Abstract: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 ju… Show more
“…Intrinsic mechanisms of local blood flow redistribution and air flow rate variations into nasal mucosa can not only modulate brain temperature, but also contribute to blood and core temperature regulation. High-flow oxygen through the upper airways of intubated rats resulted in a flow-dependent decrease in brain temperature (Einer-Jensen and Khorooshi, 2000), which was later confirmed in porcine models using transnasal dry air (Chava et al, 2017). This study showed that the rate of brain cooling was significantly higher at higher airflow rates, independent of the air temperature, and was eliminated by humidifying the air, consistent with principles of evaporative cooling.…”
Section: Discussionsupporting
confidence: 70%
“…The primary purpose of the turbinates is to warm and humidify inspired air before it reaches the sensitive tissue of the lungs. The heat transfer involved in liquid to gas phase change of nasal mucous results in heat loss, which in turn is proportional to the air flow rate setting and therapy duration (Chava et al, 2017).…”
Section: Coolstat Devicementioning
confidence: 99%
“…CoolStat is a noninvasive device capable of delivering high flow of dehumidified air into the nasal mucosa. Preclinical data have demonstrated selective brain and core temperature reduction by evaporative cooling using transnasal unidirectional high flow of dry air into the nostrils of porcine models (Chava et al, 2017). Herein, we investigated the cooling efficacy of CoolStat device in induction and maintenance of hypothermia (primary objective).…”
Targeted temperature management (TTM) is recommended as a standard of care for postcardiac arrest patients. Current TTM methods have significant limitations to be used in an ambulatory setting. We investigated the efficacy and safety of a novel noninvasive transnasal evaporative cooling device (CoolStatÔ). Eleven Yorkshire pigs underwent hypothermia therapy using the CoolStat device. CoolStat induces evaporative cooling by blowing dehumidified ambient air over the nasal turbinates in a unidirectional fashion. CoolStat's efficacy and safety were assessed by applying different cooling strategies (groups A, B and C). In group A (efficacy study; n = 5, TTM for 8 hours), time to achieve brain target temperature (2°C reduction from baseline), and the percentage of time in which the temperature ranged within -0.5°C after reaching the target temperature were investigated. In the safety assessment (groups B and C), two worst-case therapy situations were reproduced: in group B (n = 3), continuous maximum air flow (65 L/min) was applied without temperature control and, in group C (n = 3), subjects underwent 24-hour TTM (prolonged therapy). Hemodynamic and respiratory parameters, nasal mucosa integrity (endoscopic assessment), and other therapy-related adverse effects were evaluated. Efficacy study: CoolStat cooling therapy successfully induced and sustained managed hypothermia in all subjects. Brain target temperature was achieved in 0.5 -0.6 hours and kept within a -0.5°C range for the therapy duration (99.9% -0.1%). All animals completed the safety studies. Maximum air flow (group B) and 24-hour (group C) therapies were well tolerated and no significant damage was observed on nasal mucosa for neither of the groups. CoolStat was able to efficiently induce and maintain hypothermia using unidirectional high flow of dry air into the nostrils of porcine models. CoolStat therapy was well tolerated and no damage to nasal mucosa was observed under either maximum air flow or prolonged therapy.
“…Intrinsic mechanisms of local blood flow redistribution and air flow rate variations into nasal mucosa can not only modulate brain temperature, but also contribute to blood and core temperature regulation. High-flow oxygen through the upper airways of intubated rats resulted in a flow-dependent decrease in brain temperature (Einer-Jensen and Khorooshi, 2000), which was later confirmed in porcine models using transnasal dry air (Chava et al, 2017). This study showed that the rate of brain cooling was significantly higher at higher airflow rates, independent of the air temperature, and was eliminated by humidifying the air, consistent with principles of evaporative cooling.…”
Section: Discussionsupporting
confidence: 70%
“…The primary purpose of the turbinates is to warm and humidify inspired air before it reaches the sensitive tissue of the lungs. The heat transfer involved in liquid to gas phase change of nasal mucous results in heat loss, which in turn is proportional to the air flow rate setting and therapy duration (Chava et al, 2017).…”
Section: Coolstat Devicementioning
confidence: 99%
“…CoolStat is a noninvasive device capable of delivering high flow of dehumidified air into the nasal mucosa. Preclinical data have demonstrated selective brain and core temperature reduction by evaporative cooling using transnasal unidirectional high flow of dry air into the nostrils of porcine models (Chava et al, 2017). Herein, we investigated the cooling efficacy of CoolStat device in induction and maintenance of hypothermia (primary objective).…”
Targeted temperature management (TTM) is recommended as a standard of care for postcardiac arrest patients. Current TTM methods have significant limitations to be used in an ambulatory setting. We investigated the efficacy and safety of a novel noninvasive transnasal evaporative cooling device (CoolStatÔ). Eleven Yorkshire pigs underwent hypothermia therapy using the CoolStat device. CoolStat induces evaporative cooling by blowing dehumidified ambient air over the nasal turbinates in a unidirectional fashion. CoolStat's efficacy and safety were assessed by applying different cooling strategies (groups A, B and C). In group A (efficacy study; n = 5, TTM for 8 hours), time to achieve brain target temperature (2°C reduction from baseline), and the percentage of time in which the temperature ranged within -0.5°C after reaching the target temperature were investigated. In the safety assessment (groups B and C), two worst-case therapy situations were reproduced: in group B (n = 3), continuous maximum air flow (65 L/min) was applied without temperature control and, in group C (n = 3), subjects underwent 24-hour TTM (prolonged therapy). Hemodynamic and respiratory parameters, nasal mucosa integrity (endoscopic assessment), and other therapy-related adverse effects were evaluated. Efficacy study: CoolStat cooling therapy successfully induced and sustained managed hypothermia in all subjects. Brain target temperature was achieved in 0.5 -0.6 hours and kept within a -0.5°C range for the therapy duration (99.9% -0.1%). All animals completed the safety studies. Maximum air flow (group B) and 24-hour (group C) therapies were well tolerated and no significant damage was observed on nasal mucosa for neither of the groups. CoolStat was able to efficiently induce and maintain hypothermia using unidirectional high flow of dry air into the nostrils of porcine models. CoolStat therapy was well tolerated and no damage to nasal mucosa was observed under either maximum air flow or prolonged therapy.
“…The cooling effect appears to be highly dependent on the airflow rate and air dryness, as lower flow rates and humidification of the inflowing air mitigate the cooling effect. [73] The PRINCE trial, a randomized multicenter study, investigated the effects of TEC using a mixture of PFC and high-flow oxygen in patients with witnessed CA and [55] 1998…”
Therapeutic hypothermia (TH) remains one of the few proven neuroprotective modalities available in clinical practice today. Although targeting lower temperatures during TH seems to benefit ischemic brain cells, systemic side effects associated with global hypothermia limit its clinical applicability. Therefore, the ability to selectively reduce the temperature of the brain while minimally impacting core temperature allows for maximizing neurological benefit over systemic complications. In that scenario, selective brain cooling (SBC) has emerged as a promising modality of TH. In this report, we reviewed the general concepts of TH, from systemic to selective brain hypothermia, and explored the different cooling strategies and respective evidence, including preclinical and clinical data. SBC has been investigated in different animal models with promising results, wherein organ-specific, rapid, and deep target brain temperature managements stand out as major advantages over systemic TH. Nevertheless, procedure-related complications and adverse events still remain a concern, limiting clinical translation. Different invasive and noninvasive methods for SBC have been clinically investigated with variable results, and although adverse effects were still reported in some studies, therapies rendered overall safe profiles. Further study is needed to define the optimal technique, timing of initiation, rate and length of cooling as well as target temperature and rewarming protocols for different indications.
“…Safety of this approach, given the high flow exposure to the nasal mucosa of dry gas in these patients, was further assessed by an ear, nose and throat consultant as part of the team. This approach has been previously reported to be effective in pigs [3], and other related approaches such as the use of perfluorocarbon nasal sprays and/or nasal cooling balloons have also demonstrated success in patients and pigs, respectively [4,5].…”
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