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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The concept of neuroprotection' by hypothermia dates back to ancient times. This paper reviews the results of clinical trials using mild hypothermia (3235 degrees C) in patients with severe traumatic brain injury over the past decade. Induced hypothermia has been used in experimental models mostly to prevent or attenuate secondary neurological injury and has been used to provide neuroprotection in traumatic brain injury, both in animal models and clinical trials. Results from animal experiments largely confirm that hypothermia can provide protection for the injured brain; however, the results from clinical trials and from a number of meta-analyses have been conflicting. This paper reviews the evidence and explores possible reasons for the mixed results from clinical trials. Hypothermia is clearly effective in controlling intracranial hypertension. Early favourable results on neurological outcome and mortality were not confirmed in a subsequent multi-center trial. Subsequently, single-centre studies, with quicker induction of hypothermia and longer duration of cooling, again reported benefits on outcome. These differences may be explained by differences in study protocols (i.e. speed and duration of cooling, speed of re-warming), prevention of side effects and various supportive measures in the ICU. Although induced hypothermia appears to be a highly promising treatment in various forms of neurological injury including traumatic brain injury, the difficulties in realising its therapeutic potential are underscored by the negative results from a large multi-center trial. Routine usage of hypothermia in traumatic brain injury can not currently be recommended.
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PMID:[Moderate hypothermia in traumatic brain injury: results of clinical trials]. 1517 98

Severe intracranial hypertension (IH) in the setting of fulminant hepatic failure (FHF) carries a high mortality and is a challenging disease for the critical care provider. Despite considerable improvements in the understanding of the pathophysiology of cerebral edema during liver failure, therapeutic maneuvers that are currently available to treat this disease are limited. Orthotopic liver transplantation is currently the only definitive therapeutic strategy that improves outcomes in patients with FHF. However, many patients die prior to the availability of donor organs, often because of cerebral herniation. Currently, two important theories prevail in the understanding of the pathophysiology of IH during FHF. Ammonia and glutamine causes cytotoxic cerebral injury while cerebral vasodilation caused by loss of autoregulation increases intracranial pressure (ICP) and predisposes to herniation. Although ammonia-reducing strategies are limited in humans, modulation of cerebral blood flow seems promising, at least during the early stages of hepatic encephalopathy. ICP monitoring, transcranial Doppler, and jugular venous oximetry offer valuable information regarding intracranial dynamics. Induced hypothermia, hypertonic saline, propofol sedation, and indomethacin are some of the newer therapies that have been shown to improve survival in patients with severe IH. In this article, we review the pathophysiology of IH in patients with FHF and outline various therapeutic strategies currently available in managing these patients in the critical care setting.
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PMID:Therapy of intracranial hypertension in patients with fulminant hepatic failure. 1662 10

Induced hypothermia (IH) continues to become a more prevalent treatment modality in neurocritical care. Reducing core temperature has been shown to protect brain tissue during injury and disease. IH has been particularly beneficial in the medical management of refractory intracranial hypertension and malignant cerebral edema. These pathologies are often the result of diffuse cerebral edema after traumatic brain injury, malignant ischemic stroke, or intracerebral hemorrhage. Although there are many benefits to IH, it is not without complications. Chief among these is shivering, which decreases oxygen delivery to brain tissue, increases metabolic demands, and consequently reduces nutrient delivery. This article will review indications for IH administration, methods of providing IH, nursing responsibilities, and identifying and/or managing complications.
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PMID:Induced Hypothermia in Neurocritical Care: A Review. 2760 27

The depth of anesthesia is commonly assessed in clinical practice by the patient's clinical signs. However, during cardiopulmonary bypass and hypothermia, common symptoms of nociception such as tachycardia, hypertension, sweating, or movement have low sensitivity and specificity in the description of the patient nociception and hypnosis, in particular, detecting nociceptive stimuli. Better monitoring of the depth of analgesia during hypothermia under cardiopulmonary bypass will avoid underdosage or overdosage of analgesia, especially opioids. Induced hypothermia has a multifactorial effect on the level of analgesia and hypnosis. Thermoregulatory processes appear essential for the activation of analgesic mechanisms, ranging from a physiological strong negative affiliation between nerve conduction velocity and temperature, until significant repercussions on the pharmacological dynamics of the analgesic drugs, the latter decreasing the clearance rate with a subsequent increase in the effect-site concentrations. Under the hypothesis that deep hypothermia induces massive effects on the analgesia and hypnosis levels of the patient, we studied whether hypothermia effects were mirrored by several neuromonitoring indices: two hypnosis indices, consciousness index and bispectral index, and a novel nociception index designed to evaluate the analgesic depth. In this clinical trial, 39 patients were monitored during general anesthesia with coronary atherosclerosis cardiopathy who were elective for on-pump coronary artery bypass graft surgery under hypothermia. The changes and correlation between the consciousness index, bispectral index, and nociception index with respect to the temperature were compared in different timepoints at basic state, during cardiopulmonary bypass and after cardiopulmonary bypass. While the three neuromonitoring indices showed significant correlations with respect to the temperature, the nociception index and consciousness index showed the strongest sensitivities, indicating that these two indices could be an important means of intraoperative neuromonitoring during induced hypothermia under cardiopulmonary bypass.
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PMID:The effect of hypothermia during cardiopulmonary bypass on three electro-encephalographic indices assessing analgesia and hypnosis during anesthesia: consciousness index, nociception index, and bispectral index. 3138 54