Clinical study of acute brain swelling during operation for moyamoya disease

: Treatment for moyamoya disease includes direct and indirect anastomosis. During surgery, acute and massive brain swelling has been encountered infrequently just after opening of the dura mater, while mild or moderate brain swelling is frequently found just after opening of the dura mater. Four out of 866 cases operated on by the first author in the last twenty-two years showed acute and massive brain swelling and the operation had to be completed as soon as possible. In the present study, we investigated the cause of acute brain swelling just after opening of the dura mater. Partial pressure of end-tidal carbon dioxide gas (ETCO(2), mmHg) was measured and recorded just before induction of general anesthesia (preETCO(2)) and just after opening of the dura mater (postETCO(2)) in fourteen patients operated on for moyamoya disease. The distance between the opened dural edge and the top of the swelled brain surface (dbs, mm) was also measured. The relationship between increase in ETCO(2) (x, defined as postETCO(2) minus preETCO(2)) and dbs (y) was investigated and it was revealed that there was a significant positive correlation between the two parameters (y=2.59+0.31x, n=14, r=0.65048, p=0.01177<0.05). It means that decrease in carbon dioxide gas tension in various degrees before operation was normalized abruptly by the anesthesiologist and the increase in carbon dioxide gas tension was thought to increase in cerebral blood flow abruptly, resulting in acute brain swelling.