[The mechanism of cardiorespiratory arrest due to subarachnoid hemorrhage]

This report describes the clinical course of patients with sudden cardiorespiratory arrest (CRA) due to subarachnoid hemorrhage (SAH). We have seen fifteen patients of SAH that presented initially as CRA. All of them were diagnosed as SAH by CT scan. The patients were divided into two groups; one group (early DOA group) included 11 patients, who had been recognized as CRA within 60 minutes from the onset of SAH, the other group (late DOA group) consisted of 4 patients, who developed CRA more than 60 minutes after the initial onset. The major mechanism leading to delayed CRA in the late DOA group appeared to have been from brain stem herniation, but another mechanism appeared to be involved in sudden CRA in the early DOA group. Sixty percent of our patients with CRA due to SAH had a low serum potassium concentration, though hypokalemia was observed in only 4 out of 100 patients with CRA due to diseases other than SAH. These facts suggest that sympathetic hyperstimulation might result not only from stress but also from a disorder of the central autonomic nervous system. We speculate that the mechanism leading to early CRA after SAH appears to result from a disorder of the central autonomic nerve system.