Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2007
Case ReportsThe use of intraoperative ultrasound by anesthesiologists to facilitate the surgical management of peripheral nerve tumors of the upper extremity.
Traditional uses of ultrasound by anesthesiologists include transesophageal echocardiography, facilitation of vascular access, and guidance of peripheral nerve blocks. ⋯ Ultrasound can be used by anesthesiologists to facilitate the surgical management of peripheral nerve tumors.
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Anesthesia and analgesia · Dec 2007
Case ReportsThe use of brain positron emission tomography to identify sites of postoperative pain processing with and without epidural analgesia.
It is not known how different analgesic regimes affect the brain when reducing postoperative pain. We performed positron emission tomography (PET) scans on a 69-yr-old woman in the presence of moderate postoperative pain and then with epidural analgesia producing complete analgesia, during the first 2 days after total knee arthroplasty. ⋯ Other brain regions showing increased postsurgical activity were the contralateral parietal cortex, bilateral pulvinar and ipsilateral medial dorsal nucleus of the thalamus, contralateral putamen, contralateral superior temporal gyrus, ipsilateral fusiform gyrus, ipsilateral posterior lobe, and contralateral anterior cerebellar lobe. This study demonstrates the feasibility of evaluating the central processing of acute postoperative pain using PET.
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Anesthesia and analgesia · Dec 2007
Case ReportsA differential diagnosis of hyperalgesia, toxicity, and withdrawal from intrathecal morphine infusion.
Opioid-induced hyperalgesia, toxicity, and withdrawal are phenomena that may occur with intrathecal opioid infusion. We present a case in which a patient received intrathecal morphine infusion, and then experienced a clinical course that may have involved hyperalgesia, toxicity, and/or withdrawal. The possible differential diagnosis of opioid-induced hyperalgesia, toxicity, and withdrawal, and its implications in clinical pain management, are discussed. This report demonstrates the complexity of treating patients with long-term continuous intrathecal opioids when modest adjustment of the intrathecal cocktail results in a paradoxical clinical course.
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Anesthesia and analgesia · Dec 2007
Estimation of optimal modeling weights for a Bayesian-based closed-loop system for propofol administration using the bispectral index as a controlled variable: a simulation study.
Implementing Bayesian methods in a model-based closed-loop system requires the integration of a standard response model with a patient-specific response model. This process makes use of specific modeling weights, called Bayesian variances, which determine how the specific model can deviate from the standard model. In this study we applied simulations to select the Bayesian variances yielding the optimal controller for a Bayesian-based closed-loop system for propofol administration using the Bispectral Index (BIS) as a controlled variable. ⋯ We believe this system can be introduced safely into clinical testing for both induction and maintenance of anesthesia under direct observation of an anesthesiologist.
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Anesthesia and analgesia · Dec 2007
Comparative StudyThe relationship between current intensity for nerve stimulation and success of peripheral nerve blocks performed in pediatric patients under general anesthesia.
We evaluated the relationship between the lowest current amperage used to obtain a motor response, the success rate and the incidence of neurological complications with peripheral nerve blocks (PNB) in pediatric patients under general anesthesia. ⋯ In this study, a similar PNB success rate was observed with both a low (*0.5 mA) and a high stimulation threshold (>0.5 mA). Therefore, it may not be necessary to perform needle manipulations to achieve a low stimulation threshold (< or =0.5 mA), as this may increase the risk of intraneural injection.