Emanuele Catena

In the last few years prone positioning has been used increasingly in the treatment of patients with acute respiratory distress syndrome and this maneuver is now considered a simple and safe method to improve oxygenation. Hemodynamic monitoring by echocardiography may be required but prone positioning imposes certain challenges limiting standard examination. The article describes the application of the “trans‐splenic retrocardiac view,” a little‐known echographic window for obtaining Doppler parameters from the back in prone‐positioned patients.

Diastolic dysfunction is an underestimated feature in the context of the critically ill setting and perioperative medicine. Advances in echocardiography, its noninvasive, safe and easy use, have allowed Doppler echocardiography to become a cornerstone for diagnosing diastolic dysfunction in clinical practice. The diagnosis of diastolic dysfunction and increased filling pressures is nevertheless complex. Using an echocardiographic assessment and the routine application of preload stress maneuvers during echocardiographic examination can help identify early stages of diastolic dysfunction leading to better management of patients at risk of acute heart decompensation in the perioperative period or during ICU stay.

Background Survival after cardiac arrest depends on prompt and effective cardiopulmonary resuscitation (CPR). Transesophageal echocardiography (TEE) can be applied to evaluate the effectiveness of chest compression–decompression maneuvers in the setting of cardiac arrest undergoing CPR. The efficacy of chest compression can be continuously assessed by TEE that can improve the effectiveness of CPR guiding the rescuer to optimize or correct chest compression and decompression by directly examining the movements of the cardiac walls and valve leaflets. Purpose The review describes how to perform TEE in the emergency setting of cardiopulmonary arrest, its advantages, and limitations, and ultimately propose an echo-guided approach to CPR.

Background: COVID-19 induces progressive hypoxemic respiratory failure and acute respiratory distress syndrome, mostly due to a dysregulated inflammatory response. Since the first observations of COVID-19 patients, significant hypoalbuminemia was detected. This study aimed to investigate the hypothesis that hypoalbuminemia in COVID-19 patients is due to pulmonary capillary leakage and to test its correlation with indicators of respiratory function. Methods: 174 COVID-19 patients, 92 admitted to the Intermediate Medicine ward (IMW), and 82 to the Intensive Care Unit (ICU) at Luigi Sacco Hospital in Milan were included in this study. Findings: Serum albumin concentration was decreased in the whole cohort, with ICU patients displaying lower values than IMW patients [20 (18-23) vs 28 (24-33) g/L, p<0.0001]. Lower albumin values were found in patients belonging to a more compromised group (lower PaO2 to FiO2 ratio and worst chest X-ray findings). In a subset of 26 patients, analysis of bronchoalveolar lavage fluid (BALF) highlighted high protein concentrations, which were correlated to Interleukin-8 and Interleukin-10 BALF concentration. The length of hospitalisation [20 (15-29) vs 8 (5-14) days, p<0.0001] and death rate (52.4% vs 21.7%, p<0.0001) were higher in ICU than in IMW patients, while a strict relation between hypoalbuminemia and 30 day-survival was detected in the whole cohort. Electron microscopy examinations of eight out of ten autopsy lung tissues showed diffuse loosening of interendothelial junctional complex. Interpretation: The degree of hypoalbuminemia can be considered as a useful severity marker in hospitalised COVID-19 patients. Pulmonary capillary leak syndrome secondary to the hyperinflammatory state plays a key role in the pathogenesis of COVID-19 respiratory dysfunction and should be regarded as a therapeutic target.

Importance: The analysis of lung tissues of patients with COVID-19 may help understand pathogenesis and clinical outcomes in this life-threatening respiratory illness. Objective: To determine the histological patterns in lung tissue of patients with severe COVID-19. Design and participants: Lungs tissues of 38 cases who died for COVID-19 in two hospital of Northern Italy were systematically analysed. Hematoxylin-eosin staining, immunohistochemistry for the inflammatory infiltrate and cellular components, electron microscopy were performed. Results: The features of the exudative and proliferative phases of Diffuse Alveolar Disease (DAD) were found: capillary congestion, necrosis of pneumocytes, hyaline membrane, interstitial oedema, pneumocyte hyperplasia and reactive atypia, platelet-fibrin thrombi. The inflammatory infiltrate was composed by macrophages in alveolar lumens and lymphocytes mainly in the interstice. Electron microscopy revealed viral particles in the cytoplasm of pneumocytes. Conclusions and relevance: The predominant pattern of lung lesions in COVID-19 patients is DAD, as described for the other two coronavirus that infect humans, SARS-CoV and MERS-CoV. Hyaline membrane formation and pneumocyte atypical hyperplasia are frequently found. The main relevant finding is the presence of platelet-fibrin thrombi in small arterial vessels; this important observation fits into the clinical context of coagulopathy which dominates in these patients and which is one of the main targets of therapy.