Anaes · Neuraxial anaesthesia
Epidural anaesthesia and analgesia
Also known as Epidural · Thoracic epidural · Lumbar epidural · Loss of resistance · Epidural test dose · High block · Epidural top-up
Exam-exhaustive epidural anaesthesia: thoracic vs lumbar, loss of resistance, test dose, top-up and failure modes, absolute/relative contraindications, ASRA anticoagulation timing principles, and high/total spinal recognition.
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Red flags
- Sudden dense ascending block after top-up = intrathecal injection until proven otherwise — airway, vasopressors, CPR if needed.
- Severe back pain + progressive deficit after epidural = haematoma/abscess until proven otherwise — urgent MRI and decompression.
- Anticoagulation timing for insertion and catheter removal is non-negotiable (ASRA principles).
- Wet tap with Tuohy = high PDPH risk — document, follow-up, blood patch pathway.
- Unilateral or patchy block is a failure mode — do not keep topping up blindly without assessing catheter function.
Meet the patient
A fit sixty-eight-year-old is listed for an open sigmoid colectomy on an enhanced-recovery pathway, and the plan is a thoracic epidural for postoperative analgesia. He takes aspirin for ischaemic heart disease and his surgeon has charted therapeutic enoxaparin for venous thromboembolism prophylaxis — and the timing of both against your needle and your catheter removal is the conversation that decides whether this block happens at all.[1]
The epidural is the gold standard for dynamic pain after major open abdominal and thoracic surgery and the workhorse of labour analgesia, but it is high-stakes: a high block stops breathing, an unrecognised haematoma paralyses, and a wrong-route injection kills. Every line of technique below exists to prevent one of those three.[1]
References4ShowHide
- [1]Horlocker TT et al. Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Fourth Edition) Reg Anesth Pain Med, 2018.PMID 29561531
- [2]Neal JM et al. The Third American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity: Executive Summary 2017 Reg Anesth Pain Med, 2018.PMID 29356773
- [3]Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults Br J Anaesth, 2015.PMID 26556848
- [4]Thomas JM, Schug SA Recent advances in the pharmacokinetics of local anaesthetics. Long-acting amide enantiomers. Clin Pharmacokinet, 1999.PMID 9989343