Articles: closed-circuit-anesthesia.
-
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.
-
Our objective was to determine if rebreathing would reduce the gradient between arterial and end-tidal CO2 tension during positive-pressure ventilation. ⋯ Rebreathing with a Mapleson D circuit and a VF equal to VA permitted normal CO2 elimination. Arterial PCO2 to PECO2 gradient decreased significantly during rebreathing, thus improving the reliability of capnography for estimating arterial PCO2. Consideration should be given to using the Mapleson D as a rebreathing circuit.
-
Although many anaesthesia machines are equipped with circle rebreathing systems, inhalational anaesthesia remains frequently performed using relatively high fresh-gas flows. The major advantages of rebreathing techniques can be achieved only if the fresh-gas flow is reduced to 1 l.min-1 or less. Although there are potential risks associated with low-flow anaesthesia, modern anaesthesia machines meet all the technical requirements for the safe use of low-flow techniques if they are used in conjunction with equipment for monitoring inhaled and exhaled gas concentrations; these monitors are already increasingly available and, in the near future, are likely to become an obligatory safety standard in many countries. For both economic and ecological reasons, the use of new inhalational anaesthetics, with low tissue solubility and low anaesthetic potency, can be justified only if the efficiency of administration is optimised by using low-flow anaesthetic techniques.
-
Anasthesiol Intensivmed Notfallmed Schmerzther · Aug 1995
Review[Anesthesia with low fresh gas flow in clinical routine use].
Anaesthesia in low-flow techniques gains increasing interest. The possibility of cost reduction, widespread use of highly developed anaesthesia machines and monitors, and introduction of two new fluorinated inhalational anaesthetics with low solubility in human tissues encourage the use of low-flow anaesthesia techniques. Further advantages are improved climatisation of breathing gas and estimation or even measurement of the important parameter "oxygen consumption". ⋯ However, the use of multigas monitors, analyzing most parts of the breathing gas, facilitates the use of low-flow techniques. Multigas monitors and anaesthesia machines equipped with intermittent fresh gas delivery are recommended for the use of fresh gas flow rates close to the metabolic rate. Because of its physicochemical properties the new inhalational anaesthetic desflurane offers advantages for the use in low-flow anaesthesia techniques.