Investigation of the Correlation Between the Success of Obtaining Unilateral Spinal Anesthesia and the Measurement of Perfusion Index (pi).

Target sites for spinal anesthetics are spinal nerve roots and spinal cord. Differences in the anatomy of the nerve roots may explain the variability that occurs during spinal anesthesia. Spinal anesthesia is the cessation of nerve conduction for a while by injection of local anesthetic drug into the cerebrospinal fluid. It is one of the most effective and oldest regional anesthesia techniques. Unilateral spinal anesthesia, on the other hand, aims to limit the distribution of the spinal block to the operated side for all operations involving only one lower extremity. Reducing the dose of local anesthetic, pencil-point needles, injection speed, lateral decubitus position and non-isobaric anesthetic solution are the main factors in the formation of a unilateral spinal block. It requires slightly longer preparation time compared to standard spinal anesthesia, but provides fewer hemodynamic side effects with higher cardiovascular stability, increased postoperative autonomy and better patient acceptance. Perfusion index (PI) is a numerical value showing the ratio between pulsatile and nonpulsatile blood flow. PI works by measuring changes in finger peripheral perfusion via pulse oximetry. If the procedure is successful in patients undergoing spinal anesthesia, vasodilation occurs in the lower extremities due to sympathetic nerve blockage and perfusion increases. Pulse oximetry perfusion index (PI) was used in our study to indicate vasodilation associated with sympathectomy. We will examine whether the success of unilateral anesthesia in the spinal anesthesia performed in our hospital correlates with the increase of the perfusion index value measured with the finger probe, except for patient-based methods, and whether the perfusion index shows more objectively the block success than other patient-based traditional methods.