Consent

Before discussion with patients and parents, it is important to identify the most suitable block for the patient and procedure (plan A) and to have a good understanding of the benefits of regional anaesthesia for the individual child ( Table 1 ).

Conduct a thorough history-taking and clinical examination (including weight and inspection of the puncture site) to identify any contraindications for regional anaesthesia ( Table 2 ).

It is important to put the risks of regional anaesthesia ( Table 3 ) in perspective for the patient/carers and to also discuss the risks of alternatives, like opioids, so they can make informed decisions. ^, Always mention the risk of failure of the block and discuss a plan B/C wherever necessary beforehand.

A long-acting local anaesthetic has a duration of action that is usually limited to 6–12 hours after a single bolus. When moderate or severe pain is expected, intense physiotherapy is required postoperatively, or there is a history of chronic pain, consider using a catheter technique for prolonged analgesia. Discuss the insertion of a catheter and the risks/benefits associated as below.

e.g. an extensive laparotomy might require prolonged bilateral analgesia and therefore an epidural could be your plan A or plan B for this case .

Use your preoperative conversations with the patient/carers to manage expectations. You need to explain that the block is part of a multimodal approach and might not cover 100% of the pain.

You need to discuss skin markings, like bruising or puncture marks that are distant to the surgical field and intended scar site. Remember to discuss the possibility of a motor block, especially in blocks where this is not part of the desired effect.

A urinary catheter may be required when inserting an epidural or anterior QL catheter.

The goal of the block is to numb the targeted area, but it is important to recognize that the altered sensation it causes, may also be unsettling.

Preparation and planning

Choose the appropriate block:

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  Peripheral better than central

  
  
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  Consider single shot versus catheter

  
  
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  Plan B/C

Choose the appropriate timing:

Ideally: under general anaesthesia

Performing regional blocks in children under general anaesthesia is preferable to awake and is standard practice. Have a second anaesthetist present to monitor the anaesthetic.

Ideally: before knife to skin

Having a working block prior to surgical stimulation facilitates opioid-sparing/opioid-free anaesthesia. Alternatively, in situations where the surgery is long (block will have worn off) or when the surgical approach is unclear, you could run a remifentanil infusion during the surgical procedure and perform the block at the end for maximal postoperative pain relief.

Gather the necessary equipment:

This includes:

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  Resuscitation equipment: oxygen, intubation trolley, resuscitation drugs, including 20% Intralipid (see the section on local anaesthetic toxicity below)

  
  
• •
  

  Trained assistant

  
  
• •
  

  Short-bevelled needle with extension tubing (ideally non-luer locking e.g. NR-fit), NR-fit drawing up needle and appropriately sized syringe and, if required, a sharp needle to puncture the skin

  
  
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  Antiseptic solution

  
  
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  Sterile gloves

  
  
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  Local anaesthetic (LA)

  
  
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  Ultrasound machine with multiple probes

  
  
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  Sterile ultrasound gel and probe cover

Ultrasound enables more accurate placement of LA by providing non-invasive and real-time information about anatomy and needle trajectory. This reduces the risk of intravascular injection or potential damage to adjacent structures and results in shorter procedures and onset times and a longer block duration. Nerves are non-compressible structures that can appear hyperechoic, hypoechoic or honeycomb and have no flow when using doppler. The block can be performed with the needle in-plane, where the entire needle shaft is viewed, or out of plane, where only a cross-section of the needle shaft is viewed. In-plane alignment is generally recommended when possible.

Prepare your local anaesthetic: choose a long-working LA. Most commonly used are ropivacaine 2 mg/ml and levobupivacaine 2.5 mg/ml. For a singular nerve block or when a dense block is required, a higher concentration of 5 mg/ml can be used, provided that the weight-based maximum dose guidelines are observed. The maximum dose of both ropivacaine and levobupivacaine is 2.5 mg/kg (this includes what you can give AND what the surgeon might want to infiltrate). However, recommendations suggest that a block can be achieved using a maximum dose of 0.5–1.5 mg/kg. Neonates are more susceptible to LA toxicity due to having less plasma proteins and thus a higher free fraction of LA on one hand and an immature liver metabolism and blood–brain barrier on the other hand. Therefore implement a dose reduction of 30–50% in this patient population. When a higher volume is required, e.g. plane blocks, you might have to dilute your calculated dose of LA with some saline to adjust for the volume needed (e.g., neonates and small children: use a concentration of 1.25 mg/ml).

Consider the use of adjuvants: clonidine mixed with your LA will prolong the duration of the block without being overly sedative.

Performance

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  Prepare the patient: full Association of Anaesthetists of Great Britain and Ireland (AAGBI) recommended monitoring: pulse oximetry, ECG, blood pressure, end-tidal CO ₂ monitoring

  
  
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  Clean a large enough area with chlorhexidine (NOTE: use chlorhexidine 0.5% in neonates <40 weeks)

  
  
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  Sterility: gloves, mask, hat, sterile block needle and probe cover for ALL blocks; full surgical scrub when doing a central block or when inserting a block catheter.

  
  
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  Block needle: usually 50–60 mm needle. Consider the depth of the target and the angle of your trajectory when choosing the appropriate needle length (might be longer than expected, especially in patients over 20 kg).

  
  
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  Use ultrasound guidance for all blocks unless inappropriate (e.g. ring block). The linear probe is suitable for most paediatric blocks. Choose the linear probe with the larger footprint as you will be able to follow your needle over a longer trajectory when inserting the needle in-plane.

  
  
• •
  

  “Stop Before You Block” before inserting the needle

  
  
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  Do not advance the needle if you cannot find the needle tip

  
  
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  Aspirate before injecting

  
  
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  Consider using saline for hydrodissection or to confirm the needle tip position in order to not waste local anaesthetic (e.g. in neonates where the LA dose is very limited)

  
  
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  Observe the spread of LA

  
  
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  Minimize heat loss (blanket/forced under-body air warmer)

  
  
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  When performing the block in an awake patient: use Ametop/EMLA, discuss expectations, have the parents present, infiltrate with lignocaine, use Entonox where appropriate

  
  
• •
  

  Documentation of your block is important (which block, dose given, complications)

Upper limb nerve blocks

Brachial plexus:

Anatomy – the brachial plexus is formed from the anterior primary rami of C5, C6, C7, C8 and T1. These nerve roots emerge from the intervertebral foraminae and unite to form the superior, middle and lower trunks. The trunks pass from the interscalene groove over the first rib superoposterior to the subclavian artery. They divide and unite forming cords that are named based on their relation to the axillary artery. These then form the terminal nerves that supply the upper limb:

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  Lateral cord – lateral root of median nerve and the musculocutaneous nerve

  
  
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  Medial cord – medial root of median nerve, ulnar nerve and the medial cutaneous nerves of arm and forearm

  
  
• •
  

  Posterior cord – axillary and radial nerves

Indications of a brachial plexus block – surgery to the arm, forearm and hand.

The brachial plexus can be blocked above the clavicle, below the clavicle or at the level of the axilla. This article will discuss the supraclavicular and the axillar approach.

Supraclavicular blocks – provide reliable blockade of the brachial plexus with a rapid onset. The proximity of the plexus to the subclavian artery and lung, particularly in children, mandates the use of ultrasound by an experienced operator to perform this block.

Technique – position the patient supine with the head turned to the contralateral side. In infants and small children a head ring and sand bag behind the shoulders facilitates needle access. The ultrasound probe is placed above and parallel to the clavicle in the supraclavicular fossa. The hypoechoic subclavian artery is visualized above the hyperechoic first rib. At this level the plexus lies above and lateral to the artery and appears as a group of hypoechoic nodules. Needle insertion is in-plane from lateral to medial. Complete visualization of the needle is essential at all times.

Local anaesthetic: 0.2–0.5 ml/kg will usually suffice (maximum 15–20 ml), but volume should be adjusted to ensure spread of LA to encircle all the nerve bundles. It is feasible to place a catheter in proximity to the brachial plexus.

Complications: general complications of regional anaesthesia ( Table 3 ) and pneumothorax (<1% with ultrasound), Horner’s syndrome (1%), phrenic nerve palsy (1%) and epidural/subarachnoid injection.

Axillary nerve blocks carry a lower risk of causing a pneumothorax and are thus considered safer.

Technique – position the patient supine with the arm abducted 90° and elbow flexed 90°. Place the ultrasound probe transverse in the axillary crease (short axis to the arm) and insert the needle in-plane from cephalad to caudal. The round hyperechoic structures of the branches of the brachial plexus usually surround the axillary artery and can be identified based on their trajectory when scanning down towards the elbow. This block aims to target the four nerves individually:

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  The median nerve: starts superficial and lateral of the artery and will stay close to it, jumping over the artery to the medial side before reaching the elbow

  
  
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  The ulnar nerve: start superficial and medial to the artery and will move away towards the ulnar groove

  
  
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  The radial nerve: usually posterior (under the artery on the ultraound (US) image) and will dip towards the humerus

  
  
• •
  

  The musculocutaneous nerve is a hypoechoic flattened oval, with a bright hyperechoic rim found in the fascial layers between the biceps and coracobrachialis muscle.

Local anaesthetic: 0.2–0.5 ml/kg (maximum 15–20 ml) – maximum 5 ml per nerve.

If visualization is difficult, periarterial injection will suffice to obtain a brachial plexus block.

Forearm blocks: the radial, median, and ulnar nerve can be blocked under US guidance and are useful for forearm and hand surgery and as rescue block when incomplete supraclavicular/axillary block.

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  The median nerve is located mid-forearm between the flexor digitorum superficialis and flexor digitorum profundus

  
  
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  The ulnar nerve is found mid-forearm, medially to the ulnar artery

  
  
• •
  

  The radial nerve is generally best visualized above the lateral aspect of the elbow in the groove between biceps brachii and brachioradialis

Local anaesthetic: usually 5 ml/nerve suffices.

Lower limb nerve blocks

Anatomy – the anterior rami of L1-4 give rise to the femoral nerve, lateral cutaneous nerve of the thigh and the obturator nerve. The femoral nerve provides sensory innervation to the anterior and medial aspects of the thigh; the lateral cutaneous nerve to the lateral aspect of the thigh; and the obturator nerve to the medial aspect of thigh and knee joint. The saphenous nerve is a terminal branch of the femoral nerve and provides sensory supply to the medial knee, lower leg and skin over the medial malleolus. The posterior side of the lower leg is innervated by the sciatic nerve (L4-S3). At the level of the popliteal fossa, the sciatic nerve splits into the tibial nerve and the common peroneal nerve.

The combination of a femoral or adductor canal block and a sciatic or popliteal block will result in anaesthesia of the entire lower leg below the knee.

Femoral nerve: this lies in the femoral triangle lateral to the femoral artery and deep to the fascia lata and iliaca, with the latter separating it from the artery. Depositing LA around the femoral nerve produces both sensory and motor blockade. The latter will effectively reduce painful quadriceps muscle spasms.

Indication – patella lengthening, femoral osteotomy, analgesia for fractured femur, operations to the anterior thigh and to the medial side of the knee.

Technique – place the linear probe below the inguinal crease and locate the femoral artery. The nerve is triangular or elliptical in shape and may be difficult to visualize. The femoral vessels act as a reliable guide (nerve should be lateral) as do the hyperechoic fascia lata and fascia iliaca (nerve should be below both). Scan the artery and use Doppler to identify the external circumflex vessels that cross anterior to the femoral nerve to ensure safe needle placement. The needle is inserted lateral to medial in-plane and LA (0.2 ml/kg, maximum of 20 ml) is deposited just lateral to the nerve below the fascia iliaca.

Complications – general complications ( Table 3 ).

Adductor canal block (subsartorial block): the adductor canal extends from the apex of the femoral triangle to the adductor hiatus and is the passage for structures moving between the thigh to the posterior leg. It is bordered antero-medially by the sartorius, laterally by vastus medialis and posteriorly by the adductor magnus and longus muscles. It contains the femoral artery and vein, the saphenous nerve and the nerve to vastus medialis. An adductor canal block aims to block the saphenous nerve, a terminal branch of the femoral nerve that provides sensory supply to the medial aspect of knee, lower leg and ankle (skin only).

Indication – as analgesia for knee surgery, e.g. anterior cruciate ligament repair (no motor block, thus not suitable for femoral fracture) or as supplement to sciatic blocks to cover the skin of the medial aspect of lower leg and ankle.

Technique – the patient is supine, the leg to be blocked slightly bent and externally rotated. Place the linear US probe on the mid-to-distal-third of the thigh in the transversal plane and use dynamic scanning to locate the femoral vessels in the adductor canal. Using an in-plane technique, the needle is advanced in a lateral to medial direction towards the femoral artery through the sartorius muscle and into the adductor canal space (usually lateral to the artery). Check for negative aspiration then inject LA (maximum of 10 ml). If the nerve is not visible, aim for a circumferential spread around the femoral artery.

Complications – general complications ( Table 3 ) and hamstring weakness.

Sciatic nerve block/Popliteal nerve block: the sciatic nerve (L4-S3) exits the pelvis through the greater sciatic foramen, then traverses the buttock deep to the gluteus maximus before passing down the midline of the posterior thigh. Near the popliteal fossa it will split into the tibial nerve and common peroneal nerve.

Indications – proximal sciatic for hamstring release. Popliteal all operations on or below the knee (combine with femoral or saphenous nerve blocks).

Technique – position the patient in lateral decubitus with block side up. Place the linear US probe transversely on the popliteal crease and identify the popliteal vessels, with popliteal vein lying on top of the popliteal artery. The tibial nerve is located superficial to the popliteal vessels. The common peroneal nerve can be found by tracking cephalad and identifying it as it joins the tibial nerve from a lateral and more superficial position. The aim of a popliteal block is to deposit LA at the level of the bifurcation; sciatic block can be performed more proximally. Dorsi/plantar flexion of the ankle may aid identification by illustrating the nerve moving within the muscular plane. This ‘See-Saw’ sign may be absent in cerebral palsy children with marked fibrosis. Check for negative aspiration and inject 0.5 ml/kg of LA (usually 2.5 mg/ml). A weaker concentration, e.g. 1.25 mg/ml levobupivacaine may be appropriate if there are concerns regarding postoperative acute compartment syndrome. A stronger solution, e.g. 5 mg/ml levobupivacaine, can be considered where postoperative muscle spasms are likely (e.g. tendon transfers).

Complications – general complications ( Table 3 ).

Truncal blocks

Paravertebral nerve block (PVB):

Anatomy – the thoracic (T1-T6) and thoracoabdominal (T7-T11) intercostal nerves innervate the chest and abdominal walls. The paravertebral space (PVS) contains the thoracic spinal nerves as they emerge from the intervertebral foramina. It is bounded by the costotransverse ligament with the parietal pleura anteriorly and the transverse processes and ribs posteriorly.

Indications – thoracotomy, sternotomy, thoracoscopic surgery, pectus surgery, chest drains, rib fractures, tracheo-oesophageal fistula repair, upper abdominal surgery, and pyeloplasty.

Technique – lateral decubitus with block-side up. Place the US probe in a transverse position over the midline to identify the spinous processes. Scan laterally in this plane to identify the transverse process, the pleura and the paravertebral space. Angling the probe slightly so parallel with the ribs, insert the needle from lateral to medial below the costotransverse ligament. When injecting 0.5 ml/kg, the LA should displace the pleura anteriorly (pushed downwards on the US image).

Complications – general complications ( Table 3 ), pneumothorax, epidural and intrathecal spread. Cardiovascular effects, similar to an epidural, can occur with bilateral PVB blocks.

Erector spinae plane block (ESPB): this plane block can be used for abdominal, pelvic and orthopaedic procedures involving incisions from T1-L4.

Anatomy – the erector spinae (ES) are a group of deep muscles of the back, including the spinalis, iliocostalis and longissimus muscles, that are primarily responsible for extension and lateral flexion of the vertebral column, maintaining posture and supporting the spine. They flank the spinous processes on either side and are covered by the thoracolumbar fascia (TLF). An ESPB is a facial plane block where the needle tip is placed between the ES muscles and the transverse process, blocking the dorsal and ventral rami of the spinal nerves in a multi-dermatomal fashion aided by the TLF. The LA spread is 3–4 levels cranially and caudally in cadaveric studies.

Indications – thoracotomies, rib fractures, pectus surgery, breast surgery, ventral hernia repairs, spinal fusion, percutaneous nephrostomies.

Technique – the patient is placed in the lateral or prone position. Place the linear high frequency US probe in a longitudinal plane over the spinous process at the level to be blocked. Then slide the transducer parasagittally to visualize the transverse processes and the ESP. The needle is introduced in-plane from caudad to cephalad or out-of-plane until the needle tip is in the plane between ES muscles and the transverse process. After negative aspiration, 0.5 ml/kg of LA is injected. The LA should spread cranially and caudally along the transverse processes.

Complications – general complications ( Table 3 ) and pneumothorax (depending on the level).

Rectus sheath block:

Anatomy – the rectus muscles are paired muscles that run between xiphoid process and pubic bone on either side of the midline (linea alba). Anteriorly they have fibrous intersections that give it the six pack appearance. The sensory nerves that innervate the periumbilical skin arise from the T10 intercostal nerves, travel between the internal oblique and transversus abdominis muscles (TAP plane) and then anteriorly through the rectus muscle. Both rectus muscles are enveloped by a rectus sheath, formed from the aponeuroses of the three lateral abdominal muscles. It adheres tightly to the muscle anteriorly but loosely posteriorly, creating a potential space for LA deposition.

In neonates the rectus muscle can be as thin as 1–2 mm.

Indications – periumbilical surgery, e.g. umbilical hernia repair, pyloromyotomy, gastrostomy.

Technique – place the US probe transverse on the midline, immediately above the umbilicus. Identify the linea alba and the rectus muscles on either side. Slide the probe laterally to identify the rectus muscle belly and the beginning of the three abdominal muscle layers more laterally. Observe the double track line below the muscle (rectus sheath and the fascia transversalis). In older children the epigastric vessels can be located using Doppler. Insert the needle in-plane through the rectus muscle until the needle tip is just above the double hyperechoic line. After negative aspiration, give a test dose (with saline) to ensure the correct position. When injecting LA (0.1–0.3 ml/kg/side), it should spread as an ellipse, peeling the rectus muscle of its posterior sheath. The rectus sheath block should always be performed bilaterally as nerves might cross the midline. A paramedian longitudinal US probe position allows the assessment of LA spread cephalad and caudal.

Complications – general complications ( Table 3 ) and intraperitoneal injection.

Quadratus lumborum (QL) block: there are two approaches to the QL block (QLB). The lateral QLB involves injection of LA lateral to the QL muscle and is useful for lower abdominal surgery (appendicectomy, inguinal hernia, orchidopexy). The added advantage compared to a transverse abdominis plane (TAP) block is visceral analgesia. The anterior QLB involves injection of LA anterior to the QL at the level of L4 and is useful for pelvic, iliac crest and proximal femoral surgery.

Anatomy – the quadratus lumborum (QL) muscle lies medial to the aponeurosis formed from internal oblique and transversus abdominis. The thoracolumbar fascia (TLF) is a posterior abdominal fascia, connected to the paravertebral space. It encases QL, psoas and the erector spinae (ESP) muscles. The TLF contains nociceptors, sympathetic fibres and cutaneous branches of T4-L1. The lumbar plexus is formed in the psoas muscle and will travel between the psoas and the QL muscle.

Technique – for lateral QLB the patient may be placed supine with a roll under the hip. Pass the needle in-plane through the anterior abdominal muscles until it reaches the anterolateral QL. Aim to deposit 0.5 ml/kg of LA between QL and the TLF.

The anterior QL block is performed with the patient in the lateral decubitus position. With the patient in the appropriate position, place the curvilinear probe transversely above the iliac crest, below the costal margin. Identify the three abdominal muscle layers and follow them posteriorly until they form a hyperechoic line that is the aponeurosis, then identify the QL and TLF. Move the probe until the “shamrock sign” is obtained where the three cloves of the shamrock are ES, QL, psoas, and the stem is the transverse process of L4. Insert the needle from posterior. Deposit LA between the QL and the psoas.

Complications – general complications ( Table 3 ).

Penile block: this is historically performed as a blind technique but the ultrasound approach tends to be safer, more superficial and requires lower doses of LA.

Anatomy – the penis consists of two corpora cavernosa and one corpus spongiosum, with the latter containing the urethra. These three erectile bodies, enveloped by Buck’s fascia. The nerves to the penis are derived from the pudendal and cavernous nerves. At the dorsum of the penis they travel under Buck’s fascia alongside the dorsal penile arteries on either side. These can be targeted by ultrasound approach. Ventrally, a superficial ring of LA will suffice to cover the scrotal branches of the pudendal nerve.

Indications – circumcision, meatoplasty and distal hypospadias repair.

Technique – the penis should be pulled gently caudad to make the skin taut over the subpubic space. Place the linear probe transverse over the base of the penis. Identify the two corpora cavernosa, the Buck’s fascia and the penile vessels, one central vein and two dorsal arteries. When inserting your needle, consider the superficial location of the target. Pierce through Buck’s fascia and inject 1–2 ml of LA peri-arterially (maximum 5 ml). Repeat on the other side and lastly place a thin subcutaneous ring of LA at the ventral side of the penis.

Complications – general complications ( Table 3 ), vascular compromise and haematoma. Do NOT use adrenaline in this block!

Head and neck blocks

Superficial cervical plexus block:

Anatomy – the superficial cervical plexus (C2-4) provides sensory innervation to the anterolateral neck, extending from the retro-auricular region superiorly to the skin covering and immediately inferior to the clavicle.

Indications – superficial neck surgery, e.g. branchial cyst/fistula, thyroidectomy, tracheostomy, vascath insertions, mastoid surgery, etc.

Technique – place the US probe in a transverse position on the neck with the head turned away from the block side. Follow the sternocleidomastoid muscle to its posterior border. The superficial cervical plexus appears as a collection of hypoechoic nodules deep and lateral to this border. Approach from a lateral to medial direction in-plane and aim to place the LA in the plane immediately deep to the sternocleidomastoid (SCM) adjacent to the superficial cervical plexus.

Complications – general complications ( Table 3 ), pneumothorax, phrenic nerve palsy, subarachnoid/epidural injection.

Caudal block

This block was historically performed as a blind, landmark-based technique. The incidence of complications like block failure and accidental intravascular or intrathecal injection can be significantly reduced by using ultrasound. In addition to confirming the needle tip position and thus augmenting the success rate of the block, ultrasound can confirm the level of the block and identify potential contraindications for the block, e.g. tethered cord.

Anatomy – the caudal epidural space is the lowest section of the epidural space and can be accessed through the sacral hiatus, a result of an incomplete fusion of the lamina of S5 (and/or S4) in children. The sacral hiatus is bordered laterally by two sacral cornua, with a palpable dimple in between, and is covered by the sacrococcygeal ligament (SCL).

Indications – infraumbilical and lower limb surgery in small children (e.g. hypospadias, anorectal surgery, inguinal hernia and orchidopexy). In children older than 2 years the cephalad spread of LA becomes unpredictable and the sensation of pins and needles is less tolerated. Consider an alternative block if possible.

Technique – position the patient in lateral decubitus. Place the large footprint linear probe transverse over the cornua to obtain the frog’s eyes image (the cornua appear as two rounded hypoechoic structures flanking the sacral hiatus). Identify the cornua and the sacrococcygeal ligament. Rotate the probe 90° for a longitudinal view in order to insert the needle in-plane. Identify the sacral hiatus, the caudal canal, the dural sac and the sacrococcygeal ligament. Insert a cannula through the sacral hiatus to gain entrance into the epidural space. Slide of the cannula and ensure aspiration is negative for CSF and blood. Slowly inject a maximum of 1 ml/kg of LA into the space. The dural sac should be pushed anteriorly (down) and you should be able to follow the spread of the LA towards the head.

Complications – general complications ( Table 3 ), intravascular or intrathecal injection (risk for total spinal anaesthesia), hypotension, urinary retention.

Additives

Additives are drugs that can be added to LA to improve block quality, prolong block duration and reduce systemic absorption of potentially toxic LA agents. Only adjuncts which prolong block duration by 50% or more and have a known mechanism of action with a side effect profile comparable to plain LA, should be used.

A wide range of different agents have been used; epinephrine appears to prolong sensory blockade and delay systemic uptake of LA. Buprenorphine, dexamethasone, clonidine, magnesium, and dexmedetomidine show some promising results but caution is recommended due to concerns regarding potential neurotoxicity. At present, no adjuncts are licensed for use in peripheral regional anaesthesia.

Perineurial clonidine (1–2 micrograms/kg) may increase block duration 20–50% depending on type of block. This is the only adjunct the authors currently recommend for use in clinical practice.

Some agents may increase block duration when used intravenously. Dexamethasone (100–200 micrograms/kg) may provide equal analgesic benefit as perineural dexamethasone whilst reducing the potential for neurotoxicity. Systemic α-2 agonists (e.g. clonidine or dexmedetomidine) may also be used however their effect is unclear.

LA systemic toxicity (LAST)

Test doses are generally not reliable in detecting intravascular injections and thus meticulous technique, careful aspiration, fractionated dosing and continuous visualization of the target area should be performed to reduce the risk.

Presentation of LAST: the early central nervous system symptoms (perioral numbness, metallic taste and dizziness) are masked during general anaesthesia and seizures or haemodynamic instability can be the first sign. A high level of suspicion is required.

Treatment of LAST:

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  Stop LA injection immediately

  
  
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  Call for help, resus trolley and lipid rescue pack

  
  
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  Support the airway and the breathing (100% O ₂ , endotracheal tube where necessary, avoid hypercarbia)

  
  
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  Confirm/establish IV access and support the circulation where possible

  
  
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  Consider giving intralipid 20%

  
  
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  Treat seizures with benzodiazepines (consider neuromuscular blockade)

  
  
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  IF circulatory arrest: A(P)LS guidelines with following adjustments:

  
  
  
  
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    Give intralipid 20% immediately

    
    
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    Use small adrenaline doses (1 mcg/kg)

    
    
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    Return of spontaneous circulation (ROSC) can take >1 hour – do not stop; consider extracorpeal circulation (ECC)

  
  

Intralipid 20% dosing:

• 1.
  

  Give bolus of 1.5 ml/kg over 2–3 minutes

  
  
• 2.
  

  Start IV infusion at 0.25ml/kg/minutes

  
  
• 3.
  

  Evaluation at 5 minutes and 10 minutes

  
  
  
  
  • a.
    

    Repeat bolus if necessary

    
    
  • b.
    

    Increase IV infusion to 0.5ml/kg/minute

  
  

Absolute maximum dose of intralipid 20% is 10 ml/kg in the first 30 minutes. Intralipid gives a huge lipid load and the patient will require intensive follow-up to exclude the onset of pancreatitis.

Compartment syndrome

Acute compartment syndrome (ACS) is a complication or raised pressure within muscle tissue compromising tissue perfusion. This can lead to ischaemia and tissue damage. A regional block could theoretically mask pain and delay diagnosis of compartment syndrome. There is, however, no evidence that it does. The authors would recommend:

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  Discuss with the orthopaedic surgeon: will identify high risk cases

  
  
• •
  

  Discuss with parents/child, discuss ACS risks and symptoms and benefits of regional anaesthesia.

  
  
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  Single shot, use low concentration 0.125%; no additives (not even dexamethasone)

  
  
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  Surgeon needs to consider compartment pressure monitoring

  
  
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  Postoperative vigilance

Nerve catheters

Longer duration of analgesia may be provided using peripheral nerve catheter and LA infusions. Peripheral nerve catheters may facilitate early ambulation and rehabilitation. Common continuous peripheral nerve blocks include paravertebral, femoral, sciatic and supraclavicular blocks. Continuous peripheral nerve blocks are safe, effective, have few side effects and are increasingly used in children.

Indications:

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  Major orthopaedic surgery, e.g. femoral osteotomy, amputation, club foot repair

  
  
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  Correction of pectus deformity of the chest

  
  
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  To facilitate intensive physiotherapy

  
  
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  Transplant/reimplantation surgery to improve blood flow to the limb

  
  
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  Chronic pain, e.g. complex regional pain syndrome (CRPS) Type 1 as part of multimodal rehabilitation

  
  
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  Non-surgical pain, e.g. epidermolysis bullosa affecting a limb

Additional equipment and dose: continuous nerve blockade requires a standard nerve catheter kit, adhesive plasters, intravenous cannula for tunnelling, tissue glue, and a syringe driver. Most published studies recommend the use of ropivacaine 2 mg/ml or levobupivacaine 1.25 mg/ml at a rate of 0.1–0.3 ml/kg/hour.

Complications: peripheral techniques are considered safer than neuraxial techniques because complications such as bleeding and infection are less severe. Catheter dislodgement, occlusion and leakage are common if preventative measures are not taken. These include tunnelling the catheter and applying tissue glue to the puncture site (to reduce LA leakage around puncture site which may lift off the dressing). A test dose should be administered after dressing to ensure the catheter is not kinked. A longer duration of catheter placement is associated with a greater incidence of insertion site infection, therefore close follow-up and removal of catheters after 3 days is recommended. In infants LA may accumulate and duration of infusions is often limited to 2 days. More recent pharmacokinetic data suggests that longer term infusions may be safe, however care is required and risks and benefits carefully considered.