Anesthesia and analgesia
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Several characteristics of sevoflurane biotransformation are apparent from the preceding investigations. Metabolism is rapid, with fluoride and HFIP appearing in plasma within minutes after the start of sevoflurane administration (38-40,51). Peak plasma fluoride concentrations generally occur within approximately 1 h after the termination of sevoflurane administration in most patients, regardless of the dose or duration of exposure (ranging from 0.35-9.5 MAC-h) (39,48). ⋯ Although both sevoflurane and methoxyflurane may produce plasma fluoride concentrations in excess of 50 microM, they have not produced the same nephrotoxic effects. Clearly, anesthetic metabolism and anesthetic toxicity can no longer be considered synonymous. The introduction of sevoflurane into clinical practice will hopefully stimulate new investigations into biochemical mechanisms of anesthetic toxicity and continued clinical investigations regarding the relationship between anesthetic metabolism and organ toxicity.
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Sevoflurane appears to have several properties that make it an attractive alternative to the currently available anesthetics for outpatient anesthesia. The relative low solubility of sevoflurane, as well as an impressive lack of airway irritation, makes it a very useful anesthetic for inhalation induction of anesthesia. This feature is likely to make sevoflurane a population choice for pediatric outpatient anesthesia. ⋯ The relatively low solubility of sevoflurane will facilitate its use with total gas flow rates of 2-3 L/min. In the final analysis, clinicians will have to balance the cost of sevoflurane (versus halothane, enflurane, isoflurane, and desflurane) against its potential advantages in the ambulatory surgery population. Although the search for anesthetics that are more ideally suited for use in the outpatient setting will continue, sevoflurane clearly represents a step in the right direction (3).
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Anesthesia and analgesia · Dec 1995
Comparative StudyA comparison of four bedside methods of hemoglobin assessment during cardiac surgery.
The purpose of this study was to compare the accuracy of conductivity, adjusted conductivity, photometric, and centrifugation methods of measuring or estimating hemoglobin (Hb) with Coulter measured HB as the reference. These bedside methods were studied in 25 cardiac surgery patients during euvolemia and hemodilution and after salvaged autologous red blood cell transfusion. In vivo patient blood samples were obtained before induction, at the start of cardiopulmonary bypass (CPB), after CPB, and after blood transfusion. ⋯ Hb assessment by different test methods may be significantly affected during hemodilution and after blood transfusion. In vitro conditions exaggerated the inaccuracy of conductivity and adjusted conductivity Hb estimates. The rank order of closest approximation to the Coulter measurement for all in vivo blood samples was provided by bedside photometry, followed by centrifugation, adjusted conductivity, and uncorrected conductivity methods.
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Anesthesia and analgesia · Dec 1995
Comparative StudyPerformance of computer-controlled infusion of propofol: an evaluation of five pharmacokinetic parameter sets.
Computer-controlled infusion of propofol is used with increasing frequency for the induction and maintenance of anesthesia. The performance of computer-controlled infusion devices is highly dependent on how well the implemented pharmacokinetic parameter set matches the pharmacokinetics of the patient. This study examined the performance of a computer-controlled infusion device when provided with five different pharmacokinetic parameter sets of propofol in female patients. ⋯ Then, for each of the five pharmacokinetic parameter sets, the performance in the population was determined by the median absolute performance error (MDAPE), the median performance error (MDPE), the wobble (the median absolute deviation of each PE from the MDPE), and the divergence (the percentage change of the absolute PE with time). The MDPE and MDAPE were compared between the parameter sets by the multisample median test. The initially used pharmacokinetic parameter set from Gepts et al. resulted in a MDPE of 24% and MDAPE of 26%.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Dec 1995
Clinical Trial Controlled Clinical TrialTransient neurologic symptoms after spinal anesthesia.
We recently reported several cases consistent with transient radicular irritation after spinal anesthesia with hyperbaric 5% lidocaine. The present prospective, blind, nonrandomized study was performed to determine the incidence of these transient neurologic symptoms and to identify factors that might be associated with their occurrence. We studied 270 patients scheduled for gynecologic or obstetric procedures under spinal anesthesia. ⋯ Transient neurologic symptoms were observed in 37% of patients receiving 5% lidocaine, whereas only one patient receiving 0.5% bupivacaine had transient hypesthesia of the lateral aspect of the right foot. These results suggest that symptoms were the result of a specific drug effect. However, because of the limitations of the study one cannot conclude that lidocaine per se was the cause.