A system for monitoring blood flow in a patient, the system comprising: a single-element disc-shaped ultrasound transducer for fastening to the patient and a controller subsystem. The controller subsystem is configured to: control the ultrasound transducer to transmit a series of plane-wave pulses into the patient in a propagation direction; sample reflections of the plane-wave pulses, received at the ultrasound transducer, from a region within the patient, to generate pulse-Doppler response signals; and process the pulse-Doppler response signals to calculate a blood flow curve for waveform analysis.