Noninvasive Hemodynamic Assessment with Impedance Cardiography During Spinal and Epidural Anesthesia in Obstetrics.

Background/

Objectives

Spinal anesthesia (SA) for cesarean section and epidural analgesia (EA) for vaginal delivery induce hemodynamic changes that may compromise maternal and fetal safety. In this observational, hypothesis-generating study, we used impedance cardiography (ICG) to characterize maternal hemodynamic responses to EA for labor versus SA for cesarean delivery and to describe hemodynamic profiles associated with commonly used local anesthetic and vasopressor regimens.

Methods

In this observational study, 132 women at term were included (52 with epidural analgesia (EA), 80 with spinal anesthesia (SA)). Hemodynamic parameters were measured using the ICON electrical cardiometry monitor (Osypka Medical GmbH). ICON and oscillometric blood pressure (BP) monitoring captured cardiac index (CI), stroke volume (SV), heart rate (HR), systemic vascular resistance index (SVRI), and thoracic fluid content (TFC) at T0 (baseline), approximately 5 and approximately 10 min, skin incision, delivery, and oxytocin administration.

Results

CI remained stable and comparable between EA and SA (3.9 ± 0.6 vs. 3.9 ± 0.6 L/min/m2; p = 0.530). SV was higher in EA (85.1 ± 11.3 vs. 78.1 ± 9.7 mL; p < 0.001), whereas HR was higher in SA (92.2 ± 12.9 vs. 85.8 ± 12.5 bpm; p = 0.009). In EA, ropivacaine and bupivacaine showed similar hemodynamic profiles. Within the SA cohort, women managed with phenylephrine infusion had lower CI and HR but higher MAP and SVRI compared with those receiving ephedrine boluses, consistent with the expected pharmacodynamic profiles of these agents.

Conclusions

ICG was feasible and provided dynamic, noninvasive estimates of maternal cardiovascular adaptation during obstetric anesthesia. In this non-randomized, exploratory cohort, descriptive differences in hemodynamic profiles between vasopressor strategies were more pronounced than between local anesthetics. Phenylephrine-based management showed a pattern of higher BP and SVRI but lower CI and HR, whereas ephedrine-based management tended to preserve CI through chronotropic effects.