A method for performing a continuous infusion process using at least two infusion devices (1A, 1B) comprises the steps of: delivering a first fluid (M1) from a first medication container (100A) through a first delivery line (11A) at a first flow rate (F1) using a first infusion device (1A) in a first phase； and delivering a second fluid (M2) from a second medication container (100B) through a second delivery line (11B) at a second flow rate (F2) using a second infusion device (1B) in a second phase following the first phase. Herein, a relay device (2) connected to said first delivery line (11A) and said second delivery line (11B) is constituted to receive the first fluid (M1) via the first delivery line (11A) in the first phase and the second fluid (M2) via the second delivery line (11B) in the second phase, wherein the relay device (2) is further constituted to discharge the received first or second fluid (M1 M2) to an outlet delivery line (3) connected to the relay device (2) for administration to a patient (P), the outlet delivery line having a predefined delivery volume (DV). In addition it is provided that, subsequent to the delivery of the first fluid (M1) using the first infusion device (1A) in the first phase, the second infusion device (1 B) in an intermediate phase is operated for a predetermined delivery time to deliver the second fluid (M2) at the first flow rate (F1), the predetermined delivery time being determined taking the predefined delivery volume (DV) of the outlet delivery line (3) into account. In this way a method for performing a continuous infusion process using at least two infusion devices is provided, allowing for a continuous infusion at a desired, in particular constant dose rate in particular when switching from one infusion device to another.
