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Background Individualized positive end-expiratory pressure (PEEP) by electrical impedance tomography (EIT) has potential interest in the optimization of ventilation distribution in acute respiratory distress syndrome (ARDS). The aim of the study was to determine whether early individualized titration of PEEP with EIT improved outcomes in patients with ARDS. Methods A total of 117 ARDS patients receiving mechanical ventilation were randomly assigned to EIT group ( n  = 61, PEEP adjusted based on ventilation distribution) or control group ( n  = 56, low PEEP/FiO 2 table). The primary outcome was 28-day mortality. Secondary and exploratory outcomes were ventilator-free days, length of ICU stay, incidence of pneumothorax and barotrauma, and difference in Sequential Organ Failure Assessment (SOFA) score at day 1 (ΔD1-SOFA) and day 2 (ΔD2-SOFA) compared with baseline. Measurements and main results There was no statistical difference in the value of PEEP between the EIT group and control group, but the combination of PEEP and FiO 2 was different between groups. In the control group, a significantly positive correlation was found between the PEEP value and the corresponding FiO 2 ( r  = 0.47, p  < 0.00001) since a given matched table was used for PEEP settings. Diverse combinations of PEEP and FiO 2 were found in the EIT group ( r  = 0.05, p  = 0.68). There was no significant difference in mortality rate (21% vs. 27%, EIT vs. control, p  = 0.63), ICU length of stay (13.0 (7.0, 25.0) vs 10.0 (7.0, 14.8), median (25th–75th percentile); p  = 0.17), and ventilator-free days at day 28 (14.0 (2.0, 23.0) vs 19.0 (0.0, 24.0), p  = 0.55) between the two groups. The incidence of new barotrauma was zero. Compared with control group, significantly lower ΔD1-SOFA and ΔD2-SOFA were found in the EIT group ( p  < 0.001) in a post hoc comparison. Moreover, the EIT group exhibited a significant decrease of SOFA at day 2 compared with baseline (paired t-test, difference by − 1 (− 3.5, 0), p  = 0.001). However, the control group did show a similar decrease (difference by 1 (− 2, 2), p  = 0.131). Conclusion Our study showed a 6% absolute decrease in mortality in the EIT group: a statistically non-significant, but clinically non-negligible result. This result along with the showed improvement in organ function might justify further reserach to validate the beneficial effect of individualized EIT-guided PEEP setting on clinical outcomes of patients with ARDS. Trial registration : ClinicalTrials, NCT02361398. Registered 11 February 2015—prospectively registered, https://clinicaltrials.gov/show/NCT02361398 .

In this paper, we present a low-cost, adaptable, and flexible pressure sensor that can be applied as a smart skin over both stiff and deformable media. The sensor can be easily adapted for use in applications related to the fields of robotics, rehabilitation, or costumer electronic devices. In order to remove most of the stiff components that block the flexibility of the sensor, we based the sensing capability on the use of a tomographic technique known as Electrical Impedance Tomography. The technique allows the internal structure of the domain under study to be inferred by reconstructing its conductivity map. By applying the technique to a material that changes its resistivity according to applied forces, it is possible to identify these changes and then localise the area where the force was applied. We tested the system when applied to flat and curved surfaces. For all configurations, we evaluate the artificial skin capabilities to detect forces applied over a single point, over multiple points, and changes in the underlying geometry. The results are all promising, and open the way for the application of such sensors in different robotic contexts where deformability is the key point.

Purpose Higher positive end-expiratory pressure might induce lung inflation and recruitment, yielding enhanced regional lung protection. We measured positive end-expiratory pressure-related lung volume changes by electrical impedance tomography and by the helium dilution technique. We also used electrical impedance tomography to assess the effects of positive end-expiratory pressure on regional determinants of ventilator-induced lung injury. Methods A prospective randomized crossover study was performed on 20 intubated adult patients: 12 with acute hypoxemic respiratory failure and 8 with acute respiratory distress syndrome. Each patient underwent protective controlled ventilation at lower (7 [7, 8] cmH 2 O) and higher (12 [12, 13] cmH 2 O) positive end-expiratory pressures. At the end of each phase, we collected ventilation, helium dilution, and electrical impedance tomography data. Results Positive end-expiratory pressure-induced changes in lung inflation and recruitment measured by electrical impedance tomography and helium dilution showed close correlations ( R 2  = 0.78, p  < 0.001 and R 2  = 0.68, p  < 0.001, respectively) but with relatively variable limits of agreement. At higher positive end-expiratory pressure, recruitment was evident in all lung regions ( p  < 0.01) and heterogeneity of tidal ventilation distribution was reduced by increased tidal volume distending the dependent lung ( p  < 0.001); in the non-dependent lung, on the other hand, compliance decreased ( p  < 0.001) and tidal hyperinflation significantly increased ( p  < 0.001). In the subgroup of ARDS patients (but not in the whole study population) tidal hyperinflation in the dependent lung regions decreased at higher positive end-expiratory pressure ( p  = 0.05), probably indicating higher potential for recruitment. Conclusions Close correlations exist between bedside assessment of positive end-expiratory pressure-induced changes in lung inflation and recruitment by the helium dilution and electrical impedance tomography techniques. Higher positive end-expiratory pressure exerts mixed effects on the regional determinants of ventilator-induced lung injury; these merit close monitoring.

Electrical impedance tomography (EIT) is a medical imaging technique based on the injection of a current or voltage pattern through electrodes on the skin of the patient, and on the reconstruction of the internal conductivity distribution from the voltages collected by the electrodes. Compared to other imaging techniques, EIT shows significant advantages: it does not use ionizing radiation, is non-invasive and is characterized by high temporal resolution. Moreover, its low cost and high portability make it suitable for real-time, bedside monitoring. However, EIT is also characterized by some technical limitations that cause poor spatial resolution. The possibility to design wearable devices based on EIT has recently given a boost to this technology. In this paper we reviewed EIT physical principles, hardware design and major clinical applications, from the classical to a wearable setup. A wireless and wearable EIT system seems a promising frontier of this technology, as it can both facilitate making clinical measurements and open novel scenarios to EIT systems, such as home monitoring.

Phase angle (PhA) can be determined through bioelectrical impedance analysis and is a unique variable for skeletal muscle. The objective of this study was to evaluate the relationship between PhA and muscle mass/quality in older adults. In addition, we attempted to determine the cutoff value of PhA for poor muscle function. Community-dwelling Japanese older men (n=285, 81.1±7.1 years) and women (n=724, 80.4±6.8 years) participated in this study and were classified into four groups based on the Asian Working Group for Sarcopenia (normal, presarcopenia, dynapenia, and sarcopenia). We measured PhA using bioelectrical impedance analysis, muscle quantity and quality indicators using ultrasonography, muscle strength, and physical performance and compared them in four groups. We also tried to determine the cutoff value of PhA for poor muscle function. We found a significant difference in PhA among the four groups in men (P<0.05), and the dynapenia (3.61±0.75°) and sarcopenia groups (3.40±0.74°) showed significantly lower values than the normal group (4.50±0.86°) (P<0.05), but not the presarcopenia group (4.12±0.85°). In women, a significant difference was also observed among the four groups (P<0.05), and the dynapenia (3.41±0.65°) and sarcopenia groups (3.31±0.66°) showed significantly lower measures than the normal group (4.14±0.71°) (P<0.05), but not the presarcopenia group (4.07±0.51°). The receiver-operating characteristic curve analysis indicated the best cutoff value of PhA (men: 4.05°, women: 3.55°) to discriminate sarcopenia and dynapenia from normal and presarcopenia. These findings suggest that PhA is a useful indicator for muscle function.

Background In patients with acute respiratory distress syndrome undergoing mechanical ventilation, positive end-expiratory pressure (PEEP) can lead to recruitment or overdistension. Current strategies utilized for PEEP titration do not permit the distinction. Electric impedance tomography (EIT) detects and quantifies the presence of both collapse and overdistension. We investigated whether using EIT-guided PEEP titration leads to decreased mechanical power compared to high-PEEP/FiO2 tables. Methods A single-center, randomized crossover pilot trial comparing EIT-guided PEEP selection versus PEEP selection using the High-PEEP/FiO 2 table in patients with moderate–severe acute respiratory distress syndrome. The primary outcome was the change in mechanical power after each PEEP selection strategy. Secondary outcomes included changes in the 4 × driving pressure + respiratory rate (4 ΔP, + RR index) index, driving pressure, plateau pressure, PaO 2 /FiO 2 ratio, and static compliance. Results EIT was consistently associated with a decrease in mechanical power compared to PEEP/FiO 2 tables (mean difference − 4.36 J/min, 95% CI − 6.7, − 1.95, p  = 0.002) and led to lower values in the 4ΔP + RR index (− 11.42 J/min, 95% CI − 19.01, − 3.82, p  = 0.007) mainly driven by a decrease in the elastic–dynamic power (− 1.61 J/min, − 2.99, − 0.22, p  = 0.027). The elastic–static and resistive powers were unchanged. Similarly, EIT led to a statistically significant change in set PEEP (− 2 cmH 2 O, p  = 0.046), driving pressure, (− 2.92 cmH2O, p  = 0.003), peak pressure (− 6.25 cmH 2 O, p  = 0.003), plateau pressure (− 4.53 cmH 2 O, p  = 0.006), and static respiratory system compliance (+ 7.93 ml/cmH 2 O, p  = 0.008). Conclusions In patients with moderate–severe acute respiratory distress syndrome, EIT-guided PEEP titration reduces mechanical power mainly through a reduction in elastic–dynamic power. Trial registration This trial was prospectively registered on Clinicaltrials.gov (NCT 03793842) on January 4th, 2019.

Background The physiological effects of prone ventilation in ARDS patients have been discussed for a long time but have not been fully elucidated. Electrical impedance tomography (EIT) has emerged as a tool for bedside monitoring of pulmonary ventilation and perfusion, allowing the opportunity to obtain data. This study aimed to investigate the effect of prone positioning (PP) on ventilation–perfusion matching by contrast-enhanced EIT in patients with ARDS. Design Monocenter prospective physiologic study. Setting University medical ICU. Patients Ten mechanically ventilated ARDS patients who underwent PP. Interventions We performed EIT evaluation at the initiation of PP, 3 h after PP initiation and the end of PP during the first PP session. Measurements and main results The regional distribution of ventilation and perfusion was analyzed based on EIT images and compared to the clinical variables regarding respiratory and hemodynamic status. Prolonged prone ventilation improved oxygenation in the ARDS patients. Based on EIT measurements, the distribution of ventilation was homogenized and dorsal lung ventilation was significantly improved by PP administration, while the effect of PP on lung perfusion was relatively mild, with increased dorsal lung perfusion observed. The ventilation–perfusion matched region was found to increase and correlate with the increased PaO 2 /FiO 2 by PP, which was attributed mainly to reduced shunt in the lung. Conclusions Prolonged prone ventilation increased dorsal ventilation and perfusion, which resulted in improved ventilation–perfusion matching and oxygenation. Trial registration : ClinicalTrials.gov, NCT04725227. Registered on 25 January 2021.

Gastric Function has been successfully estimated by gastric electrical impedance tomography ( g EIT) Suit with dual-step fuzzy clustering. The g EIT Suit which are made of elastic cloth with dual-planar electrodes and compact data acquisition (DAQ) system measures gastric impedance Z to visualize the gastric conductivity distribution σ. The dual-step fuzzy clustering extracts the clustered gastric conductivity distribution k σ, which accurately estimates the gastric function . The g EIT Suit with dual-step fuzzy clustering are applied to eight healthy persons during liquid meal consumption to estimate the gastric function under gastric accommodation phase of 200, 400 and 600 mL based on the gastric emptying phase. As the results, the g EIT Suit successfully estimate the gastric function. By the measured impedance Z, the subjects have a mean temporal impedance Δ Z ¯ = − 9.27 [Ohm] and p -value of that Z ¯ p ( Z ) = 0.0013[–]as the t-test result. In the case of gastric conductivity distribution σ, the subjects have a value of spatial mean conductivity distribution ⟨σ⟩ = 0.23[–] and p -value of that ⟨σ⟩ p (σ) = 0.0140[–]. Lastly, in the case gastric volume V , subjects have a gastric volume V  = 12.44 [%] and p -value p ( V ) = 0.0664[–].

Background Elderly patients are prone to secretion retention and exacerbated lung infections due to weakened respiratory muscle strength and reduced ability to cough and expectorate. Airway clearance techniques (ACTs) can help to clear airway secretions, but objective bedside assessment of secretion clearance efficacy is lacking. Electrical impedance tomography (EIT) can dynamically monitor lung ventilation and provide a basis for clinical decision‐making. Methods This study was a prospective randomized controlled trial that included 50 elderly patients with severe pneumonia, who were randomized into EIT and non‐EIT groups. The EIT group received personalized ACTs guided by real‐time EIT imaging with dynamic adjustment of posture, percussion intensity, and active circulatory breathing technique (ACBT) frequency, whereas the non‐EIT group received fixed‐schedule ACTs (postural drainage every 2 h + percussion/vibration twice daily) without EIT feedback. The main observation indices included Clinical Pulmonary Infection Score (CPIS), respiratory mechanics indices, blood gas analysis indices, and extubation success rate. Results The EIT group showed significantly lower CPIS scores (p = 0.0137 on Day 7), higher dynamic compliance (p = 0.0193), lower airway resistance (p = 0.0039), lower peak airway pressure (p = 0.0288), and higher oxygenation index (p = 0.0143 on Day 5 and p = 0.0005 on Day 7) than the non‐EIT group. The extubation success rate was significantly higher in the EIT group (88% vs. 56%, p = 0.0255). Additionally, the EIT group demonstrated progressive improvements in ventilation in specific regions (D7 vs. D1: p = 0.0004 for region of interest [ROI]3; p = 0.0059 for ROI4) and a significant decrease in the global inhomogeneity index at D7 (D7 vs. D1: p = 0.0025). Conclusion EIT‐guided ACT is safe and enhances treatment efficacy by significantly improving respiratory function and extubation success rate in elderly patients with severe pneumonia. EIT‐guided personalized airway clearance significantly improves outcomes in elderly severe pneumonia patients. Real‐time electrical impedance tomography (EIT) optimized secretion clearance through dynamic adjustment of posture, percussion, and breathing techniques. This approach enhanced respiratory mechanics, oxygenation, and infection control, doubling extubation success rates (88% vs. 56%) compared with standard fixed‐schedule therapy.

Electrical impedance tomography (EIT) is an emerging technology for the non-invasive monitoring of regional distribution of ventilation and perfusion, offering real-time and continuous data that can greatly enhance our understanding and management of various respiratory conditions and lung perfusion. Its application may be especially beneficial for critically ill mechanically ventilated patients. Despite its potential, clear evidence of clinical benefits is still lacking, in part due to a lack of standardization and transparent reporting, which is essential for ensuring reproducible research and enhancing the use of EIT for personalized mechanical ventilation. This report is the result of a four-day expert meeting where we aimed to promote the consistent and reliable use of EIT, facilitating its integration into both clinical practice and research, focusing on the adult intensive care patient. We discuss the state-of-the-art regarding EIT acquisition and processing, applications during controlled ventilation and spontaneous breathing, ventilation-perfusion assessment, and novel future directions.