Desflurane enhances reactivity during the use of the laryngeal mask airway.
BACKGROUND
Desflurane and sevoflurane have markedly different pungencies. The tested hypothesis was that patients breathing equivalent concentrations of desflurane or sevoflurane through a laryngeal mask airway (LMA) would have similar responses.


METHODS
After institutional review board approval and informed consent were obtained, 60 patients were enrolled and given intravenous midazolam (14 microg/kg) and fentanyl (1 microg/kg) 5 min before induction of anesthesia. The LMA was inserted at loss of consciousness after 2 mg/kg propofol. When spontaneous breathing returned, a randomly assigned volatile anesthetic was started at an inspired concentration of either 1.8% sevoflurane or 6% desflurane at a fresh gas flow of 6 l/min in air:oxygen (50:50). After 5 min, a controlled movement of the LMA took place. Three minutes later, the inspiratory anesthetic concentration was changed to either 3.6% sevoflurane or 12% desflurane for 3 min. A blinded observer recorded movements and airway events during the start of anesthetic, LMA movement, deepening of the anesthetic, and emergence before LMA removal.


RESULTS
There were no differences at anesthetic start and LMA movement. Desflurane titration to 12% increased heart rate, increased mean arterial blood pressure, and initiated frequent coughing (53% vs. 0% sevoflurane) and body movements (47% vs. 0% sevoflurane). During emergence, there was a twofold greater incidence of coughing and a fivefold increase in breath holding in the desflurane group.


CONCLUSIONS
When airway responses to sevoflurane and desflurane were compared in elective surgical patients breathing through an LMA, there were significantly more adverse responses with desflurane at 12% concentrations and during emergence.
Arain
Shahbaz R
SR
VA Medical Center, Milwaukee, Wisconsin 53295, USA.
Shankar
Hariharan
H
Ebert
Thomas J
TJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D000077335:Desflurane; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007530:Isoflurane / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology; D017214:Laryngeal Masks; D008738:Methyl Ethers / Q000494:pharmacology; D008875:Middle Aged; D000077149:Sevoflurane
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D000077335:Desflurane; D007530:Isoflurane