Background. Stellate ganglion block (SGB) causes vasodilatation in the skin of the head and neck
because of regional sympathetic block. Its effects on cerebral haemodynamics, in health or in
disease, are not clear. We evaluated the effects of SGB on ipsilateral middle cerebral artery flow
velocity (MCAFV), estimated cerebral perfusion pressure (eCPP), zero flow pressure (ZFP),
carbon dioxide reactivity (CO2R) and cerebral autoregulation using transcranial Doppler
ultrasonography (TCD).
Methods. Twenty male patients, with pre-existing brachial plexus injury, and undergoing SGB for
the treatment of complex regional pain syndrome of the upper limb, were studied. For SGB, 10 ml
of plain lidocaine 2% was used and the onset of block was confirmed by presence of ipsilateral
Horner’s syndrome. The MCAFV, eCPP, ZFP, CO2R, and cerebral autoregulation were assessed
before and after SGB using established TCD methods. The changes in these variables were
analysed using Wilcoxon’s signed rank test.
Results. The block caused a significant decrease in MCAFV from median (inter-quartile range)
value of 61 (53, 67) to 55 (46, 60) cm s 1, a significant increase in eCPP from 59 (51, 67) to
70 (60, 78) mm Hg, and a significant decrease in ZFP from 32 (26, 39) to 25 (16, 30) mm Hg. There
were no significant changes in CO2R or cerebral autoregulation.
http://bja.oxfordjournals.org/content/95/5/669.full.pdf