Neuraxial Anesthesia Onset: Epidural
Epidural anesthesia provides lesser hemodynamic alterations than spinal anesthesia for CD. A meta-analysis including ten trials and 751 parturients indicated that patients who received spinal, versus epidural, anesthesia for CD were more likely to require treatment for hypotension with a relative risk of 1.23 (95% CI: 1.00–1.51). The results of this meta-analysis also demonstrated a slower onset time for epidural anesthesia, which perhaps allows compensatory mechanisms to mitigate the evolving sympathetic block.
Studies examining hemodynamic changes with the induction of epidural anesthesia show decreases in SVR and MAP,[39,96] increases in HR,[39,89] decreases in SV,[39,89,96] and both minimal decreases[89,96] or increases[39,97,98] in CO. The addition of epinephrine to the local anesthetic affects maternal hemodynamics. A single study showed that the addition of 5 mcg/ml of epinephrine to bupivacaine decreased maternal diastolic pressure when measured by M-mode echocardiography. Uterine blood flow and systolic pressure remained unchanged.
Expert Rev of Obstet Gynecol. 2012;7(1):59-75. © 2012 Expert Reviews Ltd.