scholarly journals In Cold Blood: Intraarteral Cold Infusions for Selective Brain Cooling in Stroke

2014 ◽  
Vol 34 (5) ◽  
pp. 743-752 ◽  
Author(s):  
Elga Esposito ◽  
Matthias Ebner ◽  
Ulf Ziemann ◽  
Sven Poli
Keyword(s):  
Side Effects ◽  
Brain Temperature ◽  
Therapeutic Option ◽  
The Body ◽  
Global Cerebral Ischemia ◽  
Body Core Temperature ◽  
Whole Body ◽  
Brain Cooling ◽  
Stroke Patients ◽  
Selective Brain Cooling

Hypothermia is a promising therapeutic option for stroke patients and an established neuroprotective treatment for global cerebral ischemia after cardiac arrest. While whole body cooling is a feasible approach in intubated and sedated patients, its application in awake stroke patients is limited by severe side effects: Strong shivering rewarms the body and potentially worsens ischemic conditions because of increased O2 consumption. Drugs used for shivering control frequently cause sedation that increases the risk of aspiration and pneumonia. Selective brain cooling by intraarterial cold infusions (IACIs) has been proposed as an alternative strategy for patients suffering from acute ischemic stroke. Preclinical studies and early clinical experience indicate that IACI induce a highly selective brain temperature decrease within minutes and reach targeted hypothermia 10 to 30 times faster than conventional cooling methods. At the same time, body core temperature remains largely unaffected, thus systemic side effects are potentially diminished. This review critically discusses the limitations and side effects of current cooling techniques for neuroprotection from ischemic brain damage and summarizes the available evidence regarding advantages and potential risks of IACI.

Selective regulation of brain and body temperatures in the squirrel monkey

1983 ◽  
Vol 245 (2) ◽  
pp. R293-R297 ◽  
Author(s):  
C. A. Fuller ◽  
M. A. Baker
Keyword(s):  
Squirrel Monkey ◽  
Brain Temperature ◽  
Human Subjects ◽  
Venous Blood ◽  
The Body ◽  
Body Core Temperature ◽  
Saimiri Sciureus ◽  
Brain Cooling ◽  
The Face ◽  
Body Core

Many panting mammals can cool the brain below body core temperature during heat stress. Studies on human subjects suggest that primates may also be able selectively to regulate brain temperature. We examined this possibility by measuring hypothalamic (Thy) and colonic (Tco) temperatures of unanesthetized squirrel monkeys (Saimiri sciureus) in two different experiments. First, Thy and Tco were examined at four different ambient temperatures (Ta) between 20 and 36 degrees C. Over this range of Ta, Thy was regulated within a narrower range than Tco. In the cold Ta, Tco was lower than Thy; whereas in warm Ta, Tco was higher than Thy. Second, monkeys maintained at 35 degrees C Ta were acutely exposed to cool air blown on the face or abdomen. Air directed at the face cooled Thy more and faster than Tco, whereas air directed at the abdomen cooled Tco and Thy at the same rate. The second experiment was repeated in anesthetized animals with a thermocouple in the right atrium, and the results showed that this brain cooling was not produced by cooling of blood in the body core. These data demonstrate that the squirrel monkey is capable of selectively regulating Thy. Further the results suggest that venous blood returning from the face may be involved in selective brain cooling in warm environments.

scholarly journals Non-invasive Monitoring of Brain Temperature during Rapid Selective Brain Cooling by Zero-Heat-Flux Thermometry

2019 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
Mohammad Fazel Bakhsheshi ◽  
Marjorie Ho ◽  
Lynn Keenliside ◽  
Ting-Yim Lee
Keyword(s):  
Heat Flux ◽  
Body Temperature ◽  
Rectal Temperature ◽  
Brain Temperature ◽  
Whole Body ◽  
Brain Cooling ◽  
Selective Brain Cooling ◽  
Non Invasive ◽  
Temperature Probe ◽  
The Brain

Introduction: Selective brain cooling can minimize systemic complications associated with whole body cooling but maximize neuroprotection. Recently, we developed a non-invasive, portable and inexpensive system for selectively cooling the brain rapidly and demonstrated its safety and efficacy in porcine models. However, the widespread application of this technique in the clinical setting requires a reliable, non-invasive and accurate method for measuring local brain temperature so that cooling and rewarming rates can be controlled during targeted temperature management. In this study, we evaluate the ability of a zero-heat-flux SpotOn sensor, mounted on three different locations, to measure brain temperature during selective brain cooling in a pig model. Computed Tomography (CT) was used to determine the position of the SpotOn patches relative to the brain at different placement locations.Methods and Results: Experiments were conducted on two juvenile pigs. Body temperature was measured using a rectal temperature probe while brain temperature with an intraparenchymal thermocouple probe. A SpotOn patch was taped to the pig’s head at three different locations: 1-2 cm posterior (Location #1, n=1), central forehead (Location #2, n=1); and 1-2 cm anterior and lateral to the bregma i.e., above the eye on the forehead (Location #3, n=1). This cooling system was able to rapidly cool the brain temperature to 33.7 ± 0.2°C within 15 minutes, and maintain the brain temperature within 33-34°C for 4-6 hours before slowly rewarming to 34.8 ± 1.1°C from 33.7 ± 0.2°C, while maintaining the core body temperature (as per rectal temperature probe) above 36°C. We measured a mean bias of -1.1°C, -0.2°C and 0.7°C during rapid cooling in induction phase, maintenance and rewarming phase, respectively. Amongst the three locations, location #2 had the highest correlation (R2 = 0.8) between the SpotOn sensor and the thermocouple probe.Conclusions: This SBC method is able to tightly control the rewarming rate within 0.52 ± 0.20°C/h. The SpotOn sensor placed on the center of the forehead provides a good measurement of brain temperature in comparison to the invasive needle probe.

Selective Brain Cooling after Traumatic Brain Injury: Effects of Three Different Cooling Methods—Case Report

2016 ◽  
Vol 78 (04) ◽  
pp. 397-402 ◽  
Author(s):  
Robert Nickl ◽  
Stefan Koehler ◽  
Patrick Fricke ◽  
Christian Stetter ◽  
Stefan Rueckriegel ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Side Effects ◽  
Therapeutic Hypothermia ◽  
Brain Temperature ◽  
Brain Cooling ◽  
Selective Brain Cooling ◽  
Adverse Side Effects ◽  
External Cooling ◽  
Systemic Hypothermia ◽  
Severe Tbi

Background In experimental models of neuronal damage, therapeutic hypothermia proved to be a powerful neuroprotective method. In clinical studies of traumatic brain injury (TBI), this very distinct effect was not reproducible. Several meta-analyses draw different conclusions about whether therapeutic hypothermia can improve outcome after TBI. Adverse side effects of systemic hypothermia, such as severe pneumonia, have been held responsible by some authors to counteract the neuroprotective effect. Selective brain cooling (SBC) attempts to take advantage of the protective effects of therapeutic hypothermia without the adverse side effects of systemic hypothermia. Methods Three different methods of SBC were applied in a patient who had severe TBI with recurrent increases of intracranial pressure (ICP) refractory to conventional forms of treatment: (1) external cooling of the scalp and neck using ice packs prior to hemicraniectomy, (2) external cooling of the craniectomy defect using ice packs after hemicraniectomy, and (3) cooling by epidural irrigation with cold Ringer solution after hemicraniectomy. Results External scalp cooling before hemicraniectomy, external cooling of the craniectomy defect, and epidural irrigation with cold fluid resulted in temperature differences (brain temperature to body temperature) of − 0.2°, − 0.7°, and − 3.6°C, respectively. ICP declined with decreasing brain temperature. Conclusion Previous external cooling attempts for SBC faced the problem that brain temperature could not be lowered without a simultaneous decrease of systemic temperature. After hemicraniectomy, epidural irrigation with cold fluid may be a simple and effective way to lower ICP and apply one of the most powerful methods of cerebroprotection after severe TBI.

Rectal temperature measurement results in artifactual evidence of selective brain cooling

2001 ◽  
Vol 281 (1) ◽  
pp. R108-R114 ◽  
Author(s):  
Shane K. Maloney ◽  
Andrea Fuller ◽  
Graham Mitchell ◽  
Duncan Mitchell
Keyword(s):  
Rectal Temperature ◽  
Brain Temperature ◽  
Brain Cooling ◽  
Selective Brain Cooling ◽  
Blood Temperature ◽  
Arterial Blood ◽  
The Status ◽  
Conscious Sheep ◽  
Surrogate Measures ◽  
Arterial Blood Temperature

Selective brain cooling (SBC) is defined as a brain temperature cooler than the temperature of arterial blood from the trunk. Surrogate measures of arterial blood temperature have been used in many published studies on SBC. The use of a surrogate for arterial blood temperature has the potential to confound proper identification of SBC. We have measured brain, carotid blood, and rectal temperatures in conscious sheep exposed to 40, 22, and 5°C. Rectal temperature was consistently higher than arterial blood temperature. Brain temperature was consistently cooler than rectal temperature during all exposures. Brain temperature only fell below carotid blood temperature during the final few hours of 40°C exposure and not at all during the 5°C exposure. Consequently, using rectal temperature as a surrogate for arterial blood temperature does not provide a reliable indication of the status of the SBC effector. We also show that rapid suppression of SBC can result if the animals are disturbed.

scholarly journals Canine hyperthermia with cerebral protection

1976 ◽  
Vol 40 (4) ◽  
pp. 543-548 ◽  
Author(s):  
R. W. Carithers ◽  
R. C. Seagrave
Keyword(s):  
Core Temperature ◽  
Cold Water ◽  
Brain Temperature ◽  
Body Core Temperature ◽  
Whole Body ◽  
Similar Time ◽  
Data Points ◽  
Body Core ◽  
Heat Transfer System ◽  
The Brain

Extreme whole-body hyperthermia was achieved without lasting side effects in canines by elevating body core temperature to 42 degrees C, using a warm water bath. Cold water irrigation of the nasal alar fold permitted an additional core temperature elevation of 0.5–1.0 degrees C above brain temperature for periods up to 1.5 h. The brain-core temperature differential was maintained by a physiological arteriovenous heat exchanger located at the base of the brain. The maximum tolerable core temperature for the 21 nonirrigated dogs was 42 degrees C for 60–90 min, whereas that for the 28 irrigated dogs was 42.5–43 degrees C for similar time intervals. A mathematical model of the total heat transfer system described the observed dynamic temperature responses. It was the solution of a differential equation which fit the normalized experimental data points and predicted reasonable values for known and unknown experimental parameters.

Integration of jugular venous return and circle of Willis in a theoretical human model of selective brain cooling

2007 ◽  
Vol 103 (5) ◽  
pp. 1837-1847 ◽  
Author(s):  
Matthew A. Neimark ◽  
Angelos-Aristeidis Konstas ◽  
Andrew F. Laine ◽  
John Pile-Spellman
Keyword(s):  
Venous Return ◽  
Mild Hypothermia ◽  
Brain Temperature ◽  
Circle Of Willis ◽  
Human Model ◽  
Anterior Communicating Artery ◽  
Moderate Hypothermia ◽  
Brain Cooling ◽  
Bioheat Equation ◽  
Selective Brain Cooling

A three-dimensional mathematical model was developed to examine the induction of selective brain cooling (SBC) in the human brain by intracarotid cold (2.8°C) saline infusion (ICSI) at 30 ml/min. The Pennes bioheat equation was used to propagate brain temperature. The effect of cooled jugular venous return was investigated, along with the effect of the circle of Willis (CoW) on the intracerebral temperature distribution. The complete CoW, missing A1 variant (mA1), and fetal P1 variant (fP1) were simulated. ICSI induced moderate hypothermia (defined as 32–34°C) in the internal carotid artery (ICA) territory within 5 min. Incorporation of the complete CoW resulted in a similar level of hypothermia in the ICA territory. In addition, the anterior communicating artery and ipsilateral posterior communicating artery distributed cool blood to the contralateral anterior and ipsilateral posterior territories, respectively, imparting mild hypothermia (35 and 35.5°C respectively). The mA1 and fP1 variants allowed for sufficient cooling of the middle cerebral territory (30–32°C). The simulations suggest that ICSI is feasible and may be the fastest method of inducing hypothermia. Moreover, the effect of convective heat transfer via the complete CoW and its variants underlies the important role of CoW anatomy in intracerebral temperature distributions during SBC.

Dehydration increases the magnitude of selective brain cooling independently of core temperature in sheep

2007 ◽  
Vol 293 (1) ◽  
pp. R438-R446 ◽  
Author(s):  
Andrea Fuller ◽  
Leith C. R. Meyer ◽  
Duncan Mitchell ◽  
Shane K. Maloney
Keyword(s):  
Drinking Water ◽  
Brain Temperature ◽  
Heat Exposure ◽  
Plasma Osmolality ◽  
Threshold Temperature ◽  
Evaporative Heat Loss ◽  
Brain Cooling ◽  
Selective Brain Cooling ◽  
Blood Temperature ◽  
Arterial Blood

By cooling the hypothalamus during hyperthermia, selective brain cooling reduces the drive on evaporative heat loss effectors, in so doing saving body water. To investigate whether selective brain cooling was increased in dehydrated sheep, we measured brain and carotid arterial blood temperatures at 5-min intervals in nine female Dorper sheep (41 ± 3 kg, means ± SD). The animals, housed in a climatic chamber at 23°C, were exposed for nine days to a cyclic protocol with daytime heat (40°C for 6 h). Drinking water was removed on the 3rd day and returned 5 days later. After 4 days of water deprivation, sheep had lost 16 ± 4% of body mass, and plasma osmolality had increased from 290 ± 8 to 323 ± 9 mmol/kg ( P < 0.0001). Although carotid blood temperature increased during heat exposure to similar levels during euhydration and dehydration, selective brain cooling was significantly greater in dehydration (0.38 ± 0.18°C) than in euhydration (−0.05 ± 0.14°C, P = 0.0008). The threshold temperature for selective brain cooling was not significantly different during euhydration (39.27°C) and dehydration (39.14°C, P = 0.62). However, the mean slope of lines of regression of brain temperature on carotid blood temperature above the threshold was significantly lower in dehydrated animals (0.40 ± 0.31) than in euhydrated animals (0.87 ± 0.11, P = 0.003). Return of drinking water at 39°C led to rapid cessation of selective brain cooling, and brain temperature exceeded carotid blood temperature throughout heat exposure on the following day. We conclude that for any given carotid blood temperature, dehydrated sheep exposed to heat exhibit selective brain cooling up to threefold greater than that when euhydrated.

Restoration of thermoregulation after exercise

2017 ◽  
Vol 122 (4) ◽  
pp. 933-944 ◽  
Author(s):  
Glen P. Kenny ◽  
Ryan McGinn
Keyword(s):  
Heat Loss ◽  
Core Temperature ◽  
Current Knowledge ◽  
Thermal Control ◽  
The Body ◽  
Body Core Temperature ◽  
Whole Body ◽  
Temperature Sensitive ◽  
Internal Core ◽  
Body Core

Performing exercise, especially in hot conditions, can heat the body, causing significant increases in internal body temperature. To offset this increase, powerful and highly developed autonomic thermoregulatory responses (i.e., skin blood flow and sweating) are activated to enhance whole body heat loss; a response mediated by temperature-sensitive receptors in both the skin and the internal core regions of the body. Independent of thermal control of heat loss, nonthermal factors can have profound consequences on the body’s ability to dissipate heat during exercise. These include the activation of the body’s sensory receptors (i.e., baroreceptors, metaboreceptors, mechanoreceptors, etc.) as well as phenotypic factors such as age, sex, acclimation, fitness, and chronic diseases (e.g., diabetes). The influence of these factors extends into recovery such that marked impairments in thermoregulatory function occur, leading to prolonged and sustained elevations in body core temperature. Irrespective of the level of hyperthermia, there is a time-dependent suppression of the body’s physiological ability to dissipate heat. This delay in the restoration of postexercise thermoregulation has been associated with disturbances in cardiovascular function which manifest most commonly as postexercise hypotension. This review examines the current knowledge regarding the restoration of thermoregulation postexercise. In addition, the factors that are thought to accelerate or delay the return of body core temperature to resting levels are highlighted with a particular emphasis on strategies to manage heat stress in athletic and/or occupational settings.

scholarly journals An injectable refrigerated hydrogel for Inducing local hypothermia and neuroprotection against traumatic brain injury

2020 ◽  
Author(s):  
yuhan Han ◽  
ZhengZhong Han ◽  
Xuyang Huang ◽  
Feng Qian ◽  
Jun Jia ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Side Effects ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Controlled Drug Release ◽  
The Body ◽  
Whole Body ◽  
Local Hypothermia ◽  
Whole Body Cooling

Abstract Hypothermia is a promising therapy for Traumatic brain injury (TBI) in the clinic. However, the neuroprotective outcomes of hypothermia-treated TBI are not consistent in clinical studies due to several severe side effects. Here, an injectable refrigerated hydrogel is designed to deliver 3-iodothyronamine (T1AM) to achieve a longer period of local hypothermia for TBI treatment. The hydrogel has four advantages: (1) It can be injected into injured site after TBI, where it forms a hydrogel and avoids the side effects of whole-body cooling. (2) The hydrogel can biodegrade and be used for controlled drug release. (3) Released T1AM can bind to trace amine-associated receptor 1 (TAAR1) to produce cyclic adenosine monophosphate (cAMP), which induces hypothermia. (4) This hydrogel has an increased medical value due to its simple operation and ability to achieve timely treatment. This hydrogel is able to cool the brain to 30.25 ± 2.25 °C for 12 hours while maintaining the body temperature at 36.80 ± 1.75 °C after TBI. More importantly, the hypothermia induced by this hydrogel leads to the maintenance of blood-brain barrier (BBB) integrity, the prevention of cell death, the reduction of the inflammatory response and brain edema, and the promotion of functional recovery after TBI. This cooling method can potentially be developed as a new approach for hypothermia treatment in TBI.

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