A device and method for detecting fault conditions in a fluid connection system between a first fluid containing system including a first pulse generator (e.g., an extracorporeal blood circuit) and a second fluid containing system including a second pulse generator (e.g., a human or animal vascular system). A pressure sensor detects first pulses from the first pulse generator and second pulses from the second pulse generator. A time-dependent monitoring signal based on data obtained from said pressure sensor is generated and processed to calculate a parameter value indicative of the shape of at least part of a first pulse in the monitoring signal. The parameter value is evaluated to detect the fault condition. The fault condition may involve disconnection of an access device； reversed connection of access devices； occlusion of the fluid path through an access device； or infiltration in tissue surrounding an access point in the vascular system.
