Endotracheal tube with inflatable cuff

Claim 2

The combination with an endotracheal tube having distal and proximal ends, of a normally collapsed flexible tubular cuff encircling the tube near its distal end and having opposite ends sealed thereto, a tubule extending from the cuff outwardly along said tube and having a distal end communicating with the inside of the cuff between the scale ends, the proximal end of the tubule having an inlet for air under pressure for inflating the cuff, and an expandable chamber having an elastic wall, the chamber being in communication with the tubule and being expandable by air forced into the chamber, said elastic wall being formed of material that will continue to stretch without a further increase in air pressure in the chamber as air continues to be forced into the chamber after reaching a predetermined pressure, said wall having an effective modulus of elasticity and unstretched thickness that will limit said predetermined air pressure to the pressure desired in the cuff.

Claim 3

The combination with an endotracheal tube having distal and proximal ends, of a normally collapsed flexible tubular cuff encircling the tube near its distal end and having opposite ends sealed thereto, a tubule extending from the cuff outwardly along said tube and having a distal end communicating with the inside of the cuff between the sealed ends, the proximal end of the tubule having an inlet for air under pressure for inflating the cuff, and an expandable chamber having an elastic wall, the chamber being in communication with the tubule and being expandable by air forced into the chamber, said elastic wall being formed of material that decreases in thickness as it is stretched by air forced into the chamber until the chamber has expanded to a size at which the air pressure therein is the same as the maximum air pressure desired in the cuff, and said wall having the property of then stretching further without increase in said maximum pressure as additional air is forced into the chamber to expand it more, whereby the desired air pressure in the cuff will be maintained as long as the chamber is larger than said size.

Claim 4

The combination with an endotracheal tube having distal and proximal ends, of a normally collapsed flexible tubular cuff encircling the tube near its distal end and having opposite ends sealed thereto, a tubule extending from the cuff outwardly along said tube and having a distal end communicating with the inside of the cuff between the sealed ends, the proximal end of the tubule having an inlet for air under pressure for inflating the cuff, and an expandable chamber having an elastic wall, the chamber being in communication with the tubule and being expandable by air forced into the chamber, said elastic wall being formed of material that decreases in thickness as it is stretched by air forced into the chamber until the chamber has expanded to a size at which the air pressure therein is the same as the maximum air pressure desired in the cuff, and said wall having the property of then stretching further without increase in said maximum pressure as additional air is forced into the chamber to expand it more, whereby the desired air pressure in the cuff will be maintained as long as the chamber is larger than said size.

Claim 5

The combination recited in claim 2, in which Said cuff is made of elastic material having the said property of said chamber elastic wall.

Claim 6

The combination recited in claim 2, in which said chamber is a balloon having a wall thickness and free diameter derived from the following equation as a guide:

Claim 7

The combination recited in claim 2, in which said cuff is made of inelastic material.

Claim 8

The combination recited in claim 2, in which said chamber is a balloon.

Claim 9

The combination recited in claim 6, in which said tubule is provided with a lateral opening, and said balloon encircles the tubule and is sealed to it at opposite sides of said opening.

Claim 10

The combination recited in claim 6, in which the modulus of elasticity of the balloon material is substantially constant and the ratio of balloon wall thickness to the free diameter of the balloon multiplied by half said modulus is substantially equal to said maximum air pressure.