The Analysis of Perfusion Index and Plethysmographic Variability Index During Elective Cesarean Section

Abstract

Hypotension following spinal anesthesia of cesarean section is mainly caused by peripheral vasodilation and venous pooling due to sympathetic blockade. The degree of sympathetic blockade is known to affect the occurrence of hypotension after spinal anesthesia. The perfusion index (PI) and plethysmographic variability index (PVI) are non-invasive tools for measuring the vasomotor tone and volume status, respectively. The purpose of this study is to compare the trends of PI and PVI values between hypotension and normotension groups during cesarean section following spinal anesthesia. Fifty-one parturients were divided into two groups whether they developed hypotension or maintained normotension after spinal anesthesia. Spinal anesthesia was performed with 0.5% hyperbaric bupivacaine (10 mg) and fentanyl (15 μg) at the L3-4 intervertebral space. The data of blood pressure, heart rate, PI and PVI were recorded every minute until delivery of baby. Hypotension occurred in 61% of parturients during cesarean section. The overall PI and PVI value after spinal anesthesia have gradually increased and decreased, respectively. The degree of increase and decrease in PI (p = 0.31) and PVI value (p = 0.35) was not significant between hypotension and normotension groups. The trend of PI value has gradually increased while the PVI value has decreased, regardless of whether the parturient has experienced hypotension or not.