Editor-in-Chief: Alaa Abd-Elsayed, MD, PhD
BACKGROUND: The clinical endpoints considered to define a successful block are reduction in pain, warmer lower extremities, increased blood flow, and disappearance of sweating. However, in the perioperative setting, existing measures to define sympathetic block success are sparse and lack sensitivity and objectivity. Perfusion index (PI) represents a noninvasive and continuous measurement of peripheral perfusion and is a ratio of the pulsatile blood flow to the nonpulsatile or static blood in peripheral tissues measured by plethysmography.
CASE REPORT: We present a case of a 35-year-old man who had a history of multiple fractures in lower limbs and who presented with complex regional pain syndrome of the right lower limb. PI was used as a marker of sympathetic block in order to objectify the block. The PI on the blocked side increased continuously compared to the nonblocked side. The patient also had significant pain relief on the side of the block.
CONCLUSION: We believe that plethysmography-based PI can be utilized as an efficient objective tool to confirm a successful sympathectomy as demonstrated in this case of diagnostic lumbar sympathetic block.
KEY WORDS: Complex regional pain syndrome (CRPS), lumbar sympathetic block, perfusion index (PI).