Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2011
Clinical TrialThe minimum effective anesthetic volume of 0.75% ropivacaine in ultrasound-guided interscalene brachial plexus block.
The use of ultrasound to monitor needle placement and spread of local anesthetics (LA) has allowed reductions in the volume of LA required to anesthetize peripheral nerves. In the current study we investigated the minimal volume necessary to accomplish surgical anesthesia with interscalene brachial plexus block. ⋯ All patients in our study had successful surgical blocks with 5 mL of LA. However, the lower limit of the CI (calculated on the assumption of a single failure) does include the possibility of a 25% failure rate; thus studies using similar stopping rules for doses higher than 5 mL are nonetheless warranted.
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Anesthesia and analgesia · Oct 2011
ReviewContinuous peripheral nerve blocks: a review of the published evidence.
A continuous peripheral nerve block, also termed "perineural local anesthetic infusion," involves the percutaneous insertion of a catheter adjacent to a peripheral nerve, followed by local anesthetic administration via the catheter, providing anesthesia/analgesia for multiple days or even months. Continuous peripheral nerve blocks may be provided in the hospital setting, but the use of lightweight, portable pumps permits ambulatory infusion as well. This technique's most common application is providing analgesia after surgical procedures. ⋯ Nearly all benefits occur during the infusion itself, but several randomized controlled trials suggest that in some situations there are prolonged benefits after catheter removal as well. Easily rectified minor complications occur somewhat frequently, but major risks including clinically relevant infection and nerve injury are relatively rare. This article is an evidence-based review of the published literature involving continuous peripheral nerve blocks.
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Anesthesia and analgesia · Oct 2011
Cannabidiol prevents the development of cold and mechanical allodynia in paclitaxel-treated female C57Bl6 mice.
The taxane chemotherapeutic paclitaxel frequently produces peripheral neuropathy in humans. Rodent models to investigate mechanisms and treatments are largely restricted to male rats, whereas female mouse studies are lacking. ⋯ Paclitaxel produced allodynia that was largely dose independent and more robust in female mice, and this effect was prevented by treatment with cannabidiol. Our preliminary findings therefore indicate that cannabidiol may prevent the development of paclitaxel-induced allodynia in mice and therefore be effective at preventing dose-limiting paclitaxel-induced peripheral neuropathy in humans.
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Anesthesia and analgesia · Oct 2011
Analysis of variance of communication latencies in anesthesia: comparing means of multiple log-normal distributions.
Anesthesiologists rely on communication over periods of minutes. The analysis of latencies between when messages are sent and responses obtained is an essential component of practical and regulatory assessment of clinical and managerial decision-support systems. Latency data including times for anesthesia providers to respond to messages have moderate (> n = 20) sample sizes, large coefficients of variation (e.g., 0.60 to 2.50), and heterogeneous coefficients of variation among groups. ⋯ Pivotal inference does not assume that the coefficients of variation of the studied log-normal distributions are the same, and can be used to assess the proportional effects of 2 factors and their interaction. Latency data can also include a human behavioral component (e.g., complete other activity first), resulting in a bimodal distribution in the log-domain (i.e., a mixture of distributions). An ANOVA can be performed on a homogeneous segment of the data, followed by a single group analysis applied to all or portions of the data using a robust method, insensitive to the probability distribution.
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Anesthesia and analgesia · Oct 2011
Pharmacokinetics and tissue penetration of cefoxitin in obesity: implications for risk of surgical site infection.
Obesity is a significant risk factor for surgical site infections (SSIs), for poorly understood reasons. SSIs are a major cause of morbidity, prolonged hospitalization, and increased health care cost. Drug disposition in general is frequently altered in the obese. Preoperative antibiotic administration, achieving adequate tissue concentrations at the time of incision, is an essential strategy to prevent SSIs. Nonetheless, there is little information regarding antibiotic concentrations in obese surgical patients. This investigation tested the hypothesis that the prophylactic antibiotic cefoxitin may have delayed and/or diminished tissue penetration in the obese. ⋯ Obese surgical patients have impaired tissue penetration of the prophylactic antibiotic cefoxitin, and inadequate tissue concentrations despite increased clinical dose (2 g). Inadequate tissue antibiotic concentrations may be a factor in the increased risk of SSIs in obese surgical patients. Additional studies are needed to define doses achieving adequate tissue concentrations.