Introducer assembly

Introducer assembly for use on the skin of a patient overlying a cavity to be formed in a patient permitting the introduction of any one of a variety of introducer tubes having different outer diameters and forming a substantially fluid-tight seal with the introducer tube, each introducer tube having a distal extremity and having a trocar therein having a distal extremity which extends beyond the distal extremity of the introducer tube, comprising a sleeve having proximal and distal extremities and having a passage extending therethrough from the proximal to the distal extremities, the diameter of the passage being at least as great as the outer diameter of the largest introducer tube to be introduced therethrough a flange having inner and outer margins, said outer margin having a bottom side adapted to make a sealing engagement with the skin of the patient, means forming a fluid-tight seal between the inner margin of the flange and the sleeve, membrane means extending across the passage and forming a fluid-tight seal with respect to said sleeve, said membrane means being formed of a material and having a thickness which can be readily pierced by the trocar of the selected introducer tube and which forms a substantially fluid-tight seal with the trocar as it penetrates the same and with the selected introducer tube after it extends through the membrane means, and releasable clamping means carried by the sleeve and spaced from the membrane means adapted to receive the selected introducer tube and adapted to retain the selected introducer tube in a desired longitudinal position of the sleeve.