The Relationship between EEG Findings and Prognosis in Out-of-Hospital Cardiac Arrest Patients during Therapeutic Hypothermia

PURPOSE: Prediction of neurologic outcome in survivors after cardiac arrest is difficult. In particular, since therapeutic hypothermia has emerged as the standard treatment for post cardiac arrest syndrome, the prediction has been more difficult. Methods for prediction of neurologic prognosis include the general neurologic examination, SSEPs, EEG, serum biomarkers, and so on. Among these, EEG was recommended for detection of non-convulsive seizure since early phase of post cardiac arrest syndrome. However, the relationship between EEG finding and neurologic outcome is not yet clear. METHODS: We conducted a retrospective observational study using a prospectively collected hypothermia database. We collected EEG findings during hypothermia and other data from January 2010 to December 2012. The EEG findings were classified according to five patterns as extremely low voltage, continuous slow wave, burst suppression, status epilepticus, and other. We analyzed the relationship between EEG pattern and one-month CPC score after cardiac arrest. RESULTS: During the study period, 121 patients were enrolled in the hypothermia database. Among these patients, 84 patients underwent EEG during hypothermia and were enrolled. The EEG patterns of enrolled patients were 20 extremely low voltage, 39 generalized slow wave, 15 burst suppression, 8 status epilepticus, and 2 alpha coma. None of the periodic, status eplilepticus, and alpha coma pattern patients showed a good neurologic outcome (CPC 1 or 2). Two of 20 extremely low voltage and 28 of 39 continuous slow wave pattern patients recovered to good neurologic outcome. CONCLUSION: Burst suppression and status epilepticus EEG pattern during hypothermia treatment showed an association with poor neurologic outcome.

The Relationship between EEG Findings and Prognosis in Out-of-Hospital Cardiac Arrest Patients during Therapeutic Hypothermia

PURPOSE: Prediction of neurologic outcome in survivors after cardiac arrest is difficult. In particular, since therapeutic hypothermia has emerged as the standard treatment for post cardiac arrest syndrome, the prediction has been more difficult. Methods for prediction of neurologic prognosis include the general neurologic examination, SSEPs, EEG, serum biomarkers, and so on. Among these, EEG was recommended for detection of non-convulsive seizure since early phase of post cardiac arrest syndrome. However, the relationship between EEG finding and neurologic outcome is not yet clear. METHODS: We conducted a retrospective observational study using a prospectively collected hypothermia database. We collected EEG findings during hypothermia and other data from January 2010 to December 2012. The EEG findings were classified according to five patterns as extremely low voltage, continuous slow wave, burst suppression, status epilepticus, and other. We analyzed the relationship between EEG pattern and one-month CPC score after cardiac arrest. RESULTS: During the study period, 121 patients were enrolled in the hypothermia database. Among these patients, 84 patients underwent EEG during hypothermia and were enrolled. The EEG patterns of enrolled patients were 20 extremely low voltage, 39 generalized slow wave, 15 burst suppression, 8 status epilepticus, and 2 alpha coma. None of the periodic, status eplilepticus, and alpha coma pattern patients showed a good neurologic outcome (CPC 1 or 2). Two of 20 extremely low voltage and 28 of 39 continuous slow wave pattern patients recovered to good neurologic outcome. CONCLUSION: Burst suppression and status epilepticus EEG pattern during hypothermia treatment showed an association with poor neurologic outcome.

Effect of Hydrogel Pad and Conventional Method on the Induction Time of Therapeutic Hypothermia in Patients with Out-of-Hospital Cardiac Arrest / 대한구급학회지

BACKGROUND: Therapeutic hypothermia has been recommended as a standard treatment of cardiac arrest patients after return of spontaneous circulation. There are various methods to drop patient's core body temperature below 33.5degrees C. We compared the cooling rate of the conventional cooling method using cold saline bladder irrigation with the commercial hydrogel pad in out-of-hospital cardiac arrest (OHCA) patients. METHODS: We collected data retrospectively from the Samsung Medical Center hypothermia database. The conventional method group was cooled with IV infusion of 2,000 ml of 4degrees C cold saline and cold saline bladder irrigation. Patients in the hydrogel pad group had their body temperature lowered with the Artic Sun(R) after receiving 2,000 ml of 4degrees C cold saline intravenously. The induction time was defined as time from cold saline infusion to the esophageal core temperature below 33.5degrees C. The esophageal temperature probe insertion to the target temperature time (ET to target BT time) was defined as the time from the esophageal probe insertion to the core temperature below 33.5degrees C. We compared these times and cooling rates between the two groups. RESULTS: Eighty one patients were enrolled. Fifty seven patients were included in the hydrogel pad group and 24 patients were in the conventional group. There were no statistical differences of baseline characteristics between the two groups. The induction time of the conventional group (138 min., IQR 98-295) was shorter than that of the hydrogel pad group (190 min., IQR 140-250). The ET to target BT time of the conventional group (106 min., IQR 68-249) was shorter than that of the hydrogel pad group (163 min., IQR 108-222). The cooling rate of the conventional group (0.93degrees C/hr., IQR 0.58-2.08) was lower than that of the hydrogel pad group (1.05degrees C/hr., IQR 0.74-1.96). However, there were no statistical differences in the induction time, the ET to target BT time and the cooling rate between the two groups. CONCLUSIONS: There was no significant statistical difference of the cooling rate of the hydrogel pad and conventional method on the induction time of therapeutic hypothermia in Patients with OHCA. The conventional cooling method can be used as an effective and efficient way to lower OHCA patient's core body temperature during the induction phase of therapeutic hypothermia.