A venous reservoir including a single inlet line clamp capable of partially or completely restricting blood flow to the venous reservoir. The venous reservoir is provided with a rigid back plate or bracket that can accommodate an inlet line capable of joining to at least one blood inlet port. The rigid back plate or bracket can accommodate a clamp capable of completely or partially closing the inlet line containing both the cardiotomy line and the venous line to manually control the blood flow drained from the patient.