Electric Cell-Substrate Impedance Sensing (ECIS) as a Platform for Evaluating Barrier-Function Susceptibility and Damage from Pulmonary Atelectrauma.

Biophysical insults that either reduce barrier function (COVID-19, smoke inhalation, aspiration, and inflammation) or increase mechanical stress (surfactant dysfunction) make the lung more susceptible to atelectrauma. We investigate the susceptibility and time-dependent disruption of barrier function associated with pulmonary atelectrauma of epithelial cells that occurs in acute respiratory distress syndrome (ARDS) and ventilator-induced lung injury (VILI). This in vitro study was performed using Electric Cell-substrate Impedance Sensing (ECIS) as a noninvasive evaluating technique for repetitive stress stimulus/response on monolayers of the human lung epithelial cell line NCI-H441. Atelectrauma was mimicked through recruitment/derecruitment (RD) of a semi-infinite air bubble to the fluid-occluded micro-channel. We show that a confluent monolayer with a high level of barrier function is nearly impervious to atelectrauma for hundreds of RD events. Nevertheless, barrier function is eventually diminished, and after a critical number of RD insults, the monolayer disintegrates exponentially. Confluent layers with lower initial barrier function are less resilient. These results indicate that the first line of defense from atelectrauma resides with intercellular binding. After disruption, the epithelial layer community protection is diminished and atelectrauma ensues. ECIS may provide a platform for identifying damaging stimuli, ventilation scenarios, or pharmaceuticals that can reduce susceptibility or enhance barrier-function recovery.

Prevalence and clinical consequences of atelectasis in SARS-CoV-2 pneumonia: a computed tomography retrospective cohort study.

BACKGROUND: The aim of the study is to estimate the prevalence of atelectasis assessed with computer tomography (CT) in SARS-CoV-2 pneumonia and the relationship between the amount of atelectasis with oxygenation impairment, Intensive Care Unit admission rate and the length of in-hospital stay. PATIENTS AND METHODS: Two-hundred thirty-seven patients admitted to the hospital with SARS-CoV-2 pneumonia diagnosed by clinical, radiology and molecular tests in the nasopharyngeal swab who underwent a chest computed tomography because of a respiratory worsening from Apr 1 to Apr 30, 2020 were included in the study. Patients were divided into three groups depending on the presence and amount of atelectasis at the computed tomography: no atelectasis, small atelectasis (< 5% of the estimated lung volume) or large atelectasis (> 5% of the estimated lung volume). In all patients, clinical severity, oxygen-therapy need, Intensive Care Unit admission rate, the length of in-hospital stay and in-hospital mortality data were collected. RESULTS: Thirty patients (19%) showed small atelectasis while eight patients (5%) showed large atelectasis. One hundred and seventeen patients (76%) did not show atelectasis. Patients with large atelectasis compared to patients with small atelectasis had lower SatO2/FiO2 (182 vs 411 respectively, p = 0.01), needed more days of oxygen therapy (20 vs 5 days respectively, p = 0,02), more frequently Intensive Care Unit admission (75% vs 7% respectively, p < 0.01) and a longer period of hospitalization (40 vs 14 days respectively p < 0.01). CONCLUSION: In patients with SARS-CoV-2 pneumonia, atelectasis might appear in up to 24% of patients and the presence of larger amount of atelectasis is associated with worse oxygenation and clinical outcome.

Electrical impedance tomography: A compass for the safe route to optimal PEEP.

Setting the proper level of positive end-expiratory pressure (PEEP) is a cornerstone of lung protective ventilation. PEEP keeps the alveoli open at the end of expiration, thus reducing atelectrauma and shunt. However, excessive PEEP may contribute to alveolar overdistension. Electrical impedance tomography (EIT) is a non-invasive bedside tool that monitors in real-time ventilation distribution. Aim of this narrative review is summarizing the techniques for EIT-guided PEEP titration, while providing useful insights to enhance comprehension on advantages and limits of EIT for current and future users. EIT detects thoracic impedance to alternating electrical currents between pairs of electrodes and, through the analysis of its temporal and spatial variation, reconstructs a two-dimensional slice image of the lung depicting regional variation of ventilation and perfusion. Several EIT-based methods have been proposed for PEEP titration. The first described technique estimates the variations of regional lung compliance during a decremental PEEP trial, after lung recruitment. The optimal PEEP value is represented by the best compromise between lung collapse and overdistension. Later on, a second technique assessing alveolar recruitment by variation of the end-expiratory lung impedance was validated. Finally, the global inhomogeneity index and the regional ventilation delay, two EIT-derived parameters, showed promising results selecting the optimal PEEP value as the one that presents the lowest global inhomogeneity index or the lowest regional ventilation delay. In conclusion EIT represents a promising technique to individualize PEEP in mechanically ventilated patients. Whether EIT is the best technique for this purpose and the overall influence of personalizing PEEP on clinical outcome remains to be determined.

Acute hypoxemia due to lung collapse in COVID-19: the role of therapeutic bronchoscopy.

Bronchoscopy is an aerosol-generating procedure and involves a high risk of transmission of SARS-CoV-2 to health care workers. There are very few indications for performing bronchoscopy in a patient with confirmed COVID-19. These include atelectasis, foreign body aspiration, and suspected superinfection in immunocompromised patients. Proper use of standard personal protective equipment is mandatory to reduce the risk of transmission to health care workers. In this article, we describe a case of acute lung collapse in a 16-year-old boy with cerebral palsy who was infected with COVID-19. This patient responded to therapeutic bronchoscopy and had complete resolution of lung collapse within 24 hours of the procedure.

Kawasaki disease shock syndrome complicated with bilateral lung consolidation in a child: A case report.

INTRODUCTION: Kawasaki disease (KD) is a systemic inflammatory disease. Standard imaging features of KD include interstitial and lobular inflammatory lesions in the lungs, while KD shock syndrome (KDSS), complicated with substantial consolidation and atelectasis in the lung, is rarely reported. PATIENTS CONCERNS: Herein, we report a single case of a 5-year-old female patient who manifested KDSS on the seventh day of the course of KD. Chest enhanced computed tomography indicated large-area consolidation in the lower lobes of the bilateral lungs. DIAGNOSIS: The patient was diagnosed with KDSS complicated with non-infective lung consolidation. INTERVENTIONS: The patient received human intravenous immunoglobulin (2 g/kg) and aspirin (30-50 mg/kgd), methylprednisolone, a vasoactive agent, and albumin. Infective factors were excluded. OUTCOMES: The consolidation in the lower lobe of the bilateral lungs was completely recovered after 3 days of treatment. CONCLUSIONS: Children with KDSS may present with pulmonary lesions such as substantial consolidation and atelectasis; thus, infective factors should be excluded. If there is no etiological evidence, antibiotics should be used with caution.

Severe immune thrombocytopenic purpura in critical COVID-19.

COVID-19 is a new disease with many undescribed clinical manifestations. We report herein a case of severe immune thrombocytopenic purpura (ITP) in a critical COVID-19 patient. A patient presented a severe episode of immune thrombocytopenia (< 10 × 109/L) 20 days after admission for a critical COVID-19. This thrombocytopenia was associated with a life-threatening bleeding. Response to first-line therapies was delayed as it took up to 13 days after initiation of intravenous immunoglobulin and high-dose dexamethasone to observe an increase in platelet count. COVID-19 may be associated with late presenting severe ITP. Such ITP may also be relatively resistant to first-line agents. Hematological manifestations of COVID-19, such as the ones associated with life-threatening bleeding, must be recognized.