PROBLEM TO BE SOLVED: To provide a catheter which can perform plural kinds of medical treatments such as transfusions simultaneously and reduces a burden on a patient.SOLUTION: A catheter related to one aspect of this invention includes: a blood return lumen which is arranged in a first region and communicates with the outside via an opening part provided in a distal end part a blood removal lumen which is arranged in a second region and communicates with the outside via a semicircular opening part arranged on a proximal end part side with respect to the opening part of the blood return lumen three or more transfusion lumens arranged in the first region and a narrow diameter part which is provided from the opening part of the blood removal lumen to the distal end part, has the blood return lumen and three or more transfusion lumens in the inside, and has a taper so that a diameter is reduced gradually toward the distal end part. Then, a cross section of the blood return lumen is formed to be bigger than cross sections of the respective transfusion lumens. The opening part of the blood removal lumen is slanted to the proximal end part side in an axial direction. The respective opening parts of the transfusion lumens are arranged in the narrow diameter part and are formed to follow the taper of the narrow diameter part.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT【課題】輸液等の医療行為を複数種類同時に実施可能で、かつ、患者にかかる負担が少ないカテーテルを提供する。【解決手段】本発明の一側面に係るカテーテルは、第1領域内に配置され、先端部に設けられる開口部を介して外部と連通する返血ルーメンと、第2領域内に配置され、返血ルーメンの開口部より基端部側に配置される半円状の開口部を介して外部と連通する脱血ルーメンと、第1領域内に配置される3つ以上の輸液ルーメンと、脱血ルーメンの開口部から先端部にかけて設けられ、返血ルーメン及び3つ以上の輸液ルーメンが配置され、先端部に近付くに従って細くなるようにテーパーを有する狭径部と、を備える。そして、返血ルーメンの断面は各輸液ルーメンの断面よりも大きく形成され、脱血ルーメンの開口部は軸方向に沿って基端部側に傾斜し、各輸液ルーメンの各開口部は、狭径部に配置され、狭径部のテーパーに沿うように形成される。【選択図】図1
