Disclosed herein are an apparatus, a system, and a method to monitor drainage from a first region of a patient to a second region. The apparatus comprises pressure sensors configured to measure the pressures of the first and second regions, a flow system to regulate drainage of fluid from the first region to the second region, a memory having a stored pressure drop across the flow system and a processor associated with the memory and configured to compare the first pressure, the second pressure, and the stored pressure drop threshold and selectively generate control signals based on the comparisons. In some instances, the apparatus further comprises an alarm, and the processor is configured to generate the control signals that trip the alarm when a pressure drop exceeds the stored pressure drop threshold.
