Transthoracic electrical impendance in anaesthesia and intensive care.

Pulmonary fluid accumulation plays an important role in the development of post-traumatic pulmonary insufficiency. Yet initially diagnosis may be difficult. The measurement of transthoracic electrical impedance was used to detect early pulmonary fluid overload. In healthy test persons infusions of isotonic electrolyte solutions and diuresis were accompanied by changes of impedance dependent on the amount of infused or withdrawn fluid. In patients with pulmonary insufficiency a relatively low mean body impedance was recorded. Enforced diuresis resulted in a rise and in diminution of the alveolar-arterial oxygen difference.