Does the Addition of Epinephrine Increase the Duration of Intrathecal Hyperbaric Bupivacaine for Repeat Cesarean Section?

Spinal anesthesia with bupivacaine is a commonly used anesthetic in the obstetric population. It is most frequently carried out as a single shot intrathecal injection. This method can be utilized for both labor analgesia and surgical anesthesia for cesarean section. One of the concerns in using a single shot spinal injection for surgical anesthesia is the duration of adequate surgical conditions. This concern is especially relevant to repeat cesarean sections, as each subsequent procedure has the potential to be more complex than the prior and, therefore, prolonged. A reliable way to prolong surgical anesthesia provided by single shot spinal injection of bupivacaine could prove invaluable in the setting of repeat cesarean section. It has been well documented that adding epinephrine to intrathecal lidocaine will increase its duration1, but the evidence for augmenting the duration of anesthesia provided by adding epinephrine to bupivacaine is much more equivocal and less robust. This is a randomized control trial investigating whether or not adding epinephrine to a standard single intrathecal injection of hyperbaric bupivacaine for repeat cesarean will prolong its duration. It will be investigated using women who are undergoing scheduled repeat cesarean section in whom neuraxial anesthesia is the appropriate primary anesthetic. The investigators will compare the onset, quality and duration of both sensory and motor components of the spinal block as well as the incidence of known side effects.