Somatosensory evoked potentials during mild hypothermia after cardiopulmonary resuscitation

Neurology. 2009 Nov 3;73(18):1457-61. doi: 10.1212/WNL.0b013e3181bf98f4.


Objective: In patients who remain in a coma after cardiopulmonary resuscitation (CPR), the bilateral absence of cortical N20 responses of median nerve somatosensory evoked potentials (SSEP) 24 hours after admission invariably correlates with a poor neurologic outcome. Nowadays, CPR patients are treated with mild hypothermia, with simultaneously administered sedative drugs, hampering clinical neurologic assessment. We investigated whether SSEP performed during hypothermia can reliably predict a poor neurologic outcome.

Methods: Between July 2006 and April 2008, this multicenter prospective cohort study included adult comatose patients admitted after CPR and treated with induced mild hypothermia (32-34 degrees C). SSEP was performed during hypothermia, and in patients who remained comatose after rewarming, a second SSEP was performed. Neurologic outcome was assessed 30 days after admission with the Glasgow Outcome Scale.

Results: Seventy-seven consecutive patients were included in 2 hospitals. In 13 patients (17%), the cortical N20 response during hypothermia was bilaterally absent. In 9 of these 13 patients in whom SSEP could be repeated during normothermia, the N20 response was also absent, yielding a positive predictive value of 1.00 (95% confidence interval [CI] 0.70-1.00). All 13 patients with absent SSEP during hypothermia had a poor neurologic outcome, yielding a positive predictive value of 1.00 (95% CI 0.77-1.00).

Conclusions: The results of this pilot study show that bilaterally absent cortical N20 responses of median nerve somatosensory evoked potentials performed during mild hypothermia after resuscitation can predict a poor neurologic outcome. We started a larger multicenter prospective cohort study to confirm these results.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cardiopulmonary Resuscitation*
  • Coma / physiopathology*
  • Confounding Factors, Epidemiologic
  • Evoked Potentials, Somatosensory*
  • Female
  • Humans
  • Hypothermia, Induced* / adverse effects
  • Male
  • Median Nerve / physiopathology
  • Middle Aged
  • Pilot Projects
  • Predictive Value of Tests
  • Prospective Studies
  • Recovery of Function
  • Severity of Illness Index
  • Time Factors
  • Treatment Outcome