Catheter with variable flexural modulus and method of using same

摘要

A catheter or like instrument having a variable flexural modulus for insertion into the body includes a length of flexible tubing having a normally relatively low flexural modulus. A first lumen inside the tubing provides a free flow path therethrough. Associated with the catheter tubing for controllably increasing its flexural modulus is a second lumen having a closed distal end and a proximal end adapted to be connected to a pressure source. An increase in pressure inside the second lumen serves to increase the flexural modulus of the catheter tubing to stiffen the same particularly during insertion of the tubing into the body. After insertion of the same, the pressure is controllable so that the catheter tubing is allowed to return to its normally low flexural modulus. A method of inserting an instrument substantially as described above comprises the steps of increasing the flexural modulus of the catheter tubing prior to insertion into the body, inserting the stiffened tubing into the body and then decreasing the flexural modulus so that the tubing returns to its normally relatively low flexural modulus after the tubing is in position in the body.