A contribution to the pathogenesis of respiratory disturbances associated with subarachnoid haemorrhage; an experimental approach using an animal model.

The present experimental work focuses on the mechanisms involved in respiratory distress observed in the course of subarachnoid haemorrhage. For this purpose, respiratory disturbances were induced in rabbits by injecting fresh autologous blood into the subarachnoid space. For six hours after this artificially induced SAH, blood PO2 and PCO2 as well as expiratory air CO2 were regularly determined, while during the same period cerebral blood flow and cerebrospinal fluid pressure measurements were recorded. The results of this study suggest that pressure effects acting the brain structures that support respiration are principally involved in the pathogenesis of respiratory disturbances following SAH. A decrease in CBF and hypoxia with hypercapnia play a contributing secondary role adding to a vicious cycle phenomenon.