CATHETER HAVING COMMUNICATING LUMENS
A catheter having a plurality of longitudinal lumens for removing biological, natural and/or man-made materials from cavities, ducts, vessels, or other locations in a patient's body. The multi-lumen catheter comprises a longitudinally-extending suction lumen with suction holes through which materials pass into the lumen in response to suction forces generated by a source of negative pressure coupled to a proximal end of the lumen. A longitudinally-extending vent lumen coupled to a source of at least neutral vent pressure through, for example, an opening to ambient air at the proximal end of the lumen, and preferably, through vent holes disposed along a length of the catheter. A dividing septum between the adjacent lumens has one or more ports fluidically coupling the lumens. The ratio of the area of the suction holes and ports is such that the suction force at unobstructed suction holes is maintained below a desired maximum force for a given negative pressure when none or more of the suctions holes are obstructed. When a suction hole obstruction occurs, fluid is drawn into the suction lumen through the communication port(s). This compensating fluid flow prevents the suction forces from exceeding a predetermined maximum value during use even when one or more suction holes become obstructed. This maximum force may be set, for example, to avoid hematoma, to permit repositioning of the catheter during use, etc. thereby allowing for continuous suction.
1 . A catheter configured to suction materials from a location inside a patient's body comprising: an elongate body having adjacent longitudinally-extending suction and vent lumens separated by a dividing septum, a proximal end of the suction and vent lumens configured to be fluidically coupled to a source of negative pressure and a source of at least neutral vent pressure, respectively, suction holes in an exterior surface of the catheter each fluidically coupling the suction lumen with an exterior environment of the catheter, and at least one port through the septum that fluidically couples the suction and vent lumens, wherein the ratio of the area of the suction holes and ports is such that suction force at unobstructed suction holes is maintained in a desired range for a given negative pressure regardless of whether none, one or more than one suction hole is obstructed.
2 . The catheter of claim 1 , further comprising:
a plurality of vent holes in an exterior surface of the catheter each fluidically coupling the vent lumen with an exterior environment of the catheter.
3 . The catheter of claim 1 , wherein the suction holes, vent holes and communicating ports are laterally aligned with each other.
4 . The catheter of claim 1 , further comprising:
a material coating the surface of one of said lumens to enhance lubricity.
5 . The catheter of claim 1 , wherein the catheter comprises:
contiguous, longitudinal sections each configured to be inserted into a different region in the patient, and each having a different arrangement of two or more of the suction holes, vent holes and communicating ports.
6 . A catheter suction system comprising:
a source of negative pressure; and
a catheter, coupled to the source of negative pressure, configured to suction materials from a location inside a patient's body comprising: an elongate body having adjacent longitudinally-extending suction and vent lumens separated by a dividing septum, a proximal end of the suction and vent lumens configured to be fluidically coupled to a source of negative pressure and a source of at least neutral vent pressure, respectively, suction holes in an exterior surface of the catheter each fluidically coupling the suction lumen with an exterior environment of the catheter, and at least one port through the septum that fluidically couples the suction and vent lumens, wherein the ratio of the area of the suction holes and ports is such that suction force at unobstructed suction holes is maintained in a desired range for a given negative pressure regardless of whether none, one or more than one suction hole is obstructed.
7 . The catheter suction system of claim 6 , further comprising:
a plurality of vent holes in an exterior surface of the catheter each fluidically coupling the vent lumen with an exterior environment of the catheter.
8 . The catheter suction system of claim 6 , wherein the suction holes, vent holes and communicating ports are laterally aligned with each other.
9 . The catheter suction system of claim 6 , further comprising:
a hydrophilic material coating the surface of one of said lumens.
10 . The catheter suction system of claim 6 , wherein the catheter comprises:
contiguous, longitudinal sections each configured to be inserted into a different region in the patient, and each having a different arrangement of two or more of the suction holes, vent holes and communicating ports.
11 . A system for cryogenic spray ablation comprising:
a cryogen source;
a catheter, connected to the cryogen source, configured to deliver the released cryogen onto target tissue of the patient;
a source of negative pressure; and
a catheter, coupled to the source of negative pressure, configured to suction materials from a location inside a patient's body comprising: an elongate body having adjacent longitudinally-extending suction and vent lumens separated by a dividing septum, a proximal end of the suction and vent lumens configured to be fluidically coupled to a source of negative pressure and a source of at least neutral vent pressure, respectively, suction holes in an exterior surface of the catheter each fluidically coupling the suction lumen with an exterior environment of the catheter, and at least one port through the septum that fluidically couples the suction and vent lumens, wherein the ratio of the area of the suction holes and ports is such that suction force at unobstructed suction holes is maintained in a desired range for a given negative pressure regardless of whether none, one or more than one suction hole is obstructed.
12 . The catheter suction system of claim 11 , further comprising:
a plurality of vent holes in an exterior surface of the catheter each fluidically coupling the vent lumen with an exterior environment of the catheter.
13 . The catheter suction system of claim 11 , wherein the suction holes, vent holes and communicating ports are laterally aligned with each other.
14 . The catheter suction system of claim 11 , further comprising:
a hydrophilic material coating the surface of one of said lumens.
15 . The catheter suction system of claim 11 , wherein the catheter comprises:
contiguous, longitudinal sections each configured to be inserted into a different region in the patient, and each having a different arrangement of two or more of the suction holes, vent holes and communicating ports.