C. Madl et al., Improved outcome prediction in unconscious cardiac arrest survivors with sensory evoked potentials compared with clinical assessment, CRIT CARE M, 28(3), 2000, pp. 721-726
Objective: To compare the prognostic ability of sensory evoked potentials i
n cardiac arrest survivors with the outcome predicted by a panel of experie
nced emergency physicians based on detailed prehospital, clinical, and labo
ratory data.
Design: Inception cohort study.
Setting: Medical intensive care unit and department of emergency medicine a
t a university hospital.
Patients: A total of 162 unconscious, mechanically ventilated patients who
survived greater than or equal to 24 hrs after resuscitation from cardiac a
rrest.
Interventions: Recording of sensory evoked potentials and outcome predictio
n after review of detailed clinical and laboratory data by emergency physic
ians within 24 hrs after cardiac arrest.
Measurements and Main Results: At 6 months, the outcome of 36 patients was
classified as favorable and 126 patients were rated as poor. After review o
f prehospital data, emergency physicians predicted favorable vs. poor outco
me with a sensitivity of 70% and a specificity of 65%. After additional ass
essment of data 1 hr after cardiac arrest, the sensitivity of emergency phy
sician predictions increased to 80%, whereas the specificity decreased to 4
8%. Outcome prediction by emergency physicians was mast accurate after obta
ining detailed patient data 24 hrs after cardiac arrest (sensitivity, 81%;
specificity, 58%). In 35 of 36 patients with favorable outcomes, the cortic
al evoked potential N70 peak was detected between 72 and 128 msec. Of 113 p
atients with an N70 peak latency >130 msec or an absent N70 peak, all excep
t one had a poor outcome. By using a cutoff of 130 msec, the N70 peak laten
cy alone had a sensitivity of 94% and a specificity of 97%. The predictive
accuracy of the N70 peak latency was significantly higher than the clinical
assessment 24 hrs after cardiac arrest (91% vs. 76%, p = .0003).
Conclusion: In unconscious cardiac arrest survivors, a recording of long-la
tency sensory evoked potentials is more accurate in predicting individual o
utcome than an emergency physician review of clinical data.