To measure the cerebral blood flow (rCBF), we used the thermal diffusion flowmetry (TD-rCBF). The TD microprobe was placed 25 mm below the cortical surface. Mean values are around 18 – 25 ml/100 g/min
A male of 34-year-old underwent surgery of right MCA (middle cerebral artery) and AcoA (anterior communicating artery) aneurysms. To observe effects of hypnotics on rCBF measured by TD-rCBF, propofol (4 mg/kg/h) and sevoflurane 0.7% were alternated, maintaining bispectral index between 45–60. Propofol series showed TD-rCBF (ml/100 g/min) values of 18, 25 and 23 Sevoflurane had values of 27, 32 and 41.
A 56-year old female suffered a subarachnoid hemorrhage (Hunt &Hess 1, Fisher 1. Aneurysm on right MCA was clipping. Median and tibial posterior somatosensory evoked potentials; a bilateral recording of motor evoked potentials elicited by transcranial electrical stimulation in upper and lower extremities. Events such as: placement of a temporal clip, the withdrawal of retractors and the weight of the temporal and frontal lobes on the clip showed sudden decreases of the blood flow to 0 ml/100 g/min. Evoked potentials did not change.
A 49-yr-old woman suffered a SAH (Hunt&Hess IV, Fischer IV. A left MCA aneurysm was treated with coils. After 24 of HSA, TD-rCBF values decreased to 7–10 ml/100 g/min, while Doppler ultrasonography showed normal values. The angiography revealed a severe vasospasm in the left MCA and AcoA territories. The nimodipine administration increased TD-rCBF values to 20 ml/100 g/min.
The TD-rCBF showed in real-time, variations of rCBF induced by anaesthetics. This monitor detected changes of cerebral blood flow earlier than evoked potentials and transcranial Doppler ultrasonography.
© 2012 European Society of Anaesthesiology