Catheter assembly

Abstract

A catheter assembly is provided with a flexible tubular body having two lumens. A solid slidable member with a sharp distal end is disposed within one of the lumens. The slidable member is capable of sliding within the lumen of the tubular body between an exposed position in which the sharp distal end of the slidable member protrudes from the distal end of the tubular body and a shielded position in which the distal end of the slidable member is within the tubular body. One advantage is that the sharp distal end of the slidable member may be withdrawn into the tubular body in order to shield a patient from unintentional cutting or irritation from the sharp distal end of the slidable member.

1 . A method of drawing blood for hemodialysis, comprising:
 placing a slidable member in an exposed position wherein said slidable member is disposed within a first lumen of a flexible tubular body with a sharp distal end of said slidable member protruding from a distal end of said first lumen of said tubular body, said slidable member being non-hollow and movement of said slidable member being longitudinally limited in relation to said tubular body, said distal end of said tubular body comprising a smoothly contoured surface sloping proximally away from said slidable member, and said tubular body further comprising a second lumen adjacent said first lumen;   puncturing a patient's skin and underlying tissue with said slidable member;   pushing said distal end of said slidable member and said distal end of said tubular body into a blood lumen of said patient;   moving said slidable member to a shielded position wherein said slidable member remains within said first lumen with said distal end of said slidable member located proximally from said distal end of said tubular body; and   drawing blood from said blood lumen through a distal end of said second lumen and out of the patient.   
     
     
         2 . The method according to  claim 1 , wherein said slidable member has a circular cross-sectional shape. 
     
     
         3 . The method according to  claim 2 , wherein said second lumen has a crescent-like cross-sectional shape wrapped around said first lumen. 
     
     
         4 . The method according to  claim 1 , wherein said distal end of said slidable member comprises at least three faces, said at least three faces forming a point at the most distal location of said distal end of said slidable member. 
     
     
         5 . The method according to  claim 1 , wherein said slidable member has a non-circular cross-sectional shape. 
     
     
         6 . The method according to  claim 5 , wherein said slidable member is curved such that said slidable member has a crescent-like cross-sectional shape. 
     
     
         7 . The method according to  claim 1 , wherein said second lumen has a circular cross-sectional shape. 
     
     
         8 . The method according to  claim 1 , wherein a hub is attached about a proximal end of said tubular body. 
     
     
         9 . The method according to  claim 1 , wherein said tubular body comprises a slot along said first lumen, a sliding mechanism being connected to said slidable member, said sliding mechanism protruding through said slot such that said sliding mechanism may be used to control the sliding of said slidable member between said exposed position and said shielded position. 
     
     
         10 . The method according to  claim 9 , wherein a hub is attached about a proximal end of said tubular body, said hub being connected to said sliding mechanism thereby allowing a user to operate said sliding mechanism with said hub. 
     
     
         11 . The method according to  claim 1 , wherein said distal end of said first lumen being located distally from said distal end of said second lumen, said distal end of said tubular body being conically tapered such that said distal end of said first lumen comprises the narrowest portion of said tapered distal end of said tubular body and said distal end of said second lumen is located proximally to said narrowest portion of said tapered distal end of said tubular body. 
     
     
         12 . The method according to  claim 1 , wherein said slidable member does not completely occupy said first lumen. 
     
     
         13 . The method according to  claim 12 , wherein said distal end of said first lumen comprises a first beveled edge, said distal end of said second lumen comprises a second beveled edge, said first beveled edge and said second beveled edge together forming a single beveled edge at said distal end of said tubular body. 
     
     
         14 . The method according to  claim 12 , wherein said distal end of said first lumen comprises a first beveled edge, said distal end of said second lumen comprises a second beveled edge, said first beveled edge being located distally from said second beveled edge. 
     
     
         15 . The method according to  claim 12 , wherein said distal end of said first lumen is located distally from said distal end of said second lumen, said distal end of said tubular body being conically tapered such that said distal end of said first lumen comprises the narrowest portion of said tapered distal end of said tubular body and said distal end of said second lumen is located proximally to said narrowest portion of said tapered distal end of said tubular body. 
     
     
         16 . The method according to  claim 12 , wherein a hub is attached about a proximal end of said tubular body. 
     
     
         17 . The method according to  claim 12 , wherein said tubular body comprises a slot along said first lumen, a sliding mechanism being connected to said slidable member, said sliding mechanism protruding through said slot such that said sliding mechanism may be used to control the sliding of said slidable member between said exposed position and said shielded position. 
     
     
         18 . The method according to  claim 1 , wherein an expandable tip is attached to said distal end of said slidable member, said tip of said slidable member comprising a first leg and a second leg, wherein said first leg extends from said distal end of said slidable member to a most distal location of said slidable member and said second leg is attached to said most distal location and extends proximally therefrom, said second leg being curved and forming a cutting surface, wherein said second leg engages an opening of said lumen when said slidable member is retracted within said lumen, thereby compressing said second leg to permit said expandable tip of said slidable member to be withdrawn into said lumen. 
     
     
         19 . The method according to  claim 18 , wherein said second leg has a distal end and a proximal end and said proximal end of said second leg is connected to said distal end of said slidable member. 
     
     
         20 . The method according to  claim 18 , wherein said second leg has a distal end and a proximal end and said proximal end of said second leg is unconnected to said slidable member. 
     
     
         21 . The method according to  claim 1 , wherein said first lumen is sealed to prevent blood flow proximally through said first lumen. 
     
     
         22 . The method according to  claim 1 , wherein said slidable member is unable to rotate in relation to said tubular body. 
     
     
         23 . The method according to  claim 1 , wherein said distal end of said slidable member is beveled and said distal end of said tubular body is beveled, said beveling of said slidable member being parallel to said beveling of said tubular body. 
     
     
         24 . The method according to  claim 1 , wherein said tubular body is made of a flexible biocompatible material of an elastomer, plastic, polyurethane, polyethelene, PTFE, silicone, polyolefin, polyester, or polyimide. 
     
     
         25 . The method according to  claim 1 , wherein said slidable member is made of a hard biocompatible material of metal, plastic, fiber-reinforced plastic, or a combination thereof.