The effect of vasospasm on cerebral perfusion: a colour duplex study of the extra- and intracranial cerebral arteries.

To assess whether middle cerebral artery (MCA) vasospasm reduces the flow volume in the corresponding extracranial internal carotid artery (ICA) or global cerebral blood flow volume (CBFV) in subarachnoid haemorrhage (SAH) patients, a colour duplex ultrasound study of the intra- and extracranial cerebral arteries was performed. MCA vasospasm was defined as a time-averaged maximum flow velocity (TAMX) exceeding 120 cm/s. ICA flow volumes and CBFV, were compared in each patient at maximum TAMX recorded in one MCA ("maximum-vasospasm") and when TAMX in the same vessel was closest to mean reference values ("no-vasospasm").

Volume measurement of cerebral blood flow: assessment of cerebral circulatory arrest.

Background: Cerebral blood flow (CBF) volume can be measured at bedside by color duplex flowmetry of the extracranial cerebral arteries. In neurointensive care patients, we prospectively tested the hypothesis that a CBF volume <100 ml/min indicates imminent cerebral circulatory arrest.

Methods: CBF volume was determined as sum of flow volumes in the internal carotid and vertebral arteries of both sides.