Article

The minimum alveolar concentration of enflurane for laryngeal mask airway extubation in deeply anesthetized children.

Department of Anesthesiology, Plastic Surgery Hospital, The Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
Anesthesia & Analgesia (impact factor: 3.29). 02/2001; 92(1):72-5.
Source: PubMed

ABSTRACT The end-tidal anesthetic gas concentration required to prevent the anesthetized patient from coughing or moving during or immediately after the laryngeal mask airway (LMA) extubation is not known. We sought to determine the minimum alveolar concentration of enflurane required for the removal of the LMA in children. We studied 21 nonpremedicated children between 4 and 11 yr of age, ASA physical status I, undergoing procedures below the umbilicus. General anesthesia was induced with a mask by using sevoflurane, nitrous oxide, and oxygen, and the LMA was inserted. Anesthesia was maintained with enflurane, nitrous oxide, and oxygen. At the end of surgery, a predetermined end-tidal enflurane concentration was achieved, and the LMA was removed. Each concentration at which the LMA extubation was attempted was predetermined by the up-and-down method (with 0.1% as a step size). When LMA removal was accomplished without coughing, clenching teeth, or gross purposeful muscular movements during or within 1 min after removal, it was considered a successful LMA removal. Removal was considered to be unsuccessful in patients who developed breath holding or laryngospasm during or immediately after LMA removal. The minimum alveolar concentration of enflurane at which 50% of children had a successful LMA removal was found to be 1.02% (95% CL, 0.95%-1.11%), and the 95% effective dose for successful extubation was 1.14% (95% CL, 1.07%-1.66%). In conclusion, the LMA removal may be accomplished without coughing or moving at 1.02% end-tidal enflurane concentration in 50% of anesthetized children aged 4-11 yr. Implications: There may be fewer problems associated with the laryngeal mask airway extubation when patients are deeply anesthetized. The purpose of this study was to determine the minimum concentration of enflurane for successful removal of the laryngeal mask in children.

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    Article: Safe and easy emergence from anesthesia in adults following removal of laryngeal mask airway: utility of oral airway and T-connector.
    Ming-Hui Hsieh, Jin-Te Ho, Chin-Min Huang, Meei-Shyuan Lee, Ta-Liang Chen, Chih-Shung Wong, Jui-An Lin
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    ABSTRACT: Removal of the laryngeal mask airway (LMA) can be executed while patients are deeply anesthetized or awake. Recent publications have focused on suitable anesthetic concentrations in the brain for removal of LMA in anesthetized patients. Here, we describe an easy and safe method for removal of LMA during deep anesthesia.
    Acta Anaesthesiologica Taiwanica 07/2009; 47(2):84-6.
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    Article: Caudal analgesia reduces the sevoflurane requirement for LMA removal in anesthetized children.
    Joon-Sik Kim, Wyun Kon Park, Min-Huiy Lee, Kyu-Hyun Hwang, Hee-Soo Kim, Jeong Rim Lee
    [show abstract] [hide abstract]
    ABSTRACT: An anesthetic state can reduce adverse airway reaction during laryngeal mask airway (LMA) removal in children. However, the anesthetic state has risks of upper airway obstruction or delayed emergence; so possibly less anesthetic depth is advisable. Caudal analgesia reduces the requirement of anesthetic agents for sedation or anesthesia; it is expected to reduce the sevoflurane requirement for LMA removal. Therefore, we determined the EC(50) of sevoflurane for LMA removal with caudal analgesia and compared that to the EC(50) without caudal analgesia. Forty-three unpremedicated children aged 1 to 6 yr were enrolled. They were allocated to receive or not to receive caudal block according to their parents' consent. General anesthesia were induced and maintained with sevoflurane and oxygen in air. EC(50) of sevoflurane for a smooth LMA removal with and without caudal analgesia were estimated by the Dixon up-and-down method. The LMA was removed when predetermined end-tidal sevoflurane concentration was achieved, and the sevoflurane concentration of a subsequent patient was determined by the success or failure of the previous patient with 0.2% as the step size; success was defined by the absence of an adverse airway reaction during and after LMA removal. EC(50) of sevoflurane with caudal block, and that without caudal block, were compared by a rank-sum test. The EC(50) of sevoflurane to achieve successful LMA removal in children with caudal block was 1.47%; 1.81% without caudal block. The EC(50) were significantly different between the two groups (P < 0.001). Caudal analgesia significantly reduced the sevoflurane concentration for a smooth LMA removal in anesthetized children.
    Korean journal of anesthesiology 06/2010; 58(6):527-31.
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Keywords

1.02% end-tidal enflurane concentration
 
21 nonpremedicated children
 
95% effective dose
 
anesthetized children
 
anesthetized patient
 
ASA physical status
 
clenching teeth
 
end-tidal anesthetic gas concentration
 
General anesthesia
 
gross purposeful muscular movements
 
laryngeal mask
 
laryngeal mask airway
 
laryngeal mask airway extubation
 
LMA removal
 
minimum alveolar concentration
 
nitrous oxide
 
predetermined end-tidal enflurane concentration
 
successful LMA removal
 
successful removal
 
undergoing procedures
 

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