Filters with gradient porosities
AssigneeTerumo Cardiovascular Systems Corporation
InventorsLouis F. Peticca, Jeffrey E. Troyan, Eric E. Brooking
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Abstract
Multiple embodiments of medical filters are described. For example, this document describes extracorporeal blood filters that have a gradient of filter pore sizes at different portions of the filter element. The gradient of filter pore sizes may enhance the filter's potential for capturing and removing gaseous bubbles that may be present in the blood or other fluid that is flowing through the filter.
Claims19
A venous blood reservoir for use in an extracorporeal circuit, the reservoir comprising:
- an outer housing defining an internal space, the outer housing having an upper housing portion and a lower housing portion;
- and
- a venous filter comprising a porous filter material disposed within the internal space, the filter having an upper filter end portion and a lower filter end portion, the upper filter end portion disposed adjacent the upper housing portion and the lower filter end portion disposed adjacent the lower housing portion,
- wherein an average pore size of the porous filter material disposed at the lower filter end portion is less than an average pore size of the porous filter material disposed at the upper filter end portion.
A method of using an extracorporeal circuit during a surgery on a patient, the method comprising:
- transferring blood from the patient into a venous blood reservoir, the venous blood reservoir comprising:
- an outer housing defining an internal space, the outer housing having an upper housing portion and a lower housing portion;
- and
- a venous filter comprising a porous filter material disposed within the internal space, the filter having an upper filter end portion and a lower filter end portion, the upper filter end portion disposed adjacent the upper housing portion and the lower filter end portion disposed adjacent the lower housing portion,
- wherein an average pore size of the porous filter material disposed at the lower filter end portion is less than an average pore size of the porous filter material disposed at the upper filter end portion;
- passing the blood through the venous filter, wherein the average pore size of the porous filter material disposed at the lower filter end portion adapts the venous filter to cause the blood to dwell within the venous filter for a longer period of time than the blood would dwell if the pore size of the lower filter end portion was the same as the pore size of the upper filter end portion, thereby allowing for improved removal of gaseous emboli from the blood;
- and
- draining the blood out of the venous blood reservoir.
A medical filter comprising:
- a housing defining an internal space and a longitudinal axis, the housing having an upper housing portion and a lower housing portion;
- and
- a filter element comprising a porous filter material disposed in general longitudinal alignment within the internal space, the filter element having an upper portion and a lower portion,
- wherein the porous filter material disposed at the lower portion is finer than the porous filter material disposed at the upper portion.
A method of filtering blood through a filtering system, the method comprising:
- inputting the blood to the filtering system at a bottom region of a chamber defined by a filter and an upper air space, the filter comprising a porous filter material, the filter having an upper end portion and a lower end portion, wherein an average pore size of the porous filter material disposed at the lower end portion is less than an average pore size of the porous filter material disposed at the upper end portion;
- and
- filtering the blood such that the blood flows outwardly through pores in the filter while gaseous bubbles prevented from flowing through the pores in the filter rise in the chamber toward the upper air space.
Dependencies are inferred from the claim text.