Theoretical simulation of temperature distribution in the brain during mild hypothermia treatment for brain injury

Abstract

Mild or moderate hypothermia (>30 degrees C) has been proposed for clinical use as a therapeutic option for achieving protection from cerebral ischaemia in brain injury patients. In this research, a theoretical model was developed to examine the brain temperature gradients during selective cooling of the brain surface after head injury. The head was modelled as a hemisphere consisting of several layers, representing the scalp, skull and brain tissue, respectively. The dimensions, physical properties and physiological characteristics for each layer, as well as the arterial blood temperature, were used as the input to the Pennes bioheat transfer equation to simulate the steady-state temperature distribution within the brain. Depending on the head surface temperature, a temperature gradient of up to 13 degrees C exists in the brain tissue. The results have shown that the volumetric-averaged brain tissue temperature Tbt,avg for adults and infants can be 1.7 and 4.3 degrees C, respectively, lower than the temperature of the arterial blood supplied to the brain tissue. The location where the probe should be placed to measure Tbt,avg was also determined by the simulation. The calculation suggests that the temperature sensor should be placed 7.5mm and 5.9 mm beneath the brain tissue surface for adults and infants, respectively, to monitor Tbt,avg continuously.

A theoretical model of selective cooling using intracarotid cold saline infusion in the human brain

“…The present theoretical model examines the effect of a continuously changing blood perfusion rate (CBF) and perfusate temperature on brain temperature. Previous mathematical models investigated the effect of transcranial cooling in humans and assumed a constant CBF and perfusate temperature (44,60) or a continuously changing CBF and a constant perfusate temperature (11,68,69). The models that employed a variable CBF as a function of temperature extrapolated the analytic expression for this relation directly from the expression for the metabolic heat generation as a function of brain temperature (Eq.…”

Differences between brain and rectal temperatures during routine critical care of patients with severe traumatic brain injury*

“…Little is known about human brain temperature, but theoretical models suggest that during normothermia the temperature of the brain is close to that of internal carotid arterial blood before the blood enters the circle of Willis [19]. In man, direct measurement of brain temperature Anaesthesia, 2005, 60, pages 759-765 …”

“…However, it is assumed that the deleterious metabolic, inflammatory and biochemical mechanisms associated with raised body temperature in animal models of stroke and trauma may operate similarly in the brain injured human [17]. This assumption underpins current opinion that even a small increase in body temperature (1-2°C) above normal (37°C) accelerates ischaemic damage and increases the size of the primary brain lesion [9,18] and should therefore be prevented [13].Little is known about human brain temperature, but theoretical models suggest that during normothermia the temperature of the brain is close to that of internal carotid arterial blood before the blood enters the circle of Willis [19]. In man, direct measurement of brain temperature Anaesthesia, 2005, 60, pages 759-765 …”

“…Little is known about human brain temperature, but theoretical models suggest that during normothermia the temperature of the brain is close to that of internal carotid arterial blood before the blood enters the circle of Willis [19]. In man, direct measurement of brain temperature has been undertaken predominantly in neurosurgical patients where study populations have included a mixture of cases (brain trauma, subarachnoid haemorrhage, haemorrhagic stroke or brain tumour), with measurements made at different intracranial sites (intraventricular, intraparenchymal or subdural) using different sensor brands.…”

Treatment of Resistant Fever: New Method of Local Cerebral Cooling

“…Compared to an intravascular cooling method, which is efficient and fast, but invasive and with several relevant side effects such as venous thrombosis or cause of infections, the advantage of a local cooling device becomes obvious. For specific cooling of the deep brain, head caps are not efficient [12][13][14], whereas neck pads covering bilateral the carotid triangle decrease the brain temperature in a mathematical simulation [13,15]. In a previous study, we simulated cerebral temperature behavior by applying different cooling devices [13].…”