Esophageal pressures in supine and prone position: evaluation using high-resolution manometry

Area of Science:

• Respiratory physiology
• Critical care medicine
• Medical instrumentation

Background:

• Esophageal pressure (PES) is crucial for assessing respiratory mechanics in mechanically ventilated patients.
• High-resolution manometry (HRM) offers detailed PES readings along the esophagus.
• Factors beyond respiratory mechanics can influence PES, necessitating further investigation.

Purpose of the Study:

• To characterize and analyze esophageal pressure (PES) variations in prone versus supine positions.
• To explore the impact of different positive end-expiratory pressure (PEEP) levels on PES.
• To compare PES readings from various esophageal regions and identify optimal sensor placements.

Main Methods:

• High-resolution manometry (HRM) was employed to measure PES in 20 mechanically ventilated patients.
• PES was recorded in both supine and prone positions at PEEP levels of 5 and 12 cmH2O.
• Mean end-expiratory PES (PES_EE), tidal variation (ΔPES), and cardiac oscillations were analyzed across different esophageal regions.

Main Results:

• Prone positioning showed significantly lower PES_EE, higher ΔPES, and smaller cardiac oscillations compared to supine.
• These differences were dependent on PEEP levels and the specific esophageal regions measured.
• Mean within-patient variability for PES_EE and ΔPES ranged from 38-540%, highlighting measurement challenges.

Conclusions:

• Significant variations in esophageal pressure exist between supine and prone positions, influenced by PEEP and sensor selection.
• Optimal sensor selection (PES_OPT) yielded lower and less variable end-expiratory pressures compared to mean PES_EE.
• Understanding these positional influences and measurement variabilities is critical for accurate respiratory mechanics assessment.