Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2019
Consensus Statement of the Malignant Hyperthermia Association of the United States on Unresolved Clinical Questions Concerning the Management of Patients With Malignant Hyperthermia.
At a recent consensus conference, the Malignant Hyperthermia Association of the United States addressed 6 important and unresolved clinical questions concerning the optimal management of patients with malignant hyperthermia (MH) susceptibility or acute MH. They include: (1) How much dantrolene should be available in facilities where volatile agents are not available or administered, and succinylcholine is only stocked on site for emergency purposes? (2) What defines masseter muscle rigidity? What is its relationship to MH, and how should it be managed when it occurs? (3) What is the relationship between MH susceptibility and heat- or exercise-related rhabdomyolysis? (4) What evidence-based interventions should be recommended to alleviate hyperthermia associated with MH? (5) After treatment of acute MH, how much dantrolene should be administered and for how long? What criteria should be used to determine stopping treatment with dantrolene? (6) Can patients with a suspected personal or family history of MH be safely anesthetized before diagnostic testing? This report describes the consensus process and the outcomes for each of the foregoing unanswered clinical questions.
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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.
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Anesthesia and analgesia · Apr 2019
ReviewEscape From Oblivion: Neural Mechanisms of Emergence From General Anesthesia.
The question of how general anesthetics suppress consciousness has persisted since the mid-19th century, but it is only relatively recently that the field has turned its focus to a systematic understanding of emergence. Once assumed to be a purely passive process, spontaneously occurring as residual levels of anesthetics dwindle below a critical value, emergence from general anesthesia has been reconsidered as an active and controllable process. ⋯ In this narrative review, we focus on the burgeoning scientific understanding of anesthetic emergence, summarizing current knowledge of the neurotransmitter, neuromodulators, and neuronal groups that prime the brain as it prepares for its journey back from oblivion. We also review evidence for possible strategies that may actively bias the brain back toward the wakeful state.