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.
Method:
(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
Interpretation
0 - 4.9 cm H2O
failure (absence of seal)
5.0 - 14.9 cm H2O
low
15.0 - 19.9 cm H2O
medium
20.0 - 40.0 cm H2O
high
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).
To read more or access our algorithms and calculators, please log in or register.
