[Regional anesthesia in pediatrics]

After having been virtually completely forgotten since the Second World War, paediatric regional anaesthesia has been undergoing a renewal in the last decade. This renewed interest in old techniques is due to several converging factors: a better knowledge of the pharmacology of local anaesthetic agents in the child, the availability of equipment adapted for children, the remarkable haemodynamic stability of the very young child during an epidural block, as well as the need to treat pain not just in the operative period. The child is not, or rather, is not only a small adult. Embryological development is not finished at birth. The incompletely myelinized nervous system as well as the incomplete skeletal ossification will influence local anaesthetic pharmacodynamics and the choice of anaesthetic technique and anatomical landmarks. Aponeurotic sheaths are only poorly attached to anatomical structures, especially nerves. This, together with the fact that epidural fat in the young child is very fluid, explains why some techniques are very efficient, but also why the volumes of required anaesthetic solution are proportionately much more important than in adults. The general pharmacology of local anaesthetic drugs is very close to adults. However, the very important regional blood flow rates, the different body water distribution, the immature neurovegetative system, the weak activity of some enzymes, and the relatively greater importance of the liver and brain by weight explain the differences found in pharmacokinetics, which are differences in degree and not in nature. The choice of the appropriate local anaesthetic agent depends on these factors. In France, the chosen drug will almost exclusively be an amide, mostly lignocaine and bupivacaine. The psychological immaturity of children makes any assessment of pain quite difficult. Moreover, body image has not yet been completely acquired in most cases, so reducing the possibility of conceptualization. The usefulness of techniques requiring an active patient participation, in particular the search for paraesthesia, is therefore rather reduced. Light general anaesthesia and peripheral nerve stimulators (for nerve blocks) are essential, and desirable at least, if not wished by most patients. Caudal anaesthesia is an important technique in the child. It is easy to perform, efficient, with small risk. Its ideal indication is surgery below the umbilicus in the infant and young child. Lumbar epidural anaesthesia requires greater experience as well as proper equipment, especially in the very young child. Peripheral nerve blocks are less used than in adults.(ABSTRACT TRUNCATED AT 400 WORDS)