Prediction of Poor Outcome in Comatose Survivors after Cardiopulmonary Resuscitation with Somatosensory Evoked Potentials and Proton Magnetic Resonance Spectroscopy

PURPOSE: The study was conducted to examine the usefulness of somatosensory evoked potentials (SEP) and proton magnetic resonance spectroscopy (1H-MRS) in predicting poor outcomes for comatose survivors after cardiopulmonary resuscitation. METHODS: We investigated 36 patients who were comatose after cardiac arrest. Among them, 35 had short latency SEP, and 27 had 1H-MRS. Both tests were performed in 26 patients. To estimate the cerebral outcome, we used the cerebral performance category (CPC) to classify the outcomes for our patients as good (CPC 1-2) or poor (CPC 3-5). RESULTS: Of the 36 patients, 11(31%) presented with good outcomes (CPC 1-2). A bilaterally absent N20 peak (n=35) predicted poor outcomes with a sensitivity of 54.2% and a specificity of 100%. A lactate-positive resonance (n=27) predicted poor outcomes with a sensitivity of 78.9% and a specificity of 100%. Using a combination of a bilaterally absent N20 peak and a lactate-positive resonance (n=26) predicted poor outcomes with a sensitivity of 94.4% and a specificity of 100%. CONCLUSION: The combination of a bilaterally absent N20 peak and a lactate-positive resonance is better than either alone in predicting poor outcomes in patients who are comatose after cardiac arrest.

The Usefulness of Proton Magnetic Resonance Spectroscopy in Comatose Patients after Successful Cardiopulmonary Resuscitation

PURPOSE: The objective of this study was to investigate whether proton magnetic resonance spectroscopy (1H-MRS) is useful in the prediction of the neurological outcome for comatose patients after successful cardiopumonary resuscitation (CPR). METHODS: We prospectively studied 22 patients with a comatose mentality existing for longer than 1 day after cardiac arrest. 1H-MRS examinations were scheduled to be performed within 5 days after restoration of spontaneous circulation (ROSC). All 1H-MRS readings were performed by a neuro-radiologist blindly. The best cerebral performance category (CPC) during 6 months after ROSC was used as the final outcome and classified as good (CPC 1-2) or poor (CPC 3-5). RESULTS: Elevated cerebral lactate resonances were found in 14 patients. All of the 14 lactate-positive patients experienced a poor outcome. Five of the 8 lactate-negative patients recovered without neurologic defects, but three of them suffered from severe neurologic defects. The elevated cerebral lactate resonance distinguished between good out-comes (n=5) and poor outcomes (n=17) with three false negatives (sensitivity 82%) and no false positives (specificit y 100%). Demonstration of brain lactate in 1H-MRS (p < 0.05) proved to be significant in terms of a poor prognosis. CONCLUSION: 1H-MRS is of great benefit in the prognostic evaluation of comatose patients with anoxic-ischemic encephalopathy after successful CPR.