Is the Variability of the Perfusion Index Predictive of Post-spinal Hypotension in Parturients Undergoing Scheduled Cesarean Section

Detailed Summary

About one-third of deliveries are performed by cesarean section, and this rate is increasing. The standard anesthetic technique for this procedure is spinal anesthesia (SA), which is associated with hypotension in nearly 70% of cases . The mechanism is a sympatholysis leading to a drop in systemic vascular resistance and cardiac output, which can be aggravated by relative hypovolemia. This hypotension is responsible for maternal dizziness, nausea, and vomiting, as well as fetal acidosis, and in extreme cases, fetal circulatory insufficiency. Currently, it is recommended to prevent post-spinal hypotension through a strategy combining co-loading with fluids and the administration of vasopressors in all patients. However, this non-individualized strategy is not always effective in preventing hypotension and may even be harmful to the mother in cases of excessive fluid administration. Current guidelines for perioperative fluid management in elective surgery advocate for an individualized approach based on preoperative assessment of preload dependence through cardiac output monitoring. Correcting this relative hypovolemia helps maintain an appropriate blood pressure for the patient's needs. In parturients, we have shown that evaluating preload dependence by measuring the variation in the time-velocity integral under the aorta (ΔTVI) using cardiac ultrasound before and after a passive leg raising test (PLR) can predict post-spinal hypotension with good sensitivity and specificity. We obtained comparable results using monitoring of the variation in stroke volume by the Clearsight™ system (Edwards Lifesciences, Irvine, California, US), before and after PLR . However, these technologies have limitations: availability of equipment, cost, operator expertise, and patient echogenicity in the case of ultrasound. Using a non-invasive, simple, and accessible method for monitoring preload dependence that can be used by an untrained operator would help easily identify patients at higher risk for post-spinal hypotension, enabling individualized management. The main objective of our study is to evaluate the ability of ΔIPELJP to predict post-rachianesthesia hypotension in parturients scheduled for a cesarean section.

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