Anesthesia Considerations 

Autonomic Hyperreflexia

 

 

Background 

 

• Spinal cord injury above T6

• Frequency variable: 20-70% of patients

• Above lesion: reflex bradycardia & vasodilation (flushed) 

• Below lesion: unopposed sympathetic stimulation (vasoconstriction/hypertension)  

• Common clinical manifestations:

  • Headache, diaphoresis,↑ BP, bradycardia

  • Flushing, piloerection, blurred vision, nasal obstruction, anxiety, nausea

• Consequences of event:

  • Bradycardia, AV block, PACs, PVCs 

  • Severe headache, seizures, subarachnoid hemorrhage, ↓ level of consciousness

  • Dyspnea, LV failure, pulmonary edema

  • Blurred vision 

  • Anxiety, agitation 

  • Chest pain/myocardial ischemia 

 

 

Considerations 

 

• Potential for hypertensive emergency with end-organ damage 

• Considerations of chronic SCI 

• Need for invasive monitoring 

• Difficult to assess success of neuraxial technique 

 

 

Management 

 

• Discussion with surgeon regarding plan for procedure 

• Remove potential triggers (e.g., full bladder, foley insertion, full rectum, surgical stimulus) 

• General anesthetic vs neuraxial technique (if GA, consider a deep anesthetic)

• Management of hypertensive event:

  • Consider deepening level of anesthesia if under GA 

  • If epidural, consider top-up 

  • Treat severe hypertension with fast-acting titratable agents:

    • Nitroprusside 0.5-3mcg/kg/min or nitroglycerin 5-200mcg/min

    • Hydralazine 10-20mg IV prn 

    • Phentolamine 5mg IV prn 

    • Look for evidence of end-organ involvement & treat accordingly 

 

 

Pregnancy Considerations 

 

• Multidisciplinary discussion regarding plan for labor & delivery 

• Consider scheduled elective cesarean section

• If vaginal delivery:

  • Admit early to monitored bed with telemetry 

  • Need continuous BP monitoring with arterial line 

  • Remove all preventable triggers of autonomic hyperreflexia (vaginal exams, full bladder = foley insertion) 

  • Start early epidural to prevent hypertensive episodes from contractions 

  • Difficult to assess success of epidural:

    • May need larger test dose to rule out subarachnoid placement 

    • Chestnut suggests two ways to assess level of epidural

      1. Sensory block cephalad to level of spinal cord lesion 

      2. Evaluating segmental reflexes below level of the lesion: lightly stroke each side of the abdomen above & below the umbilicus, looking for contraction of the abdominal muscles & deviation of the umbilicus toward the stimulus (reflexes are absent below the level of the block)

• If cesarean delivery:

  • Either general anesthetic or neuraxial technique:

    • Must have arterial line

    • Vasodilators drawn up & ready 

    • Succinylcholine contraindicated

    • Severe respiratory insufficiency or technical difficulties with neuraxial anesthesia may necessitate the use of general anesthesia