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

Abstract

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.

Trial registration: ClinicalTrials.gov NCT06391424.

Keywords: P0.1; esophageal pressure swings; intensive care unit; mechanical ventilation; pressure-time product; work of breathing.

Figure 1.

Generalized estimating equations regression line of the esophageal-derived parameters in comparison with the P0.1 with the R² value derived from the generalized linear mixed-effects models marginal R². Work of breathing (WOB) compared with P0.1 (A), pressure-time product (PTP) compared with P0.1 (B), and esophageal pressure swing (ΔPes) compared with P0.1 (C), all showed poor correlations.

Figure 2.

Generalized estimating equations regression line of the esophageal-derived parameters in comparison with each other with the R² value derived from the generalized linear mixed-effects models marginal R². Work of breathing (WOB) compared with pressure-time product (PTP) (A), WOB compared with esophageal pressure swing (ΔPes) (B), and PTP compared with ΔPes (C), all showed high correlations.