Positive end-expiratory pressure titration in COVID-19 acute respiratory failure: electrical impedance tomography vs. PEEP/FiO2 tables

Sella, Nicolò; Zarantonello, Francesco; Andreatta, Giulio; Gagliardi, Veronica; Boscolo, Annalisa; Navalesi, Paolo

doi:10.1186/s13054-020-03242-5

Cited by 41 publications

(46 citation statements)

References 6 publications

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“…Mauri et al reported in six out of seven such COVID-19 patients’ large ventilation/perfusion mismatch, with a median (IQR) dead space fraction of 22% [ 221 ]. Comparable results were reported in 15 other patients: median (IQR) dead space fraction of 27% [ 23 – 36 ] [ 222 ]. Importantly, the percentage of dead space measured by EIT differs from the measures provided by capnography, because it refers to dead space inside the lungs (minimizing the contribution of instrumental and anatomical dead space), with lung aerated volume (and not tidal volume) as the reference value.…”

Section: Perfusion Defects In Covid-19 Ards Lungs: Intensivist’s Point Of View On Endothelium and Pulmonary Vasculaturesupporting

confidence: 64%

“…Pulmonary physiological parameters could be in such future studies derived from capnography measurements (with alveolar dead space as a major study parameter), from EIT studies (with an emphasis on pulmonary perfusion parameters) and from CT studies (including pulmonary blood volume quantification). Another interesting point may be to study to which extent such an ARDS endotype could induce residual clot burden and influence post-ICU pulmonary functional abnormalities described in COVID-19 ARDS, such as a decrease in diffusing capacity of the lung for CO (DLCO) [ 222 – 226 ]. Since a decrease in lung capillary blood volume (LCBV) could influence DLCO results, it could be interesting to measure diffusing capacity of the lung for both nitric oxide (NO) and DLCO, permitting to quantify LCBV [ 227 ].…”

Section: Perfusion Defects In Covid-19 Ards Lungs: Intensivist’s Point Of View On Endothelium and Pulmonary Vasculaturementioning

confidence: 99%

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COVID-19 is a systemic vascular hemopathy: insight for mechanistic and clinical aspects

et al. 2021

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Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is presenting as a systemic disease associated with vascular inflammation and endothelial injury. Severe forms of SARS-CoV-2 infection induce acute respiratory distress syndrome (ARDS) and there is still an ongoing debate on whether COVID-19 ARDS and its perfusion defect differs from ARDS induced by other causes. Beside pro-inflammatory cytokines (such as interleukin-1 β [IL-1β] or IL-6), several main pathological phenomena have been seen because of endothelial cell (EC) dysfunction: hypercoagulation reflected by fibrin degradation products called D-dimers, micro- and macrothrombosis and pathological angiogenesis. Direct endothelial infection by SARS-CoV-2 is not likely to occur and ACE-2 expression by EC is a matter of debate. Indeed, endothelial damage reported in severely ill patients with COVID-19 could be more likely secondary to infection of neighboring cells and/or a consequence of inflammation. Endotheliopathy could give rise to hypercoagulation by alteration in the levels of different factors such as von Willebrand factor. Other than thrombotic events, pathological angiogenesis is among the recent findings. Overexpression of different proangiogenic factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF-2) or placental growth factors (PlGF) have been found in plasma or lung biopsies of COVID-19 patients. Finally, SARS-CoV-2 infection induces an emergency myelopoiesis associated to deregulated immunity and mobilization of endothelial progenitor cells, leading to features of acquired hematological malignancies or cardiovascular disease, which are discussed in this review. Altogether, this review will try to elucidate the pathophysiology of thrombotic complications, pathological angiogenesis and EC dysfunction, allowing better insight in new targets and antithrombotic protocols to better address vascular system dysfunction. Since treating SARS-CoV-2 infection and its potential long-term effects involves targeting the vascular compartment and/or mobilization of immature immune cells, we propose to define COVID-19 and its complications as a systemic vascular acquired hemopathy.

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Section: Perfusion Defects In Covid-19 Ards Lungs: Intensivist’s Point Of View On Endothelium and Pulmonary Vasculaturesupporting

confidence: 64%

Section: Perfusion Defects In Covid-19 Ards Lungs: Intensivist’s Point Of View On Endothelium and Pulmonary Vasculaturementioning

confidence: 99%

COVID-19 is a systemic vascular hemopathy: insight for mechanistic and clinical aspects

et al. 2021

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“…The resulting voltages and reconstructed regional impedance values reflect the volume changes of air and blood in the lung tissue (2). Chest EIT applications cover a broad field of clinical practice (3), including the treatment of acute respiratory distress syndrome (ARDS) (4), coronavirus disease 2019 (5)(6)(7), and acute exacerbation of chronic obstructive pulmonary disease under mechanical ventilation (8,9), as well as pulmonary function testing for patients with asthma, cystic fibrosis, and chronic obstructive pulmonary disease (10)(11)(12)(13).…”

Section: Introductionmentioning

confidence: 99%

Regional ventilation distribution in healthy lungs: can reference values be established for electrical impedance tomography parameters?

et al. 2021

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Background: Although electrical impedance tomography (EIT) is widely used for monitoring regional ventilation distribution, reference values have yet to be established for clinical use. The present study aimed to evaluate the feasibility of creating reference values for standard EIT parameters for potential clinical application.Methods: A total of 75 participants with healthy lungs were included in this prospective study (male:female, 48:27; age, 34±14 years; height, 172±7 cm; weight, 73±12 kg). The subjects were examined during spontaneous breathing in the supine position. EIT measurements were performed at the level of the 4 th intercostal space. Commonly used EIT-based parameters, including the center of ventilation (CoV), dorsal and most dorsal fractions of ventilation distribution (TV D and TV ROI4 respectively), global inhomogeneity (GI) index, and standard deviation of regional ventilation delay index (RVD SD ) were calculated.Results: Following outlier detection, EIT data from 71 subjects were finally evaluated. The values of the evaluated parameters were: CoV, 48.7%±1.7%; TVD, 48.1%±5.4%; TV ROI4 , 7.1%±1.8%; GI, 0.49±0.04; and RVD SD , 7.0±2.0. The coefficients of variation for CoV and GI were low (0.03 and 0.07, respectively), but those for TV ROI4 and RVD SD were comparatively high (0.26 and 0.28, respectively). None of the evaluated parameters showed a significant correlation with age. The GI index showed a weak but significant correlation with body mass index (R=0.29, P=0.01). The RVD SD was slightly higher in males than in females.Conclusions: Our study indicated that CoV and GI were stable parameters with small coefficients of variation in participants with healthy lungs. The creation of EIT parameter reference values for setting treatment targets may be feasible.

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“…Another C rs -based approach that has been applied for EIT-based optimization of PEEP in patients with ARDS [ 26 ] and with COVID-19 induced acute respiratory failure [ 27 , 28 ] relies on analyzing pixelwise changes in C rs during a decremental PEEP trial [ 10 , 29 ]. This PEEP trial must be started at relatively high PEEP levels (that may be associated with overdistension while applied) and must then be carried on until very low PEEP levels (that may lead to alveolar collapse and atelectasis formation) are reached.…”

Section: Discussionmentioning

confidence: 99%

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

Becher

Buchholz

Hassel

et al. 2021

Ann. Intensive Care

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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.

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Positive end-expiratory pressure titration in COVID-19 acute respiratory failure: electrical impedance tomography vs. PEEP/FiO2 tables

Cited by 41 publications

References 6 publications

COVID-19 is a systemic vascular hemopathy: insight for mechanistic and clinical aspects

COVID-19 is a systemic vascular hemopathy: insight for mechanistic and clinical aspects

Regional ventilation distribution in healthy lungs: can reference values be established for electrical impedance tomography parameters?

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

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