Effect of Paratracheal Esophagus Pressure on the Insertion of Laryngeal Mask Airway

Effect of Pressure to Left Paratracheal Esophagus During the Insertion of Laryngeal Mask Airway

Laryngeal mask airway is inserted into the oral cavity and seals the upper esophagus and the surrounding tissue, effectively securing airway. Laryngeal mask airway has been widely adopted in the clinical practice.

On the other hand, cricoid pressure has been used to reduce the risk of pulmonary aspiration of gastric contents during induction of general anesthesia. However, cricoid pressure might impede placement of the laryngeal mask airway, thereby preventing effective ventilation.

Recently, left paratracheal pressure was introduced as an alternative to cricoid pressure and reported to be more effective than cricoid pressure in the prevention of gastric air insufflation during positive-pressure ventilation by facemask. Since this method compresses low left paratracheal level, it may affect the successful insertion of laryngeal mask airway.

In this study, the investigators aimed to evaluate the effect of paratracheal esophagus pressure on the insertion of laryngeal mask airway compare to conventional cricoid pressure.

Inclusion Criteria:

• Patients who are undergoing surgery under general anesthesia where supraglottic airway management will be appropriate
• American Society of Anesthesiologists Classification 1-2

Exclusion Criteria:

• Body mass index > 35 kg/m2
• High risk of regurgitation (hiatus hernia, gastro-esophageal reflux disease, non-fasting status)
• Criteria for difficult airway (limitation of mouth opening/neck extension, Mallampati class IV),