The oropharnygeal leak pressure (OLP) describes the pressure at which gas can be heard to escape from around a laryngeal mask airway (LMA) while auscultating the upper anterior neck. This is a measure of the seal around the LMA.



(1) A laryngeal mask airway is placed into the patient.

(2) The exhaust valve is closed and fresh gas is allowed to flow into the lungs at 4 liters per minute. Pressure readings are taken using a calibrated manometer in the expiratory limb of the circle system.

(3) The side of the neck lateral to the thyroid cartilage is auscultated as the airway pressure increases.

(4) Testing is complete when either gas is heard to escape around the LMA or an airway pressure of 40 cm H2O is reached.

Airway Pressure


0 - 4.9 cm H2O

failure (absence of seal)

5.0 - 14.9 cm H2O


15.0 - 19.9 cm H2O


20.0 - 40.0 cm H2O



The OLP pressure can be increased temporarily in a patient by:

(1) anterior neck pressure (applying external pressure to the front of the neck)

(2) neck flexion


The goal is to maintain a medium to high OLP (>= 15.0 cm H2O).


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