Balloon-assisted coil embolization of intracranial aneurysm and zero bispectral index

A non-contrast computed tomographic (CT) scan of the brain showed subarachnoid hemorrhage. {Figure 1}{Figure 2} A sudden drop in BIS value has been reported during coil embolization,[1] embolization of arteriovenous malformations,[2] and with the occurrence of intraventricular hemorrhage during a third ventriculostomy. [5] The BIS monitoring can rapidly detect the intracranial aneurysmal rupture, especially during balloon-assisted coiling, as the contrast injection for detection of the rupture is not possible without deflation and withdrawal of the tamponade effect.