Rapid Induction of Therapeutic Hypothermia Using Transnasal High Flow Dry Air

Raghuram Chava, Menekhem Zviman, Madhavan Srinivas Raghavan, Henry Halperin, Farhan Maqbool, Romergryko Geocadin, Alfredo Quinones-Hinojosa, Aravindan Kolandaivelu, Benjamin A. Rosen, Harikrishna Tandri

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Early induction of therapeutic hypothermia (TH) is recommended in out-of-hospital cardiac arrest (CA); however, currently no reliable methods exist to initiate cooling. We investigated the effect of high flow transnasal dry air on brain and body temperatures in adult porcine animals. Adult porcine animals (n = 23) under general anesthesia were subject to high flow of transnasal dry air. Mouth was kept open to create a unidirectional airflow, in through the nostrils and out through the mouth. Brain, internal jugular, and aortic temperatures were recorded. The effect of varying airflow rate and the air humidity (0% or 100%) on the temperature profiles were recorded. The degree of brain cooling was measured as the differential temperature from baseline. A 10-minute exposure of high flow dry air caused rapid cooling of brain and gradual cooling of the jugular and the aortic temperatures in all animals. The degree of brain cooling was flow dependent and significantly higher at higher airflow rates (0.8°C ± 0.3°C, 1.03°C ± 0.6°C, and 1.3°C ± 0.7°C for 20, 40, and 80 L, respectively, p < 0.05 for all comparisons). Air temperature had minimal effect on the brain cooling over 10 minutes with similar decrease in temperature at 4°C and 30°C. At a constant flow rate (40 LPM) and temperature, the degree of cooling over 10 minutes during dry air exposure was significantly higher compared to humid air (100% saturation) (1.22°C ± 0.35°C vs. 0.21°C ± 0.12°C, p < 0.001). High flow transnasal dry air causes flow dependent cooling of the brain and the core temperatures in intubated porcine animals. The mechanism of cooling appears to be evaporation of nasal mucus as cooling is mitigated by humidifying the air. This mechanism may be exploited to initiate TH in CA.

Original languageEnglish (US)
Pages (from-to)50-56
Number of pages7
JournalTherapeutic Hypothermia and Temperature Management
Issue number1
StatePublished - Mar 2017


  • Therapeutic hypothermia
  • cardiac arrest
  • neuroprotection
  • out-of-hospital cardiac arrest
  • survival

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine
  • Anesthesiology and Pain Medicine


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