CONTINUOUS POSTOPERATIVE ICBF MONITORING IN ANEURYSMAL SAH PATIENTS USING A COMBINED ICP-LASER DOPPLER FIBEROPTIC PROBE

Cerebral vasospasm remains the principal cause of morbidity and mortal ity following successful clipping of intracranial aneurysms. Current m anagement often requires subjective judgments concerning presumed abno rmalities of cerebral blood flow. In this study, a combined intracrani al pressure (ICP)-laser Doppler flowmetry (LDF) fiberoptic probe that permits continuous monitoring of local cerebral blood flow (1CBF) was used in the postoperative management of 20 aneurysm patients. Using th is probe, 1CBF was simultaneously recorded and integrated on a real ti me basis with other physiological parameters, including ICP, systemic arterial pressure, pulmonary arterial pressure, central venous pressur e, and pulse oximetry. The combined probe also provided the ability to obtain precise and detailed information concerning the presence or ab sence of cerebral autoregulation and CO2 vascular reactivity, and allo wed calculation of the cerebral vascular resistance. Continuous monito ring of 1CBF in this manner complemented by transcranial Doppler and a ngiographic data permitted early detection of cerebral ischemia, helpe d to differentiate cerebral ischemia from edema and hyperemia, was use ful in titrating blood pressure and fluid management, provided direct feedback about the effectiveness of instituted therapies, and determin ed early on when medical management was of no avail and that intervent ional neuroradiology was indicated, Evidence is presented that the pre sence of angiographic vasospasm and increased velocities on TCD do not always correlate with ischemia in the microcirculation and that direc t measurements of 1CBF are often at variance with calculations of cere bral perfusion pressure (CPP).