Coasting after overpressure induction with sevoflurane.
OBJECTIVE
To evaluate the clinical feasibility of using a coasting technique to temporarily maintain anesthesia after overpressure induction with sevoflurane.


METHODS
Prospective clinical study.


METHODS
Large teaching hospital.


METHODS
12 ASA physical status I, II, and III patients receiving general anesthesia for a variety of peripheral procedures.


METHODS
After overpressure induction of anesthesia with sevoflurane (8%) in an O(2)/N(2)O mixture, the fresh gas flow (FGF) was lowered to 0.5 L/min and the vaporizer was turned off (coasting).


RESULTS
After priming a circle system with sevoflurane (8% sevoflurane vaporizer setting in 6 L/min O(2)/N(2)O [33%/66%] for 30 s), patients took several vital capacity breaths from the mixture until loss of consciousness. After 3.4 +/- 0.7 min, depth of anesthesia was considered adequate for laryngeal mask airway (LMA) insertion, and FGF was reduced to 0.5 L/min (33% O(2), 66% N(2)O) and the sevoflurane vaporizer was turned off. The end-expired sevoflurane concentration (Et(sevo)) decreased from 5.8 +/- 1.3% just before insertion of the LMA to 0.97 +/- 0.22% at 20 minutes.


CONCLUSIONS
After overpressure induction with sevoflurane, coasting during minimal flow anesthesia (FGF 0.5 L/min) is a simple technique that can maintain anesthesia for short procedures (less than 15 to 20 min), or can be used as a bridge or an adjunct to other low-flow techniques.
Hendrickx
J F
JF
Department of Anesthesiology, Intensive Care and Pain Therapy, Onze Lieve Vrouwziekenhuis, Aalst, Belgium.
Vandeput
D M
DM
De Geyndt
A M
AM
DeLoof
T
T
De Wolf
A M
AM
D000328:Adult; D000769:Anesthesia, Inhalation / Q000295:instrumentation / Q000379:methods; D018685:Anesthetics, Inhalation / Q000008:administration & dosage* / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D017214:Laryngeal Masks; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage* / Q000378:metabolism; D009330:Nebulizers and Vaporizers; D009609:Nitrous Oxide / Q000008:administration & dosage; D019637:Orthopedic Procedures; D010100:Oxygen / Q000008:administration & dosage; D011312:Pressure; D011446:Prospective Studies; D000077149:Sevoflurane; D013990:Tidal Volume; D013997:Time Factors; D014797:Vital Capacity
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D002245:Carbon Dioxide; D000077149:Sevoflurane; D009609:Nitrous Oxide; D010100:Oxygen