Therapeutic hypothermia for neuroprotection: history, mechanisms, risks, and clinical applications

Abstract

The earliest recorded application of therapeutic hypothermia in medicine spans about 5000 years; however, its use has become widespread since 2002, following the demonstration of both safety and efficacy of regimens requiring only a mild (32°C-35°C) degree of cooling after cardiac arrest. We review the mechanisms by which hypothermia confers neuroprotection as well as its physiological effects by body system and its associated risks. With regard to clinical applications, we present evidence on the role of hypothermia in traumatic brain injury, intracranial pressure elevation, stroke, subarachnoid hemorrhage, spinal cord injury, hepatic encephalopathy, and neonatal peripartum encephalopathy. Based on the current knowledge and areas undergoing or in need of further exploration, we feel that therapeutic hypothermia holds promise in the treatment of patients with various forms of neurologic injury; however, additional quality studies are needed before its true role is fully known.

Keywords: clinical; clinical specialty; nervous system; neurocritical care; neurophysiology; techniques; trauma.

Conflict of interest statement

Declaration of Conflicting Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.

Dr James Currie. Reprinted from Cosby CB. James Currie and hydrotherapy. J Hist Med Allied Sci. 1950;5(3):280-288, with permission from Oxford University Press.

Figure 2.

Dr Temple Fay. Reprinted from Alzaga AG, Salazar GA, Varon J, with permission from Elsevier.

Figure 3.

Special insulated mattress between the bed and a “zipper” blanket containing rubber tubing for continuous circulation of chilled fluids. Reprinted from Alzaga AG, Salazar GA, Varon J, with permission from Elsevier.

Figure 4.

Solid circles joined by solid lines represent mean cerebral blood flows of 4 animals at 35°C, 30°C, and 26°C. Open circles joined by broken lines represent mean cerebral O2 consumption of the same animals. Vertical lines represent standard error of each mean. Reprinted from Rosomoff HL, Holaday DA, with permission from the American Physiological Society.