph emitter optical source and the optical sensor or detector. As a particular optional example, the pleth cuff may be distal (closer to the fingertip) than the bladder cuff. The bladder and pleth cuffs may be separated or connected together, but are individually structurally distinctly formed. By having the bladder separate from the optical source and sensor pair, the volume of air required for the bladder may be reduced, such that, a smaller capacity pump may be utilized. Also, the accuracy of the reading of the plethysmograph signal from the optical source and sensor pair may be improved because of less movement of the optical source and sensor pair and intimate contact is maintained against the finger thus reducing the need for frequent calibration settings (e.g., a Physiocal algorithm), even when the finger is moving about.

[0017] In one example, disclosed is a system to measure a patient’s blood pressure and a finger cuff for use in the system, in which, the finger cuff may be 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 pleth cuff to define a pleth cuff finger cavity to receive the patient’ s finger; a bladder cuff to define a bladder cuff finger cavity to receive the patient’s finger; an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient’s finger received in the pleth cuff finger cavity; and a bladder mountable within the bladder cuff, wherein the patient’s finger received in the bladder cuff finger cavity abuts against the bladder of the bladder cuff. Further, a controller 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. In one optional example, the pleth cuff including the optical source and optical sensor pair and the bladder cuff including the bladder are de-coupled from one another. Therefore, as an optional example, two distinct cuffs may be utilized - a bladder cuff including the inflatable bladder and a pleth cuff including the plethysmograph emitter optical source and the optical sensor or detector. The bladder and pleth cuffs may be separated or connected together, but are individually structurally distinctly formed. As an optional example, the pleth cuff and the bladder cuff may be connected together to form a complete integrated housing structure. In another optional example, the pleth cuff and the bladder cuff may be separate from one another and separately connected to the patient’s finger. In one optional example, the optical source and optical sensor pair of the pleth cuff may include an emitter and detector. As one optional example, the emitter and detector pair of the pleth cuff may include an LED-PD pair. As a further optional example, the pleth cuff may be mounted closer to the patient’s fingertip distal from the bladder cuff. It should be appreciated that the optional examples may be utilized independently from one another or in combination with one another.

[0018] As an example, with reference to FIG. 1, which illustrates an example of a blood pressure measurement system according to one optional 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.

[0019] 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. Particular differing structures of the finger cuff 104 that include different types of bladder cuffs and pleth cuffs, will be described in more detail hereafter. 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, and that may be implemented with optional examples related to bladder cuffs and pleth cuffs that will be described in more detail hereafter.

[0020] In one optional example, 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 example, 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.

[0021] In another optional 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 example, 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.

[0022] 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 optional 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.

[0023] 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 optional 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 of any structural configuration that may be in wireless communication with the patient monitoring device 130, as previously described. As one example, all of the previously described structural components may be located in the finger cuff itself and are mounted on the patient’s finger as a wearable device.

[0024] 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. In this optional example, the finger cuff 104 may be 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 pleth cuff 214 to define a pleth cuff finger cavity to receive the patient’s finger; a bladder cuff 212 to define a bladder cuff finger cavity to receive the patient’s finger; an optical source and an optical sensor pair 215 mounted in the pleth cuff 214, in which, the optical source and the optical sensor pair 215 generate a pleth signal from the patient’s finger received in the pleth cuff finger cavity; and a bladder 213 mountable within the bladder cuff 212, in which, the patient’s finger received in the bladder cuff finger cavity abuts against the bladder 213 of the bladder cuff. The bladder 213 may be referred to as inflatable bladder.

[0025] Further, a controller 230 (e.g., control circuitry) may be used to control pressure applied by the bladder 213 to the patient’s finger based upon measuring the pleth signal received from the optical source and sensor pair 215 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. In one optional example, the pleth cuff 214 including the optical source and optical sensor pair 215 and the bladder cuff 212 including the bladder 213 are de-coupled from one another. Therefore, as an optional example, two distinct cuffs may be utilized - a bladder cuff 212 including the inflatable bladder 213 and a pleth cuff 214 including the plethysmograph emitter optical source and the optical sensor or detector pair, that are separate from one another. The bladder cuff 212 and the pleth cuff 214 may be separated or connected together, but are individually structurally distinctly formed. As an optional example, the pleth cuff 214 and the bladder cuff 212, although each structurally distinctly formed, may be connected together to form a complete integrated housing structure. In another optional example, the pleth cuff 214 and the bladder cuff 212 may be separate from one another and separately connected to the patient’s finger.

[0026] In one optional example, the optical source and optical sensor pair 215 of the pleth cuff 214 may include an emitter and detector. As one optional example, the emitter and detector pair 215 of the pleth cuff 214 may include an LED-PD pair. Therefore, as an optional example, the optical source and an optical sensor pair 215 may be an LED-PD pair, as they may be hereafter referred to, but may be any type of optical source and sensor pair to measure a pleth signal. It should be appreciated that the optical source may be any type of light or electromagnetic waveform emitter and the optical sensor may be any type of light or electromagnetic waveform sensor. It should be appreciated that any type of source and sensor pair that can transmit a signal through a finger to create a measurable pleth signal may be utilized.

[0027] Further, as an explanation of the optional example, control circuitry 230 of the finger cuff 104 may be configured to: control pressure applied by the inflatable bladder 213 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 from the LED-PD pair 215 (e.g., to keep the pleth signal approximately constant) to implement the volume clamp method. The finger cuff 104 may be a finger cuff, as previously described, in which, the inflatable bladder 213 may be pneumatically connected to the pressure generating and regulating system 220. In the LED-PD example, 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 213, 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 213 of the finger cuff 104 to replicate the patient’s blood pressure based upon measuring the pleth signal received from the LED-PD pair 215 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 assembly 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. [0028] With further additional reference to FIG. 3, an optional example of a de coupled bladder cuff 212 and pleth cuff 214 of a finger cuff 301 will be described. As can be seen in FIG. 3, finger cuff 301 (previously described as 104) may be connected to a patient’s finger 300 to be used in measuring the patient’s blood pressure by a blood pressure measurement system utilizing the volume clamp method.

[0029] As set forth in this optional example of FIG. 3, the inflatable bladder 213 is de-coupled from the optical source and optical sensor pair 215 (e.g., emitter and detector, LED-PD pair 310 and 315). In this optional example, two distinct cuffs may be utilized - a bladder cuff 212 including the inflatable bladder 213 and a pleth cuff 214 including optical source and sensor pair 215 (e.g., emitter and detector, LED-PD pair 310 and 315). As shown in FIG. 3, a separate bladder cuff 212 that is approximately rectangular- shaped to which the approximately rectangular- shaped inflatable bladder 213 is suitably mounted therein may wrapped around the patient’s finger 300. Further, the blood pressure sensor 211, as previously described, may be included with the bladder cuff 212. Additionally, pneumatic pressure may be supplied to the inflatable bladder 213 via appropriate tubing 123 from the pressure generating and regulating system 220 (e.g., from a pump), as previously described. Similarly, a separate distinct approximately rectangular- shaped pleth cuff 214 to which the optical sensor and sensor pair 215 (e.g., emitter and detector, LED-PD pair 310 and 315) is suitably mounted therein may be wrapped around the patient’s finger 300. The de-coupled distinct bladder cuff 212 and pleth cuff 214 may be connected together by an approximately rectangular- shaped connector 304 to keep them connected together in a simple manner. In this way, the pleth cuff 214 and the bladder cuff 212 may be connected together to form a complete integrated housing structure. As an optional example, the pleth cuff 214 may be mounted closer to the patient’s fingertip distal from the bladder cuff 212. However, the alternative is also possible, in which, the bladder cuff 212 may be mounted closer to the patient’s fingertip distal from the pleth cuff 214.

[0030] In this optional example of finger cuff 301 that includes de-coupled distinct bladder cuff 212 and pleth cuff 214 connected by connector 304, the bladder cuff 212, the pleth cuff 214, and the connector 304 may be largely formed by a flexible material. The bladder cuff 212 and pleth cuff 214 of the finger cuff 301 may be formed from flexible material so that they can be properly wrapped around the patient’s finger such that the finger cuff 301 may operate properly. Examples of flexible materials for the bladder cuff 212 and pleth cuff 214 may include suitable flexible polymers (natural or synthetic), plastics, metals, combinations thereof, or any suitable flexible material. Further, the bladder cuff 212 and pleth cuff 214 of the finger cuff 301 each may include a proper fastening mechanism (e.g., VELCRO, reusable adhesive, mechanical clip, tape, etc.) to secure the bladder cuff 212 and pleth cuff 214 of the finger cuff 301 individually to the patient’s finger. As an example, the interior sides of the each of the bladder cuff 212 and pleth cuff 214 outside of the inflatable bladder assembly 213 area or optical sensor and sensor pair 215 area, respectively, may each include a fastening mechanism (e.g., VELCRO) that mates with a fastening mechanism (e.g., VELCRO) on the opposite exterior side of the bladder cuff 212 and pleth cuff 214, respectively, to secure each of these components to the patient’s finger 300. It should be appreciated that VELCRO is just an example and that any suitable fastening mechanism may be utilized.

[0031] As shown in the optional example of FIG. 3, finger cuff 301 may be connectable to a patient’s finger 300 to be used in measuring the patient’s blood pressure utilizing the volume clamp method. Finger cuff 301 may comprise: a pleth cuff 214 to define a pleth cuff finger cavity to receive the patient’s finger 300; a bladder cuff 212 to define a bladder cuff finger cavity to receive the patient’s finger 300; an optical source and an optical sensor pair 215 suitably mounted in the pleth cuff 214, in which, the optical source and the optical sensor pair 215 generate a pleth signal from the patient’s finger 300 received in the pleth cuff finger cavity; and an inflatable bladder 213 suitably mountable within the bladder cuff 212, in which, the patient’s finger 300 received in the bladder cuff finger cavity abuts against the bladder 213 of the bladder cuff. As has been described, each of the bladder cuff 212 and pleth cuff 214 may be formed from a flexible wrappable material and may be wrapped around the patient’s finger 300 and secured with an appropriate fastening mechanism.

[0032] Further, as part of the volume clamp method, a controller (e.g., control circuitry 230) may be used to control pressure applied by the inflatable bladder 213 of the bladder cuff 212 to the patient’s finger 300 based upon measuring the pleth signal received from the optical source and sensor pair 215 of the pleth cuff 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, and as shown in FIG. 3, in one optional example, the pleth cuff 214 including the optical source and optical sensor pair 215 and the bladder cuff 212 including the bladder 213 are de-coupled from one another, and are separately wrapped around the patient’ s finger. Therefore, as an optional example, two distinct cuffs may be utilized - a bladder cuff 212 including the inflatable bladder 213 and a pleth cuff 214 including the plethysmograph emitter optical source and the optical sensor or detector pair. In this optional example, the pleth cuff 214 and the bladder cuff 212, although each structurally distinctly formed, may be connected together by connector 304 to form a complete integrated housing structure.

[0033] As has been described, in one optional example, the optical source and optical sensor pair 215 of the pleth cuff 214 may include an emitter and detector. As one optional example, the emitter and detector pair 215 of the pleth cuff 214 may include an LED-PD pair (310, 315). Therefore, as an optional example, the optical source and an optical sensor pair 215 may be an LED-PD pair (310, 315), but may be any type of optical source and sensor pair to generate a pleth signal. Continuing with this optional example, the LED-PD pair (310, 315) may be suitably mounted on the pleth cuff 214 and have appropriate circuitry to control the transmission and receipt of light signals via the LED-PD pair (310, 315) and to transmit signals and data back to control circuitry 230 to measure the pleth signal as part of the volume clamp method. Signals and data may be transmitted via a wired or wireless transmitter 308 to control circuitry 230 or another computing device to measure the pleth signal or along a wired implementation in conjunction with tube 123 from the bladder cuff 212 back to a pressure measurement controller (e.g., pressure measurement controller 120 that includes control circuitry).

[0034] Utilizing this optional example, finger cuff 301 may be connectable to a patient’s finger 300 to be used in measuring the patient’s blood pressure utilizing the volume clamp method. Finger cuff 301 may comprise: the pleth cuff 214 to define a pleth cuff finger cavity to receive the patient’s finger 300; the bladder cuff 212 to define a bladder cuff finger cavity to receive the patient’s finger 300; an optical source and an optical sensor pair 215 suitably mounted in the pleth cuff 214, in which, the optical source and the optical sensor pair 215 generate a pleth signal from the patient’s finger 300 received in the pleth cuff finger cavity; and an inflatable bladder 213 suitably mountable within the bladder cuff 212, in which, the patient’s finger received in the bladder cuff 212 finger cavity abuts against the bladder 213 of the bladder cuff. Control circuitry 230 of the finger cuff 104 may be configured to: control pressure applied by the inflatable bladder 213 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 received by the LED-PD pair 215 (e.g., to keep the pleth signal approximately constant) to implement the volume clamp method. The finger cuff 301 may be a finger cuff, as previously described, in which, the inflatable bladder 213 may be pneumatically connected to the pressure generating and regulating system 220. 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 213, and may further comprise such elements as a pump, a valve, a pressure sensor, and/or other suitable elements, as previously described. It should be appreciated that the optional examples may be utilized independently from one another or in combination with one another.

[0035] 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 301 by: applying pneumatic pressure to the inflatable bladder 213 of the finger cuff 301 to replicate the patient’s blood pressure based upon measuring the pleth signal received from the LED-PD pair 215 of the finger cuff 301 (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 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 has been described, in optional examples, finger cuff 301, blood pressure measurement controller 120, pressure generating and regulating system 220, and control circuitry 230 may be a wearable device (e.g., only on the finger, on the hand and finger, other suitable body portions, etc.) that may be in wireless or wired communication with a patient monitoring device 130. It should be appreciated that the optional examples may be utilized independently from one another or in combination with one another.

[0036] With further additional reference to FIG. 4, another optional example of a de coupled bladder cuff 212 and pleth cuff 214 of a finger cuff 401 will be described. As can be seen in FIG. 4, finger cuff 401 (previously denoted 104) may be connected to a patient’s finger 400 to be used in measuring the patient’s blood pressure by a blood pressure measurement system utilizing the volume clamp method.

[0037] As set forth, in this other optional example of FIG. 4, the inflatable bladder 213 is de-coupled from the optical source and optical sensor pair 215 (e.g., emitter and detector, FED-PD pair 410 and 415). In this optional example, two completely separate and unconnected bladder and pleth cuffs may be utilized - a bladder cuff 212 including the inflatable bladder 213 and a pleth cuff 214 including the optical source and sensor pair 215 (e.g., emitter and detector, FED-PD pair 410 and 415). As shown in FIG. 4, a separate bladder cuff 212 that is approximately rectangular- shaped to which the approximately rectangular- shaped inflatable bladder 213 is suitably mounted therein may wrapped around the patient’s finger 400. Further, a blood pressure sensor 411, as previously described, may be included with the bladder cuff 212. Additionally, pneumatic pressure may be supplied to the inflatable bladder 213 via appropriate tubing 123 from the pressure generating and regulating system 220 (e.g., from a pump), as previously described. Similarly, a separate distinct approximately rectangular- shaped pleth cuff 214 to which the optical sensor and sensor pair 215 (e.g., emitter and detector, LED-PD pair 410 and 415) is suitably mounted therein may be wrapped around the patient’s finger 400. It should be appreciated, that, in this optional example, the de-coupled distinct bladder cuff 212 and pleth cuff 214 are separated from one another and each may be separately connected to the patient’s finger 400. As an optional example, the pleth cuff 214 may be mounted closer to the patient’s fingertip distal from the bladder cuff 212. However, the alternative is also possible, in which, the bladder cuff 212 may be mounted closer to the patient’s fingertip distal from the pleth cuff 214.

[0038] In this optional example of finger cuff 401 that includes separate bladder cuff 212 and separate pleth cuff 214, the bladder cuff 212 and the pleth cuff 214 may be largely formed by flexible material. The bladder cuff 212 and pleth cuff 214 of the finger cuff 401 may be formed from flexible material so that they can be properly wrapped around the patient’s finger such that the finger cuff 401 may operate properly. Examples of flexible materials for the bladder cuff 212 and pleth cuff 214 may include suitable flexible polymers (natural or synthetic), plastics, metals, combinations thereof, or any suitable flexible material. Further, the bladder cuff 212 and pleth cuff 214 of the finger cuff 401 each may include a proper fastening mechanism (e.g., VELCRO, reusable adhesive, mechanical clip, tape, etc.) to secure the bladder cuff 212 and pleth cuff 214 of the finger cuff 401 individually to the patient’s finger. As an example, the interior sides of the each of the bladder cuff 212 and pleth cuff 214 outside of the inflatable bladder assembly 213 area or optical sensor and sensor pair 215 area, respectively, may each include a fastening mechanism (e.g., VELCRO) that mates with a fastening mechanism (e.g., VELCRO) on the opposite exterior side of the bladder cuff 212 and pleth cuff 214, respectively, to secure each of these components the patient’s finger 300. It should be appreciated that VELCRO is just an example and that any suitable fastening mechanism may be utilized.

[0039] As shown in the optional example of FIG. 4, finger cuff 401 may be connectable to a patient’s finger 400 to be used in measuring the patient’s blood pressure utilizing the volume clamp method. Finger cuff 401 may comprise: a pleth cuff 214 to define a pleth cuff finger cavity to receive the patient’s finger 400; a bladder cuff 212 to define a bladder cuff finger cavity to receive the patient’s finger 400; an optical source and an optical sensor pair 215 suitably mounted in the pleth cuff 214, in which, the optical source and the optical sensor pair 215 generate a pleth signal from the patient’s finger 400 received in the pleth cuff finger cavity; and an inflatable bladder 213 suitably mountable within the bladder cuff 212, in which, the patient’s finger 400 received in the bladder cuff 212 finger cavity abuts against the bladder 213 of the bladder cuff. As has been described, each of the bladder cuff 212 and pleth cuff 214 may be formed from a flexible wrappable material and may be wrapped around the patient’s finger 400 and secured with an appropriate fastening mechanism.

[0040] Further, as part of the volume clamp method, a controller (e.g., control circuitry 230) may be used to control pressure applied by the inflatable bladder 213 of the bladder cuff 212 to the patient’s finger 400 based upon measuring the pleth signal received from the optical source and sensor pair 215 of the pleth cuff 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, and as shown in FIG. 4, in one optional example, the pleth cuff 214 including the optical source and optical sensor pair 215 and the bladder cuff 212 including the bladder 213 are de-coupled and are completely separate from one another, and are each separately wrapped around the patient’s finger 400. Therefore, as an optional example, two distinct and separate cuffs may be utilized - a bladder cuff 212 including the inflatable bladder 213 and a pleth cuff 214 including the plethysmograph emitter optical source and the optical sensor or detector pair.

[0041] As has been described, in one optional example, the optical source and optical sensor pair 215 of the pleth cuff 214 may include an emitter and detector. As one optional example, the emitter and detector pair 215 of the pleth cuff 214 may include an LED-PD pair (410, 415). Therefore, as an optional example, the optical source and optical sensor pair 215 may be an LED-PD pair (410, 415), but may be any type of optical source and sensor pair to generate a pleth signal. Continuing with this optional example, the LED-PD pair (410, 415) may be suitably mounted on the pleth cuff 214 and have appropriate circuitry to control the transmission and receipt of light signals via the LED-PD pair (410, 415) and to transmit signals and data back to control circuitry 230 to measure the pleth signal as part of the volume clamp method. Signals and data may be transmitted via a wired or wireless transmitter 420 to control circuitry 230 or another computing device to measure the pleth signal or along a wired implementation in conjunction with tube 123 from the bladder cuff 212 back to a pressure measurement controller (e.g., pressure measurement controller 120 that includes control circuitry). [0042] Utilizing this optional example, finger cuff 401 may be connectable to a patient’s finger 400 to be used in measuring the patient’s blood pressure utilizing the volume clamp method. Finger cuff 401 may comprise: the pleth cuff 214 to define a pleth cuff finger cavity to receive the patient’s finger 400; the bladder cuff 212 to define a bladder cuff finger cavity to receive the patient’s finger 400; an optical source and an optical sensor pair 215 suitably mounted in the pleth cuff 214, in which, the optical source and the optical sensor pair 215 generate a pleth signal from the patient’s finger 400 received in the pleth cuff finger cavity; and an inflatable bladder 213 suitably mountable within the bladder cuff 212, in which, the patient’s finger received in the bladder cuff 212 finger cavity abuts against the bladder 213 of the bladder cuff. Control circuitry 230 of the finger cuff 401 may be configured to: control pressure applied by the inflatable bladder 213 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 from the LED-PD pair 215 (e.g., to keep the pleth signal approximately constant) to implement the volume clamp method. The finger cuff 401 may be a finger cuff, as previously described, in which, the inflatable bladder 213 may be pneumatically connected to the pressure generating and regulating system 220. 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 213, and may further comprise such elements as a pump, a valve, a pressure sensor, and/or other suitable elements, as previously described. It should be appreciated that the optional examples may be utilized independently from one another or in combination with one another.

[0043] 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 401 by: applying pneumatic pressure to the inflatable bladder 213 of the finger cuff 401 to replicate the patient’s blood pressure based upon measuring the pleth signal received from the LED-PD pair 215 of the finger cuff 401 (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 blood pressure sensor 411, 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 has been described, in optional examples, finger cuff 401, blood pressure measurement controller 120, pressure generating and regulating system 220, and control circuitry 230 may be a wearable device (e.g., only on the finger, on the hand and finger, other suitable body portions, etc.) that may be in wireless or wired communication with the patient monitoring device 130. It should be appreciated that the optional examples may be utilized independently from one another or in combination with one another.

[0044] As has been described, one issue that arises with present day finger cuffs is that the bladder and the optical source and sensor pair are structurally connected together, such that, as pressure is applied, and the bladder inflates, the optical source and sensor pair (e.g., the LED-PD pair) is pushed away from the finger, losing close contact with finger, and is changed in position from the initial finger contact positions, and calibration is then required. Because of this, the frequent use of a calibration algorithm (e.g., a Physiocal algorithm) is required to obtain a better plethysmograph signal by the step wise increase of pressure to the bladder and measuring the plethysmograph signal strength, and then applying that optimum pressure to the bladder. Unfortunately, current finger cuff design, with current optical source and sensor pair and bladder design structures, causes instability in the contact between the optical source and sensor pair and the patient’s finger, requires frequent calibration, and decreases the potential accuracy of the plethysmograph-based blood pressure measurement of the patient.

[0045] As has been described, examples of the disclosure relate to a finger cuff, in which, the bladder 213 is de-coupled from the optical source and sensor pair 215. In particular, in contrast to current implementations, by keeping the optical source and sensor pair 215 (e.g., an LED- PD pair) position at a fixed location, away from the inflatable bladder, with a good intimate contact against the finger, finger movement may not cause instability and the accuracy of the non- invasive plethysmograph-based blood pressure measurement of the patient may be improved. As a particular example, the inflatable bladder 213 may be de-coupled from the optical source and sensor pair 215, such as, a plethysmograph emitter and detector (e.g., an LED-PD pair). As one optional example, two distinct cuffs may be utilized - a bladder cuff 212 including the inflatable bladder 213 and a pleth cuff 214 including the plethysmograph emitter optical source and the optical sensor or detector. As has been described, the bladder cuff 212 and the pleth cuff 214 may be completely separate (e.g., the implementation of FIG. 4) or may be connected together (e.g., the implementation of FIG. 3). However, in either implementation, the pleth cuff 214 and bladder cuff 212 are structurally independently formed and implemented. By having the inflatable bladder 213 separate from the optical source and sensor pair 215, the volume of air required for the bladder may be reduced, such that, a smaller capacity pump may be utilized. Also, the accuracy of the reading of the plethysmograph signal from the optical source and sensor pair may be improved because of less movement of the optical source and sensor pair and intimate contact is maintained against the finger thus reducing the need for frequent calibration settings (e.g., a Physiocal algorithm), even when the finger is moving about. It should be appreciated that aspects of the optional examples of FIG. 3 and FIG. 4, may be used independently of one another, or in combination with one another. Further, it should be appreciated that the various previously described optional example implementations throughout the disclosure may be utilized independently from one another or in combination with one another. For example, the implementations of FIGs. 3 and 4 may be used independently from one another, or in combination with one another, and may utilize the various previously described optional example implementations as described in FIGs. 1 and 2. Accordingly, it should be appreciated that a wide variety of the previously described optional examples may be utilized independently from one another or in combination with one or more of them, in a suitable configuration.

[0046] It should be appreciated that the previously described various components: finger cuffs, blood pressure measurement controllers, pumps, patient monitoring devices, pressure generating and regulating systems, control circuitry, etc.; may be suitably mounted to the patient’s finger, other body placements, or remotely from the patient, and may be in suitable wireless or wired communication.

[0047] Also, the previously described examples relate to 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 includes the step of attaching the finger cuff to the patient’s finger, in which, the finger cuff includes a pleth cuff and a bladder cuff. Further, attaching the finger cuff includes the steps of: attaching the pleth cuff to the patient’ s finger, the pleth cuff defining a pleth cuff finger cavity to receive the patient’ s finger, the pleth cuff including an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient’s finger received in the pleth cuff finger cavity; attaching the bladder cuff to the patient’ s finger, the bladder cuff defining a bladder cuff finger cavity to receive the patient’s finger, the bladder cuff including a bladder mountable within the bladder cuff, wherein the patient’s finger received in the bladder cuff finger cavity abuts against the bladder of the bladder cuff. The method further includes the step of controlling 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. Further, the patient’s blood pressure may be measured and displayed.

[0048] Also, 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The disclosure also includes the following clauses:

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 pleth cuff to define a pleth cuff finger cavity to receive the patient’s finger; a bladder cuff to define a bladder cuff finger cavity to receive the patient’s finger; an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient’ s finger received in the pleth cuff finger cavity; a bladder mountable within the bladder cuff, wherein the patient’ s finger received in the bladder cuff finger cavity abuts against the bladder of the bladder cuff; and a controller 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. 2. The finger cuff of claim 1, wherein, the optical source and optical sensor pair of the pleth cuff include an emitter and detector.

3. The finger cuff of claim 2, wherein, the emitter and detector pair of the pleth cuff include an LED-PD pair.

4. The finger cuff of any of the claims 1-3, wherein, the pleth cuff and the bladder cuff are connected together to form a complete integrated housing structure.

5. The finger cuff of any of the claims 1-3, wherein, the pleth cuff and the bladder cuff are separate from one another and separately connected to the patient’s finger.

6. The finger cuff of any of the claims 1-5, wherein, the pleth cuff is mounted closer to the patient’s fingertip distal from the bladder cuff.

7. The finger cuff of any of the claims 1-5, wherein, the bladder cuff is mounted closer to the patient’s fingertip distal from the pleth cuff.

8. 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 utilizing the volume clamp method, the finger cuff comprising: a pleth cuff to define a pleth cuff finger cavity to receive the patient’s finger; a bladder cuff to define a bladder cuff finger cavity to receive the patient’s finger; an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient’ s finger received in the pleth cuff finger cavity; and a bladder mountable within the bladder cuff, wherein the patient’ s finger received in the bladder cuff finger cavity abuts against the bladder of the bladder cuff; and a controller 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. 9. The system of claim 8, wherein, the optical source and optical sensor pair of the pleth cuff include an emitter and detector.

10. The system of claim 9, wherein, the emitter and detector pair of the pleth cuff include an LED-PD pair.

11. The system of any of the claims 8-10, wherein, the pleth cuff and the bladder cuff are connected together to form a complete integrated housing structure.

12. The system of any of the claims 8-10, wherein, the pleth cuff and the bladder cuff are separate from one another and separately connected to the patient’s finger.

13. The system of any of the claims 8-12, wherein, the pleth cuff is mounted closer to the patient’ s fingertip distal from the bladder cuff.

14. The system of any of the claims 8-12, wherein, the bladder cuff is mounted closer to the patient’s fingertip distal from the pleth cuff.

15. 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, the finger cuff comprising a pleth cuff and a bladder cuff, wherein attaching the finger cuff includes: attaching the pleth cuff to the patient’ s finger, the pleth cuff defining a pleth cuff finger cavity to receive the patient’s finger, the pleth cuff including an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient’s finger received in the pleth cuff finger cavity; and attaching the bladder cuff to the patient’ s finger, the bladder cuff defining a bladder cuff finger cavity to receive the patient’ s finger, the bladder cuff including a bladder mountable within the bladder cuff, wherein the patient’s finger received in the bladder cuff finger cavity abuts against the bladder of the bladder cuff; controlling 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 measuring the patient’s blood pressure.

16. The method of claim 15, wherein, the optical source and optical sensor pair of the pleth cuff include an emitter and detector.

17. The method of claim 16, wherein, the emitter and detector pair of the pleth cuff include an LED-PD pair.

18. The method of any of the claims 15-17, wherein, the pleth cuff and the bladder cuff are connected together to form a complete integrated housing structure.

19. The method of any of the claims 15-17, wherein, the pleth cuff and the bladder cuff are separate from one another and separately connected to the patient’s finger.

20. The method of any of the claims 15-19, wherein, the pleth cuff is mounted closer to the patient’s fingertip distal from the bladder cuff.

21. The method of any of the claims 15-19, wherein, the bladder cuff is mounted closer to the patient’s fingertip distal from the pleth cuff.

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 pleth cuff to define a pleth cuff finger cavity to receive the patient’s finger; a bladder cuff to define a bladder cuff finger cavity to receive the patient’s finger; an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient’ s finger received in the pleth cuff finger cavity; a bladder mountable within the bladder cuff, wherein the patient’ s finger received in the bladder cuff finger cavity abuts against the bladder of the bladder cuff; and a controller 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.

2. The finger cuff of claim 1, wherein, the optical source and optical sensor pair of the pleth cuff include an emitter and detector.

8. 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 utilizing the volume clamp method, the finger cuff comprising: a pleth cuff to define a pleth cuff finger cavity to receive the patient’s finger; a bladder cuff to define a bladder cuff finger cavity to receive the patient’s finger; an optical source and an optical sensor pair mounted in the pleth cuff, wherein the optical source and the optical sensor pair generate a pleth signal from the patient’ s finger received in the pleth cuff finger cavity; and a bladder mountable within the bladder cuff, wherein the patient’ s finger received in the bladder cuff finger cavity abuts against the bladder of the bladder cuff; and a controller 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.

9. The system of claim 8, wherein, the optical source and optical sensor pair of the pleth cuff include an emitter and detector.