Medicine: Caudal Problems

So far, doctors have reported about 1,000 cases of childbirth with continuous caudal anesthesia (TIME, Feb. 1) without loss of a single mother from the anesthetic. Its advantages: it cuts off pain sensations, without impairing a mother’s ability to help the childbirth process; it usually shortens delivery time; it does not drug the child. But few medicos besides Drs. R. A. Hingson and W. B. Edwards, who developed the technique, feel absolutely sure of themselves when using it.

The method involves the ticklish business of getting a needle into the caudal canal through a puncture just above the coccyx at the base of the spine. The mis take of getting needle and anesthetic into the spinal canal, a little higher up, or between the wrong layers of tissue, may prove fatal. Milder risks are a broken needle in the caudal canal, or a useless injection under the skin.

Because of these pitfalls, many anesthetists have been reluctant to take up the method. In the Journal of the A.M.A. last week, Drs. Nathan Block and Morris Rotstein told how some of the dangers may be avoided:

> They found that when a solution flows by gravity into the spinal canal, it flows so fast that the drops cannot easily be counted — usually about 210 drops a minute. But the flow into the caudal space is only about 80 to 110 drops a minute. To determine whether the injecting tube is in the right space, they make a test flow with a harmless salt solution. If the flow is slow, they confidently go ahead with the anesthetic. If the flow is over 150 a minute, they try another anesthesia.

> As to broken needles, the doctors say that “as the quality of the needles improved, this mishap has become rare.”

> To test for a needle misplaced under the skin, they press the area just above the point of insertion. If the fluid flow stops, the needle is wrongly placed.

> To assure an even and regulated anesthetic, instead of giving separate doses from time to time through the tube, the doctors let the anesthetic solution flow continuously, at about 15 drops a minute — “a truly continuous technique.”

> Despite these safeguards, the doctors warn that “certain highly dangerous complications are possible and therefore [continuous caudal anesthesia] should be given only in well-equipped hospitals by persons experienced in the technique.”