What if a patient still has no motor function of toes 30 hours after receiving bupivacaine (local anesthetic)?

Management of Persistent Motor Block of Toes 30 Hours After Bupivacaine Administration

A patient with no motor function of toes 30 hours after receiving bupivacaine requires urgent neurological assessment and imaging to rule out serious complications such as epidural hematoma, as this duration significantly exceeds normal recovery timeframes and requires immediate medical attention.

Normal Recovery Timeline vs. Prolonged Block

• Normal recovery of sensorimotor block after neuraxial anesthesia with bupivacaine typically takes 2-3 hours for intrathecal administration and 3-5 hours for epidural administration 1
• While rare cases of unexpectedly prolonged blocks lasting 24-48 hours can occur without explanation, persistent motor block at 30 hours is concerning and should trigger immediate evaluation 1
• The Association of Anaesthetists and Obstetric Anaesthetists' Association recommends assessment of straight-leg raising ability at 4 hours post-administration as a screening tool for normal recovery 1

Immediate Assessment Required

• The anaesthetist should be called immediately to perform a full neurological assessment using the Bromage scale to document the extent of persistent motor block 1
• Assessment should include:
  • Detailed sensory examination to map the distribution of sensory deficit 1
  • Motor strength testing of all lower extremity muscle groups 1
  • Assessment for other neurological symptoms including back pain, radicular pain, or bladder/bowel dysfunction 1

Urgent Diagnostic Workup

• Urgent MRI of the spine is the preferred imaging modality and should be performed without delay to rule out epidural hematoma or abscess 1
• Epidural hematoma can cause irreversible neurological damage if not evacuated within 8-12 hours of symptom onset 1
• Delayed detection of symptoms may be exacerbated by delays in clinical diagnosis and referral for appropriate imaging, especially in busy units and out of hours 1

Risk Factors to Assess

• Evaluate for risk factors that increase likelihood of complications:
  • Coagulopathy or use of anticoagulant drugs 1
  • Multiple attempts at neuraxial block with bleeding 1
  • Pre-existing spinal pathology such as spinal stenosis 1
  • Sepsis or signs of infection 1

Management Algorithm

1. Immediate consultation with anesthesiology and neurology/neurosurgery 1
2. Urgent MRI imaging of the spine (do not delay for progressive symptoms) 1
3. If epidural hematoma is identified, emergency surgical decompression should be arranged 1
4. If no compressive lesion is found but symptoms persist:
   • Continue neurological monitoring 1
   • Consider neurological consultation for electromyography and nerve conduction studies 2
   • Document motor function using the Bromage scale (1=complete block, 4=no block) 1

Potential Causes to Consider

• Epidural/spinal hematoma requiring urgent surgical decompression 1
• Epidural abscess (though typically develops over several days) 1
• Direct trauma to nerve roots from needle or catheter 1
• Local anesthetic toxicity to neural tissues 3
• Spinal cord ischemia from prolonged hypotension 1
• Cauda equina syndrome 1
• Prolonged effect of local anesthetic (rare but reported) 1

Documentation and Follow-up

• Document all findings thoroughly, including time course of symptoms 1
• If no urgent surgical intervention is needed, continue close neurological monitoring 1
• Persistent motor weakness can have significant impact on recovery and healthcare costs 4
• Consider physical therapy consultation for rehabilitation if weakness persists 2

Key Caution

• Do not attribute prolonged motor block solely to expected effects of local anesthetic when duration exceeds 24 hours, as this may delay diagnosis of serious complications 1
• Each unit should have clear guidelines for rapid escalation and referral to achieve prompt investigation, including outside office hours 1