Solid-state esophageal pressure sensor for the estimation of pleural pressure: a bench and first-in-human validation study

Background: Advanced respiratory monitoring through the measurement of esophageal pressure (Pes) as a surrogate of pleural pressure helps guiding mechanical ventilation in ICU patients. Pes measurement with an esophageal balloon catheter, the current clinical reference standard, needs complex calibrations and a multitude of factors influence its reliability. Solid-state pressure sensors might be able to overcome these limitations. Objectives: To evaluate the accuracy of a new solid-state Pes transducer (Pessolid). We hypothesized that measurements are non-inferior to those obtained with a properly calibrated balloon catheter (Pesbal). Methods: Absolute and relative solid-state sensor Pes measurements were compared to a reference pressure in a 5-day bench setup, and to simultaneously placed balloon catheters in 15 spontaneously breathing healthy volunteers and in 16 mechanically ventilated ICU patients. Bland-Altman analysis was performed with nonparametric bootstrapping to estimate bias and upper and lower limits of agreement (LoA). Results: Bench study: Solid-state pressure transducers had a positive bias (Psolid - Pref) of around 1 cmH2O for the absolute minimal and maximum pressures, and no bias for pressure swings. Healthy volunteers: the solid-state transducer revealed a bias (Pessolid - Pesbal) [upper LoA; lower LoA] of 1.58 [8.19; -5.03], -2.37 [3.96; -8.69] and 3.94 [11.09; -3.20] cmH2O for end-expiratory, end-inspiratory and delta Pes values, respectively. ICU patients: the solid-state transducer showed a bias (Pessolid-Pesbal) [upper LoA; lower LoA] during controlled / assisted ventilation of: -0.15 [1.39; -1.70] / -0.20 [5.02; -5.41], 0.32 [3.35; -2.72] / -0.54 [4.60; -5.68] and 0.47 [3.79; -2.85] / 0.35 [3.88; -3.18] cmH2O for end-expiratory, end-inspiratory and delta Pes values, respectively. LoA were <2cmH2O for static measurements on controlled ventilation. Conclusions: the novel solid-state pressure transducer showed good accuracy on the bench, in healthy volunteers and in ventilated ICU-patients. This could contribute to the implementation of Pes as advanced respiratory monitoring technique. Trial registration: Clinicaltrials.gov identifier: NCT05817968 (patient study). Registered on 18 April 2023.