A multiple treatment fluid stream system including a multi-stream treatment machine and an accessory fluid circuit, the multi-stream treatment machine having at least two peristaltic pumps (302, 304, 306, 308, 310, 312), one of which is a blood pump and the at least one other pump is a multiple-fluid pump (302, 304, 306, 308, 310) which is configured to pump one of replacement fluid, dialysate, anti-coagulant, and spent dialysate in an extracorporeal blood treatment mode and which is configured to pump blood in an extracorporeal membrane oxygenation mode, and the accessory fluid circuit being configured to be installed on the multi-stream treatment machine, and comprising: a first junction connected to an arterial access connector; a second junction connected to a blood oxygenator connector; and at least two parallel pumping tube segments (311, 342, 344, 346) connected between the first and second junctions (322A, 322B) and fluidically connected for parallel flow between the arterial connector and said blood oxygenator connector, a first and a second of the at least two parallel pumping tube segments (311, 342, 344, 346) being configured for respectively engaging the blood pump and the at least at least one other pump (302, 304, 306, 308, 310), wherein, in the extracorporeal membrane oxygenation mode, the multi-stream treatment machine is configured to pump blood in parallel through the first and second of the at least two parallel pumping tube segments (311, 342, 344, 346) with the blood pump and the at least one other pump (302, 304, 306, 308, 310). the multi-stream treatment machine having at least two peristaltic pumps (302, 304, 306, 308, 310, 312), one of which is a blood pump and the at least one other pump is a multiple-fluid pump (302, 304, 306, 308, 310) which is configured to pump one of replacement fluid, dialysate, anti-coagulant, and spent dialysate in an extracorporeal blood treatment mode and which is configured to pump blood in an extracorporeal membrane oxygenation mode, and the accessory fluid circuit being configured to be installed on the multi-stream treatment machine, and comprising: a first junction connected to an arterial access connector; a second junction connected to a blood oxygenator connector; and at least two parallel pumping tube segments (311, 342, 344, 346) connected between the first and second junctions (322A, 322B) and fluidically connected for parallel flow between the arterial connector and said blood oxygenator connector, a first and a second of the at least two parallel pumping tube segments (311, 342, 344, 346) being configured for respectively engaging the blood pump and the at least at least one other pump (302, 304, 306, 308, 310), a first junction connected to an arterial access connector; a second junction connected to a blood oxygenator connector; and at least two parallel pumping tube segments (311, 342, 344, 346) connected between the first and second junctions (322A, 322B) and fluidically connected for parallel flow between the arterial connector and said blood oxygenator connector, a first and a second of the at least two parallel pumping tube segments (311, 342, 344, 346) being configured for respectively engaging the blood pump and the at least at least one other pump (302, 304, 306, 308, 310), wherein, in the extracorporeal membrane oxygenation mode, the multi-stream treatment machine is configured to pump blood in parallel through the first and second of the at least two parallel pumping tube segments (311, 342, 344, 346) with the blood pump and the at least one other pump (302, 304, 306, 308, 310).