Prehospital transportation to therapeutic hypothermia centers and survival from out-of-hospital cardiac arrest

Computational modeling of targeted temperature management in post-cardiac arrest patients

Our core body temperature is held around [Formula: see text]C by an effective internal thermoregulatory system. However, various clinical scenarios have a more favorable outcome under external temperature regulation. Therapeutic hypothermia, for example, was found beneficial for the outcome of resuscitated cardiac arrest patients due to its protection against cerebral ischemia. Nonetheless, practice shows that outcomes of targeted temperature management vary considerably in dependence on individual tissue damage levels and differences in therapeutic strategies and protocols. Here, we address these differences in detail by means of computational modeling. We develop a multi-segment and multi-node thermoregulatory model that takes into account details related to specific post-cardiac arrest-related conditions, such as thermal imbalances due to sedation and anesthesia, increased metabolic rates induced by inflammatory processes, and various external cooling techniques. In our simulations, we track the evolution of the body temperature in patients subjected to post-resuscitation care, with particular emphasis on temperature regulation via an esophageal heat transfer device, on the examination of the alternative gastric cooling with ice slurry, and on how anesthesia and the level of inflammatory response influence thermal behavior. Our research provides a better understanding of the heat transfer processes and therapies used in post-cardiac arrest patients.

Hospital Variation in the Utilization and Implementation of Targeted Temperature Management in Out-of-Hospital Cardiac Arrest

Background Targeted temperature management (TTM) for out-of-hospital cardiac arrest is associated with improved functional survival and is a class I recommendation in resuscitation guidelines. However, patterns of utilization of TTM and adherence to recommended TTM guidelines in contemporary practice are unknown. Methods and Results In a multicenter, prospective cohort of consecutive adults with non-traumatic out-of-hospital cardiac arrest in the Resuscitation Outcomes Consortium in 2012 to 2015, we identified all adults (≥18 years) who were potential candidates for TTM. Of 37 898 out-of-hospital cardiac arrest patients at 186 hospitals across 10 Resuscitation Outcomes Consortium sites, 8313 survived for ≥4 hours after hospital arrival, of which, 2878 (34.6%) received TTM. Mean age was 61.5 years and 36.3% were women. Median hospital rate of TTM use was 27% (interquartile range [IQR]: 14%, 45%), with an over 2-fold difference across sites after accounting for differences in presentation characteristics (median odds ratio, 2.10 [1.83-2.26]). Notably, TTM utilization decreased during the study period (57.5% [2012] to 26.5% [2015], P<0.001) including among shockable out-of-hospital cardiac arrest (73.4% to 46.3%, P<0.001). When administered, the median rate of deviation from one or more recommended practices was 60% (IQR: 40%, 78%). The median rate for delayed onset of TTM was 13% (IQR: 0%, 25%), varying by 70% for identical patients across 2 randomly chosen hospitals (median odds ratio 1.70 [1.39-1.97]). Similarly, the median rate for TTM <24 hours was 20% (IQR: 0%, 34%) and for achieved temperature <32°C was 18% (IQR: 0%, 39%), with marked variation across sites (median odds ratios of 1.44 [1.18-1.64] and 1.98 [1.62-2.31], respectively). Conclusions There has been a substantial decline in the utilization of TTM with significant variation in its real-world implementation. Further standardization of contemporary post-resuscitation practices, like TTM, is critical to ensure that their potential survival benefit is realized.