Abstract
During aneurysm surgery on 13 patients, regional cortical blood flow (CoBF) was continuously monitored with a thermal diffusion flow probe in an attempt to assess the effects of brain retraction, systemic hypotension and temporary major arterial occlusion on blood flow and outcome.
In mild brain retraction of less than 10mmHg, transient decrease in CoBF was observed. CoBF decreased to a critical level when retraction pressure exceeded 30mmHg and remained at a low value until brain retraction was completely removed.
In systemic hypotension, temporary arterial occlusion resulted in further decrease in CoBF as compared with normotension.
When the CoBF was above 30ml/100g/min, the safety period for temporary clipping applied at distal to the perforators was 15 minutes. The occlusion time should be shortened when CoBF is below 30ml/100g/min for less than 10 minutes.
Two patients revealed basal infarction, which was not detected by CoBF monitoring, in the territory of perforating branches. Occlusion time should be less than 5 or 6 minutes when a temporary clip is applied at the site proximal to the perforating branches. The intraoperative monitoring of CoBF is a useful adjunct in assessment of the safety period for temporary clipping which is applied to the major cerebral arteries.
