System and method for pressure filling of catheters

Claim 2

A catheter comprising: an elongate catheter tube having an interior, an exterior surface, a proximal end, a distal end, and at least one lumen extending through the interior from said proximal end to said distal end, said lumen being connected to a vent path which extends from the interior to the exterior surface near the distal end and which is sufficiently large to allow liquid flow therethrough; and an elastic sheath conforming to the exterior surface near the distal end of the catheter tube and preventing fluid flow through the vent path, said sheath having a modulus of elasticity and geometry selected to allow expansion of the sheath in response to a threshold fluid pressure within the lumen, said expansion of the sheath allowing gas and liquid fluid flow from the lumen through the vent path.

Claim 3

A catheter as in claim 1, wherein the sheath includes at least one port therethrough, which port is sufficiently large to allow liquid flow therethrough and connects to the flow path when the sheath is expanded.

Claim 4

A catheter as in claim 1, wherein the sheath has a modulus of elasticity in the range from about 10 to 10,000 psi.

Claim 5

A catheter as in claim 3, wherein the sheath is composed of polyethylene.

Claim 6

A catheter as in claim 1, wherein the vent path has a cross-sectional area equal to at least about 0.25 of the lumen area.

Claim 7

A vascular catheter comprising: al elongate flexible catheter tube having an interior, an exterior surface, a proximal end, a distal end, and at least one lumen extending through the interior from said proximal end to said distal end; a housing secured to the distal end of the catheter tube and having an exterior surface and an interior which is connected to said lumen, wherein a vent path extends from the interior to the exterior surface, said vent path being sufficiently large to allow liquid flow therethrough; an elastic sheath conforming to the exterior surface and extending over at least a portion of said housing to prevent fluid flow from the interior of the housing through the vent path to the exterior, said sheath having a modulus of elasticity selected to allow expansion of the sheath in response to a threshold fluid pressure within the housing interior, said expansion allowing fluid flow from the housing interior to the exterior.

Claim 8

A vascular catheter comprising: al elongate flexible catheter tube having an interior, an exterior surface, a proximal end, a distal end, and at least one lumen extending through the interior from said proximal end to said distal end; a housing secured to the distal end of the catheter tube and having an exterior surface and an interior which is connected to said lumen, wherein a vent path extends from the interior to the exterior surface, said vent path being sufficiently large to allow liquid flow therethrough; an elastic sheath conforming to the exterior surface and extending over at least a portion of said housing to prevent fluid flow from the interior of the housing through the vent path to the exterior, said sheath having a modulus of elasticity selected to allow expansion of the sheath in response to a threshold fluid pressure within the housing interior, said expansion allowing fluid flow from the housing interior to the exterior.

Claim 9

A vascular catheter as in claim 6, wherein the housing is generally cylindrical and axially aligned with the catheter tube, said housing having an aperture which is sufficiently large to allow liquid flow and forms a portion of the vent path.

Claim 10

A vascular catheter as in claim 7, wherein the sheath extends over the aperture.

Claim 11

A vascular catheter as in claim 8, wherein each end of the sheath is sealed to the catheter tube and the sheath includes at least one port therethrough, which port is axially offset from the vent path and provides a fluid flow path when the sheath is expanded.

Claim 12

A vascular catheter as in claim 6, wherein the sheath has a modulus of elasticity in the range from about 10 to 10,000 psi.

Claim 13

A vascular catheter as in claim 10, wherein the sheath is composed of polyethylene.

Claim 14

A vascular catheter as in claim 6, further comprising an ultrasonic transducer within the housing and means for directing a signal from the transducer in a transverse direction.

Claim 15

A vascular catheter as in claim 12, wherein an annular gap is formed in the housing adjacent the means for directing the ultrasonic signal, said gap defining the vent path and allowing outward propagation of the ultrasonic signal.

Claim 16

A catheter as in claim 6, wherein the vent path has a cross-sectional area equal to at least about 0.25 of the lumen area.

Claim 19

A method as in claim 15, wherein the liquid medium is sterile water or normal saline.

Claim 20

A method as in claim 15, wherein the preselected threshold pressure value is in the range from about 2 to 200 psig.

Claim 21

A method as in claim 15, wherein at least about 5 cc of liquid medium is vented from the catheter lumen.

Claim 22

A method as in claim 15, wherein the vent path is sealed by an elastic sheath when the pressure in the lumen is below the threshold value, said sheath having a modulus of elasticity and geometry selected so that it will expand to open the vent path when the lumen pressure exceeds the threshold value.

Claim 23

A method as in claim 15, further comprising the step of discharging liquid medium from the catheter lumen through the distal vent while the catheter is located within a patient's vascular system.

Claim 24

A method as in claim 20, wherein the volume of discharged liquid medium is equal to a predetermined volume introduced to the lumen at the proximal end of the catheter.

Claim 25

A method as in claim 20, wherein the liquid medium is contrast medium.

Claim 26

A method as in claim 20, wherein the liquid medium contains an anti-coagulant or a clot-dissolving drug.