The therapist is monitoring pressure from an esophageal balloon. What pressure is reflected by that device?

A. transairway pressure
B. pleural pressure
C. alveolar pressure
D. tracheal pressure

?ANS: B
A. Incorrect response: The transairway pressure is the pressure difference (gradient) between the alveolar pressure and the mouth pressure (atmospheric pressure). This pressure gradient is responsible for the flow of air into and out of the lungs during spontaneous breathing and mechanical ventilation.
B. Correct response: An esophageal balloon measures pressure in the midesophagus, which reflects pressure in the pleural space.
C. Incorrect response: During mechanical ventilation, alveolar distending pressure can be estimated by conducting an inspiratory pause. The plateau or static pressure reflects the pressure responsible for maintaining the lungs in an inflated state.
D. Incorrect response: Pressures in the distal endotracheal tube are considered tracheal pressures.