PROBLEM TO BE SOLVED: To provide an indwelling needle for extracorporeal circulation capable of disallowing a blood intake port to be blocked by a blood vessel and inhibiting the recirculation of blood.SOLUTION: An indwelling needle for extracorporeal circulation has: an outer circumference space 16 communicating with one end of a blood circuit and an inner space 2a communicating with the other end of the blood circuit, both the spaces being defined inside a tubular shaped needle 4 an opening 17 disposed on an outer circumference surface of the needle 4 for communicating the inside of a blood vessel with the outer circumference space 16 for taking in blood from the blood vessel into the outer circumference space 16 when detained in the blood vessel and an end opening 14c disposed at the end of the needle 4 for communicating into the blood vessel and the inner space 2a for retuning the blood from the inside of the inner space 2a into the blood vessel when retained in the blood vessel. On the outer circumference surface of the needle 4, a projection 28 that outwardly projects further than at least a part of an opening edge of the opening 17 is disposed between the opening 17 and a leading end opening 14c.COPYRIGHT: (C)2015,JPO&INPIT【課題】血液の取込口が血管によって閉塞される不都合を防止することができ、また、血液の再循環を抑制することができる体外循環用留置針を提供する。【解決手段】管状体で形成された針4内に、血液回路の一端と連通する外周空間16と、血液回路の他端と連通する内部空間2aとを区画形成し、針4の外周面に開設され、血管内に留置されたときに血管内と外周空間16とを連通して血液を血管内から外周空間16内へ取り込む開口部17と、針4の先端に開設され、血管内に留置されたときに血管内と内部空間2aとを連通して血液を内部空間2a内から血管内へ戻す先端開口14cと、を備え、針4の外周面のうち開口部17と先端開口14cとの間には、開口部17の開口縁の少なくとも一部よりも外方へ突出した突起28を備えた。【選択図】図3
