INTRAOPERATIVE LASER FLOWMETRY REFLECTS LEVELS OF CEREBRAL BLOOD-FLOWDURING NEUROSURGICAL PROCEDURES

Changes in cerebral blood flow (CBF) during craniotomies (mean 62.2 ye ars, n = 31) were studied using a laser flowmeter (LFM) to evaluate th e utility in CBF monitoring. A small flat probe was applied to the bra in surface near the surgical field. The output voltage from LFM was re corded as CBF changes. The percent change in CBF was calculated using the formula [intrasurgical-CBF-control-CBF]/control-CBF x 100. Postope rative neurologic status was evaluated. Control-CBF values were simila r among the groups representing different pathologies. The mean CBF de crease ranged from -7.3% following phenytoin injection (n = 9) to -32. 7% during induced intrathoracic pressure (n = 10). The mean CBF increa se was 41.4% following vascular anastomosis. A decrease > 50% for more than 15 min was associated with a severe permanent neurologic deficit . The CBF monitoring using an LFM during craniotomy may be useful in d etecting clinical CBF levels for reducing post-operative neurological deficits.