Anesthesia and analgesia
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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 · May 2013
Review Comparative StudyEstimating surgical case durations and making comparisons among facilities: identifying facilities with lower anesthesia professional fees.
Consumer-driven health care relies on transparency in cost estimates for surgery, including anesthesia professional fees. Using systematic narrative review, we show that providing anesthesia costs requires that each facility (anesthesia group) estimate statistics, reasonably the mean and the 90% upper prediction limit of case durations by procedure. The prediction limits need to be calculated, for many procedures, using Bayesian methods based on the log-normal distribution. ⋯ Such comparisons of durations among facilities should be performed with correction for the effects of the multiple comparisons. Our review also has direct implications to the potentially more important issue of how to study the association between anesthetic durations and patient morbidity and mortality. When pooling duration data among facilities, both the large heterogeneity in the means and coefficients of variation of durations among facilities need to be considered (e.g., using "multilevel" or "hierarchical" models).
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Anesthesia and analgesia · Jan 2013
Case ReportsCase report: ultrasound-guided continuous thoracic paravertebral block for outpatient acute pain management of multilevel unilateral rib fractures.
A 61-year-old man with multiple unilateral rib fractures (T3-T8) gained the ability to breathe deeply and to ambulate after ultrasound-guided continuous thoracic paravertebral block and was discharged home after being observed for 15 hours after the block. The ultrasound guidance was helpful in determining the site of rib fractures and the optimal level for catheter placement. This report also discusses the management of analgesia using continuous paravertebral block in an outpatient with trauma.
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Anesthesia and analgesia · Aug 2013
ReviewReview article: endotracheal tube cuff leaks: causes, consequences, and management.
The consequences of endotracheal tube (ETT) cuff leak may range from a bubbling noise to a life-threatening ventilatory failure. Although the definitive solution is ETT replacement, this is often neither needed nor safe to perform. Frequently, the leak is not caused by a structural defect in the ETT. ⋯ A risk/benefit analysis of each individual situation is warranted before decisions are made on how best to proceed. Alternative back-up ventilation plans should be preformulated and the necessary equipment ready before the exchange. In this review, various management concerns and plans are discussed, and a simple algorithm to manage leaky ETT cuff situations is presented.
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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).