Articles: closed-circuit-anesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Efficiency of a circle system for short surgical cases: comparison of desflurane with isoflurane.
Patients undergoing short surgical procedures but requiring ventilation of the lungs were allocated randomly to receive either desflurane or isoflurane by circle absorption system, initially at a high fresh gas flow. The inspired and expired concentrations of the volatile agent were measured and the fresh gas flows reduced to low flow (500 ml min-1 total when FE/FI = 0.8), as measured on a multigas analyser. In patients receiving desflurane (n = 32), the median time at which flows were reduced was 5 min (interquartile range (IQR) 1 min) while with isoflurane (n = 32), the median time was 19 (IQR 12) min. ⋯ In the isoflurane group the concentration continued to decrease during anaesthesia. In the desflurane group the initial decrease was followed by a slow recovery. We conclude that the circle system can be used efficiently for short anaesthetics using desflurane.
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Acta Anaesthesiol Belg · Jan 1996
Randomized Controlled Trial Clinical TrialCarboxyhemoglobin concentrations during desflurane and isoflurane closed-circuit anesthesia.
Desflurane has been implicated in carbon monoxide (CO) intoxication during general anesthesia under certain circumstances. Carboxyhemoglobin (COHb) concentrations were determined in forty-one patients who were randomly allocated to receive closed-circuit anesthesia (CCA) with 1.3 MAC of desflurane (n = 21) or isoflurane (n = 20) in oxygen. Soda lime was used to bind the produced CO2 in previous anesthetic procedures with fresh gas flows of < 21/min. ⋯ In the isoflurane group, COHb concentrations were 1.15 +/- 1.47% and 1.19 +/- 1.39% before and after 1 h of anesthesia, respectively. COHb concentrations did not increase after 2 h of CCA in seven patients. Our data suggest that closed-circuit anesthesia with desflurane or isoflurane does not produce clinically significant increases in COHb concentrations under conditions that allow the soda lime to remain sufficiently wet.
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Randomized Controlled Trial Clinical Trial
Heated breathing tubes affect humidity output of circle absorber systems.
To verify whether the airway climate in circle systems can be improved with heated breathing tubes. ⋯ Low-flow systems need at least 120 minutes to achieve a satisfactory airway climate. Heated breathing tubes effectively reduce this delay.
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Randomized Controlled Trial Clinical Trial
Effect of low fresh gas flow rates on inspired gas composition in a circle absorber system.
To determine the effects of fresh gas flow on inspired gas composition during low-flow anesthesia. ⋯ The same initial period of denitrogenation is not adequate to denitrogenate the circle system in all cases. The lower the fresh gas flow, the longer the initial period of denitrogenation should be. Various levels of fresh gas flow for low-flow anesthesia have been suggested, but none guarantees adequate control of inspired gas composition unless flowmeters are continuously adjusted.
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Cahiers d'anesthésiologie · Jan 1992
Randomized Controlled Trial Comparative Study Clinical Trial[A comparative study of the cost of open-circuit as opposed to closed-circuit ventilation].
The authors compared two open randomized groups of patients undergoing surgery through general anaesthesia. Group 1 consisted of 54 patients ventilated by a Siemens 900 B ventilator in open circuit, and group 2, 56 patients ventilated by an ELSA de Gambro ventilator in a closed circuit. Comparative hour cost for nitrous oxide (N2O), oxygen (O2) and halogen gas, Enflurane, Isoflurane, was noted. ⋯ In order to improve the effective cost of close circuit, the authors proposed: the use of closed circuit ventilation for more than 3 hours surgery, gas saturation in closed circuit after denitrogenation--which demands the use of halogen infjectors, and lime in containers cheaper than disposable cartridges. Respecting the above criteria, the total hour cost in close circuit fell to 4.90 FF, gain of 63% against open circuit. For O2 et N2O, the hour cost goes from 1.34 FF in close circuit to 13.28 FF in open circuit, 90% economy.(ABSTRACT TRUNCATED AT 250 WORDS)