Severity of airway hyperreactivity associated with laryngeal mask airway removal: correlation with volatile anesthetic choice and depth of anesthesia.
OBJECTIVE
To compare the influence of anesthetic depth and choice of volatile anesthetic drug on the incidence and severity of airway hyperreactivity associated with Laryngeal Mask Airway (LMA) removal.


METHODS
Randomized observer-blinded study.


METHODS
Ambulatory Surgical Center at a University Medical Center.


METHODS
123 ASA physical status I and II children undergoing infraumbilical procedures.


METHODS
Patients were randomly assigned to one of four treatment groups: Group 1 = anesthetic induction with halothane, maintenance with isoflurane, nitrous oxide (N(2)O), and oxygen (O(2)), LMA removed when child awakened; Group 2 =anesthetic induction and maintenance as in Group 1, LMA removed while child anesthetized with age adjusted 2 minimum alveolar concentration (MAC) end-tidal concentration of isoflurane; Group 3 = anesthetic induction and maintenance with sevoflurane, N(2)O, and O(2), LMA removed when child awakened; Group 4 = anesthetic induction and maintenance as in Group 3, but LMA removed while child anesthetized with age-adjusted 2 MAC end-tidal concentration of sevoflurane.


RESULTS
Severity of airway hyperreactivity was graded as mild, moderate, or severe. A significant difference was not found amongst the four groups with respect to mild and moderate airway hyperreactivity. Severe airway hyperreactivity leading to a critical event [partial or complete laryngospasm with oxygen saturation (SPO(2)) < 85%] was only encountered in Group 1 patients (incidence 13%). Adverse airway events (SPO(2) < 90%, vomiting and bronchospasm) were also significantly higher in Group 1 (p < 0.05). Isoflurane use was independently associated with significantly higher airway hyperreactivity when compared with sevoflurane (p < 0.05).


CONCLUSIONS
Depth of anesthesia during LMA removal does not appear to affect the incidence or severity of airway hyperreactivity when sevoflurane is the maintenance anesthetic. However, awake LMA removal during isoflurane anesthesia results in a higher incidence of adverse airway events and carries the risk of severe airway hyperreactivity.
Pappas
A L
AL
Department of Anesthesiology, Loyola University Medical Center, 2160 South First Ave., Maywood, IL 60153, USA.
Sukhani
R
R
Lurie
J
J
Pawlowski
J
J
Sawicki
K
K
Corsino
A
A
D000758:Anesthesia; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D001986:Bronchial Spasm / Q000209:etiology*; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D017214:Laryngeal Masks / Q000009:adverse effects*; D007826:Laryngismus / Q000209:etiology*; D012141:Respiratory Tract Infections / Q000209:etiology
D018685:Anesthetics, Inhalation