Critical care medicine
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Cerebral edema is a potentially life-threatening complication of acute liver failure, the syndrome of abrupt loss of liver function in a patient with a previously healthy liver. Although the prevalence of cerebral edema appears to be decreasing, patients with rapidly progressive (hyperacute) liver failure, such as after acetaminophen overdose, remain at highest risk. In severe cases of cerebral edema, intracranial hypertension develops and leads to brain death after brainstem herniation or to anoxic brain injury and permanent neurologic impairment. ⋯ Hypothermia may also ameliorate the degree of liver injury. Hypothermia has not been adequately studied for its safety and theoretically may increase the risk of infection, cardiac dysrhythmias, and bleeding, all complications independently associated with acute liver failure. Therefore, although an ample body of experimental and human data provides a rationale for the use of therapeutic hypothermia in patients with acute liver failure, multicenter, randomized, controlled clinical trials are needed to confirm that hypothermia secures brain viability and improves survival without causing harm.
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Critical care medicine · Jul 2009
ReviewMechanisms of action, physiological effects, and complications of hypothermia.
Mild to moderate hypothermia (32-35 degrees C) is the first treatment with proven efficacy for postischemic neurological injury. In recent years important insights have been gained into the mechanisms underlying hypothermia's protective effects; in addition, physiological and pathophysiological changes associated with cooling have become better understood. ⋯ Therapeutic hypothermia is a highly promising treatment, but the potential side effects need to be properly managed particularly if prolonged treatment periods are required. Understanding the underlying mechanisms, awareness of physiological changes associated with cooling, and prevention of potential side effects are all key factors for its effective clinical usage.
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Core body temperature is normally tightly regulated by an effective thermoregulatory system. Thermoregulatory control is sometimes impaired by serious illness, but more typically remains intact. The primary autonomic defenses against heat are sweating and active precapillary vasodilation; the primary autonomic defenses against cold are arteriovenous shunt vasoconstriction and shivering. ⋯ Anesthetics, for example, induce considerable tolerance, but are rarely suitable. Meperidine-especially in combination with buspirone-is especially effective while provoking only modest toxicity. The combination of buspirone and dexmedetomidine is comparably effective while avoiding the respiratory depression association with opioid administration.
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Critical care medicine · Jul 2009
Controlled Clinical TrialLungs of patients with acute respiratory distress syndrome show diffuse inflammation in normally aerated regions: a [18F]-fluoro-2-deoxy-D-glucose PET/CT study.
Neutrophilic inflammation plays a key role in the pathogenesis of acute respiratory distress syndrome (ARDS) and acute lung injury (ALI). Positron emission tomography (PET) with [F]-fluoro-2-deoxy-D-glucose (FDG) can be used to image cellular metabolism that, during lung inflammatory processes, likely reflects neutrophils activity. The aim of this study was to assess the magnitude and regional distribution of inflammatory metabolic activity in the lungs of patients with ALI/ARDS by PET with FDG. ⋯ In patients with ALI/ARDS, undergoing mechanical ventilation since days, the metabolic activity of the lungs is markedly increased across the entire lung density spectrum. The intensity of this activation and its regional distribution, however, vary widely within and between patients.
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Critical care medicine · Jul 2009
Physician attitudes toward regionalization of adult critical care: a national survey.
Regionalization has been proposed as a method to improve outcomes for patients with critical illness. We sought to determine intensivist physician attitudes and potential barriers to the regionalization of adult critical care. ⋯ Intensivist physicians have mixed opinions about regionalization, with little consensus about whether regionalization will improve outcomes. Most felt that regionalization will improve patient outcomes, but many expressed concerns about unintended adverse consequences. Respondents identified several barriers and potential implementation strategies that can help policymakers design a regionalized system of critical care in the United States.