Anesthetics are effective in reducing the pain of circumcision in newborns

Oct 18 2004

Anesthetics are effective in reducing the pain of circumcision in newborns, judging from the baby’s heart rate and time spent crying after the procedure, a new analysis finds.

A systematic review of 1,984 babies concludes that injectable or topical pain medicines significantly, but not totally, lower a baby’s heart rate and reduce crying time — two expressions of pain. Giving oral pain relievers or sugar solutions to the baby or playing comforting music had little apparent effect on pain sensations, says lead author Barbara Brady-Fryer, R.N., the Child Health Program at Stollery Children’s Hospital-Capital Health in Edmonton, Alberta.

“None of the studied interventions completely eliminated the pain response to circumcision,” Brady-Fryer says.

The review, which includes data from 35 separate randomized controlled studies, appears in the October issue of the Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

There are possible medical benefits to circumcision, says the American Academy of Pediatrics, but they are not sufficient to recommend the procedure routinely for all newborn boys. Parents who want their sons circumcised for religious, cultural or personal reasons should talk to their physicians about anesthetics that can lower pain and stress, the Academy says.

“When done without pain medicine, circumcision is painful,” says an Academy policy statement. Researchers have found that circumcision pain can increase the infant’s heart and breathing rates, decrease blood oxygen levels, increase crying, cause skin flushing and vomiting, and alter sleep/wakes states. It can also increase sensitivity to other painful procedures.

“Infants circumcised without anesthesia exhibit stronger pain responses to routine immunizations during the first six months of life than infants who were not circumcised,” Brady-Fryer says, citing one study.

The most effective method for reducing pain of circumcision, according to Brady-Fryer’s review, is the dorsal penile nerve block, using injections of the painkiller lidocaine. Compared to placebo, this technique improved pain scores and blood oxygen levels, cut crying time by 54 percent and lowered average heart rate by 30 beats per minute. Although the risks associated with dorsal penile block are very low, a similar technique called a ring block, which also uses lidocaine injections, may be as effective but easier and safer to use, she says.

“In some centers, physicians may not be experienced in using penile blocks, and in that case, anesthetic creams may be the best choice,” Brady-Fryer says.

“The injections required for these procedures may themselves cause pain, and any use of sedation or pain control carries some risk,” says Joseph Cravero, M.D., a pediatrician and anesthesiologist at the Dartmouth Hitchcock Medical Center in New Hampshire. “Practices vary from hospital to hospital, but it’s pretty common to use some type of anesthetic today.”

Anesthetic creams also reduced heart rate and crying, although not as much as the nerve block technique.

“In the U.S., the consensus among rabbis is that local anesthesia can be used,” says Rabbi Moshe Tendler, Ph.D., a professor of medical ethics and biology at Yeshiva University in New York, and chairman of the Bioethics Commission of the Rabbinical Assembly of America, an organization of Orthodox Jewish rabbis. “But doing a dorsal block usually requires a pediatric urologist, so I recommend to mothers that they apply a 30 percent lidocaine ointment an hour before the bris [circumcision ceremony] to lessen the pain. It’s important that mothers know that it’s OK to use anesthesia.”

Few adverse effects were associated with anesthetic blocks or creams, Brady-Fryer says, although each required some time after injection or application to reach their full effect. Penile nerve blocks take five minutes, and the anesthetic creams take at least 60 minutes before they’re effective. The creams can also wash off if the infant urinates during this time. Those delays may dissuade some physicians from using anesthetics.

“The time waiting for the drug to take effect is a concern for clinicians because it increases the total time required for circumcision surgery,” she says.

Alternative approaches offered little help. Testing a sugar solution given by mouth produced only modest and “inconsistent” results, possibly due to variations in sugar concentration or dosage, Brady-Fryer says.

Two trials compared the oral pain medicine acetaminophen to placebo. Only one showed any effect and that was on a measure of mother-infant feeding interactions after circumcision. Three trials reported that music or recordings of sounds from within the womb showed little effect on heart rate, blood pressure, crying or other measures.

While the review sorted out the relative advantages of these techniques, Brady-Fryer says that weaknesses in the original trials must be considered as well. Many of the trials enrolled small numbers of patients (80 or fewer in 32 of the 35 trials), while some did not describe the tools or techniques used for the circumcision.

“None of the reports included in this review offered a definition of pain, and in general, the reports did not differentiate between the painful versus the distressing/stressful aspects of the circumcision procedure,” she says.

However, that should not deter doctors from using anesthetics, she says.

“The results of this review show that dorsal penile nerve block and ring block are the most effective, and that the topical anesthetics, although less effective, can also be recommended over no treatment for attenuation of circumcision pain,” Brady-Fryer says.