Abstract: The disclosed techniques relate to an apparatus including: a pump body, an occlusion bed; and a rotor. The rotor includes: a shaft body; a roller body slidably mounted to the shaft body; and a lock mechanism selectively positioned between a first position and a second position. In the first position, the lock mechanism engages with the roller body to lock the roller body at a first roller body position relative to the shaft body where the one or more rollers can compress tubing disposed in the apparatus against the occlusion bed with a first level of compression. In the second position, the lock mechanism disengages the roller body so the roller body can slide along the track relative to the shaft body to a second roller body position configured to cause decreased or no compression of the tubing against the occlusion bed by the one or more rollers.