Ultrasound confirmation of laryngeal mask airway placement correlates with fiberoptic laryngoscope findings

ABSTRACT

Correct placement of a laryngeal mask airway [LMA] requires confirmation to appreciate the adequacy of laryngeal seal and pulmonary ventilation. The present study was designed to assess the feasibility of ultrasound use for confirmation of correct placement of LMA and its correlation with fiberoptic laryngoscopy as a confirmation tool for LMA position. 31 ASA I and II patients scheduled for same day surgery under general anesthesia underwent standard general anesthetic technique with AuraOnce[TM] or AuraFlex[TM] Disposable Laryngeal Mask Airways. The position of the LMA cuff was confirmed by transverse neck ultrasound [USG], and reconfirmed with intra-LMA fiberoptic laryngoscopy [FOL]. The ultrasound grade of LMA position strongly correlated positively with the fiberoptic grade of LMA position [r=0.92; p<0.0001]. This correlation was obtained immediately after LMA placement, as well as just before LMA removal. The Bland-Altman scatter plot showed insignificant differences between the two grading systems with small and good limits of agreement [-0.63 to +0.57]. Ultrasound examination can replace fiberoptic examination for confirmation of the correct placement of an LMA. Additionally, non-invasive ultrasound examination can further give insight into the cause of airway/ventilation events that may be interfering with the LMA placement and ventilation