Which device is used to estimate pleural pressure in the mid-thorax as a surrogate measurement?

Which device is used to estimate pleural pressure in the mid-thorax as a surrogate measurement?

• A. Endotracheal tube
• B. Nasogastric tube
• C. Esophageal balloon catheter
• D. Pulmonary artery catheter

Answer: (C)

Measuring pleural pressure directly is invasive and not practical in routine care, so a surrogate is used that reflects the pressure in the mid-thoracic pleural space. An esophageal balloon catheter is inserted into the esophagus and a small balloon is inflated; the pressure recorded by the balloon mirrors the surrounding pleural pressure because the esophagus sits within the mediastinum and transmits changes in pleural pressure. This esophageal pressure serves as a stand-in for pleural pressure, especially for understanding lung mechanics in the mid-thorax and guiding ventilation strategies. This also enables calculation of transpulmonary pressure (airway pressure minus pleural pressure), which helps tailor PEEP and tidal volumes to minimize lung overdistension or collapse. The other devices don’t estimate pleural pressure: an endotracheal tube secures the airway, a nasogastric tube measures gastric pressure, and a pulmonary artery catheter measures cardiac and pulmonary pressures and flows, not pleural pressure.

Measuring pleural pressure directly is invasive and not practical in routine care, so a surrogate is used that reflects the pressure in the mid-thoracic pleural space. An esophageal balloon catheter is inserted into the esophagus and a small balloon is inflated; the pressure recorded by the balloon mirrors the surrounding pleural pressure because the esophagus sits within the mediastinum and transmits changes in pleural pressure. This esophageal pressure serves as a stand-in for pleural pressure, especially for understanding lung mechanics in the mid-thorax and guiding ventilation strategies.

This also enables calculation of transpulmonary pressure (airway pressure minus pleural pressure), which helps tailor PEEP and tidal volumes to minimize lung overdistension or collapse. The other devices don’t estimate pleural pressure: an endotracheal tube secures the airway, a nasogastric tube measures gastric pressure, and a pulmonary artery catheter measures cardiac and pulmonary pressures and flows, not pleural pressure.