Eyres R L, Kidd J, Oppenheim R, Brown T C
Anaesth Intensive Care. 1978 Aug;6(3):243-7. doi: 10.1177/0310057X7800600312.
Blood levels of lignocaine and bupivacaine were measured in children following caudal, subcutaneous and tracheal administration. The highest peak levels were in children under 3 years following tracheal spray but all blood levels were below accepted toxic adult levels for anaesthetised patients. No toxic manifestations were seen.