Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2019
ReviewNeuroinflammation in the Developing Brain: Risk Factors, Involvement of Microglial Cells, and Implication for Early Anesthesia.
Microglia cells, the resident macrophages of the central nervous system, are key actors for specific brain functions that are critical for development and health. Microglial reactivity and functions, even when immature, play a major role if the developing brain is subjected to abnormal perinatal events. Brain exposure to general anesthesia, surgery, or analgesic drugs during early infancy may adversely affect its maturation and plasticity after injury. ⋯ This review recapitulates the most frequent perinatal circumstances associated with exacerbated systemic inflammation and neuroinflammation together with the double-edged role of microglia associated with subsequent brain damage. A role for microglial reactivity in both potential anesthetic toxicity and neuroprotection is emerging. However, further preclinical experiments are needed to better understand regulatory mechanisms of the developing microglia, and interaction between anesthesia and neuroinflammation in the developing brain.
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There are occasionally intraoperative circumstances in which reduction of mean arterial pressure (MAP) to levels well below those that occur in nonanesthetized adults is necessary or unavoidable. In these situations, clinicians are inevitably concerned about the limits of the tolerance of the brain for hypotension. ⋯ The principal theses offered by this review are: (1) that the average lower limit of cerebral blood flow autoregulation in normotensive adult humans is not less than a MAP of 70 mm Hg; (2) that there is considerable intersubject variability in both the lower limit of cerebral blood flow autoregulation and the efficiency of cerebral blood flow autoregulation; (3) that there is a substantial blood flow reserve that buffers the normal central nervous system against critical blood flow reduction in the face of hypotension; (4) that there are several common clinical phenomena that have the potential to compromise that buffer, and that should be taken into account in decision making about minimum acceptable MAPs; and (5) that the average threshold for the onset of central nervous system ischemic symptoms is probably a MAP of 40-50 mm Hg at the level of the circle of Willis in a normotensive adult in a vertical posture and 45-55 mm Hg in a supine subject. However, these MAPs should probably only be approached deliberately when the exigencies of the surgical situation absolutely require it.
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Anesthesia and analgesia · Apr 2019
ReviewLong-term Cognitive and Functional Impairments After Critical Illness.
As critical illness survivorship increases, patients and health care providers are faced with management of long-term sequelae including cognitive and functional impairment. Longitudinal studies have demonstrated impairments persisting at least 1-5 years after hospitalization for critical illness. Cognitive domains impacted include memory, attention, and processing speed. ⋯ Multifactorial prevention bundles are useful tools in improving care provided to patients in the intensive care unit. Data regarding cognitive rehabilitation are limited, while studies on functional rehabilitation have conflicting results. Continued investigation and implementation of prevention strategies and rehabilitation interventions will hopefully improve the quality of life for the ever-increasing population of critical illness survivors.