Monitoring the chest with impedance.

The application of bioelectric impedance to the measurement of tissue volume changes, long discussed, is with today's electronics innovations now a reality. The theory of this noninvasive technique is conceptually explained. Its application to continuous monitoring of the chest is described using three impedance devices, one of which was designed and developed by us. Clinical cases are described to illustrate its value in the early detection of pulmonary problems such as post-traumatic pulmonary insufficiency, congestive heart failure, and atelectasis, and in following the clinical course of patients with these special problems.