Abstract: An oxygen-sensing assembly for attachment to a urinary catheter may include a housing having a flow pathway extending between an inlet end and an outlet end thereof, an oxygen sensor in operable communication with the flow pathway of the housing, the oxygen sensor configured to detect oxygen levels of a fluid flowing through the flow pathway and a flowrate sensor configured to detect a flowrate of the fluid flowing through the flow pathway. A risk of acute kidney injury may be determined based on the mass flowrate of oxygen through the flow pathway, determined based on the detected oxygen levels and the flowrate of the fluid through the flow pathway. Related catheter assemblies and methods are also disclosed.