Overview of Therapeutic Hypothermia

Abstract

Therapeutic Hypothermia has proven neuroprotective effects in global cerebral ischemia. Indications for hypothermia induction include cardiac arrest and neonatal asphyxia. The two general methods of induced hypothermia are either surface cooling or endovascular cooling. Hypothermia should be induced as early as possible to achieve maximum neuroprotection and edema blocking effect. Endovascular cooling has the benefit of shorter time to reach target temperature but catheter insertion requires expertise and training, which may be a barrier to widespread availability. The optimum method of cooling is yet to be determined but a multimodal approach is necessary to address three phases of cooling: induction, maintentance, and re-warm. Specifying core practitioners who are well-versed in established guidelines can help integrate the multidisciplinary team that is needed to successfully implement cooling protocols. Reducing shivering to make heat exchange more efficient with tighter temperature control enables quicker time to target temperature and avoids re-warming which can lead to inadvertent increase in intracranial pressure and cerebral edema. Promising applications but yet to be determined is whether hypothermia treatment can improve outcomes in acute ischemic stroke or traumatic brain injury.

Effects of Mild Hypothermia Treatment on Rat Hippocampal β-Amyloid Expression Following Traumatic Brain Injury

“…MIH involves the rapid application of mild hypothermia regimens, as suggested and confirmed by several recent studies (Brain Trauma Foundation et al, 2007;van der Worp et al, 2007;Song and Lyden, 2012;Urbano and Oddo, 2012). In a study of 1626 patients with severe TBI, suggested that hyperthermia following TBI was a key detrimental factor to patient prognosis, accentuating delayed mechanisms that follow initial physical disruption during the primary injury and causing injury to hippocampal tissues.…”

“…In addition, Ab may also be responsible for abnormal and potentially adverse metabolic activities, such as low glucose levels, elevated neuronal excitability, oxidative stress in various tissues, intracellular calcium imbalance, and promotion of inflammatory response processes (Lindholm et al, 2006). Therapeutic hypothermia induced by either surface or endovascular cooling in clinical settings has been proven to exhibit both neuroprotective and edema blocking effects following cerebral ischemia (Song and Lyden, 2012). More recently, mild induced hypothermia (MIH) has also been shown to significantly reduce the incidence of SBI (van der Worp et al, 2007).…”

Neuroprotective action of acute estrogens: Animal models of brain ischemia and clinical implications

“…Brain ischemia remains a major health concerns in the US, but unfortunately few effective and safe treatments are available [2]. Therapeutic hypothermia and thrombolysis with tissue plasminogen activator (tPA) are the only recommended treatments to improve neurological outcomes [6]. However, due to narrow therapeutic time windows (e.g., <3 h for tPA), only few patients can receive treatment [7].…”

Use of Therapeutic Hypothermia in Cocaine-Induced Cardiac Arrest: Further Evidence

“…9 Conversely, therapeutic hypothermia has long been believed to be capable of reducing primary brain injury and preventing secondary inury, 10 and its use even in stroke patients is an area of ongoing study and scientific interest without definitive conclusions. 11 Therapeutic hypothermia is theorized to combat global ischemia in several unique ways. Global ischemia, defined as perfusion less than a twentieth of the baseline, induces selective neuronal death indicated metabolic acidosis and yielded a pH of 7.30, PCO 2 of 35.0 mm Hg, bicarbonate level of 16 mEq/L, and PO 2 of 390 mm Hg.…”