Urinary retention catheter

Claim 1

A retention drainage catheter adapted to be inserted into and retained in the bladder for the continuous drainage of waste material therefrom, said catheter comprising: A. an elongate cannula formed of a flexible and pliant material and having both distal and proximal ends, the length of said cannula being such that said distal end is disposed within the bladder and the proximal end is disposed exteriorily of the urethra, B. said cannula having an inner tubular wall surface defining a drainage lumen which extends from said distal end of said cannula substantially to said proximal end thereof, said cannula being tapered adjacent said distal end thereof to form a gradually widening portion from said distal end to facilitate passage of said cannula through the urethra, said tapered portion of said cannula commencing at said distal end and extending toward said proximal end of said cannula, C. said distal end of said cannula defining an unobstructed opening the cross-sectional area of which is substantially equal to the cross-sectional area of said drainage lumen and which lies in a plane substantially perpendicular to the longitudinal axis of said drainage lumen so as to communicate the interior of the bladder directly with the full cross-sectional area of said drainage lumen at said distal end of said cannula whereby waste material in the bladder flows directly into said drainage lumen at said distal end of said cannula and instrumentation is introduced into the bladder through said drainage lumen, D. means formed on said inner tubular wall surface adjacent to but spaced from said distal end of said cannula and defining a portion of said drainage lumen of different diameter than the diameter of the rest of said drainage lumen thereby forming an abutment means for a stylet used to insert said catheter, and E. expandable means connected to the outer wall surface of said cannula adjacent said distal end thereof for retaining said distal end within the bladder after passing through the urethra, said expandable means comprising an inflatable balloon surrounding said cannula adjacent said distal end thereof, said inflatable balloon being defined by an outer layer of flexible material connected to said distal end of said cannula and to a portion of said cannula spaced from said distal end but being otherwise unconnected thereto, said portion of said cannula being located at least as far from said distal end of said cannula as the widest portion of said gradually widening portion of said cannula so that said inflatable balloon extends at least over the length of said gradually widening portion.