Effect of Stellate Ganglion Block on the Regional Hemodynamics of the Upper Extremity: A Randomized Controlled Trial

Abstract

Background: The success of stellate ganglion block (SGB) is traditionally determined on the basis of findings such as Horner's syndrome, temperature rise in the face, hyperemia of the tympanic membrane, and nasal congestion. However, decreases in vascular resistance and increases in blood flow in the arm may be more meaningful findings. To date, the effect of SGB on the regional hemodynamics of the arm has not been evaluated using pulsed-wave Doppler ultrasound.

Methods: A total of 52 patients who were to undergo orthopedic surgery of the forearm were randomly assigned to either the mepivacaine group (SGB with 5 mL of 0.5% mepivacaine) or the saline group (SGB with 5 mL of normal saline). Before surgery, a single anesthesiologist performed a SGB under ultrasound guidance. The temperature of the upper extremity and the resistance index and blood flow in the brachial artery were measured before SGB, 15 and 30 minutes after SGB, and 1 hour after surgery. The severity of pain, requirement for rescue analgesics, and side effects of the local anesthetic agent were all documented.

Results: After SGB, the resistance index decreased significantly and the blood flow increased significantly in the brachial artery of members of the mepivacaine group (15 minutes: P = .004 and P < .001, respectively; 30 minutes: P < .001 and P < .001, respectively). However, these values normalized after surgery. The severity of pain, need for rescue analgesics, and incidence of adverse effects were not significantly different between the 2 groups.

Conclusions: Although SGB did not decrease the pain associated with forearm surgery, ultrasound-guided SGB did increase blood flow and decrease vascular resistance in the arm. Therefore, pulsed-wave Doppler may be used to monitor the success of SGB.