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Question 16#

Currently accepted uses of transcranial Doppler (TCD) include all of the following EXCEPT:

A. Diagnosing vasospasm after subarachnoid hemorrhage
B. Estimating cerebral perfusion pressure
C. Confirming brain death after clinical examination in patients under the influence of central nervous system (CNS) depressants
D. Confirming brain death after clinical examination in patients with metabolic encephalopathy

Correct Answer is B

Comment:

Transcranial Doppler (TCD) measurements of middle and anterior cerebral artery blood flow velocity are useful for the diagnosis of cerebral vasospasm after subarachnoid hemorrhage. Qureshi et al demonstrated that an increase in the middle cerebral artery mean flow velocity as assessed by TCD is an independent predictor of symptomatic vasospasm in a prospective study of patients with aneurysmal subarachnoid hemorrhage. In addition, while some have proposed using TCD to estimate ICP, studies have shown that TCD is not a reliable method for estimating ICP and CPP, and currently cannot be endorsed for this purpose. TCD also is useful to confirm the clinical examination for determining brain death in patients with confounding factors such as the presence of CNS depressants or metabolic encephalopathy.