Comparison of ring block, dorsal penile nerve block, and topical anesthesia for neonatal circumcision: a randomized controlled trial. Topical anesthesia during circumcision in newborn infants. Efficacy and safety of lidocaine-prilocaine cream for pain during circumcision.
Beliefs about the safety and effectiveness of current anesthetics have resulted in many newborns being circumcised without the benefit of anesthesia.
                To compare ring block, dorsal penile nerve block, a topical eutectic mixture of local anesthetics (EMLA), and topical placebo when used for neonatal circumcision. The placebo represented current practice, with no anesthetic for neonatal circumcision.
                A randomized controlled trial.
                Antenatal units in 2 tertiary care hospitals in Edmonton, Alberta.
                A consecutive sample of 52 healthy, full-term, male newborns, aged 1 to 3 days.
                Physiological and behavioral monitoring occurred in a series of trials: baseline, drug application, preparation, circumcision, and postcircumcision. Surgical procedures defined the following 4 stages of the circumcision: cleansing, separation, clamp on, and clamp off. Methemoglobin level was assessed 6 hours after surgery.
                Heart rate, cry, and methemoglobin level.
                Newborns in the untreated placebo group exhibited homogeneous responses that consisted of sustained elevation of heart rate and high-pitched cry throughout the circumcision and following. Two newborns in the placebo group became ill following circumcision (choking and apnea). The 3 treatment groups all had significantly less crying and lower heart rates during and following circumcision compared with the untreated group. The ring block was equally effective through all stages of the circumcision, whereas the dorsal penile nerve block and EMLA were not effective during foreskin separation and incision. Methemoglobin levels were highest in the EMLA group, although no newborn required treatment.
                The most effective anesthetic is the ring block; EMLA is the least effective. It is our recommendation that an anesthetic should be administered to newborns prior to undergoing circumcision. To determine the efficacy of topical anesthetic cream, eutectic mixture of local anesthetics (EMLA), in alleviating pain from neonatal circumcision.
                Randomized, controlled trial.
                Normal newborn nursery in a university teaching hospital.
                Twenty-seven newborn, full-term male neonates, aged 1 to 3 days.
                Heart rate, transcutaneous oxygen saturation, facial activity, and crying.
                Compared with baseline, all newborns experienced pain as evidenced by increased heart rate of an average of 40 beats per minute (F [8, 25] = 14.12; P < .0001), decreased oxygen saturation of 3% (F [8, 25] = 15.02; P < .0001), and more facial actions indicative of pain (F [8, 25] = 5.25; P < .002) during all phases of the procedure. Compared with placebo, EMLA significantly attenuated the pain response as shown by lower heart rate of an average of 25 beats per minute (F [1, 25] = 14.92; P < .001), higher oxygen saturation of 5%, particularly during the clamping and lysis phases (F [1, 25] = 19.83; P < .0001), 20% less facial activity (F [1, 25] = 12.01; P < .002), and 15% less crying during the clamping, Gomco clamp application, and incision of the foreskin. There were no differences between groups in the spectral crying parameters.
                Circumcision procedure produces pain responses that EMLA diminishes. Thus, EMLA may be a useful agent for pain management in neonatal circumcision. Neonatal circumcision is a painful surgical procedure often performed without analgesia. We assessed the efficacy and safety of 5 percent lidocaine-prilocaine cream (Emla) in neonates undergoing circumcision.
                We carried out a double-blind, randomized, controlled trial in 68 full-term male neonates: 38 were assigned to receive lidocaine-prilocaine cream, and 30 to receive placebo. One gram of lidocaine-prilocaine or placebo cream was applied to the penis under an occlusive dressing for 60 to 80 minutes before circumcision. Behavioral (facial activity and time spent crying) and physiologic (heart rate and blood pressure) responses were recorded during the procedure. Blood samples were obtained at various times after drug application for measurements of methemoglobin and plasma lidocaine, prilocaine, and o-toluidine (a metabolite of prilocaine).
                A total of 68 and 59 neonates were included in the safety and efficacy analyses, respectively. Demographic characteristics such as gestational age and birth weight did not differ between the lidocaine-prilocaine and placebo groups. During circumcision, the neonates in the lidocaine-prilocaine group had less facial activity (P= 0.01), spent less time crying (P<0.001), and had smaller increases in heart rate (P=0.007) than the neonates in the placebo group. Facial-activity scores were 12 to 49 percent lower during various steps of the procedure in the lidocaine-prilocaine group. As compared with neonates in the placebo group, infants in the lidocaine-prilocaine group cried less than half as much and had heart-rate increases of 10 beats per minute less. Blood methemoglobin concentrations (expressed as a percentage of the hemoglobin concentration) were similar (1.3 percent) in both groups. Lidocaine and prilocaine were detected in plasma in 23 (61 percent) and 21 (55 percent) of the infants treated with lidocaine-prilocaine cream, respectively.
                Lidocaine-prilocaine cream is efficacious and safe for the prevention of pain from circumcision in neonates.
EMLA reduces pain response during circumcision in newborn male infants. Other potentially more effective forms of analgesia for circumcision (such as dorsal penile nerve block, ring block) should be subjected to systematic reviews.