Use of atracurium in neonatal anaesthesia.

Atracurium was administered to neonatal patients on 270 occasions without any difficulties being encountered. More detailed observations in 60 patients showed that, in 16 neonates 3 days of age and older, with a core temperature greater than 36 degrees C, the standard dose of atracurium 500 micrograms kg-1 had a mean duration of clinical effect of 23.1 +/- 3.4 min--the shortest in any group of children so far studied in Liverpool. In only three of the 16 was antagonism of residual neuromuscular blockade considered to be necessary. In 34 infants, anaesthetized within 48 h of birth, we identified distinct subgroups. In 12, comparable except for age to the patients described above, 500 +/- 50 micrograms kg-1 lasted a mean time of 32.4 +/- 8.6 min, nearly 50% longer and with more than twice the standard deviation. In eight infants in whom the central body temperature decreased to less than 36 degrees C, the standard dose of atracurium lasted a mean time of 47.5 +/- 11.8 min. These results suggest that it might be advantageous to reduce the initial dose of atracurium in the smaller newborn infants, particularly if their body temperature is less than normal. To date, a reduced dose of 300 +/- 30 micrograms kg-1 has been given to 10 patients and in this small group the mean duration of clinical effect was 24.5 +/- 10.1 min.