The 3 cm of Head Elevation Provides Higher Insertion Success Than do the 6 cm of it for ProSeal Laryngeal Mask Airway Insertion in Adult Patients

Background: The "sniffing position" (i.e., the neck flexed and head extended by means of a pillow) eases tracheal intubation because the three axes, namely, the axis of the mouth, the pharyngeal axis and the laryngeal axis, are put in almost a straight line. The benefit of the sniffing position that align three axis could possibly be applicable when the ProSeal LMA is inserted. For the endotracheal intubation, it has been recommended to elevate the patient's head 8 to 10 cm with pads under the occiput (shoulder remaining on the table) and extend the head at the atlanto-occipital joint to align the oral, pharyngeal, and laryngeal axes such that the passage and line of vision from the lips to the glottic opening are most nearly a straight line.

There have been several clinical studies about the effect of head and neck position including neutral, flexion or extension on the ease of LMA insertion.

However, it has not been much recommended or investigated about the influence of head elevation on the insertion success of PLMA until now. The purpose of the present study is to evaluate the success and pharyngeal trauma when 3 or 6 cm height of pillow is used for the ProSeal laryngeal mask airway insertion in adult patients.