Air accidentally trapped in the lungs due to mechanical ventilation is known as which of the fol-lowing?

a. Plateau pressure (Pplateau)
b. Functional residual capacity (FRC)
c. Extrinsic positive end expiratory pressure (extrinsic PEEP)
d. Intrinsic positive end expiratory pressure (intrinsic PEEP)

ANS: D
The definition of intrinsic PEEP is air that is accidentally trapped in the lung. Another name for this is auto-PEEP. Extrinsic PEEP is the positive baseline pressure that is set by the operator. Functional residual capacity (FRC) is the sum of a patient's residual volume and expiratory re-serve volume and is the amount of gas that normally remains in the lung after a quiet exhalation. The plateau pressure is the pressure measured in the lungs at no flow during an inspiratory hold maneuver.