The Era of Caudal Labor Analgesia
Abstract Number: S-47
Abstract Type: Other
BACKGROUND: Epidural anesthesia is an essential part of modern obstetric anesthesia. We explore the caudal anesthesia technique which predated the lumbar approach to epidural anesthesia.
CAUDAL ANESTHESIA:Caudal anesthesia was first described for treatment of sciatic pain in 1901 by Sicard and Cathelin.(1,2) In 1909 Stoeckel reported 141 cases using caudal labor analgesia with procaine.(3) The use of a caudal catheter was first described in laboring women by Aburel in 1931.(4) Following this, Hingson and Edwards published their accounts of continuous caudal analgesia during labor and delivery in the US.(5) Caudal analgesia underwent several modifications (Fig 1) including the use of ureteric catheters instead of needles, continuous drips instead of serial injections, and single injections of long lasting analgesics rather than intermittent short acting solutions.(6,7)
ADVANTAGES AND DISADVANTAGES OF CAUDAL ANALGESIA: Caudal anesthesia could be maintained for many hours and therefore reduced medication requirement during the first stage. The caudal route provided good analgesia to areas supplied by the sacral spinal roots, such as the perineum, which was advantageous for the second stage of labor and also caused less PDPH than subarachnoid blockade. Later the use of a double catheter technique was described which utilized lumbar analgesia for the first stage and caudal analgesia for the second stage of labor.
Anatomic variations however resulted in unpredictable cephalad spread of anesthetics. Overlying ligaments and the cornua thicken with age which also makes identification of the hiatal margins challenging. The lack of sterility at the sacral hiatus, which may be contaminated by feces and meconium, limited the use of a continuous catheter technique by many during active labor. Ultimately dissatisfaction with the technique occurred due to poor reliability, safety concerns (including accidental injection of local anesthetic into the fetal scalp or perforation of the fetal head), and the feeling of lower limb paralysis when given large doses of local anesthetic.
PARADIGM SHIFT TO LUMBAR EPIDURAL: Lumbar epidural was deemed easier to perform, required less local anesthetic for first-stage analgesia and preserved motor function of the lower limbs and abdominal muscles. Lumbar epidural also provides better control of sympathectomy, resulting in less maternal hypotension and the block can be extended for cesarean section which could not be reliably provided by caudal analgesia. In the early 1960s, the lumbar epidural replaced caudal analgesia as the preferred technique for labor analgesia. The use of lumbar epidural catheters in the 1970s permitted administration of pain relief earlier in labor.
REFERENCES:(1)CR Soc Biol Paris 1901;53:452 (2)CR Soc Biol Paris 1901;53:396 (3)Anaesthesia 1990;45:468-471 (4)Bull Soc Obstet Gynecol Paris 1931;20:35-39 (5)Curr Res Anaesth 1942;21:301-311 (6)J Indiana Med Ass 1942;35:564 (7)J Amer Med Ass 1943;122:582