Neurogenic shock

Background

  • Do not confuse with Spinal Shock
  • Diagnosis of exclusion
    • Never presume hypotension in trauma patient is due to neurogenic shock
  • Injury to cervical or thoracic vertebrae causes peripheral sympathetic denervation
    • Above T1: full sympathetic denervation
    • T1-L3: Partial sympathetic denervation
    • Below L4: no sympathetic denervation
  • Lasts 1-3 wk

Evaluation

  • Hypotension(well tolerated)
  • Bradycardia
  • Peripherally vasodilated (warm extremities)
    • However, this leads to hypothermia
    • Ensure monitoring of core temperatures and warming of patient

Differential Diagnosis

Shock

Management

  1. Exclude other causes of shock
  2. Supplemental O2 to perfuse injured spinal cord
  3. Mechanical ventilation and oxygenation if spinal perfusion is compromised
    1. Manual in-line stabilization reduces cervical movement better than C-collar, but be careful of tracheal pressures inadvertently applied which can worsen laryngeal visualization[1][2]
    2. Direct laryngoscopy causes C-spine extension at atlanto-occipital junction, C1-C2, and C4-C7 in order from most to least
    3. Consider video laryngoscopy with hyperangulated stylet or bougie assisted DL to intubate higher-grade laryngoscopy views of vocal cords without C-spine overextension[3]
    4. Post-intubation sedation takes into consideration hemodynamics and potential intraoperative EMG and evoked potential monitoring by anesthesia
  4. Prevent hypothermia
  5. Judicious IVF, with UOP > 30 cc/hr
  6. Norepinephrine first line, with MAP goal of 85-90 for the first 5-7 days after spinal cord injury[6]
    1. Consider adding phenylephrine if BP refractory to first line agent
    2. Phenylephrine alone without beta-1 stimulation will cause reflex bradycardia
    3. Atropine if needed, keeping HR 60-100 bpm in NSR
    4. May titrate down on norepinephrine and atropine, to favor more phenylephrine α agonism in ICU setting
  7. High risk of VTE in paraparesis or tetraparesis
    1. Up to 40% in non-prophylaxed
    2. Must weigh benefits of VTE prophylaxis and risk of bleed from LMWH
    3. Low dose SC heparin at 500 units q8hrs plus SCDs may be alternative
  8. Corticosteroid use is controversial, but consider usage in consultation with spine specialist
    1. 2006 survey of ~300 US neurosurgeons revealed ~90% will use them for nonpenetrating traumatic spinal cord injury within 8 hours despite modest evidence[7]
    2. Treatment is not guideline mandatory, however, per the American Association of Neurological Surgeons, which lists methylprednisolone as a treatment option and not standard of care
    3. Methylprednisolone bolus 30 mg/kg over 1 hour, then infusion of 5.4 mg/kg/hr for 23 hours, given within 3-8 hours following injury[8]

References

  1. ↑ The effect of laryngoscopy of different cervical spine immobilisation techniques. Heath KJ. Anaesthesia. 1994 Oct; 49(10):843-5.
  2. ↑ Manual in-line stabilization increases pressures applied by the laryngoscope blade during direct laryngoscopy and orotracheal intubation. Santoni BG, Hindman BJ, Puttlitz CM, Weeks JB, Johnson N, Maktabi MA, Todd MM. Anesthesiology. 2009 Jan; 110(1):24-31.
  3. ↑ Cervical spinal motion during intubation: efficacy of stabilization maneuvers in the setting of complete segmental instability. Lennarson PJ, Smith DW, Sawin PD, Todd MM, Sato Y, Traynelis VC. J Neurosurg. 2001 Apr; 94(2 Suppl):265-70.
  4. ↑ Improvement of motor-evoked potentials by ketamine and spatial facilitation during spinal surgery in a young child. Erb TO, Ryhult SE, Duitmann E, Hasler C, Luetschg J, Frei FJ. Anesth Analg. 2005 Jun; 100(6):1634-6.
  5. ↑ Effects of dexmedetomidine on intraoperative motor and somatosensory evoked potential monitoring during spinal surgery in adolescents. Tobias JD, Goble TJ, Bates G, Anderson JT, Hoernschemeyer DG. Paediatr Anaesth. 2008 Nov; 18(11):1082-8.
  6. ↑ Blood pressure management after acute spinal cord injury. Hadley MN, Walters BC, Grabb PA, Oyesiku NM, Przybylski GJ, Resnick DK, Ryken TC. Neurosurgery. 2002 Mar; 50(3 Suppl):S58-62.
  7. ↑ Questionnaire survey of spine surgeons on the use of methylprednisolone for acute spinal cord injury. Eck JC, Nachtigall D, Humphreys SC, Hodges SD. Spine (Phila Pa 1976). 2006 Apr 20; 31(9):E250-3.
  8. ↑ Steroids for acute spinal cord injury. Bracken MB. Cochrane Database Syst Rev. 2002; (3):CD001046.

See Also

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