Temperature control in acute brain injury

Intensive Care Medicine: Published 20 April 2026

Purpose

Temperature is a key determinant of cerebral vulnerability after acute brain injury and a physiological variable that can be continuously monitored and actively controlled in the intensive care unit. Its therapeutic role has evolved from hypothermia-centred strategies toward early recognition of fever and controlled normothermia. This review examines the physiological rationale, clinical evidence, and contemporary practice of temperature management in neurocritical care.

Methods

We synthesised evidence from major randomised trials, observational studies, and international consensus recommendations across traumatic brain injury, acute vascular brain injury, and post-cardiac arrest encephalopathy, together with current monitoring and implementation approaches.

Results

Fever is consistently associated with worse neurological outcomes. In traumatic brain injury, hypothermia reduces intracranial pressure but does not improve functional outcome when used prophylactically and is reserved for refractory intracranial hypertension. In acute vascular brain injury, neutral trials and feasibility constraints have shifted practice toward early detection and treatment of fever rather than hypothermia. In post-cardiac arrest care, contemporary guidelines recommend protocolised temperature control with selection and maintenance of a constant target between 32°C and 37.5°C and active prevention of fever, rather than mandatory hypothermia.

Conclusions

Temperature control is a fundamental component of care aimed at protecting the injured brain through continuous monitoring, early detection of fever, and prevention of temperature-related harm.

 

 

Fever and hypothermia represent two populations of sepsis patients and are associated with outside temperature

 

by Daniel O. Thomas-Rüddel, Peter Hoffmann, Daniel Schwarzkopf, Christian Scheer, Friedhelm Bach, Marcus Komann, Herwig Gerlach, Manfred Weiss, Matthias Lindner, Hendrik Rüddel, Philipp Simon, Sven-Olaf Kuhn, Reinhard Wetzker, Michael Bauer, Konrad Reinhart and Frank Bloos 

 

Critical Care volume 25, Article number: 368 (2021) 

 

Background

Fever and hypothermia have been observed in septic patients. Their influence on prognosis is subject to ongoing debates.

Methods

We did a secondary analysis of a large clinical dataset from a quality improvement trial. A binary logistic regression model was calculated to assess the association of the thermal response with outcome and a multinomial regression model to assess factors associated with fever or hypothermia.

Results

With 6542 analyzable cases we observed a bimodal temperature response characterized by fever or hypothermia, normothermia was rare. Hypothermia and high fever were both associated with higher lactate values. Hypothermia was associated with higher mortality, but this association was reduced after adjustment for other risk factors. Age, community-acquired sepsis, lower BMI and lower outside temperatures were associated with hypothermia while bacteremia and higher procalcitonin values were associated with high fever.

Conclusions

Septic patients show either a hypothermic or a fever response. Whether hypothermia is a maladaptive response, as indicated by the higher mortality in hypothermic patients, or an adaptive response in patients with limited metabolic reserves under colder environmental conditions, remains an open question.

Revisited: A Systematic Review of Therapeutic Hypothermia for Adult Patients Following Traumatic Brain Injury

Revisited: A Systematic Review of TherapeuticHypothermia for Adult Patients Following Traumatic Brain Injury

by Watson, Hannah I.; Shepherd, Andrew A.; Rhodes, Jonathan K. J.; Andrews, Peter J. D. 

Objectives: Therapeutic hypothermia has been of topical interest for many years and with the publication of two international, multicenter randomized controlled trials, the evidence base now needs updating. The aim of this systematic review of randomized controlled trials is to assess the efficacy of therapeutic hypothermia in adult traumatic brain injury focusing on mortality, poor outcomes, and new pneumonia. Data Sources: The following databases were searched from January 1, 2011, to January 26, 2018: Cochrane Central Register of Controlled Trial, MEDLINE, PubMed, and EMBASE. Study Selection: Only foreign articles published in the English language were included. Only articles that were randomized controlled trials investigating adult traumatic brain injury sustained following an acute, closed head injury were included. Two authors independently assessed at each stage. Data Extraction: Quality was assessed using the Cochrane Collaboration’s tool for assessing the risk of bias. All extracted data were combined using the Mantel-Haenszel estimator for pooled risk ratio with 95% CIs. p value of less than 0.05 was considered statistically significant. All statistical analyses were conducted using RevMan 5 (Cochrane Collaboration, Version 5.3, Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014). Data Synthesis: Twenty-two studies with 2,346 patients are included. Randomized controlled trials with a low risk of bias show significantly more mortality in the therapeutic hypothermia group (risk ratio, 1.37; 95% CI, 1.04–1.79; p = 0.02), whereas randomized controlled trials with a high risk of bias show the opposite with a higher mortality in the control group (risk ratio, 0.70; 95% CI, 0.60–0.82; p < 0.00001). Conclusions: Overall, this review is in-keeping with the conclusions published by the most recent randomized controlled trials. High-quality studies show no significant difference in mortality, poor outcomes, or new pneumonia. In addition, this review shows a place for fever control in the management of traumatic brain injury.

What is the right temperature to cool post-cardiac arrest patients?

What is the right temperature to cool post-cardiac arrest patients?
Chandrasekaran PN et al.
Critical Care 2015, 19:406


Background: Brain ischemia and reperfusion injury leading to tissue degeneration and loss of neurological function following return of spontaneous circulation after cardiac arrest (CA) is a well-known entity. Two landmark trials in 2002 showed improved survival and neurological outcome of comatose survivors of out-of-hospital cardiac arrest (OHCA) of presumed cardiac origin when the patients were subjected to therapeutic hypothermia of 32 to 34 °C for 12 to 24 hours. However, the optimal target temperature for these cohorts is yet to be established and also it is not clear whether strict fever management and maintaining near normal body temperature are alone sufficient to improve the outcome.
Methods: Objective: The objective is to determine whether a hypothermic goal of a near-normal body temperature of 36 °C reduces all-cause mortality compared with a moderate hypothermia of 33 °C for the unconscious survivors of OHCA of presumed cardiac origin when subjected randomly to these different targeted temperatures.
Design: A multicenter, international, open label, randomized controlled trial. Setting: Thirty-six ICUs in Europe and Australia participated in this study.Participants: Unconscious adults (older than 18 years of age) who survived (Glasgow coma scale less than 8) OHCA due to presumed cardiac origin with subsequent persistent return of spontaneous circulation (more than 20 minutes without chest compressions).
Intervention: The above participant cohorts were randomized to targeted body temperature of either 33 °C or 36 °C for 36 hours after the CA with gradual rewarming of both groups to 37 °C (hourly increments of 0.5 °C) after the initial 28 hours. Body temperatures in both the groups were then maintained below 37.5 °C for 72 hours after the initial 36 hours.
Outcomes: Primary outcome measure of all-cause mortality in both the groups at the end of the trial with the secondary outcome measure of all-cause mortality, composite neurological function as evaluated by cerebral performance category scale and modified ranking scale at the end of 180 days were studied.
Results: Out of the 939 participants, all-cause mortality at the end of the trial was 50 % in the 33 °C group (225 of 466 patients) compared with 48 % in the 36 °C group (235 of 473 patients); the hazard ratio with a temperature of 33 °C was 1.06 (95 % confidence interval (CI) 0.89 to 1.28, P = 0.51). At the end of 180 days, 54 % of patients in the 33 °C group versus 52 % in the 36 °C group had died or had poor neurological outcome according to cerebral performance category (risk ratio 1.02, 95 % CI 0.88 to 1.16, P = 0.78) but the modified ranking scale at the end of 180 days was unchanged (52 %) in both groups (risk ratio 1.01, 95 % CI 0.89 to 1.14, P = 0.87).
Conclusions: Maintaining targeted lower normothermia of 36 °C had similar outcomes compared with induced moderate hypothermia of 33 °C for unconscious survivors of OHCA of presumed cardiac cause.

Diagnosis and management of temperature abnormality in ICUs

Diagnosis and management of temperature abnormality in ICUs: A EUROBACT investigators survey. Critical care, Dec 2013, Vol. 13(6), R289.

Niven, D., et al.

http://ccforum.com/content/17/6/R289/abstract

Although fever and hypothermia are common abnormal physical signs observed in patients admitted to intensive care units (ICU), little data exists on their optimal management. The objective of this study was to describe contemporary practices and determinants of management of temperature abnormalities among patients admitted to ICUs.