Effects on hemodynamic variables and echocardiographic parameters after a stellate ganglion block in 15 healthy volunteers

Background The sympathetic nervous system has an important role in generating pain. Various pathomechanisms are involved that respond well to the application of local anesthetics (LA), for example to the stellate ganglion block (SGB). Objectives We wanted to know more about the effects of SGB on cardiovascular parameters. Methods We included 15 healthy volunteers; another 15 healthy volunteers as a control group (sham injection of LA). In order to produce a more precise SGB, we employed only a small volume of LA (3 mL), a LA with a lower permeability (procaine 1%), and a modified injection technique. Systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), and echocardiographic parameters were recorded before and after SGB. We also investigated whether there are side differences (left and right SBG). Results At baseline all parameters were within the normal range. After performing right and left SGB DBP significantly increased (on the right side from 68.73 ± 8.61 to 73.53 ± 11.10, p = 0.015; on the left side from 70.66 ± 13.01 to 77.93 ± 10.40, p = 0.003). In the control group no increase in DBP was observed. No side-specific differences were found, except a significant reduction in the maximum velocity of myocardial contraction during the systole with left-sided SGB. Conclusions Even with our methods we could not prevent the simultaneous occurrence of a partial parasympatholytic effect. For this reason, the SGB has only minor hemodynamic effects, which is desirable as it enhances the safety of the SGB.