Fig. 1

Simplified algorithms on the use of TCD to assess intracranial hypertension, brain death, autoregulation, and cerebral vasospasm in clinical practice. PI, pulsatility index; Vd, diastolic flow velocity; Vm, mean flow velocity; Vs, systolic flow velocity; LR, Lindegaard ratio; CCA, cerebral circulatory arrest. *The three reported images represent reverberating flow (top), systolic pikes (middle), and no flow (bottom), respectively