Optimizing PEEP by Electrical Impedance Tomography in a Porcine Animal Model of ARDS

Hochhausen, Nadine; Biener, Ingeborg; Rossaint, Rolf; Follmann, Andreas; Berne, Christian; Braunschweig, Till; Leonhardt, Steffen; Czaplik, Michael

doi:10.4187/respcare.05060

Cited by 26 publications

(16 citation statements)

References 45 publications

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“…As the only bedside tool available, retrospective evaluations of EIT-guided PEEP titration confirmed its feasibility [15, 16, 20, 23, 31]. Two prospective outcome studies were conducted in lavaged pigs, one of them confirming that EIT-guided PEEP selection was superior to the ARDSnet table [17, 32]. The ARDSnet table recommends PEEP according to FiO 2 levels, which is less individualized than selection based on lung mechanics, blood gases or imaging.…”

Section: Discussionmentioning

confidence: 99%

Positive end-expiratory pressure titration with electrical impedance tomography and pressure–volume curve in severe acute respiratory distress syndrome

Zhao

Chang

et al. 2019

Ann. Intensive Care

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BackgroundThe study objective was to compare titration of positive end-expiratory pressure (PEEP) with electrical impedance tomography (EIT) and with ventilator-embedded pressure–volume loop in severe acute respiratory distress syndrome (ARDS).MethodsWe have designed a prospective study with historical control group. Twenty-four severe ARDS patients (arterial oxygen partial pressure to fractional inspired oxygen ratio, PaO2/FiO2 < 100 mmHg) were included in the EIT group and examined prospectively. Data from another 31 severe ARDS patients were evaluated retrospectively (control group). All patients were receiving medical care under identical general support guidelines and protective mechanical ventilation. The PEEP level selected in the EIT group was the intercept point of cumulated collapse and overdistension percentages curves. In the control group, optimal PEEP was selected 2 cmH2O above the lower inflection point on the static pressure–volume curve.ResultsPatients in the EIT group were younger (P < 0.05), and their mean plateau pressure was 1.5 cmH2O higher (P < 0.01). No differences in other baseline parameters such as APACHE II score, PaO2/FiO2, initial PEEP, driving pressure, tidal volume, and respiratory system compliance were found. Two hours after the first PEEP titration, significantly higher PEEP, compliance, and lower driving pressure were found in the EIT group (P < 0.01). Hospital survival rates were 66.7% (16 of 24 patients) in the EIT group and 48.4% (15 of 31) in the control group. Identical rates were found regarding the weaning success rate: 66.7% in the EIT group and 48.4% in the control group.ConclusionIn severe ARDS patients, it was feasible and safe to guide PEEP titration with EIT at the bedside. As compared with pressure–volume curve, the EIT-guided PEEP titration may be associated with improved oxygenation, compliance, driving pressure, and weaning success rate. The findings encourage further randomized control study with a larger sample size and potentially less bias in the baseline data.Trial Registration NCT03112512Electronic supplementary materialThe online version of this article (10.1186/s13613-019-0484-0) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Positive end-expiratory pressure titration with electrical impedance tomography and pressure–volume curve in severe acute respiratory distress syndrome

Zhao

Chang

et al. 2019

Ann. Intensive Care

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“…Initially, Zhao et al were able to demonstrate that the GI index may be useful to guide PEEP settings [25]. The idea of PEEP guidance by GI index was taken up in experimental and clinical studies several times [26,27]. Overall, the GI index focuses on spatial heterogeneity within the lung.…”

Section: Discussionmentioning

confidence: 99%

Comparison of two experimental ARDS models in pigs using electrical impedance tomography

et al. 2019

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BackgroundAnimal trials contribute to major achievements in medical science. The so-called lavage model is frequently used to evaluate ventilation strategies in acute respiratory distress syndrome (ARDS) using electrical impedance tomography (EIT). But, the lavage model itself might have systematic impacts on EIT parameters. Therefore, we established an additional experimental model, in which ARDS is caused by intravenously administered lipopolysaccharide (LPS). In this study, we want to examine if EIT measurements provide consistent results in both experimental models or whether the pathophysiology of the model influences the findings. Overall, we want to compare both experimental models regarding clinical parameters and EIT-derived indices, namely the global inhomogeneity (GI) index and the regional ventilation delay (RVD) index.MethodsNineteen pigs were included in this study, allocated to the control group (CO; n = 5), lavage group (LAV; n = 7) and LPS group (LPS; n = 7). After baseline measurements and the establishment of ARDS, assessment of respiratory mechanics, hemodynamics, gas exchange and EIT recordings were performed hourly over eight hours.ResultsIn both experimental ARDS models, EIT measurements provided reliable results. But, the GI and the RVD index did not show consistent results as compared to the CO group. Initially, GI and RVD index were higher in the LAV group but not in the LPS group as compared to the CO group. This effect disappeared during the study. Furthermore, the GI index and the RVD index were higher in the LAV group compared to the LPS group in the beginning as well. This, once again, disappeared. Clinical lung injury parameters remained more stable when using LPS.ConclusionThe two models showed quite different influences on the GI and RVD index. This implies, that the underlying pathophysiology affects EIT parameters and thus the findings. Hence, translation to EIT-guided clinical therapy in humans suffering from ARDS might be limited.

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“…The assessment of regional overdistension and atelectasis can be visualized using EIT during changes in PEEP and has been validated by histological examination of lung tissue [28]. An animal study used by Wolf et al was the first prospective study wherein EIT guided ventilator settings were used [18], followed by other animal and human studies [22, 29]. …”

Section: Discussionmentioning

confidence: 99%

Clinical implementation of electric impedance tomography in the treatment of ARDS: a single centre experience

Heines

Strauch

Poll

et al. 2018

J Clin Monit Comput

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To report on our clinical experience using EIT in individualized PEEP titration in ARDS. Using EIT assessment, we optimized PEEP settings in 39 ARDS patients. The EIT PEEP settings were compared with the physicians' PEEP settings and the PEEP settings according to the ARDS network. We defined a PEEP difference equal to or greater than 4 cm HO as clinically relevant. Changes in lung compliance and PaO/FiO-ratio were compared in patients with EIT-based PEEP adjustments and in patients with unaltered PEEP. In 28% of the patients, the difference in EIT-based PEEP and physician-PEEP was clinically relevant; in 36%, EIT-based PEEP and physician-PEEP were equal. The EIT-based PEEP disagreed with the PEEP settings according to the ARDS network. Adjusting PEEP based upon EIT led to a rapid increase in lung compliance and PaO/FiO-ratio. However, this increase was also observed in the group where the PEEP difference was less than 4 cm HO. We hypothesize that this can be attributed to the alveolar recruitment during the PEEP trial. EIT based individual PEEP setting appears to be a promising method to optimize PEEP in ARDS patients. The clinical impact, however, remains to be established.

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Optimizing PEEP by Electrical Impedance Tomography in a Porcine Animal Model of ARDS

Abstract: PEEP setting by EIT facilitates a more individual ventilation therapy. However, in our relatively short ARDS observation period of 24 h, no significant differences appeared in common clinical parameters compared with a control group.

Cited by 26 publications

References 45 publications

Positive end-expiratory pressure titration with electrical impedance tomography and pressure–volume curve in severe acute respiratory distress syndrome

Positive end-expiratory pressure titration with electrical impedance tomography and pressure–volume curve in severe acute respiratory distress syndrome

Comparison of two experimental ARDS models in pigs using electrical impedance tomography

Clinical implementation of electric impedance tomography in the treatment of ARDS: a single centre experience

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