Transdiaphragmatic pressure

Real-time tracing of esophageal pressure as a reflection of pleural pressure and abdominal pressure as a reflection of gastric pressure in a patient with bilateral diaphragmatic paralysis. Decreased intrathoracic pressure (more negative pleural pressure) on inspiration is associated with an abnormal decrease in gastric pressure (more negative gastric pressure). At the same time, there is outward displacement of the ribcage (upward deflection of ribcage) with a paradoxical decrease in abdominal volume (downward deflection of abdomen). The ribcage and abdomen tracings are obtained from inductance plethysmographic coils placed around the chest and abdomen to monitor movement.