Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2013
ReviewReview article: the anesthetic considerations of intraoperative electrocorticography during epilepsy surgery.
Epilepsy surgery is a well-established therapeutic intervention for patients with medically refractory seizures. Success of epilepsy surgery depends on the accurate localization and complete removal of the epileptogenic zone. Despite the advances in presurgical localization modalities, electrocorticography is still used in approximately 60% to 70% of the epilepsy centers in North America to guide surgical resection of the epileptogenic lesion and to assess for completeness of surgery. In this review, we discuss the principles and intraoperative use of electrocorticography, the effect of anesthetic drugs on electrocorticography, and the use of pharmacoactivation for intraoperative localization of epileptogenic zone.
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Anesthesia and analgesia · Aug 2013
Outcomes of early delirium diagnosis after general anesthesia in the elderly.
Postoperative delirium in the elderly, measured days after surgery, is associated with significant negative clinical outcomes. In this study, we evaluated the prevalence and in-hospital outcomes of delirium diagnosed immediately after general anesthesia and surgery in elderly patients. ⋯ Delirium in the PACU is common, but not universal. It is associated with subsequent delirium on the ward, and potentially with a decline in cognitive function and increased institutionalization at hospital discharge.
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Anesthesia and analgesia · Aug 2013
Comparative StudyFormulation and evaluation of lidocaine base ethosomes for transdermal delivery.
Although transdermal preparations of local anesthetics have been used to reduce pain caused by skin surgery, these preparations cannot effectively penetrate through the epidermis because of the barrier formed by the stratum corneum and the thick epidermis. Ethosomes can effectively transport drugs across the skin because of their thermodynamic stability, small size, high encapsulation efficiency, and percutaneous penetration. We evaluated lidocaine base ethosomes by measuring their loading efficiency, encapsulation efficiency, thermodynamic stability, and percutaneous penetration capability in vitro, and their effectiveness and cutaneous irritation in vivo. ⋯ Ethosomes are potential carriers of local anesthetics across the skin and may have applicability for other percutaneous drugs that require rapid onset.
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Anesthesia and analgesia · Aug 2013
Explanation for the near-constant mean time remaining in surgical cases exceeding their estimated duration, necessary for appropriate display on electronic white boards.
Consider a case that has been ongoing for longer than the scheduled duration. The anesthesiologist estimates that there is 1 hour remaining. Forty-five minutes later the case has not yet finished, and closure has not yet started. We showed previously that the mean (expected) time remaining is approximately 1 hour, not 15 minutes. The relationship is a direct mathematical consequence of the log-normal probability distributions of operating room (OR) case durations. We test the hypothesis that, with an accurate probabilistic model, until closure begins the estimated mean time remaining would be the mean time from the start of closure to OR exit. ⋯ If a case is taking longer than the expected (scheduled) duration, closure has not yet started, and someone in the OR is asked how much time the case likely has remaining, the value recorded on a clipboard for viewing later should be the estimated time remaining (e.g., "1 hour") not an end time (e.g., "5:15 pm"). Electronic whiteboard displays should not show that the estimated time remaining in the case is less than the mean time from start of closure to OR exit. Similarly, if closure has started, the expected time remaining that is displayed should not be longer than the mean time from closure to OR exit. Finally, our results match previous reports that, before a case starts, statistical methods can reliably be used to assist in decisions involving the longest amount of time that cases may take (e.g., conflict checking for resources, filling holes in the OR schedule, and preventing holes in the schedule).
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Anesthesia and analgesia · Aug 2013
Comparative StudyThe cytotoxicity of bupivacaine, ropivacaine, and mepivacaine on human chondrocytes and cartilage.
Intraarticular injections of local anesthetics are frequently used as part of multimodal pain regimens. However, recent data suggest that local anesthetics affect chondrocyte viability. In this study, we assessed the chondrotoxic effects of mepivacaine, ropivacaine, and bupivacaine. We hypothesized that specific cytotoxic potencies directly correlate with analgesic potencies, and that cytotoxic effects in intact cartilage are different than in osteoarthritic tissue. ⋯ Bupivacaine, ropivacaine, and mepivacaine are chondrotoxic in a time-dependent, concentration-dependent, and drug-dependent manner. Chondrotoxic and analgesic potencies do not directly correlate. Cellular death rates were higher in osteoarthritic compared with intact cartilage after local anesthetic treatment.