Identification of lung overdistension caused by tidal volume and positive end-expiratory pressure increases based on electrical impedance tomography

2021 ◽  
Author(s):  
Zhanqi Zhao ◽  
Ling Sang ◽  
Yimin Li ◽  
Inéz Frerichs ◽  
Knut Möller ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Positive End Expiratory Pressure ◽  
Impedance Tomography ◽  
Lung Overdistension

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

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tobias Becher ◽  
Valerie Buchholz ◽  
Daniel Hassel ◽  
Timo Meinel ◽  
Dirk Schädler ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Predicted Body Weight ◽  
Impedance Tomography ◽  
Mechanically Ventilated ◽  
Global Strain ◽  
Lung Overdistension ◽  
Ventilator Settings ◽  
Lung Stress

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.

scholarly journals Individualization of PEEP and Tidal Volume in ARDS Patients with Electrical Impedance Tomography

2020 ◽  
Author(s):  
Tobias Hermann Becher ◽  
Valerie Buchholz ◽  
Daniel Hassel ◽  
Timo Alexander Meinel ◽  
Dirk Schädler ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Predicted Body Weight ◽  
Impedance Tomography ◽  
Mechanically Ventilated ◽  
Lung Overdistension ◽  
Fraction Of Inspired Oxygen ◽  
Ventilator Settings ◽  
Lung Stress

Abstract BackgroundIn 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. Methods20 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 fraction of inspired oxygen. Subsequently, ventilator settings were adjusted according to the EIT-based protocol once every 30 minutes for a duration of 4 hours. To assess global overdistension, we determined whether lung stress and strain remained below 27 and 2.0, respectively. ResultsWe found that prospective optimization of mechanical ventilation with EIT led to global lung stress 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.ConclusionsAdjustment 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.

scholarly journals A Modified Method to Assess Tidal Recruitment by Electrical Impedance Tomography

2019 ◽  
Vol 8 (8) ◽  
pp. 1161 ◽  
Author(s):  
Thomas Muders ◽  
Benjamin Hentze ◽  
Philipp Simon ◽  
Felix Girrbach ◽  
Michael R.G. Doebler ◽  
...  
Keyword(s):  
Lung Injury ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Characteristic Curve ◽  
Receiver Operator Characteristic Curve ◽  
Positive End Expiratory Pressure ◽  
Regional Ventilation ◽  
Impedance Tomography ◽  
Modified Method ◽  
Tidal Recruitment

Avoiding tidal recruitment and collapse during mechanical ventilation should reduce the risk of lung injury. Electrical impedance tomography (EIT) enables detection of tidal recruitment by measuring regional ventilation delay inhomogeneity (RVDI) during a slow inflation breath with a tidal volume (VT) of 12 mL/kg body weight (BW). Clinical applicability might be limited by such high VTs resulting in high end-inspiratory pressures (PEI) during positive end-expiratory pressure (PEEP) titration. We hypothesized that RVDI can be obtained with acceptable accuracy from reduced slow inflation VTs. In seven ventilated pigs with experimental lung injury, tidal recruitment was quantified by computed tomography at PEEP levels changed stepwise between 0 and 25 cmH2O. RVDI was measured by EIT during slow inflation VTs of 12, 9, 7.5, and 6 mL/kg BW. Linear correlation of tidal recruitment and RVDI was excellent for VTs of 12 (R2 = 0.83, p < 0.001) and 9 mL/kg BW (R2 = 0.83, p < 0.001) but decreased for VTs of 7.5 (R2 = 0.76, p < 0.001) and 6 mL/kg BW (R2 = 0.71, p < 0.001). With any reduction in slow inflation VT, PEI decreased at all PEEP levels. Receiver-Operator-Characteristic curve analyses revealed that RVDI-thresholds to predict distinct amounts of tidal recruitment differ when obtained from different slow inflation VTs. In conclusion, tidal recruitment can sufficiently be monitored by EIT-based RVDI-calculation with a slow inflation of 9 mL/kg BW.

Assessment of electrical impedance tomography to set optimal positive end-expiratory pressure for veno-venous ECMO-treated severe ARDS patients

2020 ◽  
Vol 60 ◽  
pp. 38-44 ◽  
Author(s):  
Floriane Puel ◽  
Laure Crognier ◽  
Christelle Soulé ◽  
Fanny Vardon-Bounes ◽  
Stéphanie Ruiz ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Positive End Expiratory Pressure ◽  
Impedance Tomography
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