Paediatric regional anaesthesia for surgical procedures - A guide to drug choice

Paediatric regional anaesthesia plays an important role in stress reduction and perioperative pain control. Aminoamide local anaesthetics such as mepi vacaine, bupivacaine and, more recently, ropivacaine are widely used. Becau se of the differences in anatomy and physiology between children and adults , low concentrations and high volumes have to be used to ensure that these drugs are effective and well tolerated in paediatric patients. Mepivacaine, because of its short duration of effect, is mainly used for br ief procedures, while the long-lasting action of bupivacaine makes it the m ost commonly used local anaesthetic for both single dose administration and continuous infusion through an epidural catheter. Ropivacaine, the S-enant iomer of bupivacaine, has only recently been introduced for use in children , but the results of preliminary studies suggest that it will probably have a predominant place in paediatrics. Adjuvants are often administered to prolong the action of local anaesthetic s in the postoperative period. Epinephrine (adrenaline) and opioids were us ed for many years as adjuvants. While opioids still have a place in regiona l anaesthesia, their adverse effects (mainly respiratory depression) requir e that they are used in combination with accurate monitoring of vital param eters. Nowadays, clonidine and keramine are more likely to be used as adjuv ants and they have been associated with impressive results. Clonidine 1 to 2 mu g/kg prolongs the action of mepivacaine, bupivacaine and ropivacaine a nd neither hypotension nor respiratory depression have been described. The only adverse effect of clonidine is sedation, which is often useful in the postoperative period in children. Ketamine seems to be the most effective o f the adjuvants; preliminary results indicate that it can prolong analgesia for at least 10 hours, but these findings require confirmation.