In a peristaltic medical infusion pump unit, comprising a peristaltic assembly and a counter surface or anvil facing said peristaltic assembly and provided by the inner surface of a door pivotally mounted on a housing of the unit, the door is readily non-destructively removable and replaceable. In use of the peristaltic pump unit, a flexible resilient tube forming part of a medical fluid delivery line is extended between the peristaltic assembly and the counter surface or anvil provided by the door. The medical fluid delivery line has first and second color coded fittings spaced therealong upstream and downstream of the peristaltic assembly and the region of the housing of the pump unit across which the infusion line is extended is provided, correspondingly spaced above and below the peristaltic assembly with correspondingly color coded support means for these fittings.