Intracerebral Temperature in Neurosurgical Patients

Neurosurgery ◽  
1991 ◽  
Vol 28 (5) ◽  
pp. 709-713 ◽  
Author(s):  
Pekka Mellergård ◽  
Carl-Henrik Nordström
Keyword(s):  
Rectal Temperature ◽  
Clinical Judgment ◽  
Brain Temperature ◽  
Mean Value ◽  
Body Core Temperature ◽  
Severe Condition ◽  
Neurosurgical Patients ◽  
Body Core ◽  
The Difference ◽  
The Brain

Abstract Recent laboratory results have indicated that the ischemic brain is very sensitive to minor variations in temperature. This has created new interest in hypothermia and brain temperature. There is, however, very little information available regarding human intracerebral temperature and its relation to body core temperature during normal and pathological circumstances. We therefore made continuous measurements of the temperature of the lateral ventricle in 15 neurosurgical patients utilizing a newly developed technique with copper-constantan thermocouples introduced through a plastic catheter also used for monitoring intracranial pressure. The intraventricular temperature was higher than the rectal temperature during approximately 90% of all measurements. The largest temperature gradient measured was 2.3°C. Usually the difference between the temperature of the rectum and the brain was much smaller, the mean value being 0.33°C. For the patients in the most severe condition, the rectal temperature was sufficiently close to the brain temperature to afford a reliable basis for adequate clinical judgment.

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.

scholarly journals Selective brain hypothermia: feasibility and safety study of a novel method in five patients

Perfusion ◽  
2019 ◽  
Vol 35 (2) ◽  
pp. 96-103 ◽  
Author(s):  
Seyed Mohammad Seyedsaadat ◽  
Silvana F Marasco ◽  
David J Daly ◽  
Robin McEgan ◽  
James Anderson ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Brain Temperature ◽  
The Body ◽  
Body Core Temperature ◽  
Safety Study ◽  
Cardiopulmonary Function ◽  
Cooling Fluid ◽  
Body Core ◽  
Novel Method ◽  
The Brain

Background/objective: Reduction of brain temperature remains the most common method of neuroprotection against ischemic injury employed during cardiac surgery. However, cooling delivered via the cardiopulmonary bypass circuit is brief and cooling the body core along with the brain has been associated with a variety of unwanted effects. This study investigated the feasibility and safety of a novel selective brain cooling approach to induce rapid, brain-targeted hypothermia independent of the cardiopulmonary bypass circuit. Methods: This first-in-human feasibility study enrolled five adults undergoing aortic valve replacement with cardiopulmonary bypass support. During surgery, the NeuroSave system circulated chilled saline within the pharynx and upper esophagus. Brain and body core temperature were continuously monitored. Adverse effects, cardiopulmonary function, and device function were noted. Results: Patient 1 received cooling fluid for an insignificant period, and Patients 2-5 successfully underwent the cooling procedure using the NeuroSave system for 56-89 minutes. Cooling fluid was 12°C for Patients 1-3, 6°C for Patient 4, and 2°C for Patient 5. There were no NeuroSave-related adverse events and no alterations in cardiopulmonary function during NeuroSave use. Brain temperature decreased by 3°C within 15 minutes and remained at least 3.5°C colder than the body core. During a brief episode of hypotension in one patient, the brain cooled an additional 4°C in 2 minutes, briefly reaching 27.4°C. Conclusion: The NeuroSave system can induce rapid brain-targeted hypothermia and simultaneously maintain a favorable body–brain temperature gradient, even during hypotension. Further studies are required to evaluate the function of the system during longer periods of use.

Temperature Difference Between the Body Core and the Arterial Blood Supplied to the Brain During Hyperthermia or Hypothermia

2001 ◽  
Author(s):  
Liang Zhu ◽  
Maithreyi Bommadevara
Keyword(s):  
Blood Vessel ◽  
Temperature Difference ◽  
Carotid Arteries ◽  
Brain Temperature ◽  
Indirect Evidence ◽  
Blood Perfusion ◽  
The Body ◽  
Arterial Blood ◽  
Body Core ◽  
The Brain

Abstract In this study a theoretical model was developed to evaluate the temperature difference between the body core and the arterial blood supplied to the brain. Several factors including the local blood perfusion rate, blood vessel bifurcation in the neck, and blood vessel pairs on both sides of the neck were considered in the model. The theoretical approach was used to estimate the potential for cooling of blood in the carotid artery on its way to the brain by heat exchange with its countercurrent jugular vein and by the radial heat conduction loss to the cool neck surface. It shows that blood temperature along the common and internal carotid arteries typically decreases up to 0.86°C during hyperthermia. Selectively cooling the neck surface during hypothermia increases the heat loss from the carotid arteries and results in approximately 1.2°C in the carotid arterial temperature. This research could provide indirect evidence of the existence of selective brain cooling (SBC) in humans during hyperthermia. The simulated results can also be used to evaluate the feasibility of lowering brain temperature effectively by selectively cooling the head and neck surface during hypothermia treatment for brain injury or multiple sclerosis.

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.

Inhibition of the preoptic area and anterior hypothalamus by tetrodotoxin alters thermoregulatory functions in exercising rats

2005 ◽  
Vol 98 (4) ◽  
pp. 1458-1462 ◽  
Author(s):  
Hiroshi Hasegawa ◽  
Takayuki Ishiwata ◽  
Takehito Saito ◽  
Toru Yazawa ◽  
Yasutsugu Aihara ◽  
...  
Keyword(s):  
Preoptic Area ◽  
Anterior Hypothalamus ◽  
Treadmill Running ◽  
Body Core Temperature ◽  
Microdialysis Probe ◽  
Male Wistar Rats ◽  
Body Core ◽  
Freely Moving ◽  
The Brain

We have previously demonstrated a functional role of the preoptic area and anterior hypothalamus (PO/AH) in thermoregulation in freely moving rats at various temperature conditions by using microdialysis and biotelemetry methods. In the present study, we perfused tetrodotoxin (TTX) solution into the PO/AH to investigate whether this manipulation can modify thermoregulation in exercising rats. Male Wistar rats were trained for 3 wk by treadmill running. Body core temperature (Tb), heart rate (HR), and tail skin temperature (Ttail) were measured. Rats ran for 120 min at speed of 10 m/min, with TTX (5 μM) perfused into the left PO/AH during the last 60 min of exercise through a microdialysis probe (control, n = 12; TTX, n = 12). Tb, HR, and Ttail increased during the first 20 min of exercise. Thereafter, Tb, HR, and Ttail were stable in both groups. Perfusion of TTX into the PO/AH evoked an additional rise in Tb (control: 38.2 ± 0.1°C, TTX: 39.3 ± 0.2°C; P < 0.001) with a significant decrease in Ttail (control: 31.2 ± 0.5°C, TTX: 28.3 ± 0.7°C; P < 0.01) and a significant increase in HR (control: 425.2 ± 12 beats/min, TTX: 502.1 ± 13 beats/min; P < 0.01). These results suggest that the TTX-induced hyperthermia was the result of both an impairment of heat loss and an elevation of heat production during exercise. We therefore propose the PO/AH as an important thermoregulatory site in the brain during exercise.

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.

Keeping a Cool Head

Physiology ◽  
1986 ◽  
Vol 1 (2) ◽  
pp. 41-44 ◽  
Author(s):  
M Cabanac
Keyword(s):  
Heat Stress ◽  
Core Temperature ◽  
Heat Exchangers ◽  
The Body ◽  
Body Core Temperature ◽  
Mammalian Brain ◽  
Poor Tolerance ◽  
Selective Cooling ◽  
Body Core ◽  
The Brain

The mammalian brain has poor tolerance to increased temperature. However, when body core temperature rises during exercise or heat stress, the temperature of the brain can remain at a lower level, somewhat independent of the rest of the body. In several mammals the cooling of the brain is related to anatomically well-defined countercurrent heat exchangers. Humans lack these distinct anatomic structures, but significant cooling of the brain can nevertheless occur. Such selective cooling of the brain may have important medical implicantions.

scholarly journals Brain thermal kinetics at brain-eyelid thermal tunnels overcoming COVID-19 thermometry limitations for automated asymptomatic infection detection in concert with physical and biological principles

2021 ◽  
Author(s):  
M Marc Abreu ◽  
Ricardo L Smith ◽  
Trevor M Banack ◽  
Alexander C Arroyo ◽  
Robert F Gochman ◽  
...  
Keyword(s):  
Light Emission ◽  
Brain Temperature ◽  
Viral Evolution ◽  
Asymptomatic Infection ◽  
Temperature Measurements ◽  
Body Core Temperature ◽  
Thermal Kinetics ◽  
Infection Detection ◽  
Spot Check ◽  
Body Core

For centuries, temperature measurement deficiencies attributable to biological barriers and low thermo-conductivity (k) have precluded accurate surface-based fever assessment. At this stage of the pandemic, infection detection in children (who due to immature immune system may not effectively respond to vaccines) is critical because children can be readily infected and also become a large mutation reservoir. We reveal hitherto-unrecognized worldwide body temperature measurements (T°), in children and adults, over tissue typified by low-k similar to wood that may reach 6.8°C in thermal variability, hampering thereby COVID-19 control. Brain-eyelid thermal tunnels’ (BTT) integration of low-k and high-k regions creating a thermal pathway for undisturbed heat transmission from hypothalamus to high-k skin eliminates current shortcomings and makes the brain indispensable for defeating COVID-19 given that brain thermoregulatory signals are not limited by mutations. Anatomo-histologic, emissive, physiologic, and thermometric bench-to-bedside studies characterized and overcome biophysical limitations of thermometry through high-k eyelid-enabled brain temperature measurements in children and adults. BTT eyelid features fat-free skin (~900 µm) and unique light emission through a blood/fat configuration in the underlying tunnel. Contrarily, forehead features variable and thick dermis (2000–2500 µm) and variable fat layers (1100–2800 µm) resulting in variable low-k as well as temperatures 1.97 °C lower than BTT temperature (BTT°). Highest emission present in only ~3.1% of forehead averaged 1.08±0.49 °C (mean±SD) less than BTT° (p=0.008). Environmental and biological impacts during fanning revealed thermal imaging limitations for COVID-19 screening. Comparison of paired measurements for 100 pediatric patients showed that in the children subgroup above 37°C, BTT° exceeded body core temperature (Core°) in 60/72 patients; the average difference in the 72 patients was 0.62±0.7°C  (p<0.001 by unpaired t-test); and in the subgroup beyond 37.5°C, BTT° exceeded Core° in 30/32 patients. Delineating hypothalamic activity in children facilitates early infection detection, which is essential because children’s immunogenicity prevents effective vaccination and causes accelerated viral evolution. Capturing hypothalamic thermal signals from BTT was further supported by brain thermal kinetics via BTT using wearables during anesthesia, sedation, sleep, brain injury, exercise, and asymptomatic infection, which revealed brain/core discordance and enabled automated noninvasive afebrile infection detection for interrupting asymptomatic human-to-human transmission. BTT-based spot-check thermometry can be harmlessly implemented for children worldwide without undue burden and costs; meanwhile, continuous brain-eyelid T° in concert with biological and physical principles affords a new dimension for combating pandemics. The “detection–vaccination” pair solution presented is required to mitigate COVID-19 from spreading indefinitely through mutations and vaccine evasion while opening a viable path for eradicating COVID-19.

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