Association of time-temperature curves with outcomes in temperature management for cardiac arrest.

Background/Purpose: Cardiac arrest is a common cause of death and neurological injury; therapeutic cooling for neuroprotection is standard of care. Despite numerous and ongoing trials targeting a specified cooling temperature for a target duration, the concept of temperature dose-the duration spent at a given depth of hypothermia-is not as well explored. Methods: In this retrospective study, we examined 66 patients 18 years of age or older undergoing therapeutic hypothermia for cardiac arrest between 2007 and 2010 to assess the relationship of temperature dose with outcomes. Demographic, clinical, outcome and temperature data were collected. Demographic and clinical data underwent bivariate regression analysis for association with outcome. Time-temperature curves were divided into pre-determined temperature thresholds and assessed by logistic regression analysis for association with outcome. A second, multivariate regression analysis was performed controlling for factors associated with poor outcomes. Results: Old age was significantly associated with poor outcome and a shockable arrest rhythm was significantly associated with positive outcome. Subjects spent an average of 2.82 hours below 35°C, 7.31 hours ≥35°C to ≤36.5°C, 24.75 hours >36.5 to <38.0°C and 7.06 hours ≥38°C. Logistic regression analysis revealed borderline significant positive association between good outcome and time at a cooling depth (35°C-36.5°C, p=0.05); adjusted for old age, the association became significant (p=0.04). Conclusion: Controlling for old age, longer durations between >35°C, ≤36.5°C during therapeutic hypothermia for cardiac arrest were significantly associated with good clinical outcomes. Time spent within a given temperature range may be useful for measuring the effect of temperature management.

Use of Subtemporal Electrode Chains and Their Contribution to Presurgical Evaluation.

Subtemporal electrode chains are part of the international 10-10 system. Since 2012, they have been routinely used at our institution in adult patients with intractable epilepsy who are undergoing video EEG evaluation for epilepsy surgery. In 2016, this was extended to the pediatric population. However, there are few data regarding the utility of these electrodes. We performed a retrospective study to investigate the sensitivity and specificity for detection and lateralization of an ictal EEG pattern in patients with temporal lobe epilepsy. Neurophysiologists and EEG technologists were randomly shown samples containing interictal EEG or ictal patterns in standard biploar montage (anterior-posterior bipolar with international 10-20 electrodes only), modified bipolar montage with subtemporal chains, or modified bipolar montage with T1 and T2 electrodes added. Subtemporal chains improved sensitivity compared with standard bipolar, but they also reduced the specificity. T1 and T2 electrodes showed a nonsignificant trend towards improved sensitivity and specificity compared with standard bipolar. There was no difference in sensitivity for correct lateralization among the three montages.