Hemodynamic adaptation after spinal anesthesia in cesarean section

Abstract

Neuraxial anesthesia is the preferred technique for cesarean section (CS), as recommended by the National Institute for Health and Care Excellence. Among these, spinal anesthesia (SA) is preferred over general anesthesia for its rapid onset, reliable blockade, and improved maternal safety. In addition, it minimizes airway-related complications such as failed intubation and aspiration while allowing maternal consciousness and early maternal–neonatal bonding. CS involves the surgical delivery of the fetus, placenta, and amniotic fluid through abdominal and uterine incisions and is typically indicated in maternal or fetal compromise. Despite its advantages, SA is commonly associated with considerable hemodynamic changes, particularly post-spinal hypotension, which is a major concern in obstetric anesthesia. Previous studies have primarily focused on hypotension management using vasopressors or fluid therapy, often in isolation. As a result, a comprehensive understanding of the overall hemodynamic adaptation following SA remains limited. The incidence of hypotension varies widely (29.0%–80.0%), thus reflecting the complexity of maternal cardiovascular responses. Moreover, dynamic parameters such as cardiac output, systemic vascular resistance, and maternal–fetal circulatory interactions have been insufficiently explored. The objective of this review is to critically synthesize contemporary evidence regarding the physiological mechanisms, determinants, and management strategies underlying hemodynamic adaptation following SA in CS. This narrative review was conducted through a comprehensive literature search across major electronic databases, including PubMed, Google Scholar, and the Cochrane Library, focusing on studies that address hemodynamic changes and management strategies associated with SA during CS. It examines the mechanisms and determinants of SAinduced hypotension, including maternal positioning, body mass index, and drug effects (oxytocin, propofol, thiopental, opioids, and local anesthetics). Furthermore, it discusses preventive and management strategies, including vasopressors, mechanical measures, and optimized fluid therapy, with special consideration for pre-eclampsia. In conclusion, hemodynamic adaptation following SA is multifactorial. It requires an individualized, multimodal management approach to preserve maternal cardiovascular stability and optimize fetal outcomes, and future research should focus on establishing standardized, evidence-based preventive strategies. Early identification of high-risk patients and optimized vasopressor-based management strategies may improve maternal hemodynamic stability and fetal outcomes during CS delivery under SA.