Background: Mild methemoglobinemia is a known side-effect of one of the constituents of EMLA cream, this topical local anesthetic is used with great caution in neonates.
Population and methods: One hundred and sixteen neonates admitted from January to July 1994 in an intensive care unit were included in the study. All required skin punctures which were performed 1 h 30-2 hours after EMLA had been applied on the skin. A reaction score (0 to 5) to skin puncture was established 157 times (120 after and 37 without local anesthesia); methemoglobin (Met Hb) concentrations were measured in 47 blood samples, 18-24 hours (40.4% of samples) or 2-3 days (36.2%) after application of EMLA.
Results: Ninety-four neonates were quiet before puncture (score 0-1). Among them, 57% of those who were given EMLA had a low score (2 or less) vs 18% without EMLA. A low reaction was observed in 65% when the dressings had been kept in place for at least 90 minutes vs 15% with a shorter application. A lower reaction was noted in 78.8% of cases after venopuncture (41% after arterial puncture). No Met Hb level was above 5% and 7 (15%), in five neonates, were between 3 and 5%. There was no clear relationship between methemoglobinemia and gestational age or duration of dressing.
Conclusion: EMLA cream is effective and safe in neonates including preterms, when it is applied in a small amount once a day.