Individualization of PEEP and tidal volume in ARDS patients with electrical impedance tomography: a pilot feasibility study

Abstract

Background In mechanically ventilated patients with acute respiratory distress syndrome (ARDS), electrical impedance tomography (EIT) provides information on alveolar cycling and overdistension as well as assessment of recruitability at the bedside. We developed a protocol for individualization of positive end-expiratory pressure (PEEP) and tidal volume (VT) utilizing EIT-derived information on recruitability, overdistension and alveolar cycling. The aim of this study was to assess whether the EIT-based protocol allows individualization of ventilator settings without causing lung overdistension, and to evaluate its effects on respiratory system compliance, oxygenation and alveolar cycling. Methods 20 patients with ARDS were included. Initially, patients were ventilated according to the recommendations of the ARDS Network with a VT of 6 ml per kg predicted body weight and PEEP adjusted according to the lower PEEP/FiO2 table. Subsequently, ventilator settings were adjusted according to the EIT-based protocol once every 30 min for a duration of 4 h. To assess global overdistension, we determined whether lung stress and strain remained below 27 mbar and 2.0, respectively. Results Prospective optimization of mechanical ventilation with EIT led to higher PEEP levels (16.5 [14–18] mbar vs. 10 [8–10] mbar before optimization; p = 0.0001) and similar VT (5.7 ± 0.92 ml/kg vs. 5.8 ± 0.47 ml/kg before optimization; p = 0.96). Global lung stress remained below 27 mbar in all patients and global strain below 2.0 in 19 out of 20 patients. Compliance remained similar, while oxygenation was significantly improved and alveolar cycling was reduced after EIT-based optimization. Conclusions Adjustment of PEEP and VT using the EIT-based protocol led to individualization of ventilator settings with improved oxygenation and reduced alveolar cycling without promoting global overdistension. Trial registrationThis study was registered at clinicaltrials.gov (NCT02703012) on March 9, 2016 before including the first patient.

Measurement of Electrical Impedance Tomography-Based Regional Ventilation Delay for Individualized Titration of End-Expiratory Pressure

“…Previous research [16] showed that slow inflation with a constant gas flow is obligatory for sufficient RVDI calculation and the assessment of tidal recruitment. In a recent study in patients with ARDS, Becher et al [30] used EIT to individually adjust PEEP and V T . Using a modified algorithm for RVDI measurements during a slow inflation of 12 mL/kg BW, Becher et al demonstrated that time disparities in regional ventilation were reduced with EIT-based PEEP settings in comparison with clinical PEEP settings.…”

Designing a bench for testing medically and technically an information and measuring system for multi-frequency electrical impedance tomography of human lungs

“…Possible directions of development of this area were shown. Just as in paper [4], the aspects of personalization of the parameters of the EIT examination itself, such as the parameters of injected current, the type of used electrodes, the place of their imposition, remained unresolved. In these works, the importance of the influence of these factors on the final result of the examination is evidently underestimated.…”

“…Currently, the problem of long-term monitoring of the functional state of human lungs is one of the most important areas of respiratory support for patients. Among them, the possibility of long-term bedside monitoring of the breathing process in the pre-and postoperative period, including patients connected to devices of artificial ventilation of lungs (AVL) [4][5][6], is of great clinical importance.…”

“…Research [4] showed that the application of the EIT method to patients with acute respiratory distress syndrome (ARDS) with mechanical ventilation of lungs makes it possible to obtain bedside information about the alveolar cycle and overdose. The authors used the EIT to individualize positive exhalation end pressure (PEEP) and tidal volume (VT).…”

Effect of Prone Positioning With Individualized Positive End-Expiratory Pressure in Acute Respiratory Distress Syndrome Using Electrical Impedance Tomography

“…EIT generates cross-sectional images of the impedance distribution within the thorax and measures continuously regional lung volume changes at the bedside ( Hinz et al, 2003 ; Kotani et al, 2016 ; Aguirre-Bermeo et al, 2018 ; Holanda et al, 2018 ). EIT is widely used in lung ventilation assessment in hypoxemia patients, including the PEEP titration (Dalla Corte et al, 2020 ; He et al, 2021 ; He et al, 2020 ; Yun et al, 2016 ; Becher et al, 2021 ; Gibot et al, 2021 ; Muders et al, 2021 ; Scaramuzzo et al, 2020b ).…”