Peristaltic pump

A surgical cassette configured to engage a first plurality of rollers of a first roller head, comprising:

• a face coupled to a first pump substrate, the face being at a first angle with respect to an axis of rotation of the first roller head and a wall of the first pump substrate being at a second angle with respect to the axis of rotation of the first plurality of rollers, wherein the first angle is different from the second angle;
• and
• a first sheet positioned on a surface of the wall, wherein:
• the first sheet and the wall form first one or more pump segments configured to engage the first plurality of rollers in a position where force applied by each one of the first plurality of rollers on the first one or more pump segments has a direction that is not parallel to the axis of rotation of the first roller head, and
• the wall comprises a first inlet aperture and a first outlet aperture;
• and a base having a plurality of inlet ports and a plurality of outlet ports, wherein the first pump substrate is rotatable relative to the base to:
• (i) selectively fluidically couple the first inlet aperture with one of the plurality of inlet ports and decouple the first inlet aperture from at least one other inlet port of the plurality of inlet ports, and simultaneously (ii) selectively fluidically couple the first outlet aperture with one of the plurality of outlet ports and decouple the first outlet aperture from at least one other outlet port of the plurality of outlet ports.