The invention relates an infusion pump unit, comprising a pump device, a pressure sensor and a monitoring device. The infusion pump unit is configured to operate in a detection mode to locate an anatomical structure in the body of a patient, and in an infusion mode to infuse fluid into a patient. In the infusion mode, the monitoring device is configured to compare the sensor signal with a threshold pressure value, and to provide a warning signal when the sensor signal exceeds the threshold pressure value. In the detection mode, the monitoring device is configured to continuously provide on the basis of the sensor signal, a pressure level signal representative of a pressure level and/or pressure variation in the fluid.
