Articles: closed-circuit-anesthesia.
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In contrast to hypnosis, there is no surrogate parameter for analgesia in anesthetized patients. Opioids are titrated to suppress blood pressure response to noxious stimulation. The authors evaluated a novel model predictive controller for closed-loop administration of alfentanil using mean arterial blood pressure and predicted plasma alfentanil concentration (Cp Alf) as input parameters. ⋯ The authors' controller has a similar set-point precision as previous hypnotic controllers and provides adequate alfentanil dosing during surgery. It may help to standardize opioid dosing in research and may be a further step toward a multiple input-multiple output controller.
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Acta Anaesthesiol Taiwan · Mar 2006
Randomized Controlled TrialClosed-circuit anesthesia preserves skin blood flow during surgery.
Closed-circuit anesthesia (CCA) has been suggested to provide better hemodynamic stability, but the relative contribution of CCA to the control of blood flow in microcirculation is not defined. It is hypothesized that isoflurane-based CCA provides a favorable skin blood flow mediating via lesser circulatory response to surgical stimulation. This study was purposed to compare the effects of isoflurane conveyed by CCA with that by semiclosed anesthesia (SCA) on the preservation of skin blood flow in the forearm. ⋯ Closed circuit technique for isoflurane anesthesia is feasible and advantageous. It not only facilitates favorable skin blood flow but also provides better hemodynamic stability in comparison with semiclosed technique for isoflurane anesthesia.
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Journal of anesthesia · Jan 2006
Randomized Controlled TrialSite of fresh gas inlet and ratios of the delivered fraction and inspired fraction of inhaled isoflurane and sevoflurane in low-flow anesthesia.
The use of low-flow anesthesia causes a discrepancy between the delivered fraction (FD) and the inspired fraction (FI) of inhaled gases. We compared the FI/FD ratios of a new circle (fresh gas inlet located between the inspiratory valve and the patient) to those of the conventional circle (fresh gas inlet located between the inspiratory valve and the CO2 absorber) in low-flow isoflurane and sevoflurane anesthesia, using three anesthetic machines (Dräger NM-GS, Dräger Fabius-GS, and ACOMA KMA-1300-III). ⋯ The positioning of the fresh gas inlet between the inspiratory valve and the patient improved the FI/FD ratios of both isoflurane and sevoflurane during low-flow anesthesia in two decoupling-style anesthetic machines (ACOMA and Fabius).