Differential Roles of the Right and Left Toe Perfusion Index in Predicting the Incidence of Postspinal Hypotension...

Aortocaval compression by the gravid uterus, low baseline vasomotor tone, and spinal anesthesia-related sympathetic blockade contribute to spinal anesthesia-induced hypotension during cesarean delivery. The finger perfusion index (PI) can predict spinal hypotension by reflecting baseline vasomotor tone, but cannot directly reflect aortocaval compression by the gravid uterus. This study aimed to examine whether baseline toe PIs predict the incidence of maternal hypotension and reflect aortocaval compression by the gravid uterus during cesarean delivery under spinal anesthesia.

One hundred parturients undergoing elective cesarean delivery were enrolled. The relationship between baseline toe PI and the incidence of hypotension after induction of spinal anesthesia was quantified using area under the receiver operator curves, and results compared for the right and left toe PIs.

The area under the receiver operator curves for left and right toe baseline PIs were 0.81 (95% confidence interval, 0.71-0.88) and 0.76 (95% confidence interval, 0.66-0.84), respectively. After induction of spinal anesthesia, the toe PIs did not change in parturients with hypotension, but increased significantly among those who did not develop hypotension.

Our study demonstrated that baseline toe PIs were inversely associated with the incidence of postspinal hypotension during cesarean delivery. Continuous monitoring of toe PIs during induction of spinal anesthesia might help to predict the development of postspinal hypotension and reflect the aortocaval compression by the gravid uterus.