Description

The combination of a general anaesthetic supplemented by regional anaesthesia is the technique of choice for many surgical procedures in children. The provision of effective prolonged postoperative analgesia with minimum side effects is essential with increasing emphasis on day case surgery. Various aids to improve accuracy can be used when performing both central neuraxial blocks and peripheral nerve blockade. The use of ultrasound when performing these techniques is becoming common and may become a routine aid in future in the same way it has for central venous cannulation. The benefits of ultrasound, such as avoiding local structures adjacent to the desired nerve or plexus and direct visualisation of the injectate during injection with a reduction in the volume of local anaesthetic required, are valuable.

Thoracic and lumbar epidurals can be inserted via the caudal route in children as old as 10 years. There are multiple tests that can confirm epidural catheter tip position when inserted by this route, including X-ray techniques, ultrasound, surface ECG markers or the Tsui test. Peripheral nerve blocks may be inserted using surface nerve mapping prior to invasive nerve stimulation. The stimulation thresholds for peripheral nerves are not as consistent as once thought. A stimulating needle may be intraneural and still require up to 5 mA before a motor response is elicited.

Peripheral nerves can also be identified using ultrasound which avoids the need for nerve stimulation. Continuous catheter techniques for peripheral nerve blocks remove the risks associated with continuous epidural infusions and are becoming popular. Several caudal additives (adrenaline, opioids, clonidine and ketamine) may be used to prolong the effect of local anaesthetic solution in the caudal epidural space. None of these drugs are free from side effects and a risk benefit analysis is required before they are used.