Catheter with variable flexural modulus

Claim 2

A catheter having a variable flexural modulus for insertion into a human body comprising: a length of cathetertubing having a normally relatively low 100 flexural modulus, said tubing having a lumen for providing afree path fortheflow of fluid through said tubing; and means associated with said tubing for controllably increasing the flexural modulus of said tubing to stiffen same during insertion of said 105 tubing into the human body, said means adapted to allow said tubing to return to its normally relatively low flexural modulus after being positioned in the body.

Claim 3

A catheter as defined in Claim 1 wherein said 110 means for increasing the flexural modulus of said tubing includes a second lumen in said tubing extending substantially parallel to said lumen for providing fluid flow, said second lumen having a closed distal end and a.proximal end adapted to be 115 connected to a pressure source, whereby an increase in pressure in said second lumen serves to increase the flexural modulus of said cathetertubing, said pressure being controllable so that the flexural modulus of said cathetertubing if also 120 controllable.

Claim 4

A catheter as defined in Claim 2 wherein said second lumen is a second tubing associated with said cathetertubing.

Claim 5

A catheter as defined in Claim 3 wherein one 125 of said tubings is located inside the other.

Claim 6

A catheter as defined in Claim 4 wherein said second tubing is located inside said cathetertubing, said second tubing lying in said path forflow of fluid with its distal end facing the insertion end of said 130 cathetertubing, and, in its normal condition, said 4 GB 2 044 109 A 4 second tubing providing a clearance between itself and the inside wall of said cathetertubing so that fluid is free to pass through said lumen, said second tubing being expandable under pressure to provide 5 a snug fit against the inside wall of said catheter tubing when pressurized to thereby increase the flexural modulus of said cathetertubing.

Claim 7

A catheter as defined in Claim 5 wherein the distal end of said second tubing is adapted to 10 protrude slightly out of the insertion end of said cathetertubing when pressurized to thereby provide a smooth tip for said catheter upon its insertion into the human body.

Claim 8

A catheter as defined in Claim 5 wherein said 15 second tubing is removable from said catheter tubing whereby after said catheter is positioned in said body the second tubing may be removed to completely free the fluid path in said lumen.

Claim 9

An instrument having a variable flexural mod-20 ulus for insertion into an animal body comprising: a length of flexible tubing having a normally relatively low flexural modulus, said tubing having a lumen for providing a free flow path therethrough; and means associated with said tubing for controllably increas-25 ing the flexural modulus of said tubing to stiffen same during insertion of said tubing into the animal body, said means adapted to allow said tubing to return to its normally relatively lowflexural modulus after being positioned in the body. 30

Claim 10

An instrument having a variable flexural mod-20 ulus for insertion into an animal body comprising: a length of flexible tubing having a normally relatively low flexural modulus, said tubing having a lumen for providing a free flow path therethrough; and means associated with said tubing for controllably increas-25 ing the flexural modulus of said tubing to stiffen same during insertion of said tubing into the animal body, said means adapted to allow said tubing to return to its normally relatively lowflexural modulus after being positioned in the body. 30

Claim 11

A catheter having a variable flexural modulus for insertion into a human body comprising: a length of flexible cathetertubing having a normally relatively lowflexural modulus, said tubing having a first lumen therethrough with both the proximal end and 35 the distal end having openings for providing a free path forthe flow of fluid through said tubing, said tubing having a second lemen therein extending substantially parallel to said first lumen, said second lumen having a closed distal end and a proximal end 40 adapted to be connected to a pressure source, whereby an increase in pressure inside said second lumen serves to increase the flexural modulus of said cathetertubing, said pressure being controllable so that the flexural modulus of said catheter 45 tubing is also controllable.

Claim 12

A catheter having a variable flexural modulus for insertion into a human body comprising: a length of flexible cathetertubing having a normally relatively lowflexural modulus, said tubing having a first lumen therethrough with both the proximal end and 35 the distal end having openings for providing a free path forthe flow of fluid through said tubing, said tubing having a second lemen therein extending substantially parallel to said first lumen, said second lumen having a closed distal end and a proximal end 40 adapted to be connected to a pressure source, whereby an increase in pressure inside said second lumen serves to increase the flexural modulus of said cathetertubing, said pressure being controllable so that the flexural modulus of said catheter 45 tubing is also controllable.

Claim 15

A method as defined in Claim 10 wherein said means for increasing the flexural modulus of said tubing includes a second lumen associated with said catheter tubing, said second lumen having a closed distal end and a proximal end adapted to be 65 connected to a pressure source, and wherein the step of increasing the flexural modulus comprises increasing the pressure inside said second lumen, and the step of decreasing the flexural modulus comprises decreasing the pressure inside said 70 second lumen.

Claim 16

A catheter according to claim 1 or 9, substantially as described with reference to any Figure(s) of the accompanying drawings. Printed for Her Majesty's Stationery Office by Croydon Printing Company Limited, Croydon Surrey, 1980. Published by the Patent Office, 25 Southampton Buildings, London, WC2A1 AY, from which copies may be obtained.