[Changes in intracranial pressure and impedance in the presence of air and gad embolism].

In biophysical models and in acute experiments on animals, the air was administered in measured volumes into the artificial blood flow and into the common carotid artery in dogs. When air bubbles get into the electric field between electrodes, specific changes of impedance depending on the bubbles size could be recorded. A lot of small bubbles sharply increased the impedance according to their total volume. Ih the air compression up to 10 kgs/cm2 and in following decompression, the intracranial impedance and pressure smoothly changed according to barogram. After 15 min of stying under pressure the dogs developed during decompression a sharp increase of the intracranial impedance and pressure which, similarly to the results of the model experiments, should be regarded as the consequence of formation of a free gas phase in the system of intracranial circulation.