Is Spinal Analgesia or Anesthesia Safe After Labor Epidural Analgesia? Reporting Two Cases of High Neuraxial Block and Mini-Review of the Literature.

Single-shot spinal anesthesia for intrapartum Cesarean section has recently been incriminated in carrying a high risk of high neuraxial block (HNB) occurrence in parturients receiving labor epidural analgesia. The so-called volume effect of the epidurally injected solution causes a contraction of the dural sack and unexpected HNB. We present two cases of HNB in parturients receiving epidural analgesia. The first case describes the 36-year-old patient G3P2, who was administered a repeated rescue analgesia single-shot spinal injection with low-dose local anesthetic (levobupivacaine, 3 mg) following non-functional combined spinal-epidural analgesia. The second case describes the 28-year-old parturient G1P0, who experienced HNB after single-shot spinal anesthesia with hyperbaric bupivacaine (7.5 mg) following labor epidural analgesia. Intrathecal administration of local anesthetic for the purpose of spinal analgesia or anesthesia in a parturient with epidural analgesia can cause unexpected HNB and could occur even at low doses of intrathecally administered medications. The interplay of numerous variables and circumstances in the specific case can result in the occurrence of HNB. We assume that in our first case, the volume effect and repeated dural puncture, and in the second case, the low height of the parturient coupled with the volume effect, played significant role in the occurrence of HNB.