PROBLEM TO BE SOLVED: To provide an indwelling needle cap for extracorporeal circulation indwelling needles capable of facilitating preparation work of blood extracorporeal circulation, extracorporeal circulation indwelling needle with a cap, blood circulation, and priming method of the blood circulation.SOLUTION: An indwelling needle cap 6 is detachably mounted on an extracorporeal indwelling needle 1 that is formed by comparting a needle 4 formed of a tubular body into an outer peripheral space 16 communicated to a blood removal-side blood circuit 102, and an inner space 2a communicated to a retransfusion-side blood circuit 103. The indwelling needle cap includes: a storage part 6a that can store, in the same space, both of an opening part 17 opened to the needle 4 for opening the outer peripheral space 16, and a tip-end opening 2b opened separately from the opening part 17 for opening the inner space 2a and an O-ring 29 for storing the needle 4 in the storage part 6a in a liquid-tight state.COPYRIGHT: (C)2016,JPO&INPIT【課題】血液の体外循環の準備作業を簡単に行うことが可能となる体外循環用留置針の留置針用キャップ、キャップ付体外循環用留置針、血液回路、および血液回路のプライミング方法を提供する。【解決手段】管状体で形成された針4内に、脱血側血液回路102と連通する外周空間16と、返血側血液回路103と連通する内部空間2aとが区画形成された体外循環用留置針1に着脱自在に装着される留置針用キャップ6であって、針4に開設されて外周空間16を開放する開口部17と、該開口部17とは別個に開設されて内部空間2aを開放する先端開口2bとの両方を同一空間内に収納可能な収納部6aと、収納部6aに針4を液密状態で収納するためのОリング29と、を備えた。【選択図】図2
