Complications of Regional Anesthesia

Complications of Regional Anesthesia

Complications of Regional Anesthesia

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Overview & Classification - The Initial Rundown

Complications are classified by:

  • Scope of Effect:
    • Systemic: Affecting entire body (e.g., LAST, high spinal).
    • Local: At injection site (e.g., nerve injury, hematoma).
  • Timing of Onset:
    • Immediate: During or soon after block.
    • Delayed: Hours to weeks later.

Common risk factors (📌 PPA):

  • Patient: Coagulopathy, pre-existing neuropathy, systemic illness.
  • Procedure: Technique, multiple attempts, needle type.
  • Anesthetic: Drug choice, total dose, vasoconstrictors.

⭐ Most complications are preventable with meticulous technique and careful patient selection.

Local Anesthetic Systemic Toxicity (LAST) - When LAs Go Rogue

  • Definition: Systemic adverse reaction due to high blood concentrations of local anesthetic.
  • Pathophysiology: Dose-dependent Na+ channel blockade in CNS & cardiovascular system (CVS).
  • Susceptible LAs: Bupivacaine > Ropivacaine > Lidocaine (potency & cardiotoxicity).
  • CNS Symptoms:
    • Early: Tinnitus, metallic taste, perioral numbness, dizziness, visual disturbances, muscle twitching, agitation.
    • Late: Seizures, unconsciousness, coma, respiratory arrest.
    • 📌 Mnemonic for CNS signs (LAST): Lips numb/tingling, Agitation/Auditory changes, Seizures/Slurred speech, Twitching.
  • CVS Symptoms: Initial hypertension/tachycardia → bradycardia, hypotension, ventricular arrhythmias (VT/VF), asystole, cardiac arrest.
  • Risk Factors:
    • High dose or rapid injection.
    • Site of injection (vascularity): IV > Tracheal > Intercostal > Caudal > Epidural > Brachial plexus > Sciatic/Femoral > Subcutaneous.
    • Patient factors: Extremes of age, pregnancy, cardiac/hepatic/renal dysfunction, low protein.
  • Prevention:
    • Use lowest effective dose.
    • Aspirate before & during injection.
    • Incremental injection (3-5 mL, wait 15-30s).
    • Ultrasound guidance.
    • Test dose for epidurals.
    • Adhere to maximum recommended doses (e.g., Bupivacaine ~2 mg/kg).
  • Management:
    • STOP LA injection immediately.
    • Call for help (get LAST kit).
    • ABCs: Maintain Airway (100% O2), ensure adequate Breathing (ventilate if needed), support Circulation.
    • Seizure control: Benzodiazepines (e.g., Midazolam 0.05-0.1 mg/kg IV). Avoid large doses of propofol if CVS unstable.
    • Lipid Emulsion Therapy (Intralipid 20%): Administer at first sign of severe LAST (arrhythmias, refractory seizures, rapid progression).
      • Bolus: 1.5 mL/kg (lean body mass) over 1 minute.
      • May repeat bolus 1-2 times for persistent CVS instability.
      • Infusion: 0.25 mL/kg/min.
      • Continue infusion for at least 10 minutes after hemodynamic stability.
      • Maximum total dose: approx. 10-12 mL/kg in the first 30 minutes.

⭐ Lipid emulsion therapy (Intralipid 20%) is a critical and specific antidote for severe Local Anesthetic Systemic Toxicity (LAST).

LA Injection Sites & LAST Risk

Neurological Complications (PDPH, Nerve Injury, CES, TNS) - Brain & Nerve Blues

  • Post-Dural Puncture Headache (PDPH)

    • Patho: CSF leak → ↓ICP.
    • Symptoms: Postural headache (↑upright), neck stiffness, nausea, photophobia, tinnitus.
    • Risk Factors: 📌 NEEDLE: Needle (large/cutting Quincke 22G > pencil-point Whitacre 27G), Experience↓, Earlier PDPH, Dural punctures (multiple), Low CSF (young, female, pregnancy).
    • Prevention: Small (25-27G), pencil-point (Whitacre, Sprotte); bevel parallel dural fibers.
    • Treatment: Conservative (hydration, analgesics, caffeine); Epidural Blood Patch (EBP).

    ⭐ Pencil-point needles (Whitacre, Sprotte) ↓ PDPH vs. cutting (Quincke). Spinal Needles: Pencil-Point vs. Cutting & CSF Leak

  • Direct Nerve Injury

    • Mechanism: Needle trauma, intraneural injection, LA neurotoxicity.
    • Symptoms: Persistent paresthesia, motor/sensory deficit.
    • Prevention: Ultrasound, nerve stimulator; avoid injection on paresthesia/high pressure.
  • Cauda Equina Syndrome (CES) ⚠️

    • Symptoms: 📌 SADDLE: Saddle anesthesia, Anal tone↓, Dysfunction (bowel/bladder), Lower limb weakness, Emergency.
    • Causes: High LA conc., maldistribution, hematoma. (Old: microcatheters).
  • Transient Neurological Symptoms (TNS)

    • Symptoms: Buttock/lower limb pain/dysaesthesia post-spinal.
    • LA: Lidocaine. Self-limiting.

Hematoma, Infection & Catheter Issues - Site-Specific Setbacks

  • Spinal/Epidural Hematoma: Neurological emergency!
    • Risks: Coagulopathy, anticoagulants (check specific timing guidelines!), traumatic tap, indwelling catheter.
    • Symptoms: 📌 PAIN (Progressive deficit, Acute onset, Incontinence, Numbness), severe back/radicular pain, progressive motor/sensory deficits, bowel/bladder dysfunction.
    • Dx: Urgent MRI.
    • Rx: Neurosurgical consultation for decompressive laminectomy within 8-12 hours.
  • Infection (Epidural Abscess, Meningitis):
    • Risks: Poor asepsis, immunocompromise, prolonged catheterization.
    • Sx: Fever, localized back pain/tenderness, erythema, neuro deficits.
    • Dx: MRI, CSF analysis. Rx: Antibiotics, surgical drainage (if abscess).
  • Catheter Issues: Breakage, knotting, migration, occlusion, shearing.
  • Allergic Reactions: Rare with amides; esters (PABA metabolite) more common.
  • Backache: Common, usually musculoskeletal, transient. MRI: Epidural Hematoma vs. Epidural Abscess

⭐ Spinal epidural hematoma is a neurological emergency requiring prompt diagnosis (MRI) and surgical decompression, ideally within 8-12 hours, to maximize chances of neurological recovery.

High‑Yield Points - ⚡ Biggest Takeaways

  • LAST: CNS excitation (seizures) then depression, CVS toxicity (arrhythmias). Treat with lipid emulsion.
  • PDPH: Postural headache, worse upright. Epidural blood patch for severe, persistent cases.
  • Nerve Injury: Paresthesia, motor deficits from direct trauma, hematoma, or chemical irritation.
  • Epidural Hematoma/Abscess: Back pain, fever, progressive neurological deficits. Urgent MRI and intervention.
  • Total Spinal Anesthesia: Apnea, profound hypotension, unconsciousness. Immediate airway management.
  • Pneumothorax: Risk with supraclavicular/intercostal blocks. Sudden dyspnea, chest pain.

Practice Questions: Complications of Regional Anesthesia

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A patient is brought to the emergency following a head-on collision road traffic accident. His BP is 90/60 mmHg. Tachycardia is present. Most likely diagnosis is

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Flashcards: Complications of Regional Anesthesia

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The insertion and use of catheters for continuous spinal anesthesia _____ increase the risk of PDPH

TAP TO REVEAL ANSWER

The insertion and use of catheters for continuous spinal anesthesia _____ increase the risk of PDPH

does not (does/does not)

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