Articles: closed-circuit-anesthesia.
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Anesthesia and analgesia · Feb 2011
Reinforcement learning: a novel method for optimal control of propofol-induced hypnosis.
Reinforcement learning (RL) is an intelligent systems technique with a history of success in difficult robotic control problems. Similar machine learning techniques, such as artificial neural networks and fuzzy logic, have been successfully applied to clinical control problems. Although RL presents a mathematically robust method of achieving optimal control in systems challenged with noise, nonlinearity, time delay, and uncertainty, no application of RL in clinical anesthesia has been reported.
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IEEE Trans Biomed Eng · Jan 2011
Closed-loop anesthetic drug concentration estimation using clinical-effect feedback.
This letter presents a novel closed-loop approach to anesthetic drug concentration estimation using clinical-effect measurement feedback. Compared with the open-loop prediction used in current target-controlled infusion systems, closed-loop estimation exploits the discrepancy between the measured and predicted clinical effects to make corrections to the drug-concentration estimate, achieving improved robustness against variability in the patient pharmacokinetics and pharmacodynamics. ⋯ Initial proof of principle of the closed-loop estimation is demonstrated using the Monte Carlo simulation of surgical procedures with a wide range of patient models. Closed-loop estimation results in statistically significant reductions in median percentage, median absolute percentage, and maximum absolute percentage drug-concentration errors compared to open-loop prediction.
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Carbon monoxide (CO) has been detected within anaesthesia breathing systems. One potential source in this setting is exhaled endogenous CO. We hypothesized that CO is re-breathed during low-flow anaesthesia (LFA) in infants and children. ⋯ LFA increased exhaled and inspired CO and increased COHb% in children <2 yr of age. Thus, LFA resulted in re-breathing of exhaled CO and exposure, especially in the youngest children. Re-breathing exhaled gas during LFA could pose a risk for an acute CO exposure in patients who have elevated COHb and high baseline levels of exhaled CO. If practitioners match or exceed minute ventilation with FGF to avoid LFA, CO re-breathing can be limited.
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Anesthesia and analgesia · Nov 2010
Randomized Controlled TrialThe accuracy of the anesthetic conserving device (AnaConDa©) as an alternative to the classical vaporizer in anesthesia.
The Anesthetic Conserving Device--AnaConDa® (ACD)--has been compared with a conventional vaporizer. However, the accuracy of the administered concentration of volatile anesthetics was not examined. In the present study we measured the accuracy of the ACD when used as a portable vaporizer. ⋯ We found that the ACD may be a valid alternative to the conventional vaporizer. The ACD is very simple to use, delivery rate needs to be adjusted only once per hour, and the anesthetic savings are independent of the circuit characteristics and fresh gas flow rate.