Can Perfusion Index or Pleth Variability Index Predict Spinal Anesthesia Induced Hypotension During Caesarean Section?

Objective: Although spinal anesthesia is the preferred anesthetic method for cesarean sections, it leads to hypotension in a significant proportion of the patients. In this study, we assessed the predictive ability of perfusion index (PI) and Pleth variability index (PVI) in different positions, for prediction of hypotension after spinal anesthesia administered for cesarean delivery. Methods: Ninety parturients scheduled for elective lower segment cesarean section under spinal anesthesia were enrolled in the study. In the preoperative holding area, PI and PVI values were recorded in the supine, semi-recumbent, passive leg raise and left lateral positions. Then, parturients were taken to the operating room; their PI and PVI values were recorded again in the supine and sitting positions. Spinal anesthesia was performed with 0.5% hyperbaric bupivacaine (10 mg) injected through L3-L4 or L4-L5 interspaces with the patient in the sitting position. PI and PVI values were recorded one minute after induction of spinal anesthesia as postspinal measurements. The effects of independent variables on hypotension were examined with logistic regression analysis. The relationship between PI and PVI values and incidence of hypotension was evaluated using ROC analysis. Results: The incidence of hypotension was 60 percent. Postspinal PVI was found to have a weak predictive value for postspinal hypotension (AUC=0.663, 95% CI 0.530-0.796, p=0.024). Conclusion: Among the parameters evaluated, only postspinal PVI was associated with spinal anesthesia-induced hypotension in cesarean section. However, it may not be useful in routine clinical practice due to its low specificity and sensitivity.