System and method for detecting intravenous needle dislocation

In one aspect, a method and system for detecting a hydrodynamic change in a fluid flowing through an extracorporeal circuit is disclosed, the method and system comprising: establishing an acoustic resonance in a lateral dimension of at least a portion of a line associated with the extracorporeal circuit through which the fluid flows; monitoring a phase signal of the resonant sound wave; and identifying an occurrence of a hydrodynamic change in the flowing fluid when the observed phase signal of the resonant acoustic wave is indicative of a deviation from the expected fluid flow characteristic. The hydrodynamic change may be used to indicate an intravenous needle dislocation event. 在一个方面中，公开了一种用于检测流经体外回路的流体的流体动力学变化的方法和系统，所述方法和系统包括：在与流体流经的体外回路相关联的管线的至少一部分的横向维度上建立声波谐振；监测谐振声波的相位信号；以及当观察到的谐振声波的相位信号指示与预期的流体流动特征的偏差时，识别流动的流体的流体动力学变化的发生。流体动力学变化可以用于指示静脉针离位事件。