High Central Neuraxial Blockade

• In short, there is unintentional upward spread of local anaesthetic within the intrathecal or epidural space
• Therefore factors affecting the spread of LA within the central neuraxis can increase the chance of high block

• Unrecognised, inadvertent placement of an intrathecal catheter
• Accidental subdural or intra-dural injection/catheter placement
• Greater speed of injection
• Barbotage i.e. repeated injection/aspiration of fluid was historically felt to increase spread although this isn't borne out in the evidence
• Spinal following failed epidural top-up

• Excessive dose of local anaesthetic
• Excessive volume of local anaesthetic
• Low baricity of local anaesthetic i.e. heavy bupivacaine less likely than plain bupivacaine to cause high block

• Positioning, particularly Trendelenburg
• Short stature, due to reduced lumbosacral CSF volume
• Reduced central neuraxial compartment volume owing to venous engorgement from raised intra-abdominal pressure/adiopse tissue, e.g.:
• Obesity
• Pregnancy

• Cardiovascular sequelae due to block of cardiac sympathetic innervation at T1-4
• This compounds existing block-related vasodilation and may be exacerbated by aorto-caval compression in Obstetrics
• Causes:
• Hypotension
• Bradycardia
• Nausea ± vomiting
• Rarely cardiac arrest

• Upper limb neurological sequelae manifest, such as:
• Paraesthesia of the hands
• Reduced grip strength
• Weakness or paralysis of the upper limbs
• There may also be difficulty breathing or a feeling of breathlessness owing to loss of intercostal muscle innervation

• Respiratory sequelae become more pronounced as the phrenic nerve is affected, including:
• Difficulty speaking or coughing
• Reduced tidal volume
• Hypoxia
• Apnoea/respiratory arrest due to loss of motor supply to the diaphragm

• Slurred speech
• Sedation
• Loss of consciousness

• Foetal distress
• Neonatal HIE due to delayed maternal resuscitation

• Ensure access to resuscitation equipment and drugs in case of high block


• Standard monitoring (HR, RR, BP, SpO₂, temperature) following neuraxial administration e.g. every 5 mins for 20mins, then every 30mins thereafter
• Frequent checking of the block level


• High degree of vigilance during block performance to recognise incorrect-site epidural catheter placement
• Close monitoring of block level following administration of LA e.g. for spinal or epidural top-up
• High index of suspicion of incorrect location of LA placement if unexpected neurology e.g. dense lower limb motor block following initiation of low-dose epidural
• Ensure test catheter position prior to epidural top-up
• Provide top-up doses of LA incrementally

• The exact degree of intervention will depend on the level of the block
• In general care is supportive whilst waiting for the block level to recede

High spinal is an anaesthetic emergency and I would seek senior anaesthetic support as well as making a rapid but thorough assessment of the patient

1. May require I&V if apnoea, respiratory arrest or significant hypoventilation


2. Apply high-flow, 100% oxygen


3. Monitor circulation with frequent cycling of BP
• Ensure left lateral tilt in Obstetrics
• Administer fluid
• Administer vasopressor e.g. phenylephrine or ephedrine
• Consider atropine or glycopyrrolate for bradycardia
• Exclude other causes of cardiovascular compromise such as anaphylaxis, LA toxicity, major haemorrhage, embolic phenomenon e.g. AFE


4. Monitor neurology; provide reassurance


5. Foetal monitoring and consideration of LSCS

• May require ICU if ventilated for a long time
• Document events in the notes
• Critical incident form
• Fulfil duty of candor i.e. inform patient of events
• Loco-regional learning e.g. M&M presentation