The inspiratory impedance threshold device (ITD) was put forward by Lurie in 1995, and was assigned as a class Ⅱa recommendation by the International Liaison Committee on Resuscitation (ILCOR) resuscitation guidelines in 2005. The ITD is used to augment negative intrathoracic pressure during recoil of the chest so as to enhance venous return and cardiac output, and to decrease intracranial pressure. In the recent years many researches on the ITD have been1 carried out, but all the researches can not take out a clear evidence to support or refute the use of the ITD. This paper introduces the structure and working principle of the ITD in detail, the research results and the debates about the use of the ITD for the past years.
