[Brain temperature in patients with central nervous system lesions]

Area of Science:

• Neurosurgery
• Physiology
• Medical Technology

Background:

• Human brain temperature knowledge is limited.
• Understanding brain temperature is vital for neurosurgical patients, particularly during normothermia and fever.
• Potential temperature gradients within the brain require investigation.

Purpose of the Study:

• To investigate the relationship between brain and trunk temperature in neurosurgical patients.
• To assess temperature gradients within the brain.
• To evaluate the accuracy of indirect temperature measurements (oesophageal, rectal, tympanic) compared to direct brain temperature.

Main Methods:

• Direct intracranial temperature recordings using thermocouples in 63 neurosurgical patients.
• Simultaneous monitoring of oesophageal, rectal, and tympanic temperatures.
• Analysis of temperature differences and gradients under various physiological conditions.

Main Results:

• Indirect core temperatures (rectal, oesophageal) can have errors up to 1.3°C when estimating brain temperature.
• Tympanic temperature offers better approximation but can still vary by 1°C.
• Brain temperature was consistently the highest measured body temperature.
• Intracranial temperature gradients (up to 0.6°C) were observed, increasing with intracranial pressure and decreased consciousness.
• Temperature gradients may worsen biochemical injury during ischemia and fever.

Conclusions:

• Indirect core temperature measurements may lead to significant errors in estimating brain temperature.
• Intracranial temperature monitoring is desirable in neurosurgical intensive care.
• Intracranial temperature gradients could exacerbate brain injury, especially when combined with fever and ischemia.