Systems and methods for characterizing inflatable cuff

Abstract

The present disclosure relates to a system for characterizing an inflatable cuff arranged around a tracheal catheter for providing respiratory support to a patient, the system comprising: at least one flow unit, such as a pump, in fluid connection with a cuff tube connected to the inflatable cuff, wherein the at least one flow unit is adapted to fill the inflatable cuff with a gas or liquid; at least one pressure sensor configured to measure a pressure in the inflatable cuff; at least one flow sensor for measuring the flow of gas or liquid to and / or from the inflatable cuff; a processing unit for estimating a volume of gas or liquid or a change in volume of gas or liquid in the inflatable cuff based on a measurement of a flow rate of gas or liquid to and / or from the inflatable cuff, wherein the processing unit is configured to: extract a pressure-volume relationship between the measured pressure and an estimated volume of gas or liquid or a change in volume of gas or liquid in the inflatable cuff, and comparing the pressure-to-volume relationship to a previously measured or predetermined reference pressure-to-volume relationship to characterize the inflatable cuff. The present disclosure also relates to a method for characterizing an inflatable cuff disposed around a tracheal catheter for providing respiratory support to a patient.

Description

Technical Field

[0001] The present disclosure relates to a system for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient. The present disclosure also relates to a method for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient. Background Art

[0002] As is known, ventilated patients (particularly those in intensive therapy) are intubated with an endotracheal tube or endotracheal tube. Many tubes have an inflatable cuff to seal the trachea, preventing air leakage and aspiration of gastric contents, blood, secretions and other fluids, while allowing the patient to breathe through the endotracheal tube.

[0003] The properties of such an inflatable tube cuff may deteriorate over time, which may result in leaks around the cuff. The presence of such leaks may reduce the efficiency of the ventilator and may also result in the aspiration of bacteria into the lungs, thereby potentially increasing the risk of pneumonia, which may prolong the patient's stay in the hospital.

[0004] Patients with pneumonia have significantly increased length of hospital stay, which is directly attributed to increased mortality and increased reintubation rates.

[0005] Several techniques are used to monitor and control cuff pressure over time. For example, the pressure can be maintained above a certain minimum pressure or within a certain pressure range. However, monitoring the pressure of the cuff or maintaining a certain pressure in the cuff does not provide any detailed information about the status of the cuff, possible leaks around the cuff, or other problems with the cuff or the patient. Summary of the invention

[0006] An object of the present disclosure is to provide a system for characterizing an inflatable cuff arranged around an endotracheal tube for providing respiratory support to a patient. Therefore, a first aspect of the present disclosure relates to a system for characterizing an inflatable cuff arranged around an endotracheal tube for providing respiratory support to a patient, the system comprising:

[0007] at least one flow unit, such as a pump, in fluid connection with a cuff conduit connected to the inflatable cuff, wherein the at least one flow unit is adapted to fill the inflatable cuff with a gas or a liquid;

[0008] at least one pressure sensor configured to measure pressure within the inflatable cuff;

[0009] at least one flow sensor for measuring the flow of gas or liquid to and / or from the inflatable cuff;

[0010] a processing unit for estimating the volume of gas or liquid or a change in the volume of gas or liquid in the inflatable cuff based on a measurement of the flow of gas or liquid to and / or from the inflatable cuff, wherein the processing unit is configured to:

[0011] extracting a pressure-volume relationship between the measured pressure and an estimated volume of gas or liquid in the inflatable cuff or a change in volume of gas or liquid, and

[0012] The pressure-volume relationship is compared to a previously measured or predetermined reference pressure-volume relationship to characterize the inflatable cuff.

[0013] By extracting a pressure-volume relationship between the measured pressure and the estimated volume of gas or liquid in the inflatable cuff or the change in the volume of gas or liquid, and comparing the pressure-volume relationship with a previously measured or predetermined reference pressure-volume relationship, the change in the pressure-volume relationship over time can be obtained. The pressure-volume relationship can be, for example, a coefficient that converts or transforms at least one given volume to a corresponding pressure, or converts or transforms at least one given pressure to a corresponding volume. The change in the pressure-volume relationship can be used to non-invasively characterize the inflatable cuff.

[0014] Characterization of the inflatable cuff can provide a measure of the elasticity of the inflatable cuff, but can also provide information about the structure surrounding the inflatable cuff (typically the trachea). The pressure-volume relationship in a given configuration can be represented by a coefficient that converts at least one given volume into a corresponding pressure or converts at least one given pressure into a corresponding volume. A higher coefficient generally means that a higher pressure is required to obtain a given volume. As will be understood by a person skilled in the art, equivalently, coefficients with opposite meanings can be used. A processing unit can then be used to interpret changes in the pressure-volume relationship. If the coefficient is less than the coefficient of the previous measurement, it means that a lower pressure than in the first measurement is required to obtain a given volume. This can indicate a more elastic inflatable cuff. If the change in elasticity exceeds a predetermined limit, the system can classify the inflatable cuff as worn. The predetermined limit is generally not a limit for all inflatable cuffs in all patients, but a limit for a specific inflatable cuff, perhaps in a specific patient and perhaps at a specific time. If the coefficient is higher than the coefficient of the previous measurement, it means that a higher pressure than in the first measurement is required to obtain a given volume. Since an inflatable cuff generally does not become more difficult to fill with gas or liquid over time, the change to a higher coefficient can be interpreted as the structure surrounding the inflatable cuff providing external pressure on the inflatable cuff. Therefore, in one embodiment, the system is also configured to identify a harder trachea of ​​a patient due to an increase in the coefficient.

[0015] The present disclosure also relates to a method for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient, the method comprising the steps of:

[0016] measuring a pressure in the inflatable cuff in an inflated configuration;

[0017] measuring the flow of gas to and / or from the inflatable cuff;

[0018] estimating the volume of gas or the change in volume of gas or liquid in the inflatable cuff based on a measurement of the flow of gas to and / or from the inflatable cuff;

[0019] extracting a pressure-volume relationship between the measured pressure and an estimated volume of gas or a change in volume of gas or liquid in the inflatable cuff, and

[0020] The pressure-volume relationship is compared to a previously measured or predetermined reference pressure-volume relationship to characterize the inflatable cuff.

[0021] As will be appreciated by one skilled in the art, the presently disclosed method for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient may be performed using any embodiment of the presently disclosed system for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient, and vice versa.

[0022] The method may be implemented as a computer program having instructions that, when executed by a computing device or computing system, cause the computing device or computing system to perform a method for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient. A non-transitory storage medium may include a computer program product having instructions embodied thereon, wherein the computer program product, when executed by a computing device or system, causes the computing device or system to perform a method for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention will now be described with reference to the accompanying drawings. The drawings are examples of embodiments and are not limiting for characterizing the presently disclosed system for an inflatable cuff arranged around an endotracheal tube for providing respiratory support to a patient.

[0024] Figure 1 An illustrative embodiment of the presently disclosed system for characterizing an inflatable cuff disposed about an endotracheal tube is shown.

[0025] Figure 2 Another illustrative embodiment of the presently disclosed system for characterizing an inflatable cuff disposed about an endotracheal tube is shown.

[0026] Figure 3 AC shows an example of a process for extracting the pressure-volume relationship between the measured pressure and the estimated volume of gas or liquid in the inflatable cuff.

[0027] Figure 4 AC shows an example of a pressure-volume relationship between measured pressure and the estimated volume of gas or liquid in the inflatable cuff.

[0028] Figure 5 AC shows an example of a sequence of inflating and deflating an inflatable cuff to establish a pressure-volume relationship.

[0029] Figure 6 AC shows an example of a sequence of deflation and inflating an inflatable cuff to establish a pressure-volume relationship.

[0030] Figure 7 Examples of pressure-volume relationships for the same inflatable cuff at different times are shown. DETAILED DESCRIPTION

[0031] The present disclosure relates to a system for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient, the system comprising:

[0032] at least one flow unit, such as a pump, in fluid connection with a cuff conduit connected to the inflatable cuff, wherein the at least one flow unit is adapted to fill the inflatable cuff with a gas or a liquid;

[0033] at least one pressure sensor configured to measure pressure within the inflatable cuff;

[0034] at least one flow sensor for measuring the flow of gas or liquid to and / or from the inflatable cuff;

[0035] a processing unit for estimating the volume of gas or liquid or a change in the volume of gas or liquid in the inflatable cuff based on a measurement of the flow of gas or liquid to and / or from the inflatable cuff, wherein the processing unit is configured to:

[0036] extracting a pressure-volume relationship between the measured pressure and an estimated volume of gas or liquid in the inflatable cuff or a change in volume of gas or liquid, and

[0037] The pressure-volume relationship is compared to a previously measured or predetermined reference pressure-volume relationship to characterize the inflatable cuff.

[0038] By characterizing the inflatable cuff, in particular by analyzing the pressure-volume relationship over time, conclusions can be drawn about the inflatable cuff itself and the structures surrounding it. Characterization of the inflatable cuff can provide a measure of the elasticity and / or a measure of the compliance of the inflatable cuff. The system can be part of a ventilator or operate as a stand-alone system.

[0039] The term "endotracheal tube" should be broadly interpreted to include any suitable tube for maintaining a patient's airway, including but not limited to endotracheal tubes and tracheostomy tubes. Thus, the inflatable cuff may be referred to as an inflatable endotracheal tube cuff or an inflatable tracheostomy tube cuff.

[0040] "Processing unit" should also be interpreted broadly to include any suitable device for processing and computing data. The processing unit may be a local device, optionally integrated in the ventilator system, but may also be provided on a remote device, such as in a cloud computing device.

[0041] Flow sensors can be used to measure the flow rate of a gas or liquid. All types of flow sensors can be used to measure the flow rate of a gas or liquid to and from an inflatable cuff according to the present disclosure. Based on the flow rate of the gas or liquid over some time, the volume of the gas or liquid in the inflatable cuff or the change in the volume of the gas or liquid can be estimated. The presently disclosed system for characterizing an inflatable cuff is not limited to a specific flow sensor.

[0042] Figure 1 An illustrative embodiment of the general concept of intubating a patient P with an endotracheal tube 2 and an inflatable cuff 3 is shown. A system 1 for characterizing an inflatable cuff 3 arranged around an endotracheal tube 3 for providing respiratory support to a patient P is disclosed. As described above, the system 1 can be connected to or integrated in a ventilator for ventilation of a patient P. The endotracheal tube 2 has a side wall 2c and extends between a first end 2a and a second end 2b. The endotracheal tube 2 is preferably made of PVC or the like, but can be made of any suitable material. The endotracheal tube 2 has an associated inflatable cuff 3. The inflatable cuff 3 can be configured to seal the trachea of ​​the patient P so as to isolate the second end 2b from the external environment. The inflatable cuff 3 can be an annular element externally mounted to the side wall 2c of the endotracheal tube 2. The inflatable cuff 3 divides the endotracheal tube 2 into a first portion 4a and a second portion 4b. When positioned in the trachea, the inflatable cuff 3 also divides the trachea of ​​the patient into an isolation zone Z1 and a non-sterile zone Z2.

[0043] The inflatable cuff 3 may have a generally annular shape (a donut shape). As will be appreciated by those skilled in the art, the inflatable cuff 3 may have any other suitable shape. Preferably, the inflatable cuff 3 is placed in fluid connection with at least the flow unit 5 via a conduit 6. The inflatable cuff 3 may have a chamber defined by an outer membrane. The outer membrane may be made of, for example, PVC having a thickness of less than 100 microns or polyurethane having a thickness of less than 50 microns.

[0044] A flow unit 5 may also be connected to the endotracheal tube 2. This may be a different flow unit than the flow unit for the inflatable cuff 3. It may be configured to generate positive pressure and pause pressure, and it may be connected to the endotracheal tube 2 via at least one connection nozzle 13; 14 having an inlet nozzle 13 and an outlet nozzle 14, both of which are fluidly connected to the endotracheal tube 2 via a dual input single output connector 15.

[0045] Figure 2 Another exemplary embodiment of the presently disclosed system 1 for featuring an inflatable cuff 3 arranged around an endotracheal tube 2 is shown. Figure 3 The processing unit or control unit 9 controls the flow unit 5. The processing unit 9 can also estimate the volume of gas or liquid in the inflatable cuff or the change in the volume of gas or liquid based on the measurement of the flow rate of gas or liquid to and / or from the inflatable cuff 3 by the flow sensor 12. The flow sensor 12 can be placed in any suitable position. The pressure sensor 11 is configured to measure the pressure in the inflatable cuff 3. The pressure sensor 11 can be placed in any suitable position. The system 1 in the example of the figure has an exhaust duct 7, which can be used for parallel flow. Figure 2 The system 1 also comprises a fork 8 placed along the pipe 6 .

[0046] According to one aspect of the present disclosure, a system and / or method includes the step of inflating or deflating the inflatable cuff by flow or pressure control or a combination of both to estimate endotracheal tube cuff or endotracheal tube cuff characteristics in an intubated patient.

[0047] Preferably, the step of generating a continuous inflation or deflation of said inflatable cuff controlled by flow or pressure, or a combination of both, comprises the step of generating a cyclically continuous overpressure inside the inflatable cuff followed by a normal pressure setting inside the inflatable cuff, or generating a cyclically continuous negative pressure inside the inflatable cuff followed by a normal pressure setting inside the inflatable cuff, or a combination of both, in order to measure a pressure / volume correlation inside the inflatable cuff.

[0048] The flow unit may be switchable between an inflated configuration, in which the flow unit inflates and / or keeps the inflatable cuff inflated, and a deflated configuration, in which the flow unit deflates and / or keeps the inflatable cuff deflated, or a combination of inflation / deflation configurations.

[0049] In accordance with the presently disclosed systems and methods, the flow cell may be manually or automatically switched continuously in cycles of a first inflated configuration, a deflated configuration, or a combination of both.

[0050] The control module, which may include a processing unit, may be configured to control signals to the flow unit in order to activate or deactivate inflation or deflation. This may involve the opening and closing of a valve.

[0051] In one embodiment, the system is configured to determine degradation of the inflatable cuff based on characterization of the inflatable cuff. Degradation of the inflatable cuff may be indicated when the inflatable cuff loses elasticity (i.e., its ability to withstand compression without rupturing). Degradation may also be viewed as a more elastic inflatable cuff. The processing unit is configured to calculate or extract a measure of the elasticity of the inflatable cuff based on a pressure-volume relationship.

[0052] A pressure-volume relationship may describe the relationship between one or more given volumes and one or more corresponding pressures. A pressure-volume relationship describes the relationship between one or more given pressures and one or more corresponding volumes. This may be done, for example, by Figure 7 , where the volumes and pressures of two inflatable cuffs (or the same inflatable cuff at different points in time) A and B are shown. The pressure-volume relationship can be represented by a pressure-volume curve that includes measurements of multiple pressure levels and multiple volumes extracted from multiple measurements of the flow of gas to and / or from the inflatable cuffs. The pressure is set on a first axis of the curve (such as the Y axis) and the volume is set on a second axis of the curve (such as the X axis). The pressure-volume relationship can be represented by a coefficient or formula that converts at least one given volume to a corresponding pressure or converts at least one given pressure to a corresponding volume. If it is a single pressure and volume, it can be a single coefficient. If there are multiple measurements, the relationship can be expressed as an equation. A higher coefficient can indicate that a higher pressure is required to obtain a given volume, and a lower coefficient can indicate that a lower pressure is required to obtain a given volume, or a higher coefficient can indicate that a smaller volume is required to obtain a given pressure, and a lower coefficient can indicate that a larger volume is required to obtain a given pressure. In Figure 7 In the example of , the inflatable cuff of scenario A requires a higher pressure to obtain a given volume than scenario B. Scenarios A and B can be used for the same inflatable cuff. If B occurs later than A, it can be seen that B becomes more elastic. If pressure is set on the Y axis and volume is set on the X axis, as in Figure 7In an example, a steeper curve may indicate a less elastic inflatable cuff and / or a higher coefficient, and a flatter curve indicates a more elastic inflatable cuff and / or a lower coefficient. In one embodiment, the processing unit is configured to classify the inflatable cuff as worn based on a change in the pressure-volume relationship over time. If the coefficient is less than a previously measured coefficient, the processing unit may be configured to classify the inflatable cuff as worn. Possibly, the coefficient needs to be greater than a predetermined limit below a previously measured coefficient in order to classify the inflatable cuff as worn.

[0053] The processing unit may additionally or alternatively be configured to identify changes in the structure surrounding the cuff as changes in the pressure-volume relationship. Thus, the system may be configured to characterize the structure surrounding the inflatable cuff based on the characterization of the inflatable cuff. The processing unit may be configured to identify a harder trachea of ​​the patient due to an increase in the previously described coefficient, and / or to identify a softer trachea of ​​the patient due to a decrease in the coefficient. Figure 7 In the example of , if scenario B represents a first round of measurements and scenario A represents a subsequent second round of measurements, a higher coefficient for A may indicate that the patient has a stiffer trachea.

[0054] To characterize the inflatable cuff, the system can be configured to collect the desired measurements. In one embodiment, the system can be configured to gradually fill the inflatable cuff with gas, or gradually empty the inflatable cuff, while the pressure sensor and the flow sensor continuously or at discrete time points measure the pressure in the inflatable cuff and the flow of gas to and / or from the inflatable cuff to generate a pressure-volume curve.

[0055] Figure 3 AC shows an example of a process for extracting the pressure-volume relationship between the measured pressure and the estimated volume of gas or liquid in the inflatable cuff.

[0056] In scenario A, the inflatable cuff is first inflated from a first pressure P_0 or a first volume V_0 to a second pressure P_1 or a second volume V_1 within a second time interval Δt1. Preferably, both pressure and volume are measured continuously or at discrete time points. The second pressure P_1 or the second volume V_1 is then reduced to a third pressure P_2 or a third volume V_2 within second and third time intervals Δt2 and Δt3. The third pressure P_2 or the third volume V_2 is then increased back to the first pressure P_0 or the first volume V_0 within a fourth time interval Δt4.

[0057] In scenario B, the inflatable cuff is first inflated from a first pressure P_0 or a first volume V_0 to a second pressure P_1 or a second volume V_1 within a second time interval Δt1. The second pressure P_1 or the second volume V_1 is then reduced to the first pressure P_0 or the first volume V_0 within a second time interval Δt2.

[0058] In scenario C, the inflatable cuff first deflates from the first pressure P_0 or first volume V_0 to a third pressure P_2 or third volume V_2 within a third time interval Δt3. The third pressure P_2 or third volume V_2 then increases to the first pressure P_0 or first volume V_0 within a fourth time interval Δt4.

[0059] Preferably, the time interval is at least 0.01 seconds.

[0060] Preferably, the second pressure is at least 1 cmH2O higher than the first pressure. Preferably, the third pressure is at least 1 cmH2O lower than the first pressure.

[0061] Preferably, the second volume is at least 0.1 mL greater than the first volume. Preferably, the third volume is at least 0.1 mL less than the first volume.

[0062] Figure 5 AC shows an example of a sequence of inflating and deflating an inflatable cuff to establish a pressure-volume relationship. Figure 5 The initial state shown in A is started. The pressure is then increased to Figure 5 The second state is shown in B. The pressure is then reduced to Figure 5 The third state shown in C.

[0063] Figure 6 AC shows an example of a sequence of deflation and inflation of an inflatable cuff to establish a pressure-volume relationship. Figure 6 It starts from the initial state shown in A. Then the pressure is reduced to Figure 6 The second state is shown in B. The pressure is then increased to Figure 6 The third state shown in C.

[0064] Advantageously, in this way it is possible to characterize an endotracheal tube in an intubated patient by correlating the measured pressure with the inflatable volume, e.g. Figure 4 as shown in . Figure 4 AC shows an example of a pressure-volume relationship between measured pressure and the estimated volume of gas or liquid in the inflatable cuff. Figure 4 A can be considered as the initial pressure-volume relationship between the pressure and the volume of the gas or liquid in the inflatable cuff. Then Figure 4 B and 4C may be subsequent measurements of the pressure-volume relationship between the pressure and the volume of gas or liquid in the inflatable cuff. Figure 4 B can represent a harder trachea, while Figure 4 C may represent a more elastic inflatable cuff.

[0065] The inflation volume of the inflatable cuff will be determined according to the type of patient and is therefore proportional to the size of the trachea and related to the target pressure to be generated in the inflatable cuff. However, the pressure within the inflatable cuff can be determined independently of the volume. Indicatively, to prevent ischemia, the pressure P_0 within the inflatable cuff is preferably between 20 and 30 cmH2O.

[0066] The present disclosure also relates to a method for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient, the method comprising the steps of:

[0067] measuring a pressure in the inflatable cuff in an inflated configuration;

[0068] measuring the flow of gas to and / or from the inflatable cuff;

[0069] estimating a volume of gas in the inflatable cuff based on a measurement of the flow of gas to and / or from the inflatable cuff;

[0070] extracting a pressure-volume relationship between the measured pressure and an estimated volume of gas in the inflatable cuff, and

[0071] The pressure-volume relationship is compared to a previously measured or predetermined reference pressure-volume relationship to characterize the inflatable cuff.

[0072] The method may include the following steps:

[0073] gradually filling the inflatable cuff with gas, and / or gradually emptying the inflatable cuff;

[0074] Continuously or at discrete points in time, the pressure in the inflatable cuff and the flow rate of gas to and / or from the inflatable cuff are measured to generate a pressure-volume curve.

[0075] More details

[0076] 1. A system for characterizing an inflatable cuff disposed about an endotracheal tube for providing respiratory support to a patient, the system comprising:

[0077] at least one flow unit, such as a pump, in fluid connection with a cuff conduit connected to the inflatable cuff, wherein the at least one flow unit is adapted to fill the inflatable cuff with a gas or a liquid;

[0078] at least one pressure sensor configured to measure pressure within the inflatable cuff;

[0079] at least one flow sensor for measuring the flow of gas or liquid to and / or from the inflatable cuff;

[0080] a processing unit for estimating the volume of gas or liquid or a change in the volume of gas or liquid in the inflatable cuff based on a measurement of the flow of gas or liquid to and / or from the inflatable cuff, wherein the processing unit is configured to:

[0081] extracting a pressure-volume relationship between the measured pressure and an estimated volume of gas or liquid in the inflatable cuff or a change in volume of gas or liquid, and

[0082] The pressure-volume relationship is compared to a previously measured or predetermined reference pressure-volume relationship to characterize the inflatable cuff.

[0083] 2. The system for characterizing an inflatable cuff according to item 1, wherein the system is configured to determine degradation of the inflatable cuff based on the characterization of the inflatable cuff.

[0084] 3. The system for characterizing an inflatable cuff according to any of the preceding clauses, wherein the system is further configured to characterize a structure surrounding the inflatable cuff based on the characterization of the inflatable cuff.

[0085] 4. A system for characterizing an inflatable cuff according to any of the preceding items, wherein the pressure-volume relationship describes a relationship between one or more given volumes and one or more corresponding pressures, or wherein the pressure-volume relationship describes a relationship between one or more given pressures and one or more corresponding volumes.

[0086] 5. System for characterizing an inflatable cuff according to any of the preceding clauses, wherein the pressure-volume relationship is represented by a coefficient converting at least one given volume to a corresponding pressure or converting at least one given pressure to a corresponding volume.

[0087] 6. A system for characterizing an inflatable cuff according to item 5, wherein a higher coefficient indicates that a higher pressure is required to obtain a given volume and a lower coefficient indicates that a lower pressure is required to obtain a given volume, or a higher coefficient indicates that a smaller volume is required to obtain a given pressure and a lower coefficient indicates that a larger volume is required to obtain a given pressure.

[0088] 7. The system for characterizing an inflatable cuff according to any of items 4 to 6, wherein the processing unit is configured to classify the inflatable cuff as worn based on a change in the pressure-volume relationship over time.

[0089] 8. The system for characterizing an inflatable cuff according to clause 7, wherein if the coefficient is less than a previously measured coefficient, the processing unit is configured to classify the inflatable cuff as worn.

[0090] 9. A system for characterizing an inflatable cuff according to any of the preceding clauses, wherein the pressure-volume relationship is represented by a pressure-volume curve comprising measurements of multiple pressure levels and multiple volumes extracted from multiple measurements of flow of gas to and / or from the inflatable cuff.

[0091] 10. The system for characterizing an inflatable cuff according to item 9, wherein pressure is provided on a first axis of the graph, such as the Y-axis, and volume is provided on a second axis of the graph, such as the X-axis.

[0092] 11. A system for characterizing an inflatable cuff according to any of items 9 to 10, wherein a steeper curve indicates a less elastic inflatable cuff and / or a higher coefficient, and a flatter curve indicates a more elastic inflatable cuff and / or a lower coefficient.

[0093] 12. The system for characterizing an inflatable cuff according to any of the preceding items, wherein the at least one flow cell is configured to gradually fill the inflatable cuff with gas, or gradually empty the inflatable cuff, while the pressure sensor and the flow sensor measure the pressure in the inflatable cuff and the flow rate of gas to and / or from the inflatable cuff continuously or at discrete time points to generate a pressure-volume curve.

[0094] 13. System for characterizing an inflatable cuff according to any of the preceding items, wherein the processing unit is configured to calculate or extract a measure of elasticity of the inflatable cuff based on the pressure-volume relationship.

[0095] 14. The system for characterizing an inflatable cuff according to any of the preceding items, wherein the processing unit is further configured to identify changes in the structure surrounding the cuff as changes in the pressure-volume relationship.

[0096] 15. A system for characterizing an inflatable cuff according to any one of items 5 to 6, wherein the processing unit is further configured to identify a harder trachea and / or a smaller inner diameter of the trachea of ​​the patient due to an increase in the coefficient, and / or wherein the processing unit is further configured to identify a softer trachea and / or a larger inner diameter of the trachea of ​​the patient based on a change in the pressure-volume relationship over time.

[0097] 16. A system for characterizing an inflatable cuff according to any one of items 5 to 6, wherein the processing unit is further configured to identify a harder trachea and / or a smaller inner diameter of the trachea of ​​the patient due to an increase in the coefficient, and / or wherein the processing unit is further configured to identify a softer trachea and / or a larger inner diameter of the trachea of ​​the patient due to a decrease in the coefficient.

[0098] 17. System for characterizing an inflatable cuff according to any of the preceding items, wherein the inflatable cuff is an inflatable endotracheal tube cuff or an inflatable tracheostomy catheter cuff.

[0099] 18. A method for characterizing an inflatable cuff disposed about an endotracheal tube for providing respiratory support to a patient, the method comprising the steps of:

[0100] measuring a pressure in the inflatable cuff in an inflated configuration;

[0101] measuring the flow of gas to and / or from the inflatable cuff;

[0102] estimating the volume of gas or the change in volume of gas or liquid in the inflatable cuff based on a measurement of the flow of gas to and / or from the inflatable cuff;

[0103] extracting a pressure-volume relationship between the measured pressure and an estimated volume of gas in the inflatable cuff, and

[0104] The pressure-volume relationship is compared to a previously measured or predetermined reference pressure-volume relationship to characterize the inflatable cuff.

[0105] 19. A method for characterizing an inflatable cuff disposed around an endotracheal tube for providing respiratory support to a patient according to item 18, comprising the steps of:

[0106] gradually filling the inflatable cuff with gas, and / or gradually emptying the inflatable cuff;

[0107] Continuously or at discrete points in time, the pressure in the inflatable cuff and the flow rate of gas to and / or from the inflatable cuff are measured to generate a pressure-volume curve.

[0108] 20. The method according to any one of items 18 to 19, performed on a system for characterizing an inflatable endotracheal catheter cuff according to any one of items 1 to 17.

[0109] 21. A computer program having instructions which, when executed by a computing device or computing system, cause the computing device or computing system to perform a method according to any one of items 18 to 20 for characterizing an inflatable cuff arranged around an endotracheal tube for providing respiratory support to a patient.

Claims

1. A system for characterizing an inflatable cuff disposed about an endotracheal tube for providing respiratory support to a patient, the system comprising: at least one flow unit, such as a pump, the at least one flow unit being in fluid connection with a cuff conduit connected to the inflatable cuff, wherein the at least one flow unit is adapted to fill the inflatable cuff with a gas or a liquid; at least one pressure sensor configured to measure pressure within the inflatable cuff; at least one flow sensor for measuring the flow of gas or liquid to and / or from the inflatable cuff; a processing unit for estimating the volume of gas or liquid or a change in the volume of gas or liquid in the inflatable cuff based on a measurement of the flow of gas or liquid to and / or from the inflatable cuff, wherein the processing unit is configured to: extracting a pressure-volume relationship between the measured pressure and an estimated volume of gas or liquid or an estimated change in volume of gas or liquid in the inflatable cuff, and The pressure-volume relationship is compared to a previously measured or predetermined reference pressure-volume relationship to characterize the inflatable cuff.

2. The system for characterizing an inflatable cuff according to claim 1, wherein: The system is configured to determine degradation of the inflatable cuff based on the characterization of the inflatable cuff.

3. A system for characterizing an inflatable cuff according to any one of the preceding claims, wherein: The system is also configured to characterize a structure surrounding the inflatable cuff based on the characterization of the inflatable cuff.

4. A system for characterizing an inflatable cuff according to any one of the preceding claims, wherein: The pressure-volume relationship describes a relationship between one or more given volumes and one or more corresponding pressures, or wherein the pressure-volume relationship describes a relationship between one or more given pressures and one or more corresponding volumes.

5. A system for characterizing an inflatable cuff according to any one of the preceding claims, wherein: The pressure-volume relationship is represented by a coefficient that converts at least one given volume to a corresponding pressure or at least one given pressure to a corresponding volume.

6. The system for characterizing an inflatable cuff according to claim 5, wherein: A higher coefficient indicates that a higher pressure is required to obtain a given volume and a lower coefficient indicates that a lower pressure is required to obtain a given volume, or a higher coefficient indicates that a smaller volume is required to obtain a given pressure and a lower coefficient indicates that a larger volume is required to obtain a given pressure.

7. A system for characterizing an inflatable cuff according to any one of claims 4 to 6, wherein: The processing unit is configured to classify the inflatable cuff as worn based on the change in the pressure-volume relationship over time, preferably wherein the processing unit is configured to classify the inflatable cuff as worn if the coefficient is smaller than a previously measured coefficient.

8. A system for characterizing an inflatable cuff according to any one of the preceding claims, wherein: The pressure-volume relationship is represented by a pressure-volume curve comprising measurements of multiple pressure levels and multiple volumes extracted from multiple measurements of flow of gas to and / or from the inflatable cuff.

9. A system for characterizing an inflatable cuff according to any one of the preceding claims, wherein: The at least one flow cell is configured to gradually fill the inflatable cuff with gas, or gradually empty the inflatable cuff, while the pressure sensor and the flow sensor measure the pressure in the inflatable cuff and the flow rate of gas to and / or from the inflatable cuff continuously or at discrete time points to generate a pressure-volume curve.

10. A system for characterizing an inflatable cuff according to any one of the preceding claims, wherein: The processing unit is configured to calculate or extract a measure of elasticity of the inflatable cuff based on the pressure-volume relationship.

11. A system for characterizing an inflatable cuff according to any one of the preceding claims, wherein: The processing unit is further configured to identify a change in the structure surrounding the cuff as a change in the pressure-volume relationship.

12. A system for characterizing an inflatable cuff according to any one of claims 5 to 6, wherein: The processing unit is also configured to identify a harder trachea and / or a smaller inner diameter of the trachea of ​​the patient due to an increase in the coefficient, and / or wherein the processing unit is also configured to identify a softer trachea and / or a larger inner diameter of the trachea of ​​the patient based on changes in the pressure-volume relationship over time.

13. A system for characterizing an inflatable cuff according to any one of claims 5 to 6, wherein: The processing unit is further configured to identify a harder trachea and / or a smaller inner diameter of the trachea of ​​the patient due to an increase in the coefficient, and / or wherein the processing unit is further configured to identify a softer trachea and / or a larger inner diameter of the trachea of ​​the patient due to a decrease in the coefficient.

14. A method for characterizing an inflatable cuff disposed about an endotracheal tube for providing respiratory support to a patient, the method comprising the steps of: measuring a pressure in the inflatable cuff in an inflated configuration; measuring the flow of gas to and / or from the inflatable cuff; estimating the volume of gas or the change in volume of gas or liquid in the inflatable cuff based on a measurement of the flow of gas to and / or from the inflatable cuff; extracting a pressure-volume relationship between the measured pressure and the estimated volume of gas in the inflatable cuff, and The pressure-volume relationship is compared to a previously measured or predetermined reference pressure-volume relationship to characterize the inflatable cuff.

15. A computer program having instructions which, when executed by a computing device or computing system, cause the computing device or computing system to perform the method of claim 14 for characterizing an inflatable cuff disposed about an endotracheal tube for providing respiratory support to a patient.

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