A plurality of pump cassettes are connected through distribution tubing to
a single inlet tube such that the inlet tube is shared by the pump
cassettes through the distribution tubing. The plurality of pump
cassettes may be symmetrically attached to the distribution tubing. A
four-port coupling may be inserted in the distribution tubing for making
connection to the inlet tube and a middle one of the pump cassettes when
the number of cassettes is an odd number.