P0.1 is an Unreliable Measure of Effort in Support Mechanical Ventilation in Comparison With Esophageal-Derived Measures of Effort: A Comparison Study.

OBJECTIVE

Respiratory effort should be assessed in patients on mechanical ventilation in support mode. With the insertion of esophageal balloons, it is possible to measure different parameters of effort, such as change in esophageal pressure (ΔPes), work of breathing (WOB), and pressure-time product (PTP). Although some studies advocate for the use of P0.1 as a measure of effort, there is significant controversy as it is considered more a measure of respiratory drive. This study investigates the correlation between P0.1 and esophageal-derived parameters of effort.

DESIGN

This was a retrospective observational comparison study.

SETTING

This study is conducted in the mixed medical-surgical ICU at the Leiden University Medical Center (Leiden, The Netherlands).

PATIENTS

Data were collected from 30 mechanically ventilated patients in spontaneous breathing mode.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From each patient, a minimum of three different time frames of 5 minutes were used to collect the average values of P0.1, WOB, PTP, and ΔPes over this time frame. Statistical models accounting for repeated measurements were applied to assess correlations among these parameters. In total, 117 timeframes were analyzed from 39 patient cases. The analysis revealed poor correlations between P0.1, as measured in this study, and WOB ( R2 = 0.111), PTP ( R2 = 0.113), and ΔPes ( R2 = 0.034), whereas the esophageal-derived parameters showed high correlations with each other (PTP vs. WOB, R2 = 0.886; ΔPes vs. WOB, R2 = 0.848; and ΔPes vs. PTP, R2 = 0.876).

CONCLUSIONS

The results demonstrated poor correlations between P0.1 and the other effort parameters, whereas strong correlations were observed among ΔPes, WOB, and PTP. These findings underscore the need for careful consideration of monitoring tools to ensure appropriate assessment and management, and the importance of using esophageal catheters for accurate monitoring of respiratory effort, particularly in spontaneously breathing patients.