Refractory circulatory failure in COVID-19 patients treated with veno-arterial ECMO: A retrospective single-center experience

Objectives: Data about COVID-19 patients treated with veno-arterial-ECMO (VA-ECMO) is limited. Reported survival rates range from 27.9% to 77.8%, depending on VA-ECMO indication. A subgroup of patients suffers from circulatory failure due to a COVID-19 associated hyperinflammatory state (CovHI). In these patients, differentiation between inflammation and sepsis is difficult but important. In this retrospective case series, differential diagnoses of COVID-19 associated refractory circulatory failure and survival rates in different indications for VA-ECMO are investigated. Method(s): Retrospective analysis of 28 consecutive COVID-19 patients requiring VA-ECMO at the University Hospital Regensburg between March 2020 and May 2022. Specific treatment for COVID-19 was in accordance with respective guidelines. Mycotic infections were either invasive or met current definitions of COVID19-associated-pulmonary aspergillosis. Result(s): At VA-ECMO initiation, median age was 57.3 years (IQR: 51.4 - 61.8), SOFA score 16 (IQR: 13 - 17) and norepinephrine dosing 0.53mug/kg/min (IQR: 0.32 - 0.78). Virus-variants were: 61% wild-type, 14% Alpha, 18% Delta and 7% Omicron. Survival to hospital discharge was 39%. 17 patients were primarily supported with VA-ECMO only (survival 42%), 3 patients were switched from VV to VA-ECMO (survival 0%), and 8 patients were converted from VA to VAV or VV-ECMO (survival 50%). Indications for VA-ECMO support were pulmonary embolism (PE) (n=5, survival 80%), right heart failure due to secondary pulmonary hypertension (n=5, survival 20%), cardiac arrest (n=4, survival 25%), acute left heart failure (ALHF) (n=11, survival 36%) and refractory vasoplegia (n=3, survival 0%). Inflammatory markers at VA-ECMO initiation were higher in patients with ALHF or vasoplegia;in these patients a higher rate of invasive fungal infections (10/14, 71% vs. 4/14, 29%;p=0.023) compared to the other patients was found. Conclusion(s): Survival on VA-ECMO in COVID-19 depends on VA-ECMO indication, which should be considered in further studies and clinical decisions making. Circulatory failure due to vasoplegia should be considered very carefully as indication for VA-ECMO. A high rate of mycotic infections mandates an intense microbiological workup of these patients and must be considered as an important differential diagnosis to CovHI.

Long-term support of COVID-19 patients with veno-venous extracorporeal membrane oxygenation: Complications, predictors of mortality and long-term outcome

Objectives: Treatment of severe respiratory distress syndrome (ARDS) due to COVID-19 by veno-venous extracorporeal membrane oxygenation (VV-ECMO) had a mortality of up to 70% in Germany. Many patients with COVID-19 need VV-ECMO support longer than 28 days (long-term VV-ECMO). Evidence on mortality, complications during intensive care, functional status after discharge and mortality-predictors for patients supported with long-term VV-ECMO is lacking. Method(s): Retrospective study of 137 consecutive patients treated with VV-ECMO for ARDS due to COVID-19 at University Hospital Regensburg from March 2020 to March 2022. Result(s): 38% (n=52;87% male) of patients needed longterm VV-ECMO support. In these, SOFA score (median [IQR]) at ECMO initiation was 9 [8-11], age 58.2 [50.6- 62.5] years, PaO2/FiO2-ratio 67 [52-88] mmHg, pCO262 [52-74] mmHg, Murray-Score 3.3 [3.0-3.6] and PEEP 15 [13 - 16] cmH2O. Duration of long-term support was 45 [35-65] days. 26 (50%) patients were discharged from the ICU. Only one patient died after hospital discharge. At VVECMO initiation, baseline characteristics did not differ between deceased and survivors. Complications were frequent (acute kidney injury: 31/52, renal replacement therapy: 14/52, pulmonary embolism: 21/52, intracranial hemorrhage 8/52, major bleeding 34/52 and secondary sclerosing cholangitis: 5/52) and more frequent in the deceased. Karnofsky index (normal 100) after rehabilitation was 70 [57.5-82.5]. Twelve of the 18 patients discharged from rehabilitation had a satisfactory quality of life according to their own subjective assessment. Four patients required nursing support. Mortality-predictors within the first 30 days on VV-ECMO only observed in those who deceased later, were: Bilirubin >5mg/dl for > 7 days, pulmonary compliance <10ml/mbar for >14 days, and repeated serum concentrations of interleukin 8 >150ng/L. Conclusion(s): Long-term extracorporeal lung support in patients with COVID-19 resulted in 50 % survival and subsequently lead to a satisfactory quality of life and functionality in the majority of patients. It should preferably be performed in experienced centers because of a high incidence of complications. Several findings during the early course were associated with late mortality but need validation in large prospective studies.

Differences in nosocomial infections in patients on VV-ECMO for COVID-19 and influenza

Objectives: In COVID-19 associated acute respiratory distress syndrome (ARDS) requiring VV-ECMO, ventilator-associated-pneumonia (VAP), pulmonary aspergillosis and viral reactivations are observed frequently, but there is only little knowledge on incidence, onset and causative pathogens. This study analyzes frequency of VAP, pulmonary aspergillus infections, and viral reactivations in a large cohort of patients with ARDS treated with VV-ECMO due to either COVID-19 or Influenza. Method(s): Retrospective analysis of all consecutively patients at the University Hospital Regensburg requiring VVECMO due to COVID-19 (March 2020 and May 2022) or Influenza (May 2012 and December 2022). VAP was diagnosed according to current guidelines. Pulmonary Aspergillosis met criteria of probable COVID-associated Aspergillosis according to current guidelines. Result(s): 147 patients (age (median [IQR]) 55.3 [48.7 - 61.7], SOFA at VV-ECMO initiation 9 [8 - 12], 23 [14 - 38] days on VV-ECMO) suffering from COVID-19 and 72 influenza patients (age 55.3 [46 - 61.3], SOFA at VV-ECMO initiation 13 [10 - 15], 16 [10 - 23] days on VV-ECMO) were included in the analysis. Pulmonary superinfections were more frequent in COVID-19 than in influenza (VAP: 61% vs. 39%, pulmonary Aspergillosis: 33% vs. 22%, CMV reactivation: 19% vs. 4%, HSV reactivation: 49% vs. 26%.) The first episode of VAP in COVID-19 and Influenza was detected 2 days [1 - 15] after and 1 day (-3 - 22) before ECMO initiation, respectively. First VAP-episode in COVID-19 were mainly caused by Klebsiella spp. (29%,), Staphylococcus aureus (27%) and E. coli (11%). Further VAP-episodes (30% in COVID-19) and relapses of VAP were mainly caused by Klebsiella spp. (53%, 64%, respectively). In Influenza, VAP was mainly caused by Staphylococcus aureus (28%) and Streptococcus pneumoniae(28%), further VAP episodes were not observed. Conclusion(s): Superinfections were common in patients treated with VV-ECMO and occur more frequently in COVID-19 ARDS compared to Influenza. VAP occurs early and may significantly contribute to the need of VV-ECMO. Therefore, a meticulous routine microbiologic workup is advisable. The observed differences in the spectrum of secondary infectious agents in COVID19 compared to Influenza are not understood yet.

Could out-of-centre initiation of extracorporeal membrane oxygenation with mobile equipment improve outcome and prognosis in COVID-19 patients? A retrospective study from the ECMO centre Regensburg

Objectives: Besides in-centre ECMO care, the certificated ECMO centre of the University Hospital Regensburg (UKR) offers out-of-centre ECMO initiation with mobile equipment. During the pandemic situation, this treatment was especially meant for patients with critical cardiopulmonary failure in remote hospitals who present themselves as too unstable for interhospital transfer. We evaluated if treatment with outof-centre ECMO initiation could benefit patients;outcome, by comparing this group with a group of COVID-19 patients who received ECMO therapy at the UKR by in-hospital initiation. Method(s): Retrospective single-centre study including 169 patients who received ECMO due to COVID-19- induced cardiopulmonary failure between March 2020 till March 2022. Patients;population was separated into two groups according to the location of ECMO initiation, out-of-centre or in-centre, and into two subgroups by the used ECMO mode, venovenous (VV) or venoarterial (VA). We compared demographics, treatment duration, adverse events and patient;s outcome. The primary endpoint of the investigation was patients;survival to hospital discharge rate or death on ECMO or after ECMO explant. Result(s): Regarding the total study population, 98 (58.0%) of the 169 patients could be discharged from the UKR. Before initiation of ECMO therapy and with regard to complications during the course of intensive care, such as renal failure requiring dialysis or bleeding, there were no relevant differences between the two groups and subgroups. The out-of-centre group showed a significantly higher survival rate with 70 (63.6%) survivors out of 110 externally cannulated patients. Conclusion(s): In the study population, external ECMO cannulation was beneficial in terms of survival, although the reasons did not show significant differences between the groups. A possible approach for the good overall survival of the study groups in international comparison could be the existing centre expertise. (Figure Presented).

Coronavirus disease 2019 is associated with multi-lineage, morphologic changes in peripheral blood cells

Introduction: The clinical course of coronavirus disease 2019 (COVID-19) varies from mild symptoms to acute respiratory distress syndrome, hyper-infammation and coagulation disorder. The hematopoietic system plays a critical role in the observed hyperinfammation, particularly in severely ill patients. Method(s): We conducted a prospective diagnostic study performing a blood differential analyzing morphologic changes in peripheral blood of COVID-19 patients. COVID-19 associated morphologic changes were defned in a training cohort and subsequently validated in a second cohort (n=45). Morphologic aberrations were further analyzed by electron microscopy (EM) and fow cytometry of lymphocytes was performed. Result(s): We included 45 COVID-19 patients in our study (median age 58 years;82% on intensive care unit). The blood differential showed a specific pattern of pronounced multi-lineage aberrations in lymphocytes (80% of patients) and monocytes (91%). 84%, 98%, and 98% of patients exhibited aberrations in granulopoiesis, erythropoiesis and thrombopoiesis, respectively. Electron microscopy revealed the ultrastructural equivalents of the observed changes and confrmed the multi-lineage aberrations already seen by light microscopy. Conclusion(s): The morphologic pattern caused by COVID-19 is characteristic and underlines the serious perturbation of the hematopoietic system. We defned a hematologic COVID-19 pattern to facilitate further independent diagnostic analysis and to investigate the impact on the he-matologic system during the clinical course of COVID-19 patients.

Interstitial lung opacities in patients with severe COVID-19 pneumonia by bedside high-resolution ultrasound in association to CO2 retention.

BACKGROUND: Coronavirus disease 2019 (COVID-19) can cause acute respiratory distress syndrome (ARDS). OBJECTIVE: This single centre cross-section study aimed to grade the severity of pneumonia by bed-side lung ultrasound (LUS). METHODS: A scoring system discriminates 5 levels of lung opacities: A-lines (0 points),≥3 B-line (1 point), coalescent B-lines (2 points), marked pleural disruptions (3 points), consolidations (4 points). LUS (convex 1-5 MHz probe) was performed at 6 defined regions for each hemithorax either in supine or prone position. A lung aeration score (LAS, maximum 4 points) was allocated for each patient by calculating the arithmetic mean of the examined lung areas. Score levels were correlated with ventilation parameters and laboratory markers. RESULTS: LAS of 20 patients with ARDS reached from 2.58 to 3.83 and was highest in the lateral right lobe (Mean 3.67). Ferritin levels (Mean 1885µg/l; r = 0.467; p = 0.051) showed moderate correlation in spearman roh calculation. PaCO2 level (Mean 46.75 mmHg; r = 0.632; p = 0.005) correlated significantly with LAS, while duration of ventilation, Horovitz index, CRP, LDH and IL-6 did not. CONCUSIONS: The proposed LAS describes severity of lung opacities in COVID-19 patients and correlates with CO2 retention in patients with ARDS.