What is the role of transdiaphragmatic pressure testing in the workup of diaphragmatic paralysis?

Updated: Oct 10, 2018
  • Author: Justina Gamache, MD; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
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Answer

This is the criterion standard for diagnosis.

The transdiaphragmatic pressure is measured by placing a thin-walled balloon transnasally at the lower end of the esophagus, allowing reflection of the changes in pleural pressure. Then, a second balloon manometer is placed in the stomach to measure changes in intra-abdominal pressure. Gastric pressure should become more positive during inspiration. Esophageal pressure should become more negative during inspiration, demonstrating an increase in gradient during normal inspiration. In cases in which the sniff test is negative and clinical suspicion for diaphragmatic paralysis is still high, transdiaphragmatic pressure should be considered.

Normal transdiaphragmatic pressure is approximately 148 cm water in men and 122 cm water in women. [17] Unilateral diaphragmatic paralysis is associated with a maximal transdiaphragmatic pressure of greater than 70 cm water, and thus does not significantly effect transdiaphragmatic pressure generation during normal ventilatory behaviors, but can compromise higher-force, nonventilatory, behaviors like coughing or sneezing. Bilateral diaphragmatic paralysis, however, can impair normal ventilatory behaviors as it is associated with a maximal transdiaphragmatic pressure of less than 40 cm water. [18, 19, 20]

Consult with an expert to perform the test and interpret the results. This measurement can help differentiate diaphragmatic paralysis from other causes of respiratory failure.


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