referring first to fig1 there is illustrated the catheter of the invention comprising a tube generally indicated 10 having a continuous bore 11 to the distal end 12 . the catheter is divided into three segments namely an intra - abdominal portion 15 below line 13 , a body portion 16 between lines 13 and 14 , and an external body portion 18 above line 14 . a plurality of ingress and egress ports 20 are located at the end of intra - abdominal portion 15 spaced about the circumference of tube 10 . they are preferably graded longitudinally from the largest 22 to the smallest 24 . the distal end 12 may also contain an additional port 26 indicated in fig4 which is created by installing a plug 25 having a port no larger than 1 . 35 mm . in the distal end 12 . a one - half helical turn 28 is formed in body portion 16 , the configuration of which is further shown by reference to top view fig2 . by the body portion what is meant is that portion of the catheter which will reside in the abdominal wall of the patient , i . e . the anatomical structure adjoining the peritoneum between the rectus muscle and the skin . it is essential that the body portion be formed with a helical turn in a fashion so that it will retain its shape after implantation in order that the function of the one - half turn be carried out . the helical , rotary motion imparted to the fluid by the helical half turn imparts an even distribution of the fluid over the many exit ports rather than allowing exit of the fluid through one dominant hole . this reduces the force of the fluid flow and consequently reduces the trauma inherent in running dialysis fluids into the abdominal cavity . further it is equally important to drain the fluid with similarly little trauma that is accomplished by dividing the fluid reentrance into the catheter over a large area through many holes which limits the flow velocity in any one place . optionally and as is the practice with such catheters , one or two fibrous cuffs 30 composed of dacron , for example , may be positioned over the body portion to seal the subcutaneous channel from bacteria by means of cellular ingrowth . the outer cuff is positioned so that it may be sutured to the subcutaneous tissue while the inner cuff is sutured to the posterior rectus sheath . in accordance with the above disclosure , a catheter was constructed of silicone rubber or other suitable polymeric compound tubing having an inside diameter of 2 . 64 mm ., an outside diameter of 4 . 87 mm . and an overall length of 47 cm .. the horizontal distance from the proximal end to the beginning of the turn ( line 14 ) is 16 cm . and the vertical distance from that point to the distal end is 22 - 24 cm . the vertical length of the turn is on the order of 1 . 3 cm . with an outside radius of 1 . 4 cm .. the distance from the end of the turn to the first port is 7 . 2 cm ., after which 24 holes in four staggered rows of 6 each of a diameter of 1 . 12 mm . were placed a length of 7 . 0 cm .. these are followed by a similar series of 0 . 61 mm . holes spaced over approximately the same remaining length . tests utilizing dyed water gravity fed to the catheter immersed in clear water showed a thoroughly uniform dispersion pattern in accordance with the object of the invention . the invention shows even distribution of flow where the conventional prior art has essentially increased velocity and poorly distributed flow at the proximal and distal ends . tests of conventional catheters and the invention illustrate interesting flow data . for example , a conventional catheter averages a discharge of 77 . 6 ml of fluid in 60 sec . while the invention discharges 82 . 8 ml in 60 sec . with a hydrostatic head of 13 cm . the invention shows , therefore an average of 6 . 7 % better inflow and better outflow than the control unit of the prior art . clinical studies on humans have been conducted and the catheter has performed perfectly for periods of nine up to eighteen months and clinically , significantly better inflow and outflow has been noted but measurement data was not recorded . these results are to be compared to average implant time for standard catheters of eight months . the longevity of the implant indicates that there was no attachment by the omentum to the catheter of the invention . the catheter is preferably composed of silicone elastomer coated with ultra - low temperature isotropic ( ulti ) carbon , or another non - reactive material , which serves to round the edges of the ports and coat the ports which reduces or eliminates body reaction to the entire device . the particular coating which in essence is applied in molecular layers to the surface of the catheter is an important element of the catheter . carbon coatings are generally applied by a sputtering or vacuum vapor process at elevated temperature that is not possible with a silicone rubber catheter . the ulti carbon coating is achieved by a hybrid low pressure process where isotropic carbon can be deposited from a gaseous precursor at ambient temperatures by using a proprietary catalyst and is successful on devices having a certain degree of flexibility and a low melting point . it will be apparent from the foregoing that the advance in the catheter is the curved component section coupled with graduated diameter holes and the coating with ultra - low temperature isotropic carbon . the curve imparts centrifugal motion to the fluid flowing in which allows the fluid stream to exit the catheter through all the holes rather than through only a few or one end hole . the distribution of holes also avoids pulling abdominal structures into the flow path and drainage can proceed without obstruction . the method of use and improved and advantageous operation of the apparatus are as described above . variations of the device disclosed herein may occur to those skilled in the art . accordingly , the invention is defined by the following claims .
a peritoneal catheter for introducing and withdrawing fluid from an abdominal cavity which catheter has a plurality of ingress and egress ports spaced about the circumference and along the length of the intra - abdominal portion , which ports are arranged to decrease in size from the proximal to the distal end and , further which has a body portion formed into at least a one - half turn . the catheter tubing and the ports therein are coated with ultra - low temperature isotropic carbon .