[The effect of sympathectomy on the cochlear oxygen pressure (pO2) under conditions of haemorrhagic hypotension (author's transl)].

Oxygen partial pressure was measured in the endolymph area of the cat cochlea under conditions of hemorrhagic hypotension. The experiments took place after unilateral upper cervical sympathectomy and under control conditions. The pO2-measurements were carried out with the aid of polarographic micro-coaxial needle electrodes according to Baumgärtl and Lübbers (1, 2, 3). In animals which had not been sympathectomized, the cochlear pO2 decreased continuously parallely to blood pressure, with the beginning of bleeding. After sympathectomy pO2-decrease in cochlea only occurred at substantially lower aortal blood pressure. This allows the following conclusions: 1. Under conditions of hemorrhagic shock the blood flow of the inner ear is not as much included in central circulation as brain and heart. 2. The blood pressure dependence of the inner ear blood flow depends on the sympathetic innervation, it can practically be abolished up to a blood pressure of 65 mm Hg by denervation. 3. It is being discussed, which therapeutic consequences can be drawn from the evident influence of the sympathetic innervation on the inner ear blood flow.