[Desflurane and isoflurane in minimal-flow anesthesia. Consumption and costs with forced fresh gas reduction].
BACKGROUND
In the present investigation we compared the consumption of desflurane (DES) and isoflurane (ISO) using a standardized minimal-flow protocol with a forced reduction of the fresh gas flow (FGF).


METHODS
54 adult women were examined. After induction of anaesthesia a forced reduction of the FGF was started: 5 min 0.5 l/min O(2) + 1 l/min N(2)O, 10 min 0.5 l/min O(2) + 0.5 l/min N(2)O; finally 0.3 l/min O(2) + 0.2 l/min N(2)O up to the end of surgery. The consumption of DES/ISO was determined with a precision balance.


RESULTS
In the DES group the uptake was around 0.3 vol-%, i.e. less than 8% of the target 2/3 MAC value was taken up. For ISO the uptake was around 0.25 vol-%, i.e. the uptake was approximately 30% of the target 2/3-MAC value. The DES consumption was after 60 min 17.0+/-1.1 g, 120 min--27.3+/-1.8 g and 180 min--36.5+/-1.7 g. ISO consumption was significantly lower: 7.6+/-0.8 g, 12.4+/-1.7 g and 15.5+/-1.6 g. The use of DES yielded higher costs, i.e. 2.28 EUR for 60 min, 3.63 EUR for 120 min and 4.97 EUR for 180 min. The consumption of the inhaled anaesthetics can be calculated as: DES (g)=4.84+0.184 x duration (min) (R(2)=0.981), ISO (g)=2.049+0.0826 x duration (R(2)=0.979). The costs are: DES (EUR)=0.85+0.0323 x duration (min); ISO (EUR)=0.19+0.0077 x duration (min).


CONCLUSIONS
With a forced reduction of the FGF the DES consumption is still higher.
Buchinger
H
H
Klinik für Anaesthesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum des Saarlandes, 66421 Homburg/Saar. heiko.buchinger@uniklinik-saarland.de
Kreuer
S
S
Paxian
M
M
Larsen
R
R
Wilhelm
W
W
D000328:Adult; D000368:Aged; D000769:Anesthesia, Inhalation / Q000191:economics* / Q000379:methods*; D018685:Anesthetics, Inhalation / Q000191:economics; D003365:Costs and Cost Analysis; D000077335:Desflurane; D016527:Drug Costs; D005260:Female; D013509:Gynecologic Surgical Procedures; D006801:Humans; D007530:Isoflurane / Q000031:analogs & derivatives* / Q000191:economics; D008875:Middle Aged; D009609:Nitrous Oxide / Q000191:economics
D018685:Anesthetics, Inhalation; D000077335:Desflurane; D007530:Isoflurane; D009609:Nitrous Oxide