Effects of stellate ganglion block on cardiac coronary circulation

Abstract

Since the stellate ganglion contains cardiac sympathetic nerves, stellate ganglion block (SGB) may influence cardiac and coronary hemodynamics. We investigated this influence of SGB by measuring the heart rate (HR), the left circumflex coronary artery blood flow (CBF), the maximum rate of increase of the left ventricular pressure (LV max dP/dt), the cardiac output (CO), the myocardial oxygen consumption (MVO₂), and the myocardial oxygen extraction ratio (MOER) in nine dogs before and after performing SGB by means of injection of 2 ml 1% mepivacaine. Left SGB resulted in a decrease of 10% in CBF and a decrease of 15% in LV max dP/dt, but HR, CO, and MVO₂ remained unchanged. On the other hand, right SGB resulted in a decrease of 30% in CBF and a decrease of 25% in LV max dP/dt, as well as a decrease of 20% in HR, 15% in CO, and 25% in MVO₂. SGB on either side resulted in an increase in MOER that was slight but nonetheless significant (P<0.05) in that it suggested a relative deficit in CBF with respect to MVO₂. Inhalation of 100% oxygen decreased MOER to the pre-SGB level in either side, thus improving the myocardial oxygen supply-demand relationship. This study suggests the possibility that SGB has deteriorative effects on the myocardial oxygen supply-demand relationship. Those effects were counteracted by the inhalation of 100% oxygen.