Perfusion Index and Pleth Variability Index in Predicting Hypotension Following Spinal Anesthesia Performed in Sitting Position in Cesarean Section.

Spinal anesthesia has been widely used all over the world due to its superiority to general anesthesia in cesarean section. However, as a result of the sympathetic blockade in spinal anesthesia, vascular tone decreases and hypotension occurs. The incidence of hypotension increases up to 70% in pregnant women due to increased sensitivity to local anesthetics and increased intraabdominal pressure. Improper management of postspinal hypotension may lead to maternal and fetal complications. Predicting the risk of hypotension in patients undergoing spinal anesthesia may allow applications such as volume loading or prophylactic vasopressor use. The perfusion index, measured by pulse Oximeters, correlates with blood flow changes at the tip of the finger so that it can detect hypotension and thus decrease in blood flow after spinal anesthesia. Pleth variability index (PVI) is a non-invasive value found in the new generation pulse oximeters. It is a parameter used in the dynamic measurement of response to fluid therapy in intensive care units. PVI can dynamically give an idea about the fluid status of the pregnant woman. Previous studies have shown that PVI may be a marker for predicting hypotension following spinal anesthesia.