Purpose: In 2015, a new medical device designed to perform targeted temperature management (TTM) through the esophagus became available to the European market. The device was originally approved for 36h duration, but in 2016 the approval was expanded to 120h. The purpose of this study is to evaluate device performance and user experience in extended duration cases.
Materials and methods: Patient records indicating treatment using an esophageal heat transfer device (EnsoETM, Attune Medical [formerly Advanced Cooling Therapy], Chicago, IL) for at least 72h and core temperature readings recorded at least every 4h were identified at three clinical sites. Deidentified clinical data were pooled for statistical analysis and clinicians at participating sites completed a short phone interview about user experience. Temperature readings were plotted on a control chart to visualize whether they remained within +/- 1°C of target. User feedback was transcribed and subjected to content analysis. 
Results: 18 records were included, providing 1237 data points for analysis. Indications for temperature management in this cohort included treatment with hypothermia post cardiac arrest and refractory fever control. The average treatment duration was 137.7h (range 72h- 452h) and the target temperature ranged from 33-38°C. Across all treatment scenarios, 81% (996) of measures were within +/- 1°C of goal. User feedback indicated that the device was placed quickly (insertion steps were completed in under 3 minutes), the device was unobtrusive during transport and imaging, and no injury to the esophagus was reported.
Conclusion: This initial analysis suggests that esophageal heat transfer meets the needs of extended duration target temperature management protocols. Additional research is needed to confirm anecdotal reports conveyed during user interviews, such as reduced shivering burden and reduced sedation.

An Evaluation of Esophageal Temperature Management in Cases Longer than 72h