Anesthesiology clinics
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Anesthesiology clinics · Dec 2011
Current sedation practices: lessons learned from international surveys.
Limitations are inherent to surveys. Most surveys have low response rates, which raises the issue of responder bias. Another limitation of self-report surveys stems from the possible differences between stated and actual practice. ⋯ Overall, there is a trend toward lighter sedation, along with a shift from benzodiazepines toward propofol, and from morphine toward fentanyl and remifentanil. Despite the publication of numerous studies and guidelines for sedation and analgesia, actual practice differs from recommended practice, suggesting that the impact of clinical trials and guidelines on physician practice is quite low. It is clear that there remain substantial barriers to the incorporation of sedation scales, protocols,and daily interruption into routine ICU care.
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Protocolized target-based sedation and analgesia is central to effective management of sedation. Important components include identifying goals and specific targets,using valid and reliable tools to measure pain, agitation, and sedation, and titrating a logically selected combination of sedatives and analgesics to defined end-points. A variety of approaches to structured management have been tested in controlled trials with major categories of (1) sedation algorithms and protocols and (2) daily interruption of sedation. ⋯ The somewhat discrepant results illustrate, however, that various approaches,such as DIS, may not be optimal for all patients. Further research will be necessary to define these patients and examine alternative strategies. Finally, implementation of structured approaches to sedation management is a challenging, time-consuming process for clinicians that must be supported with sufficient resources to be successful.
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Anesthesiology clinics · Dec 2011
Pharmacology of commonly used analgesics and sedatives in the ICU: benzodiazepines, propofol, and opioids.
The ideal sedative or analgesic agent should have a rapid onset of activity, a rapid recovery after drug discontinuation, a predictable dose response, a lack of drug accumulation,and no toxicity. Unfortunately, none of the earlier analgesics, the benzodiazepines,or propofol share all of these characteristics. ⋯ In addition, the ever-changing dynamics of patients who are critically ill makes the use of sedation a continual challenge during the course of each patient’s admission. To optimize care, clinicians should be familiar with the many pharmacokinetic, pharmacodynamic, and pharmacogenetic variables that can affect the safety and efficacy of sedatives and analgesics.
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As the armamentarium for sedation in the critically ill expands, opportunities will develop to modulate the immune responses of patients by way of the direct immune and neural-immune interactions of the sedatives. Control of autonomic activity through the use of appropriate sedation may be critical in this matter. Likewise analgesic-based sedation, with increased opioid dosage, may not prove beneficial in the setting of infection; whether avoidance of morphine in preference for a fentanyl derivative will help is unclear. ⋯ Similarly, the present evidence suggests benzodiazepines are deleterious in infection; further studies are required urgently to evaluate this evidence. As an alternative to benzodiazepine-based sedation, dexmedetomidine has shown a remarkable 70% mortality benefit in a small secondary analysis of septic patients from the MENDS trial. Further powered clinical studies should now be undertaken to investigate the potential benefit of the α2-adrenoceptor agonist in this setting, with comparisons with propofol.
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Anesthesiology clinics · Dec 2011
Pharmacology of sedative-analgesic agents: dexmedetomidine, remifentanil, ketamine, volatile anesthetics, and the role of peripheral Mu antagonists.
In this article, the authors discuss the pharmacology of sedative-analgesic agents like dexmedetomidine, remifentanil, ketamine, and volatile anesthetics. Dexmedetomidine is a highly selective alpha-2 agonist that provides anxiolysis and cooperative sedation without respiratory depression. It has organ protective effects against ischemic and hypoxic injury, including cardioprotection, neuroprotection, and renoprotection. ⋯ Ketamine is a nonbarbiturate phencyclidine derivative and provides analgesia and apparent anesthesia with relative hemodynamic stability. Volatile anesthetics such as isoflurane, sevoflurane, and desflurane are in daily use in the operating room in the delivery of general anesthesia. A major advantage of these halogenated ethers is their quick onset, quick offset, and ease of titration in rendering the patient unconscious, immobile, and amnestic.