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EP-4734835-A1 - APPARATUS FOR USE IN NON-INVASIVE HEMODYNAMIC PARAMETER MEASUREMENT

EP4734835A1EP 4734835 A1EP4734835 A1EP 4734835A1EP-4734835-A1

Abstract

Provided is a cuff for use in hemodynamic parameter measurement, the cuff comprising a shell portion for surrounding a body part of a subject and a pressure application means surrounding the shell portion, such that the shell portion is disposed between the actuator and the body part. The shell portion is formed so as to comprise at least two circumferential sections which, when the cuff is assembled on the subject's body part, together form a closed loop around the subject's body part. The shell portions for example overlap at their respective ends, to form at least a first overlap region and a second overlap region. By forming the shell structure with multiple circumferential sections, this permits opening of the shell from the side by sliding apart the shell pieces at least at one tangential meeting point between the pieces. For example, in some embodiments, the shell structure may be opened by tangentially sliding the at least two shell portions apart at a first overlap area.

Inventors

  • SCHIPPER, NIELS
  • YAU, Kam, Hing
  • LOUWSMA, Hendrik, Klaas
  • VAN DE VEEN, EGBERT
  • WESSELS, Arnoldus, Cornelis
  • VAN DER VLIS, PETER, HANS
  • DUINEVELD, PAULUS, CORNELIS
  • AMINE EL SAYED, Achraf
  • TAMMINGA, STEPHANUS, JACOB, GERARDUS

Assignees

  • Koninklijke Philips N.V.

Dates

Publication Date
20260506
Application Date
20240620

Claims (15)

  1. 1. An apparatus for use in non-invasive hemodynamic parameter measurement, comprising: a cuff (20) for extending around a body part (10) of a subject, wherein the cuff comprises a pressure actuator (52) for applying a controllable pressure to the body part, and further comprises a shell structure (22) for extending around the body part and, when the cuff is worn, is disposed between the actuator and the body part; wherein the shell structure (22) is configurable in each of a closed state and an open state, wherein, in the closed state, the shell structure (22) forms a closed loop around a central lumen, the central lumen for receiving the body part (10) of a subject, and wherein, in the open state, an opening is defined in a circumference of the shell structure to permit insertion of the arm into the lumen; wherein the shell structure is composed of at least a first and second shell portion (22a, 22b), each for defining a respective portion of a circumference of the shell structure when the shell structure is in the closed state, the shell portions (22a, 22b) overlapping tangentially in the closed state in at least a first overlap area (32) and a second overlap area (34); wherein transition from the closed state to the open state comprises tangentially separating the shell portions (22a, 22b) at least at one of the overlap areas.
  2. 2. The apparatus of claim 1 , further comprising a releasable securement means (42) at the first overlap area for, when secured, preventing lateral sliding between the first and second shell portions in a tangential direction at the first overlap area (32) when the shell is in the closed state.
  3. 3. The apparatus of claim 2, wherein the releasable securement means (42) permits securement of the first and second shell portions at the first overlap area (32) at a plurality of different relative tangential positions.
  4. 4. The apparatus of claim 3, wherein the securement means (42) comprises a hook-and-loop fastening.
  5. 5. The apparatus of any preceding claim, wherein, at least at the second overlap area (34), the first and second shell portions are freely laterally slidable in a tangential direction when the shell is in the closed state.
  6. 6. The apparatus of any preceding claim, wherein, when the cuff is in use on the body part, the pressure actuator (52) is arranged to radially support the shell structure against radial separation of the at least first and second shell portion.
  7. 7. The apparatus of any preceding claim, further comprising a sheet article (26) disposed, when the cuff is applied to the arm, between the shell structure (22) and a surface of the body part (10), and arranged for contacting the body part during use, wherein the shell structure (22) is slidable tangentially relative to the sheet article.
  8. 8. The apparatus of claim 7, wherein the sheet article (26) is attached to the shell structure (22), wherein the sheet article is arranged to extend continuously around a radially interior face of the shell structure between a first attachment point (28a) on the first shell portion (22a) and a second attachment point (28b) on the second shell portion (22b), and preferably wherein the first and second attachment points are located at the first overlap area (32).
  9. 9. The apparatus of claim 8, wherein the sheet article (26) extends uninterrupted across the second overlap area (34) and is discontinuous at the first overlap area (32), wherein a first end is attached to the first shell portion (22a) at the first overlap area (32) and the second end is attached to the second shell portion (22b) at the first overlap area (32).
  10. 10. The apparatus of any preceding claim, wherein one of the at least two shell portions (22a, 22b) has a greater stiffness than the other of the two shell portions, and optionally wherein the first and second shell portions are formed of different materials.
  11. 11. The apparatus of any preceding claim, wherein the shell structure includes a first shell portion (22a) and a second shell portion (22b), and wherein, at both the first (32) and second (34) overlap regions, the second shell portion (22b) is disposed radially atop the first shell portion (22b).
  12. 12. The apparatus of claim 11, wherein the second shell portion (22b) is less stiff than the first shell portion (22a).
  13. 13. The apparatus of any preceding claim, further comprising a tissue pressure sensor for sensing a pressure between the cuff (20) and the body part (10) when the cuff is worn, the tissue pressure sensor comprising a sensing pad (4) for disposal, in use, between the shell structure (22) and the body part, and optionally wherein the second shell portion (22b) is less stiff than the first shell portion (22a), and wherein the tissue pressure sensor pad (6) is arranged so as to be disposed between the first shell portion (22a) and the body part during use.
  14. 14. The apparatus of any preceding claim, wherein the pressure actuator (52) is attached, fixedly or removably, to the shell structure (22).
  15. 15. The apparatus of claim 14, wherein the actuator has a closed state and an open state, wherein, in the closed state, the actuator forms a closed loop around the central lumen, and wherein, in the open state, an opening is defined in a circumference of the actuator to permit insertion of the arm into the lumen, wherein transition from the closed to open state comprises unrolling the actuator to tangentially separate two ends of the actuator.

Description

APPARATUS FOR USE IN NON-INVASIVE HEMODYNAMIC PARAMETER MEASUREMENT FIELD OF THE INVENTION The present invention relates to the field of non-invasive hemodynamic parameter measurement. BACKGROUND OF THE INVENTION The most common method for non-invasive blood pressure (NIBP) measurement is the use of an oscillometric blood pressure measurement cuff. The cuff comprises an inflatable bladder. The cuff wraps around the upper arm of a patient and is controlled to progress through an inflation and deflation cycle during which a pressure inside the bladder is sampled and a single set of values for systolic arterial pressure and diastolic arterial pressure are derived through processing of the pressure signal. A variant approach to non-invasive blood pressure measurement has previously been proposed. This also uses a cuff which wraps around the body part of the patient. A cross-sectional illustration is shown in Fig. 1. The cuff 2 is shown wrapped around the arm 10 of a patient, and the brachial artery 8. The cuff 2 includes a pressure actuator 14, which optionally may be an inflatable bladder, as in the traditional NIBP cuff. In variance with the traditional NIBP cuff, the variant cuff also includes a separate tissue pressure sensor 4 arranged to measure a pressure between the body part 10 and the cuff. The tissue pressure sensor in some examples comprises a fluid-filled sensor pad, wherein a pressure in the pad varies as a function of pressure exerted on the pad. Also, in variance with the traditional NIBP cuff, the variant cuff includes a hard shell 12 which extends around the body part and is disposed (radially) between the actuator 14 and the body part 10. The pulse waves in the brachial artery 8 cause a change in the skin movement. This change in skin movement causes a compression of the liquid in the sensor pad 4. The sensor pad is fluidly connected via a flexible tube filled with similar liquid to a pressure transducer which measures the pressure signal. The pressure sensor pad 8 is enclosed by a hard shell 12 to enable stiffness and enable a sufficient signal from the pressure sensor. In similarity with a standard NIBP cuff, the pressure actuator 14 which may comprise a bladder which is inflatable with an air pump, to compress the arm tissue, so that the brachial artery 8 can be closed. Due to the inclusion of the separate tissue pressure sensor 4 with hard shell 12 backing, this cuff can obtain a real time pulse signal for the patient, and, from this, multiple different hemodynamic parameters can be obtained, including stroke volume and cardiac output. In the current state of the art, the shell structure 12 has a tangentially continuous structure, and, in the most common design, is formed from a single piece of material which is curled round to define a complete (closed) loop. Fig. 2 schematically shows an example shell structure 12 according to the state of the art. Fig. 2 (left) shows a cross-section across a plane normal to a longitudinal axis of the shell and parallel with tangential and radial axes of the shell. Fig. 2 (right) shows a cross-section across a plane parallel with a longitudinal axis of the shell. It can be seen that the shell structure is tangentially continuous. In the current state of the art, there are multiple different cuff sizes to accommodate different arm diameters of patients, due to the fact that the rigid shell 12 is relatively inflexible in terms of the arm diameter that it fits to. EP2953528B1 describes one example implementation of the above-described variety of blood pressure measurement cuff. Suitable algorithms for processing the tissue pressure measurements to derive one or more hemodynamic parameters can be found for example in the documents: WO 2018/210931, WO 2020/148137, WO 2019/211210, US10485432, EP2759258B1, and US10349849. For example, and as described in WO 2018210931, in some embodiments, values for SAP, DBP and MAP can be obtained based on identifying a peak in the amplitude of a series of measured tissue pressure pulses. The various blood pressure measures can then be determined based on identifying amplitude values of the tissue pressure pulse sequence at pre-defined reduced proportions of the peak amplitude value. The reader is referred to WO 2018/210931 for more details. SUMMARY OF THE INVENTION It is the recognition of the inventors that a problem with the current shell-backed measurement cuff described above is the relative impracticality of mounting the cuff to the arm of the patient. Due to the presence of the rigid shell structure, which has a one-piece coil structure, the cuff has to be slid onto the arm via the hand. However, in practice, the hand may be cannularised for intravenous infusion. Thus, to fit the cuff requires first ceasing the infusion and removing the cannula. In addition, the need to slide the cuff onto the arm via the hand is physically challenging for the caregiver. Due to the tangentially closed architecture of the shell, to