Device and method for mixing medical fluids

A method for enabling mixing of medical fluids, said method comprising the steps of:

• providing a mixing device exhibiting an inlet port, an injection port and an outlet port,
• coupling said inlet port to a fluid transfer port of a fluid container containing a first medical fluid,
• connecting a fluid transfer device having an injection needle to said injection port by means of a double-membrane bayonet coupling,
• penetrating fluid-proof membranes included in said double-membrane bayonet coupling by means of said injection needle,
• injecting a second medical fluid from a second medical fluid-reservoir connected to said fluid transfer device into said first medical fluid,
• passing a mixed flow of said first and second medical fluids through said outlet port into an infusion line, and
• providing a combined friction coupling and snap connection in said device between a first portion which is made of a first material and exhibits said inlet port and said injection port and a second portion which is made of a second material being substantially more resilient than said first material and which exhibits said outlet port.