Epidural analgesia is the ideal method for providing adequate pain relief during labor while minimally effecting maternal and fetal physiology. Local anesthetic spreads horizontally and longitudinally throughout the epidural space where it bathes nerve roots and diffuses into the cerebrospinal fluid to achieve analgesia. The epidural space also contains blood vessels, which introduces the risk of inadvertent absorption of local anesthetic into the systemic circulation. If large amounts of local anesthetic reach the systemic circulation, supratherapeutic blood levels can cause toxicity. Patients undergo many physiologic changes during pregnancy that increase their risk for local anesthetic systemic toxicity, therefore, the lowest possible dose of local anesthetic should be used. Although the continuous epidural infusion technique is the standard of care, current literature shows that programmed intermittent boluses result in more extensive spread of local anesthetic in the epidural space, which ultimately reduces the total drug consumption and improves maternal safety.
Learning Objectives:
Discuss the background of epidural labor analgesia.
Review the anatomy of the epidural space.
Review the physiologic alterations that occur during pregnancy.
Discuss the significance of local anesthetic use during pregnancy.
Discuss the current literature related to the effect of epidural administration techniques on total local anesthetic consumption.
