24/09/2026
𝐌𝐚𝐧𝐚𝐠𝐞𝐦𝐞𝐧𝐭 𝐨𝐟 𝐭𝐨𝐭𝐚𝐥 𝐬𝐩𝐢𝐧𝐚𝐥 𝐛𝐥𝐨𝐜𝐤 𝐢𝐧 𝐨𝐛𝐬𝐭𝐞𝐭𝐫𝐢𝐜𝐬
Definition:
A high neuraxial block is a sensorimotor block that has reached a spinal segmental level higher than that required to achieve surgical anaesthesia. The terms high, total or complete block are used interchangeably. A sensory level of T3 or above can be associated with significant cardiovascular and respiratory compromise and can hence be considered a high block. Involvement of the cranial nerves signifies intracranial spread of local anaesthetic which can culminate in complete loss of consciousness and cardiorespiratory arrest.
Aetiology:
• Dosage:
o The baricity, volume/dose and injection technique can have an effect on the cephalad spread of intrathecal LA.
o A dose of 10mg hyperbaric bupivacaine plus 10 microgram fentanyl is usually appropriate for caesarean section. If no fentanyl is available, administer hyperbaric bupivacaine 10mg alone.
o The faster injections produce greater spread with plain solutions, but that the effect is less marked with hyperbaric solutions.
o Short stature can be a risk factor for a high spinal as height influences lumbosacral CSF volume and hence intrathecal spread of drug.
o It is assumed that in obesity and pregnancy, the area of central neuraxial compartment could be reduced due to venous engorgement from raised intraabdominal pressure, and excessive adipose tissue.
• Positioning of patient: Position of patient during and immediately after injection of local anaesthetic may determine the cephalad spread.
• Pre-existing epidural block: Unexpected high block can happen when a spinal is administered after the epidural space has presumably been expanded – and the subarachnoid space compressed – by recent epidural top-ups.
• Unrecognised dural puncture and intrathecal injection of local anaesthetic following epidural top up.
• Accidental subdural block: Subdural needle or catheter placement may account not only for delayed onset, profound and extensive conduction blockade, but also for ‘unexplained’ post epidural headaches, false negative aspiration tests and test doses, accidental total spinal, both early and late, some unilateral block and ‘unexplained’ neurological sequelae of spinal and epidural blockade.
• Accidental intradural space:
o Local anaesthetic can be injected into the substance of the dura, to create an intradural space, to form a localised and swelling collection within the layers of the dura.
o Repeated doses of local anaesthetic may escape retrogradely from the intradural space to the epidural space around the outside of the epidural catheter, eventually producing a clinically acceptable block.
o But there is a slight risk of an extensive block developing some time later, following rupture of the remaining layers of dura and sometimes the arachnoid as well, leading to diversion of the intradural solution into the subdural or subarachnoid spaces.
Prevention:
• Unrecognised subdural or intrathecal placement of an epidural catheter and an intended spinal technique after a failed epidural analgesia are two main identified causes of high spinal block.
• The anaesthetist performing these procedures must be aware of this serious complication and must remain vigilant throughout with continual assessment of progression of the block in a well monitored environment.
• Any abnormally functioning epidural must be followed up closely.
• Development of a dense motor block of lower limbs during epidural analgesia using a low dose epidural infusion is abnormal and a high-level suspicion of intrathecal placement must be maintained.
o This suspicion must be shared with the entire team looking after the patient and emphasised during handover care.
o Physical barriers in the form of prominent labels must be placed over the epidural catheter to prevent an accidental top up with large volume of LA.
• Preparation prior to performing any neuraxial block:
o Ensure airway and resuscitation equipment, vasopressors and drugs essential for an emergency general anaesthesia are within immediate reach.
o In obstetrics, the team must be aware of the location of a perimortem caesarean section pack.
o A designated emergency team and a cardiac arrest team must be identifiable.
• Procedure:
o After a sub-arachnoid injection or epidural top up, close monitoring of heart rate, blood pressure, oxygen saturations, respiratory rate and level of neuraxial block is necessary.
o Monitoring should follow clear written protocols. The frequency of observations should be determined by normal clinical considerations.
o Sensory levels can be tested with ice cubes, ice packs, ethyl chloride sprays, alcohol wipes or with pin-prick
• During a spinal block, focus on:
o Dose of local anaesthetic required,
o Baricity of drug,
o Position of patient after spinal
• During epidural test dose/top up:
o Always aspirate with a 2ml syringe for blood/CSF before any top up.
o For labour analgesia, test dose with a weaker solution, i.e., 10ml of 0.1% Levobupivacaine is enough to rule out sub arachnoid block. But go as per hospital protocol.
o Always check the level of neuraxial block before any epidural top up.
o If possible, top up epidural for procedural anaesthesia in theatre only for ease of managing emergencies.
o Always give local anaesthetic solution in increments.
• Post procedure:
o Written documentation of any difficulty in neuraxial block is of utmost importance.
o Staffing levels sufficient to provide the necessary standard of care are essential in areas providing care for patients with neuraxial blocks, but the individuals need to be trained to the requisite standard as well, and they must know when (and how) to obtain anaesthetic advice.
How to recognise high/total spinal block:
• One should have a high level of suspicion of a high spinal while giving a test dose or topping up an epidural in the delivery suite or in the theatre especially if there is a rapid development of sensory and motor block within minutes.
• After any neuraxial block, there should be constant monitoring of heart rate, blood pressure, respiratory rate and level of neuraxial block.
• Constant communication with the mother is very important as it will help to detect any early changes in the voice, effort of breathing or the conscious levels.
• Symptoms and signs of a high spinal correlate with the ascending level of neuraxial block.
• Early detection and management can prevent deleterious effects to both mother and foetus.
MANAGEMENT OF HIGH SPINAL BLOCK:
1. Recognition of high spinal and call for help
2. If only circulatory compromise:
• Correction of bradycardia and hypotension.
• Lateral displacement of uterus manually, with a wedge under the patient or by tilting the theatre table.
• Vagolytics like Atropine 0.6mg can be useful for severe bradycardia.
• For hypotension, Phenylephrine boluses of 50-100mcg can be given. It can also be given as an infusion 20-40ml/hr (in a concentration of 100mcg/ml or as per hospital protocol).
• Ephedrine13 in 6mg boluses can also be given if there is hypotension and bradycardia.
• Metaraminol boluses of 0.5mg or as an infusion in a concentration of 0.5mg/ml.
• Mephentermine has been used as a 3-5mg intravenous bolus or intravenous infusion of 2-5mg/min, or 25-50mg intramuscularly.
• IV fluids -500ml to 1 litre to be given rapidly. To be cautious in cardiac patients and in those with pre-eclampsia.
• Reassure the patient as she might be nauseous and will feel faint. Keeping a conversation also will help to assess if the neuraxial block is ascending.
3. If circulatory and respiratory compromise +/- neurological deterioration:
• If neuraxial block is ascending with breathing difficulties and desaturation, then reassure the patient, assess the airway, and give supplemental oxygen.
• If the patient loses her airway, becomes sedated or unconscious, then secure the airway which includes intubation with Rapid Sequence Intubation (RSI).
• If high doses of vasopressors are required, consider epinephrine boluses of 50-100mcg (epinephrine dilution of 100mcg/ml) or infusion.
• Maintain anaesthesia as there is possibility for awareness in an apparently unconscious patient.
• Patient will have to be sedated and ventilated until neuraxial block has worn off, so intensive care will need to be involved.
• In the event of a cardiac arrest, immediate cardiopulmonary resuscitation (CPR) as per Advanced Life support and to start perimortem caesarean section within 4 minutes of arrest.
4. Foetal monitoring:
• Assess the foetal wellbeing. If compromised, then the obstetric team to consider emergency delivery of foetus.
5. To rule out other causes of cardiovascular deterioration
• These causes may include local anaesthetic toxicity if intravascular injection, thromboembolism, major haemorrhage, amniotic fluid embolism, profound vasovagal effect
6. Written documentation of the events is of utmost importance for continual care of patient, for future reference and for medico legal purposes.
7. After patient has been resuscitated and woken up (if applicable), update the patient and family on course of events and offer follow up if needed.
Symptoms, Signs And Management Of The Different Levels Of Spinal Block:
1. Symptoms and signs: Bradycardia, Hypotension+/-, Nausea
Root levels: T 1-4
System affected: Cardiac sympathetic fibres blocked
Management:
• Vagolytics like Atropine 0.6mg
• Sympathomimetics such as Ephedrine 6 mg boluses
• Left lateral tilt /wedge
• Phenylephrine 50-100mcg boluses
• Metaraminol 0.5mg boluses
• Mephentermine 3-5 mg boluses
• IV Fluids
2. Symptoms and signs: Tingling of hand with progressive weakness of hand grip
Root levels: C 6-8
System affected: Arms and hands, Accessory muscles of respiration
Management:
• Reassure patient
• Reverse Trendelenburg position in spinal block
• Stop local anaesthetic injection in epidural top up
3. Symptoms and signs: Difficulty in breathing, Difficulty in speaking, Desaturation
Root levels: C 3-5
System affected: Shoulder weakness, Diaphragmatic innervation involved
Management:
• Assess airway
• Oxygen supplementation
• May require intubation and ventilation
4. Symptoms and signs: Slurring of speech,Sedation, Loss of consciousness
Root levels: Intracranial spread
Management:
• Call for help
• Airway, Breathing, Circulation (ABC)approach
• RSI with intubation and ventilation
• Circulatory support with sympathomimetics or vasopressors
• Epinephrine boluses of 50-100mcg may be required if persistent hypotension.
• Foetal monitoring
