High flow cooled air can decrease brain temperature without injuring the snout or brain in Swine

Introduction: Targeted temperature management plays an important role in the treatment of myriad critical illnesses. Non-invasive, quick-onset options for isolated brain temperature control remain lacking. The goal of this study was to assess the safety and efficacy of a novel intranasal high flow cooled air device using a large animal model. Methods: Yorkshire swine were instrumented with temperature probes in the rectum, brain, ear, and snout, and a novel intranasal cooled air device was applied to half. The primary outcome was effectiveness of brain and snout cooling by the study device. Secondary outcomes included tympanic cooling and absence of rectal cooling, CT, CT perfusion, and histologic evidence of injury in the short- and medium-term. Results: 10 animals (54.7 kgs.+/- 19.4 SD) underwent non-survival evaluation, 3 underwent delayed evaluation (56.1 kgs.+/-6.4). From baseline to cooling period, intranasal (38.1 °C vs. 34.9 °C, p = 0.01), intracranial (38.6 °C vs. 37.2 °C, p = 0.01) and tympanic temperatures (38.3 °C vs. 37.5 °C, p = 0.01) decreased, while rectal temperature remained unchanged. After cooling, nasal temperature (34.9 °C vs. 37.6 °C, p = 0.004) and intracranial temperatures (37.2 °C vs. 37.9 °C, p = 0.01) increased. Rectal temperatures remained unchanged. A mixed effects model showed association between temperature and study period (p<0.0001), temperature and probe location (p = 0.002), with interaction between study period and probe location (p<0.0001). There was no evidence of injury to the snout or CT cerebral perfusion metrics, or in histologic end points. Conclusion: This novel, non-invasive, intranasal high flow cooled air device provides isolated brain and head cooling without any evidence injury in the short or medium term.