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Published on: March 3, 2021
Exploratory Study of Selective Brain Hypothermia Using Transnasal Evaporative Cooling Under Controlled Normothermia
Mitsuaki Nishikimi1,2, Kazuya Kikutani1, Mayumi Higashi1
1Department of Emergency and Critical Care Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8551, Japan.
Introduction:
Selective brain hypothermia has been investigated to improve neurological outcomes in patients with cardiac arrest; however, an optimal clinical method has not yet been established. This study aimed to evaluate the feasibility of a technique combining transnasal evaporative cooling with simultaneous endovascular temperature management to achieve selective brain hypothermia while preventing systemic hypothermia.
Methods:
Three adult male Göttingen swine were anesthetized and mechanically ventilated. Transnasal cooling was initiated at maximum output while endovascular warming preserved systemic temperature. Brain parenchymal and rectal temperatures, mean arterial pressure (MAP), heart rate (HR), and cardiac output (CO) were continuously monitored for 60 min. Temperature differences between brain and rectum at 60 min were analyzed.
Results:
A brain-rectal gradient ≥1.0 °C was achieved in all swine at 25, 40, and 30 min, respectively, and maintained at 1.0-1.5 °C thereafter. Brain temperature (34.5 ± 0.34 °C) was significantly lower than rectal temperature (35.8 ± 0.35 °C) at 60 min after initiation of the selective cooling procedure (p = 0.0048). MAP, HR, and CO showed no deviations from baseline.
Conclusions:
The combination of transnasal cooling and endovascular warming reliably induced selective brain hypothermia of 1-1.5 °C without adverse effects on hemodynamic parameters in swine.
