Method and system for determining collateral ventilation

Abstract

A method and system for determining collateral stimuli are disclosed. [Solution] The method includes the steps of introducing a diagnostic catheter into a lung compartment via an assisted ventilator, inflating an occluding member to isolate the lung compartment, and performing a diagnostic procedure with the catheter while the patient is being ventilated by the assisted ventilator. In the diagnostic procedure, the expiratory volume from the isolated lung compartment is determined over a predetermined period while the patient is being ventilated by the assisted ventilator. Based on the expiratory volume from the isolated lung compartment over the predetermined period, it is determined whether collateral ventilation is occurring.

Description

Technical Field

[0001] [Citation of Related Applications] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 050,632, filed on July 10, 2020 (Attorney Docket No.: 20920 - 779.101), which is hereby incorporated by reference in its entirety and made a part of this specification.

[0002] The present invention generally relates to methods for diagnosing and treating lung diseases.

Background Art

[0003] Chronic obstructive pulmonary disease (COPD), including emphysema and chronic bronchitis, is currently a major medical problem affecting approximately 16 million people in the United States alone (about 6% of the U.S. population). Generally, two diagnostic tests are performed on patients to determine the spread and severity of COPD, namely 1) imaging tests, and 2) functional tests. Imaging tests, such as chest X-rays, computed tomography (CT) scans, magnetic resonance imaging (MRI) images, perfusion scans, and bronchograms, provide good indicators of the location, homogeneity, and progression of the affected tissue. However, imaging tests do not provide a direct indicator of how much the disease is affecting the patient's overall lung function and breathing. Lung function can be well evaluated using functional tests, such as, among others, spirometry, plethysmography, oxygen saturation, and oxygen consumption stress tests. These imaging and functional diagnostic tests are used together to determine the course of treatment for the patient.

[0004] One of the newly emerging treatments for COPD involves the endoscopic introduction of an intrabronchial occlusion device or a one-way valve device ("intrabronchial valve," i.e., "EBV") into the pulmonary passage to reduce the volume of one or more overinflated lung compartments, thus creating healthy compartments with more space for breathing, and possibly reducing the pressure on the heart. Examples of such methods and implants are described, for example, in U.S. Patent Application No. 11 / 682,986 and U.S. Patent No. 7,798,147, which are cited by reference and whose entire disclosures are incorporated herein by reference. A one-way valve implanted in the airway leading to a lung compartment restricts airflow in the inspiratory direction, allowing air to escape from the lung compartment during exhalation, thus causing adjacent lung compartments to collapse over time. The occlusion device inhibits both inhalation and exhalation, which also leads to lung collapse over time.

[0005] It has been suggested that the use of lung volume reduction implants may be most effective when applied to lung compartments unaffected by collateral ventilation. Collateral ventilation occurs when air flows from one lung compartment to another through collateral pathways rather than the primary airway pathway. When collateral airflow pathways are present within a lung compartment, implanting a one-way valve or occluder may not be effective, as the compartment may continue to fill with air from the collateral source and thus will not collapse as intended. Often, COPD manifests as the generation of numerous collateral pathways resulting from alveolar rupture or destruction and weakening of alveolar tissue due to overinflation.

[0006] A diagnostic system using an intrabronchial catheter, commonly used for measuring collateral ventilation, is disclosed in U.S. Patent Application Publication 2003 / 0051733 (by reference of this U.S. Patent Application Publication, the entirety of which is part of this specification), in which a catheter is used to isolate a lung compartment using an occlusion member, and instruments are used to collect data, such as changes in inspiratory / expiratory pressure and volume. Methods for measuring collateral ventilation are disclosed in U.S. Patent No. 7,883,471, and U.S. Patent Application Publications 2008 / 0027343, 2014 / 0336484, and 2007 / 0142742 (by reference of all of these patent documents, the entirety of which is part of this specification), in which an isolation catheter is used to isolate a target lung compartment, and changes in pressure within this target lung compartment are detected to detect the extent of collateral ventilation. These specifications also disclose methods for measuring gas concentrations to determine the gas exchange efficiency within a lung compartment. A similar method is disclosed in the international patent application publication WO2009 / 135070(A1) brochure (which is cited by reference and whose entire disclosure is incorporated herein by reference), in which collateral ventilation can be determined by changes in gas concentration in a portion of the lung isolated by a catheter.

[0007] Quantifying collateral ventilation by measuring and calculating collateral resistance typically takes about 2–5 minutes. During this time, the physician must ensure the patient tolerates sedation, manage secretions to prevent obstruction within the catheter lumen, and maintain the balloon seal / position within the target airway. Any one of these factors can prolong the assessment time and impair the assessment results. Thus, there is a need for a more rapid and efficient way to quantify the magnitude of collateral ventilation within lung compartments (lobes, segments, subsegments, etc.). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] U.S. Patent Application No. 11 / 682,986 [Patent Document 2] U.S. Patent No. 7,798,147 [Patent Document 3] U.S. Patent Application Publication No. 2003 / 0051733 [Patent Document 4] U.S. Patent No. 7,883,471 [Patent Document 5] U.S. Patent Application Publication No. 2008 / 0027343 [Patent Document 6] U.S. Patent Application Publication No. 2014 / 0336484 [Patent Document 7] U.S. Patent Application Publication No. 2007 / 0142742 [Patent Document 8] Brochure for International Patent Application Publication WO2009 / 135070(A1) [Overview of the project] [Problems that the invention aims to solve]

[0009] Therefore, it is advantageous to provide novel diagnostic techniques for evaluating the progression of lung disease and determining, for example, the presence and degree of collateral ventilation. At least some of these objectives are achieved by the embodiments described herein. [Means for solving the problem]

[0010] This application discloses a method and system for determining collateral ventilation in a patient. In one aspect, the method for determining collateral ventilation in a patient includes the steps of introducing a diagnostic catheter into a lung compartment via an assisted ventilator, inflating an occlusion member to isolate the lung compartment, and performing a diagnostic procedure with the catheter while the patient is being ventilated by the assisted ventilator. The diagnostic catheter has a distal end with an occlusion member and a proximal end configured to be attached to a console. Data obtained from the diagnostic procedure can be displayed on the console. In one embodiment, the diagnostic procedure includes the steps of determining the expiratory volume from the isolated lung compartment over a predetermined period while the patient is being ventilated by the assisted ventilator, and determining whether collateral ventilation is occurring in the isolated lung compartment based on the expiratory volume from the isolated lung compartment over the predetermined period. Preferably, the step of determining whether collateral ventilation is occurring in the isolated lung compartment includes determining that collateral ventilation is not occurring if the expiratory volume from the isolated lung compartment over the predetermined period falls below a threshold. The step of determining whether collateral ventilation is occurring within the isolated lung compartment preferably includes the step of determining that collateral ventilation is occurring when the expiratory volume from the isolated lung compartment remains above a threshold over a predetermined period of time. In one embodiment, the degree of collateral ventilation is preferably determined based on the expiratory volume from the isolated lung compartment over a predetermined period of time while remaining at a plateau.

[0011] Further aspects and embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0012] This embodiment has other advantages and features that will be readily apparent from the following detailed description made in conjunction with the attached drawings and from the description of the attached claims. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows a diagnostic or evaluation catheter used in a method disclosed according to several embodiments of the present invention. [Figure 2]This is a diagram showing the state where the catheter shown in FIG. 1 is placed in the lung. [Figure 3] This is a diagram showing a console configured to receive the catheter shown in FIG. 1. [Figure 4] This is a graph showing the relationship between flow rate and volume for illustrating one embodiment of the present invention.

Mode for Carrying Out the Invention

[0014] The detailed description includes many details, but these details should not be construed as limiting the scope of the present invention, and should simply be construed as showing different examples and different viewpoints of the present disclosure. It should be understood that the scope of the present invention includes other viewpoints and other embodiments not described in this specification. Other modifications, changes, and variations that are obvious to various persons skilled in the art can be implemented with respect to the arrangement, operation, and details of the methods, apparatuses, and systems according to the viewpoints and embodiments disclosed herein without departing from the spirit and scope of the present invention described in this specification.

[0015] Throughout the scope of this specification and the patent specification, the following terms have the meanings explicitly associated herein unless otherwise specified in the context. The singular forms "a", "an", and "the" in the original specification include the plural form in meaning. "In" in the original specification (often translated as "inside" in the translation) includes "in" and "on" (sometimes translated as "on" in the translation) in meaning. Referring to the drawings, the same reference numerals indicate the same parts throughout the drawings. In addition, when referring to the singular, this includes the plural unless otherwise specified or inconsistent with the disclosure in this specification.

[0016] As used in this specification, the term "exemplary" is used to mean "one embodiment, one case, or serving as one exemplification." Specific examples described as "exemplary" in this specification are not necessarily construed as being advantageous as compared to any other specific embodiments.

[0017] This application provides a method and system for targeting, accessing, and diagnosing an affected lung compartment. Such a compartment may be an entire lobe, segment, sub-segment, or any other portion of the lung. In the disclosed embodiments, the diagnosis is achieved by isolating the lung compartment to obtain various measurements, thereby determining lung function. Although COPD is taken as an example, the industrial applicability of these methods for treatment and diagnosis is not limited to COPD and can be applied to any lung disease.

[0018] Such a method is minimally invasive in that the required instrument is introduced through the mouth, tracheostomy, or other site, typically through the mouth, via a bronchoscope passed into the trachea and airways, an assisted (or assisted by an assistive device) ventilation device, or other non-surgical device. In some embodiments, the patient is allowed to breathe normally during the procedure. Some embodiments may be used with an assisted (or positive pressure) ventilation mode. Such a method detects the presence or characteristics (e.g., concentration or pressure) of one or more naturally occurring or introduced gases to determine the presence or absence of collateral (or accessory) ventilation and / or measures one or more other characteristics of the target lung compartment, such as tissue oxygen saturation.

[0019] In some embodiments of this invention, lung isolation involves sealing the distal end of a catheter in the airway supplying air to a lung compartment, as shown in Figures 1 and 2. Such a catheter is disclosed in published U.S. Patent Application No. 10 / 241,733, which is incorporated herein by reference and whose disclosures are part of this specification. As shown in Figure 1, the catheter 100 comprises a catheter body 110 and an expandable occlusion member 120 provided on the catheter body. The catheter body 110 has a distal end 102, a proximal end 101, and at least one lumen 130 extending from or near the distal end to or near the proximal end.

[0020] The proximal end of catheter 100 is configured to be connected to an external control unit (or "console" (not shown)), and this proximal end optionally has an inflation port (not shown). The distal end of catheter 100 is designed to be advanced through a passage in the body, such as the pulmonary airway. An expandable occlusion member 120 is located near the distal end of the catheter body, and this occlusion member is designed to expand in the airway supplying air to a target lung compartment. In one embodiment, the occlusion member 120 is a flexible balloon made of a transparent material. The transparent material allows for visualization through the balloon using a bronchoscope. The occlusion member 120 can be inflated by a syringe configured to be connected to the inflation port. Optionally, catheter 100 has visual markers located at the proximal and distal ends of the balloon to identify the location of the occlusion member 120 in the airway prior to inflation. The material of the occlusion member 120 is inflated to an inflation pressure of 5-20 psi to tightly seal and prevent balloon movement within the airway. This inflation pressure also helps the occlusion member 120 maintain a symmetrical shape within the airway, thereby ensuring that the catheter (centered within the occlusion member 120) remains centered within the airway. The material and attachment of the occlusion member 120 are also configured to minimize longitudinal movement of the occlusion member 120 relative to the catheter body 110 itself. To accommodate high inflation pressures, the occlusion member 120 is made of polyurethane, such as Pellethane 80A, but may be made of any material that maintains structural integrity under high inflation pressure conditions.

[0021] Additionally, and as an option, the catheter 100 further includes at least one sensor 140 located within or in a line with the lumen 130 for detecting the characteristics of various gases in the air delivered to and from the lung compartment. The sensor may be any suitable sensor or any combination of suitable sensors, and these sensors are configured to communicate with the control unit 200. Examples of sensors include pressure sensors, temperature sensors, airflow sensors, oxygen sensors, carbon dioxide sensors, gas-specific sensors, or other types of sensors. As shown in Figure 1, the sensor 140 is preferably located near the distal end 102 of the catheter 100. In a modified example, the sensor 140 may be located at one or more locations along the catheter 100 or in a line with the catheter 100 within a control unit having one or more measuring components.

[0022] In some embodiments, the system includes a unidirectional flow element positioned within or in line with the lumen 130. An example of a unidirectional flow element is described in U.S. Patent Application No. 15 / 358483, which is incorporated herein by reference and whose entire disclosure is part of this specification. The unidirectional flow element is preferably configured to allow flow from an isolated lung compartment in a distal-proximal direction, but to block or inhibit flow returning into the lung compartment in a proximal-distal direction.

[0023] As shown in Figure 2, at least the distal portion of the catheter body 110 is designed to be advanced into and through the trachea (T). The catheter may optionally be introduced through or along an introduction device, such as a bronchoscope. The distal end 102 of the catheter body 110 is then directed towards the lung lobe (LL) to reach the airway (AW) supplying air to the target lung compartment (TLC) to be evaluated. When the occlusion member 120 is expanded within the airway, the corresponding compartment is isolated, and an entrance and exit to this compartment is provided through the lumen 130.

[0024] The proximal end of the catheter 100 is configured to be coupled to a control unit (or "console") 200, as shown in Figure 3. The control unit 200 includes one or more measurement components (not shown) for measuring lung function. The measurement components can take many forms and perform various functions. For example, such measurement components include a lung mechanics unit, a physiological testing unit, a gas dilution unit, an imaging unit, a mapping unit, a therapeutic unit, a pulse oximetry unit, or any other suitable unit. These components may be located within the control unit 200 or may be attached to the unit 200 from an external source. The control unit 200 includes an interface and a display screen 210 for receiving user input. The display screen 210 may optionally be a touch-sensitive screen that can display preset values. Optionally, the user inputs information to the control unit 200 via a touch-sensitive screen mechanism. Additionally and optionally, the control unit 200 may be associated with an external display device, such as a printer or a chart recorder. At least some of the above-described embodiments of the system are used in the manner described below.

[0025] Figure 4 is a graph showing the relationship between flow rate and volume, illustrating one embodiment of a method for determining whether collateral ventilation is occurring based on expiratory volume over a predetermined period. In one embodiment, a diagnostic catheter is introduced into a lung compartment via an auxiliary ventilator, an occlusion member is inflated to isolate the lung compartment, and a diagnostic procedure is performed with the catheter while the patient is being ventilated by the auxiliary ventilator. It is preferable to display the data obtained from the diagnostic procedure on a console. In one embodiment, the diagnostic procedure includes the step of determining the expiratory volume from the isolated lung compartment over a predetermined period while the patient is being ventilated by the auxiliary ventilator. The expiratory volume can be determined by measuring the flow rate and integrating to obtain the volume. In one embodiment, the predetermined period is approximately 20 seconds. In other embodiments, the predetermined period ranges from approximately 2 seconds to approximately 60 seconds. Each data point on the volume graph represents the expiratory volume over the predetermined period. After the predetermined period, the volume over the previous predetermined period is time-recorded by progressing moment by moment. As can be seen in Figure 4, if collateral ventilation is not occurring, the expiratory volume from the isolated lung compartment over the predetermined period decreases to close to zero. Short-term flow spikes may occur, but only a very small volume is exhaled. The system is preferably configured to detect collateral ventilation deficiency when the exhaled volume from the isolated lung compartment falls below a threshold over a predetermined period. When collateral ventilation is occurring, the exhaled volume from the isolated lung compartment levels off in terms of leakage rate over a predetermined period and remains relatively flat in terms of leakage rate. The system is preferably configured to detect collateral ventilation when the exhaled volume from the isolated lung compartment levels off above a threshold over a predetermined period. In one embodiment, the degree of collateral ventilation is preferably determined based on the exhaled volume from the isolated lung compartment over a predetermined period while it is level. A high value for the volume while level indicates a high degree of collateral ventilation.

[0026] While certain embodiments of the present invention have been described in detail, certain modifications and alterations will be obvious to those skilled in the art, including embodiments that do not provide all of the features and advantages described herein. As will be understood to those skilled in the art, the present invention extends beyond the specifically disclosed embodiments to include other modifications or additional embodiments and / or uses and obvious alterations and equivalents thereof. In addition, while many modifications have been illustrated and described in various details, other alterations that fall within the scope of the present invention will be readily apparent to those skilled in the art based on this disclosure. Furthermore, various combinations or subcombinations of the specific features and aspects of the embodiments can be formed, and these still fall within the scope of the present invention. Thus, it should be understood that various features and aspects of the disclosed embodiments can be combined or substituted for each other, for the purpose of forming various embodiments of the present invention. Thus, the scope of the present invention as disclosed herein should not be limited by the specific disclosed embodiments described above. With respect to all of the embodiments described above, the steps of any method do not need to be performed sequentially.

Claims

1. A method for determining collateral ventilation in a patient, wherein the method is: The procedure includes the step of introducing a diagnostic catheter into a lung compartment via an assisted ventilation device, wherein the diagnostic catheter has a distal end with an occlusion member and a proximal end configured to be attached to a console. The step includes inflating the occluding member to isolate the lung compartment, The procedure includes performing a diagnostic procedure using the catheter while the patient is being ventilated by the assisted ventilation device, and the data obtained from the diagnostic procedure is displayed on the console. The diagnostic procedure is characterized by comprising the steps of: determining the expiratory volume from the isolated lung compartment over a predetermined period of time while the patient is being ventilated by the assisted ventilation device; and determining whether collateral ventilation is occurring within the isolated lung compartment based on the expiratory volume from the isolated lung compartment over the predetermined period of time.

2. The method according to claim 1, wherein the step of determining whether collateral ventilation is occurring in the isolated lung compartment includes the step of determining that collateral ventilation is not occurring if the expiratory volume from the isolated lung compartment over a predetermined period of time decreases to below a threshold.

3. The method according to claim 1, wherein the step of determining whether collateral ventilation is occurring in the isolated lung compartment includes the step of determining that collateral ventilation is occurring if the expiratory volume from the isolated lung compartment remains above a threshold over a predetermined period of time.

4. The method according to claim 3, further comprising the step of determining collateral ventilation based on the expiratory volume from the isolated lung compartment over a predetermined period of time in the aforementioned horizontal position.

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