The role of calcium in parenchymal cell injury in subarachnoid haemorrhage.

Experimental subarachnoid haemorrhage and intraparenchymal haematoma were produced in 20 cats serving as a model for parenchymal cell injury in patients with head trauma. There was a typical and constant cellular membrane dysfunction characterized by K+ outflux and Ca2+ influx. It appears that both of these events have a major influence on subsequent development of cellular dysfunction, anatomically characterized as cellular swelling. In addition, the calcium influx appears to have a specific role in the cell membrane destruction process by initiating an autolytic destruction of cell membranes. This mechanism may be crucial in the development of secondary irreversible injuries in cells destabilized, but not completely destroyed, at the time of the initial trauma.