Volume status evaluation by IVC diameter and pleth variability index in spinal anesthesia

Objective: We aimed to predict the risk of hypotension due to spinal anesthesia (HSA) by measuring the diameter and area of the inferior vena cava (IVC-D, IVC-A) through ultrasound and pleth variability index (PVI) in patients who underwent endovenous radiofrequency ablation under spinal anesthesia (SA). Method: This cross-sectional, observational, and prospective study was completed with 64 patients. Before SA, PVI IVC-D, and IVC-A were measured. Patients were divided into two groups as hypotension group (Group 1) and patients who did not developed hypotension after SA (Group 2). Shapiro-Wilk normality test and student's t-test were used for statistical analysis. Results: The mean PVI of Group 1 was higher than Group 2, whereas the mean IVC-D and IVC-A in Group 2 was significantly higher than Group 1 (p = 0.000, p = 0.000, p = 0.001). Cutoff values for hypotension PVI > 15% and IVC-A <= 2.98 mm2 (p = 0.001, p < 0.05). Conclusion: PVI and IVC-D and IVC-A measurements are effective and reliable methods that should be used to predict the risk of developing HSA in patients who will undergo surgery under SA.