Fig. 6From: Point-of-care transcranial Doppler by intensivistsProgression of intra-cranial circulatory arrest via transcranial Doppler of middle cerebral artery flows. a Normal systolic upstroke with normal step-down of diastolic flow. b Increased peak systolic flow with decreasing diastolic flow and eventual blunting of diastolic flow. c Diastolic flow reversal. d Biphasic or oscillating flow—where diastolic flow reversal approaches equal size to systolic flow. e Isolated sharp systolic peak flows of < 200 ms and small systolic amplitude of < 50 cm/s. f Zero flow—where there was previously documented TCD flow. The red box denotes states (d, e, f) in which cerebral circulatory arrest can be diagnosedBack to article page