FRCA Notes

Regional Anaesthesia in the Anticoagulated Patient

This topic isn't explicitly mentioned in the curricula, but presumably falls under the auspices of knowing the 'risks...and contraindications of regional blockade'.

Neuraxial anaesthesia in those receiving thromboprophylaxis has come up as part of two CRQs on venous thromboembolism.

Resources

  • Patients with abnormalities of coagulation, typically due to antiplatelet and/or anticoagulant drugs, are relatively common
  • Although this cohort may be most likely to benefit from regional techniques, the decision to proceed must be individualised and balance:
    • The increased risk of complications of regional/neuraxial anaesthesia in those receiving anti-platelet/-coagulant medications, including drug cessation
    • The benefit to the patient with respect to their comorbidities, the planned procedure and the risks of alternatives

  • NB the recommendations replicated in the tables below are from the AAGBI guidance, as this is both applicable to UK practice and the FRCA exams
  • There are separate and subtly different guidelines from both ASRA and ESRA (see links above)
  • Where a drug is not covered by the AAGBI Guidance, it is denoted by an asterisk (e.g. cilostazol*) and the ASRA guidance used instead

Vertebral canal haematoma

  • A potentially catastrophic complication of neuraxial anaesthesia
  • May lead to paraplegia unless urgent diagnosis and intervention (within 8-12hrs) occurs

  • Epidemiology
    • Overall rare e.g. 1 in 117,000 neuraxial blocks in NAP3
    • More common in obstetric patients receiving epidural analgesia 1 in 168,000-200,000
    • More common still in those undergoing epidural or CSE for perioperative analgesia e.g. 1 in 16,000

  • Risk factors which increase the risk of haemorrhagic complications include:
    • Female gender
    • Age >65yrs
    • History of easy bruising or excessive surgical bleeding
    • Spinal column abnormalities e.g. spinal stenosis, scoliosis
    • Renal insufficiency
    • Epidural/CSE (vs. spinal)

Peripheral nerve block techniques

  • There's little evidence for the incidence of haemorrhagic complications after peripheral nerve or plexus blocks
  • One review found it to be 0.6%, although the external validity is poor
  • Trends from the evidence suggest:
    • Anticoagulant medication increases risk of haemorrhagic complication following peripheral nerve block (unsurprisingly)
    • The greatest risk is from deeper blocks (e.g. lumbar plexus block, proximal sciatic nerve approaches)
    • The complications seem to mostly arise due to blood loss rather than neurological damage, and there is often no evidence of vessel trauma
    • Neurological deficit following haemorrhagic complication completely recovered in all patients by 12 months
    • If complications do arise they tend to lead to hospitalisation, and often a prolonged or complicated stay


Antiplatelet agent Time to neuraxial block after cessation Administration with neuraxial catheter in situ Time to dose after block or catheter removal
NSAIDs No additional precautions No additional precautions No additional precautions
Aspirin No additional precautions No additional precautions No additional precautions
Clopidogrel 7 days Not recommended 6hrs
Prasugrel 7 days Not recommended 6hrs
Ticagrelor 5 days Not recommended 6hrs
Cangrelor* 3hrs Not recommended 8hrs
Ticlopidine* 10 days Acceptable for 1-2 days but no loading Immediately, or loading dose after 6hrs
Abciximab 48hrs Not recommended 6hrs
Tirofiban 8hrs Not recommended 6hrs
Eptifibatide 8hrs Not recommended 6hrs
Dipyridamole No additional precautions No additional precautions 6hrs
Cilostazol* 2 days Not recommended 6hrs



Heparinoid agent Time to neuraxial block after cessation Administration with neuraxial catheter in situ Time to dose after block or catheter removal
Unfractionated heparin (SC) 4hrs (prophylactic dose) or normal APTTr Caution 1hr
Unfractionated heparin (IV) 4hrs (treatment dose) or normal APTTr Caution ± follow local guidelines 4hrs
LMWH (prophylactic dose) 12hrs Caution 4hrs
LMWH (treatment dose) 24hrs Not recommended 4hrs (24hrs if traumatic block)
Fondaparinux (prophylactic dose) 36 - 42hrs + consider anti-Xa levels Not recommended 6 - 12hrs
Fondaparinux (treatment dose) Avoid + consider anti-Xa levels Not recommended 12hrs
Danaparoid Avoid + consider anti-Xa levels Not recommended 6hrs
Danaparoid 4hrs or normal APTTr Not recommended 6hrs
Bivalirudin 10hrs or normal APTTr Not recommended 6hrs
  • For higher doses of UH may be prudent to wait 12hrs or 24hrs if greater daily doses (>10,000units or >20,000units respectively) are being given
  • ASRA guidance also recommend a platelet count if patient has received >4 days of UH via any route to check for HIT


Anticoagulant agent Time to neuraxial block after cessation Administration with neuraxial catheter in situ Time to dose after block or catheter removal
Rivaroxiban (prophylactic dose) 18hrs (if CrCl >30ml/min) Not recommended 6hrs
Rivaroxiban (treatment dose) 48hrs (if CrCl >30ml/min) Not recommended 6hrs
Edoxaban* <72hrs + consider anti-Xa levels/td> Not recommended 6hrs
Apixaban 24 - 48hrs Not recommended 6hrs
Dabigatran CrCl >80ml/min: 48hrs
CrCl 50-80ml/min: 72hrs
CrCl 30-50ml/min: 96hrs 		Not recommended 6hrs
Warfarin INR ≤1.4 Not recommended After catheter removal
Thrombolytics 10 days Not recommended 10 days


  • In general, one should consider the risk vs. benefit of peripheral nerve block techniques in the individual patient
  • Ultrasound guidance is recommended (/mandatory)
  • Catheter techniques are likely to be higher risk including risk with catheter removal
  • AAGBI guidelines grade peripheral nerve and plexus blocks according to risk

    • Risk Block category Examples
    Highest Central neuraxial techniques Spinal
    Epidural ± catheter
    ↑ Paravertebral Paravertebral block
    Lumbar plexus block
    Lumbar sympathectomy
    Deep cervical plexus block
    ↑ Deep blocks Coeliac plexus block
    Stellate ganglion
    Proximal sciatic blocks
    Obturator block
    Infraclavicular or supraclavicular BPB
    ↑ Superficial/perivascular Popliteal sciatic
    Femoral nerve
    Intercostal
    Interscalence BPB
    Axillary BPB
    ↑ Fascial blocks Ilio--inguinal
    Ilio-hypogastric
    TAP
    Fascia iliaca
    ↑ Superficial blocks Forearm nerves
    Adductor canal
    Ankle block
    Superficial cervical plexus
    Wrist, digital or Bier's block
    Lowest Local anaesthetic infiltration Wound infiltration

  • ASRA guidelines:
    • Peri-neuraxial, deep plexus or deep peripheral blocks should be managed as per neuraxial block
    • Other regional techniques should be performed in the context of the vascularity and compressibility of the site, and the consequences of bleeding at that site

Patient with a hip fracture

  • 30-40% of patients with neck of femur fractures take anti-platelet or -coagulant medications; 2% take DOACs
  • In some of these patients, the risk of vertebral canal haematoma may be lower than the risk of either GA or delaying surgery
  • Where a senior anaesthetist considers a spinal anaesthetic to be the optimum treatment, any single anti-platelet agent is not an absolute contraindication
  • Dual anti-platelet therapy is also not an absolute contraindication but there must be a compelling reason why GA isn't preferable
  • There are separate guidelines from the AAGBI, which can be found on the neck of femur fracture page

High-risk pain procedures

  • Includes insertion of spinal cord stimulators
  • ASRA guidelines are more aggressive than for central neuraxial block, suggesting aspirin and NSAIDs should be routinely stopped beforehand
  • Other pain procedures e.g. sympathetic blocks are deemed intermediate risk
  • Peripheral nerve blocks and facet joint injections are deemed low risk

Haemophilia

  • Patients usually aware of their disease
  • Seek Haematology advice as to how best normalise coagulation
  • Consider regional anaesthesia carefully

Major trauma and massive transfusion

  • Trauma and major haemorrhage can cause coagulopathy via multiple mechanisms
  • Recommended platelet function (e.g. TEG/ROTEM) is assessed prior to any RA technique

Sepsis

  • May lead to either pro-coagulant state or consumptive coagulopathy
  • Neuraxial techniques relatively contraindicated due to concern re: epidural abscess or CNS infection

Acute and chronic liver failure

  • High-risk group owing to disrupted pro- and anti-coagulant clotting factor balance
  • Require formal assessment of coagulation prior to proceeding

Uraemia

  • Thrombocytopaenia ± reduced platelet function can occur
  • There may also be residual anticoagulation from patients on haemodialysis
  • Need to formally assess platelet function prior to proceeding
  • May need to use ddAVP to improve platelet function

DIC

  • Contraindicates neuraxial techniques
  • Peripheral nerve blocks may be acceptable at compressible sites where there is suitable benefit vs. risk