TCD ability to predict clinical deterioration and infarction from delayed cerebral ischemia is still not yet validated in a prospective trial. In spite of this, TCD examination is non-invasive, inexpensive and the pattern of CBFV’s observed
in patients after SAH of different etiology is very distinctive, enabling immediate detection of abnormally high CBFV’s and appears to be predictive of VSP [16] and [17]. Recent evidence suggests TCD holds promise for the detection of critical elevations of ICP and decreases in cerebral perfusion pressure (CPP). Using the PI, Bellner et al. [12] have demonstrated that ICP of 20 mm Hg can be determined with a sensitivity of 0.89 and Nutlin-3a specificity of 0.92. They concluded that the PI may provide guidance in those patients with suspected intracranial hypertension and that repeated measurements may be of use in the neurocritical care unit. There is significant evidence that independent of the type of intracranial pathology, a strong correlation between PI and ICP exists [12], [18], [19] and [20]. A recent study indicated that TCD had 94% of sensitivity to identify high ICP/low CPP at admission and a negative predictive value of 95% to identify normal ICP at admission; the sensitivity to
predict abnormal cerebral perfusion pressure was 80% [20]. In 2011 Bouzat and co-authors showed that in patients with mild to moderate TBI, the TCD test on admission, together with brain CT scan, could accurately
screen patients at risk for secondary neurological damage [21]. At the same time, to the best of our Etoposide knowledge, no one as yet has suggested using the PI as an accurate method to quantitatively assess ICP. Nevertheless, even at this juncture, quantitative and qualitative changes in CBFV values and TCD waveform morphologies may persuade physicians to undertake other diagnostic steps and/or change medical treatment that will improve care of these patients and their outcomes. At the moment TCD appears to be useful for following PI’s trends and it is a practical ancillary technique for estimating the direction of CBFV changes in response to increasing ICP or falling CPP, and it may also reveal whether there is a response to therapeutic interventions. Plasmin Though, further sophistication of TCD data analysis is essential before it may be used with confidence to measure ICP and CPP in the ICU. This study has some limitations. First, we were not able to correlate clinical VSP with angiographic VSP and combine TCD data with other neuroimaging methods which help to identify VSP and impaired CPP in patients with traumatic SAH. Secondary, current data should be validated prospectively. Additionally, the lack of established TCD criteria for VSP in younger patients presents interpretative issues.