The present disclosure is generally related to an apparatus that allows for the exchange of gases in a liquid sample. More specifically, the disclosure relates to a blood oxygenator having a wound filter membrane and a flow diffuser to allow external oxygen to be incorporated into a blood sample while carbon dioxide is removed from the blood sample.
Blood oxygenators are commonly used to accomplish the gas exchange functions normally performed by the lungs. Conventional blood oxygenators contain a gas exchange medium, such as a filter membrane made from hollow fibers, across which blood is flowed. The filter membrane is connected to an oxygen supply such that oxygen is diffused from the filter membrane into the blood and carbon dioxide is removed from the blood into the filter membrane.
Conventional oxygenators are commonly used in medical situations when a patient's lungs are temporarily disabled and/or incapable of performing their normal function. In some medical situations, blood oxygenators are used as a temporary gas exchange member to substitute or supplement the lung function during, for example, open heart surgery. During such procedures, vital functions of the circulatory system are assumed by an extracorporeal bypass circuit where a pump sends the patient's blood through a blood oxygenator to deliver oxygen to the patient. In other medical situations, a patient may have an indwelling catheter connected to a pump to deliver blood to a blood oxygenator. In these applications, the oxygenator can be used for an indefinite term.
Membrane blood oxygenators transfer oxygen into the blood as it flows over a bundle of hollow fiber membranes. The liquid side boundary layer is the limiting factor in transferring oxygen. Increasing the mixing of blood around the hollow fiber membranes decreases the liquid side boundary layer thickness and increases the exchange of oxygen. A solution for existing blood oxygenators is to increase the amount of fiber membrane surface area or to increase the mixing of blood around the fibers through impellers or rotation of the fibers. However, increasing the amount of fiber surface area increases the foreign surface to blood contact area, which can lead to adverse events such as thrombosis or platelet activation. Additionally, implementing active mixing technologies adds complication to the manufacturing and design of the oxygenator.
There is a need in the art for a blood oxygenator that is suitable for use for an indefinite term to provide gas exchange function without imposing a significant load onto the patient's heart. It would be further desirable to have a blood oxygenator having an increased gas exchange efficiency and a smaller size compared to conventional blood oxygenators.
In some examples or aspects of the present disclosure, an improved blood oxygenator is provided for use for an indefinite term to provide gas exchange function without imposing a significant load onto the patient's heart. The improved blood oxygenator has an increased gas exchange efficiency and a small size.
In some examples or aspects of the present disclosure, a blood oxygenator may have a housing with a first end opposite a second end and a sidewall extending between the first end and the second end along a longitudinal axis. The housing may define an interior chamber having a fluid inlet and a fluid outlet. The blood oxygenator may have a gas exchange medium positioned within the interior chamber. The gas exchange medium may have a plurality of hollow fibers rolled into a spiral shape. The blood oxygenator may have a flow diverter positioned within the interior chamber and configured for guiding fluid flow through the gas exchange medium.
In other examples or aspects of the present disclosure, the flow diverter may have a fixed end connected to a central portion of the housing and a free end extending from the first end along the longitudinal axis. The flow diverter may have a spiral shape between the fixed end and the free end. A diameter of the flow diverter may increase or decrease between the fixed end and the free end. The flow diverter may extend along 25% to 100% of a longitudinal length of the gas exchange medium.
In other examples or aspects of the present disclosure, the flow diverter may have one or more annular sleeves extending longitudinally through the gas exchange medium. The one or more sleeves may be offset longitudinally relative to each other to define a tortuous fluid path therebetween. The one or more sleeves may be arranged concentrically relative to the longitudinal axis. The flow diverter may be a baffle positioned between a first section of the gas exchange medium and a second section of the gas exchange medium. The baffle may be configured to permit at least a portion of the fluid flow to pass through the baffle in a radial direction. The flow diverter may be a screen having a plurality of openings, pores, or slots. A size of the openings, pores, or slots may increase or decrease between the first end and the second end of the housing. The one or more sleeves, baffle, or screen may include a combination of regions with openings, pores, and/or slots.
In other examples or aspects of the present disclosure, the flow diverter may include at least one first ring and at least one second ring arranged in an alternating manner Each first ring may be a solid plate and each second ring may be an annular plate.
In other examples or aspects of the present disclosure, the flow diverter may be an inflatable balloon positioned in a central portion of the interior chamber. The inflatable balloon may be in fluid communication with a pump via a fluid line, and wherein the pump is configured for selectively inflating or deflating the inflatable balloon via the fluid line.
Various other aspects of the present disclosure are recited in one or more of the following clauses:
Clause 1: A blood oxygenator comprising: a housing having a first end opposite a second end with a sidewall extending between the first end and the second end along a longitudinal axis, the housing defining an interior chamber having a fluid inlet and a fluid outlet; a gas exchange medium positioned within the interior chamber, the gas exchange medium having a plurality of hollow fibers rolled into a spiral shape; and a flow diverter positioned within the interior chamber and configured for guiding fluid flow through the gas exchange medium.
Clause 2. The blood oxygenator of clause 1, wherein the flow diverter has a fixed end connected to a central portion of the housing and a free end extending from the first end along the longitudinal axis, and wherein the flow diverter has a spiral shape between the fixed end and the free end.
Clause 3. The blood oxygenator of clause 2, wherein a diameter of the flow diverter increases or decreases between the fixed end and the free end.
Clause 4. The blood oxygenator of any of clauses 1-3, wherein the flow diverter extends along 25% to 100% of a longitudinal length of the gas exchange medium.
Clause 5. The blood oxygenator of any of clauses 1-4, wherein the flow diverter has one or more annular sleeves extending longitudinally through the gas exchange medium.
Clause 6. The blood oxygenator of clause 5, wherein the one or more sleeves are offset longitudinally relative to each other to define a tortuous fluid path therebetween.
Clause 7. The blood oxygenator of clause 5 or 6, wherein the one or more sleeves are arranged concentrically relative to the longitudinal axis.
Clause 8. The blood oxygenator of clause 1, wherein the flow diverter is a baffle positioned between a first section of the gas exchange medium and a second section of the gas exchange medium and wherein the baffle is configured to permit at least a portion of the fluid flow to pass through the baffle in a radial direction.
Clause 9. The blood oxygenator of clause 1, wherein the flow diverter is a screen having a plurality of openings, pores, or slots.
Clause 10. The blood oxygenator of clause 9, wherein a size of the openings, pores, or slots increases or decreases between the first end and the second end of the housing.
Clause 11. The blood oxygenator of any one of clauses 5-10, wherein the one or more sleeves, baffle, or screen may include a combination of regions with openings, pores, and/or slots.
Clause 12. The blood oxygenator of clause 1, wherein the flow diverter includes at least one first ring and at least one second ring arranged in an alternating manner.
Clause 13. The blood oxygenator of clause 12, wherein each first ring is a solid plate and each second ring is an annular plate.
Clause 14. The blood oxygenator of clause 1, wherein the flow diverter is an inflatable balloon positioned in a central portion of the interior chamber.
Clause 15. The blood oxygenator of clause 14, wherein the inflatable balloon is in fluid communication with a pump via a fluid line, and wherein the pump is configured for selectively inflating or deflating the inflatable balloon via the fluid line.
Further details and advantages of the various examples or aspects described in detail herein will become clear upon reviewing the following detailed description of the various examples in conjunction with the accompanying drawing figures.
The illustrations generally show preferred and non-limiting examples or aspects of the apparatus and methods of the present disclosure. While the description presents various aspects of the apparatus, it should not be interpreted in any way as limiting the disclosure. Furthermore, modifications, concepts, and applications of the disclosure's aspects are to be interpreted by those skilled in the art as being encompassed, but not limited to, the illustrations and descriptions herein.
The following description is provided to enable those skilled in the art to make and use the described examples contemplated for carrying out the disclosure. Various modifications, equivalents, variations, and alternatives, however, will remain readily apparent to those skilled in the art. Any and all such modifications, variations, equivalents, and alternatives are intended to fall within the spirit and scope of the present disclosure.
For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal”, and derivatives thereof shall relate to the disclosure as it is oriented in the drawing figures.
As used herein, the terms “parallel” or “substantially parallel” mean a relative angle as between two objects (if extended to theoretical intersection), such as elongated objects and including reference lines, that is from 0° to 5°, or from 0° to 3°, or from 0° to 2°, or from 0° to 1°, or from 0° to 0.5°, or from 0° to 0.25°, or from 0° to 0.1°, inclusive of the recited values.
As used herein, the term “perpendicular” or “substantially perpendicular” mean a relative angle as between two objects (if extended to theoretical intersection), such as elongated objects and including reference lines, that is from 85° to 90°, or from 87° to 90°, or from 88° to 90°, or from 89° to 90°, or from 89.5° to 90°, or from 89.75° to 90°, or from 89.9° to 90°, inclusive of the recited values.
It is to be understood, however, that the disclosure may assume alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary aspects of the disclosure. Hence, specific dimensions and other physical characteristics related to the examples disclosed herein are not to be considered as limiting.
It should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.
In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, the use of “or” means “and/or” unless specifically stated otherwise, even though “and/or” may be explicitly used in certain instances. Further, in this application, the use of “a” or “an” means “at least one” unless specifically stated otherwise.
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During operation, blood enters the oxygenator 10 through the liquid inlet 14 along an axial path extending along the longitudinal axis 24 from the first end 20 toward the second end 22. The blood must be radially diverted so that it can pass through the gas exchange medium 30. Various devices for radially diverting the flow of blood within the interior chamber 28 and promoting mixing flow of the blood between the fibers of the gas exchange medium 30 are disclosed herein with reference to
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In further examples or aspects, the flow diverter 32e may be made from a mesh 56 defining a plurality of pores 58 configured to permit fluid to flow therethrough. The pores 58 may have a substantially quadrilateral shape. In some examples or aspects, the size of the pores 58 may increase from the first end 44 to the second end 46.
In further examples or aspects, the flow diverter 32e may have a plurality of slots 60 configured to permit fluid to flow therethrough. The slots 60 may have an elongated shape. In some examples or aspects, the size (i.e., width) of the slots 60 may increase from the first end 44 to the second end 46.
In further examples or aspects, the flow diverter 32e may include a combination of regions with openings 54, mesh 56 with pores 58, and/or slots 60.
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Inflation of the balloon 64 is configured to force the fluid within the interior chamber 28 to flow radially outward through the fibers of the gas exchange medium 30. In some examples or aspects, the balloon 64 may be expanded such that an outer diameter of the balloon 64 is the same as the inner diameter of the gas exchange medium 30 to force any fluid present in the space between the balloon 64 and the gas exchange medium 30 into the space between individual fibers of the gas exchange medium 30. Deflation of the balloon 64 allows additional fluid to enter the interior chamber 28 so that the fluid can be forced radially outward with the subsequent inflation of the balloon 64.
The controller 69 controls operation of the pump 68 to selectively inflate and deflate the balloon 64. In some examples or aspects, the controller 69 can be configured to operate the pump 68 in a pulsatile manner to selectively inflate and deflate the balloon 64 according to a pre-defined pressure profile. In other examples or aspects, the controller 69 can be configured to operate the pump 68 to selectively inflate and deflate the balloon 64 based on input from at least one sensor that measures a physiological characteristic of a patient. For example, the controller 69 can operate the pump 68 to inflate and deflate the balloon 64 based on input received from a heart rate sensor. Thus, inflation/deflation of the balloon 64 may be coordinated with the patient's heart rate.
The present disclosure also provides a method of operating a blood oxygenator. The method includes introducing blood into the interior chamber 28 through the liquid inlet 14 along an axial path in a direction of the longitudinal axis 24. The blood is radially diverted toward the outer portion of the interior chamber such that the blood passes around the fibers of the gas exchange medium 30. As the blood flows around the fibers of the gas exchange medium 30, gas exchange takes place between the blood and the gas flowing through the fibers of the gas exchange medium 30. In order to facilitate the gas exchange, the method further includes introducing a gas, such as oxygen or air, into the gas inlet 18 such that the gas passes through the gas exchange medium 30 and exits through the gas outlet. Oxygenated blood is directed through the liquid outlet 16. Radial diverting of the blood may be facilitated using one or more of the diverter, the baffle, the separator screen, or the inflatable balloon described herein.
While examples or aspects of an improved blood oxygenator are provided in the foregoing description, those skilled in the art may make modifications and alterations to these examples or aspects without departing from the scope and spirit of the disclosure. Accordingly, the foregoing description is intended to be illustrative rather than restrictive. The disclosure described hereinabove is defined by the appended claims, and all changes to the disclosure that fall within the meaning and the range of equivalency of the claims are to be embraced within their scope.
This application is a continuation of International Application No. PCT/US2020/055201, filed Oct. 12, 2020, which claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/915,175, filed on Oct. 15, 2019, the disclosures of which are incorporated herein by reference.
Number | Date | Country | |
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62915175 | Oct 2019 | US |
Number | Date | Country | |
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Parent | PCT/US2020/055201 | Oct 2020 | US |
Child | 17706304 | US |