摘要 |
A catheter (100) having a first lumen (110) having a first distal tip (112) and a second lumen (130) having a second distal tip (132). The first and second distal tips (112,132) include openable portions that are normally closed when undeflected by lumen fluid pressure imbalance relative to the blood pressure of the patient. The first lumen (110) has an openable portion, flap (114) that opens proximally into the first lumen when the first lumen is under negative pressure to withdraw blood from the vessel through the first lumen to be dialysed (but that can open distally into the vessel under positive lumen pressure to permit blood flow into the vessel). The second lumen (130) extends distally beyond the first distal tip (112) to its second distal tip (132), and its openable portion is several lip sections (135) that are normally closed against each other when undeflected but that open outwardly when the second lumen is positively pressurized during hemodialysis, permitting blood to return to the patient's vessel. |