Peripheral nerve blocks and infusion

What is a peripheral nerve block?

As part of your child’s general anaesthetic, your child may be offered a peripheral nerve block.

Local anaesthetic (numbing medicine) is placed near to a nerve or a group of nerves to numb the area where your child is having their operation.

Peripheral nerve blocks can provide a safe and effective form of pain relief both during and after your child’s operation.

How is a nerve block done?

Once your child is asleep under general anaesthetic, a peripheral nerve block can be done by an anaesthetist. It is usually done before the start of the operation which allows it to work well during the operation. Sometimes it is done at the end of the operation, before your child wakes up.

The anaesthetist will usually use an ultrasound machine to see the nerve and the other structures around it.

The particular nerve or nerves that will be blocked depends on your child’s operation. Your child’s anaesthetist will discuss this with you at their pre-operative visit. The block should last for between 6 and 24 hours after the operation.

Occasionally a nerve block catheter (plastic tube) may be left in place to allow an infusion of local anaesthetic after surgery. This would mean the the numbness lasts until the infusion is stopped.

What are the benefits?

The benefits of using a nerve block include:

• providing pain relief during the operation and afterwards
• strong pain relief medications may be avoided or given in smaller doses
• the side effects associated with these strong medications, such as feeling and being sick, drowsiness, difficulty passing wee and itchiness, can be reduced
• recovery time after the operation can be faster

What are the risks?

As with all injections, there is a risk of bleeding, bruising or infection at the injection site, or allergy to the medicine being injected.

Nerve damage

Damage to nerves can happen. After a nerve block, some children may notice a patch of numbness or tingling. This usually gets better within a few weeks, but it could last up to a year.

Permanent nerve damage is very rare. Exact numbers are not known but it is thought to happen in between 1 in 5,000 and 1 in 30,000 nerve blocks. A recent study looking at more than 100,000 nerve blocks in children showed a rate of temporary nerve damage of 2.4 per 10,000 patients. There were no cases of permanent nerve damage found in this study.

Toxicity

Local anaesthetic toxicity is a very rare but potentially serious risk that can happen if local anaesthetic solution is accidentally injected into a blood vessel.

Your child will be closely monitored to recognise any signs of this. Your child’s anaesthetic team is also trained to respond to this if it was to happen.

Other risks

Some nerve blocks may carry some other risks specific to them which your anaesthetist will discuss with you.

Other alternatives

You can discuss other methods of pain relief with your child’s anaesthetist. For example, strong pain medications taken either by mouth or given into a vein, or local anaesthetic injected into the operation site by the surgeon.

How long will the nerve block last?

It may take up to 24 hours after the operation or after stopping the infusion for the numb sensation to fully return to normal.

Your child may be discharged with the block still working. If the numb sensation lasts longer than 48 hours and you are no longer in the hospital, you should contact theatre admissions department on 0114 271 7343 or 0114 271 7393.  A member of staff will take your child’s details and an anaesthetist will return your call to discuss your concerns. You may be given telephone advice or asked to return to the hospital for an anaesthetist to examine your child.

Will I need to give my child other pain relief?

Whilst the block is still working, it is important to give your child simple pain relief, such as paracetamol or ibuprofen. This will make sure your child remains comfortable as the block wears off.

Your child may need other medication to help with pain once the block wears off. Your child’s anaesthetist will discuss this with you at their pre-operative visit and advise you how to manage this after the operation.

Safety information

Please also see our other resource looking after your arm, hand and leg after a block for more information.

It is very important that you protect the numb part of your child’s body until the sensation has fully returned. This means not exposing it to heat (such as hot water bottles, radiators or hot baths) as they are unable to feel if the temperature is too hot. It is also important to avoid any trauma to the numb part of your child’s body.

If the block is performed on a limb, it is important to remember that your child’s limb will not be as strong as usual.

If your child has a numb leg, your child will need to be supervised walking or crawling until the block is fully worn off as there could be a risk of falls.

If your child has a numb arm, they will be given a sling to help protect it and should not sleep on top of the affected arm if it is still numb.