T. Ikeda et al., STELLATE GANGLION BLOCK IS ASSOCIATED WITH INCREASED TIBIAL NERVE MUSCLE SYMPATHETIC ACTIVITY IN HUMANS, Anesthesiology, 84(4), 1996, pp. 843-850
Background: Left stellate ganglion block has been shown to increase he
art rate and blood pressure, possible because of blockade of afferent
vagal fibers from arterial baroreceptors in the aortic arch. Because e
fferent muscle sympathetic nerve activity (MSNA) is influenced by the
arterial baroreflex, the hypothesis that left stellate ganglion block
increases efferent MSNA recorded from the tibial nerve of humans was t
ested. Methods: Twenty healthy male volunteers were sequentially assig
ned to one of three groups: stellate ganglion block (n = 10), in which
7 ml 1% mepivacaine was injected into the left stellate ganglion; pla
cebo (n = 5), in which 7 ml of saline was injected into the left stell
ate ganglion; and intramuscular injection (n = 5), in which 7 ml mepiv
acaine was injected into the left deltoid muscle. Direct intraneural m
icroneurographic recording with a tungsten microelectrode was used to
record MSNA in the left tibial nerve. MSNA, heart rate, and blood pres
sure were recorded before and after Injection in all groups. An additi
onal five volunteers were studied with transthoracic echocardiography
to examine the effect of stellate ganglion block on preload changes. R
esults: Tibial nerve MSNA increased after mepivacaine injection to the
left stellate ganglion but was unchanged after saline injection to th
e left stellate ganglion or mepivacaine injection into the deltoid mus
cle. Heart rate increased significantly after the left stellate gangli
on block but did not change significantly after saline injection to th
e left stellate ganglion or after mepivacaine injection to the deltoid
muscle. Systemic blood pressure did not change significantly in all g
roups. Left ventricular end-diastolic area and left ventricular end-di
astolic circumference did not change after stellate ganglion block. Co
nclusions: Tibial nerve MSNA increased during left stellate ganglion b
lock with mepivacaine.