Clinical review: Brain-body temperature differences in adults with severe traumatic brain injury

Abstract

Surrogate or 'proxy' measures of brain temperature are used in the routine management of patients with brain damage. The prevailing view is that the brain is 'hotter' than the body. The polarity and magnitude of temperature differences between brain and body, however, remains unclear after severe traumatic brain injury (TBI). The focus of this systematic review is on the adult patient admitted to intensive/neurocritical care with a diagnosis of severe TBI (Glasgow Coma Scale score of less than 8). The review considered studies that measured brain temperature and core body temperature. Articles published in English from the years 1980 to 2012 were searched in databases, CINAHL, PubMed, Scopus, Web of Science, Science Direct, Ovid SP, Mednar and ProQuest Dissertations & Theses Database. For the review, publications of randomised controlled trials, non-randomised controlled trials, before and after studies, cohort studies, case-control studies and descriptive studies were considered for inclusion. Of 2,391 records identified via the search strategies, 37 were retrieved for detailed examination (including two via hand searching). Fifteen were reviewed and assessed for methodological quality. Eleven studies were included in the systematic review providing 15 brain-core body temperature comparisons. The direction of mean brain-body temperature differences was positive (brain higher than body temperature) and negative (brain lower than body temperature). Hypothermia is associated with large brain-body temperature differences. Brain temperature cannot be predicted reliably from core body temperature. Concurrent monitoring of brain and body temperature is recommended in patients where risk of temperature-related neuronal damage is a cause for clinical concern and when deliberate induction of below-normal body temperature is instituted.

Considerations for the measurement of core, skin and mean body temperatures

“…Thus, any similarity between brain and rectal temperatures is not mechanistically linked. Therefore, unless a mechanistic connection exists, then it is very misleading to suggest that thermal equivalence, or the lack thereof, between any two indices validates, or invalidates, either measurement (Roth et al, 1996;Gass and Gass, 1998;Craig et al, 2000Craig et al, , 2002Hissink Muller et al, 2008;Ganio et al, 2009;Childs and Lunn, 2013), particularly when equilibration requirements may have been violated.…”

Concordance of Brain and Core Temperature in Comatose Patients After Cardiac Arrest

“…Histogram of total hours of observation and differences between brain and core temperature. trauma and stroke (Karaszewski et al, 2009;Childs and Lunn, 2013). Since the landmark TTM trial showing equivalent effects of treatment at 33°C versus 36°C on patient outcomes (Nielsen et al, 2013), clinical practice has shifted toward targeting 36°C in comatose survivors of cardiac arrest Leary et al, 2015;Deye et al, 2016).…”

“…In other populations with severe acquired brain injury, core temperature is systematically lower than brain temperature (Childs and Lunn, 2013;Karaszewski et al, 2013).…”

Multi-parameter brain tissue microsensor and interface systems: Calibration, reliability and user experiences of pressure and temperature sensors in the setting of neurointensive care

“…rectum, bladder). In a recent systematic review of the literature, the polarity (direction) of difference between brain and body temperature after severe traumatic brain injury (TBI) was shown to be inconsistent; the brain being higher, lower or the same as body temperature [7]. However, treatment and therapy may influence the magnitude of differences.…”

“…However, treatment and therapy may influence the magnitude of differences. For example, therapeutic hypothermia was associated with the largest differences between brain and body sites in the majority of studies reviewed, whilst patients who were 'normothermic' or febrile had smaller differences [7].…”