Can Bispectral Index aid laryngeal mask placement in children?

Background: Laryngeal mask airway (LMA) placement requires an adequate depth of anesthesia to prevent patient movement and adverse airway responses. Patient movement, coughing, stridor or laryngospasm at LMA placement may result in transient hypoxia, injury to the patient and prolong time spent in the anesthetic room. The Bispectral Index Score (BIS) is a relatively new tool that has not yet established its place in routine clinical pediatric anesthesia practice. One potential use may be to predict an adequate depth of anesthesia for successful intraoperative interventions such as LMA placement in children.

Methods: A total of 116 children aged between 1 and 16 years due to have an LMA placed under general anesthesia were enrolled into this prospective, blinded observational study. Complication or success of LMA placement was then analyzed in relation to the BIS value at the time of placement. Other clinical variables were also considered.

Results: The difference in BIS values in children with complicated compared with successful LMA placement was small and BIS therefore appears not to be a reliable predictor for either. Inexperience of the anesthetist and a history of recent upper respiratory tract infection (URTI) may be better indicators for complications.

Conclusions: Bispectral Index Score appears, from this study, not to be a useful tool to help predict complications of LMA placement or to help reduce airway complications during LMA placement. Other markers may be more useful predictors of adverse airway events.