Agreement between cardiac output measurements by pulse wave analysis using the Pressure Recording Analytical Method and transthoracic echocardiography in patients with veno-venous extracorporeal membrane oxygenation therapy: An observational method comparison

BACKGROUND

Measuring cardiac output (CO) is important in patients treated with veno-venous extracorporeal membrane oxygenation (vvECMO) because vvECMO flow and CO need to be balanced. Uncalibrated pulse wave analysis with the Pressure Recording Analytical Method (PRAM) may be suitable to measure CO in patients with vvECMO therapy.

OBJECTIVE

To assess the agreement between CO measured by PRAM (PRAM-CO; test method) and CO measured by transthoracic echocardiography (TTE-CO; reference method).

DESIGN

A prospective observational method comparison study.

SETTING

The ICU of a German university hospital between March and December 2021.

PATIENTS

Thirty one adult patients with respiratory failure requiring vvECMO therapy: 29 of the 31 patients (94%) were treated for COVID-19 related respiratory failure.

MAIN OUTCOME MEASURES

PRAM-CO and TTE-CO were measured simultaneously at two time points in each patient with at least 20 min between measurements. A radial or femoral arterial catheter-derived blood pressure waveform was used for PRAM-CO measurements. TTE-CO measurements were conducted using the pulsed wave Doppler-derived velocity time integral of the left ventricular outflow tract (LVOT) and the corresponding LVOT diameter. PRAM-CO and TTE-CO were compared using Bland-Altman analysis and the percentage error (PE). We defined a PE of <30% as clinically acceptable.

RESULTS

Mean ± SD PRAM-CO was 6.86 ± 1.49 l min -1 and mean TTE-CO was 6.94 ± 1.58 l min -1 . The mean of the differences between PRAM-CO and TTE-CO was 0.09 ± 0.73 l min -1 with a lower 95% limit of agreement of -1.34 l min -1 and an upper 95% limit of agreement of 1.51 l min -1 . The PE was 21%.

CONCLUSIONS

The agreement between PRAM-CO and TTE-CO is clinically acceptable in adult patients with vvECMO therapy.

Renaissance of glucocorticoids in critical care in the era of COVID-19: ten urging questions

The 40-year-old experience with glucocorticosteroids (GCs) in the context of severe infections is complex and troublesome. Recently, however, a clear indication for GCs in severe COVID-19 has been established. This may constitute a harbinger of a wider use of GCs in critical illnesses. A fundamental prerequisite of such an action is a better understanding of the heterogeneity of critical illness and GCs operationalization within the precision medicine approach. In this perspective, we formulate ten major questions regarding the use of GCs in critical illness. Answering them will likely facilitate a new era of effective and personalized GCs use in modern critical care.

Activation of Sphingomyelinase-Ceramide-Pathway in COVID-19 Purposes Its Inhibition for Therapeutic Strategies

Effective treatment strategies for severe coronavirus disease (COVID-19) remain scarce. Hydrolysis of membrane-embedded, inert sphingomyelin by stress responsive sphingomyelinases is a hallmark of adaptive responses and cellular repair. As demonstrated in experimental and observational clinical studies, the transient and stress-triggered release of a sphingomyelinase, SMPD1, into circulation and subsequent ceramide generation provides a promising target for FDA-approved drugs. Here, we report the activation of sphingomyelinase-ceramide pathway in 23 intensive care patients with severe COVID-19. We observed an increase of circulating activity of sphingomyelinase with subsequent derangement of sphingolipids in serum lipoproteins and from red blood cells (RBC). Consistent with increased ceramide levels derived from the inert membrane constituent sphingomyelin, increased activity of acid sphingomyelinase (ASM) accurately distinguished the patient cohort undergoing intensive care from healthy controls. Positive correlational analyses with biomarkers of severe clinical phenotype support the concept of an essential pathophysiological role of ASM in the course of SARS-CoV-2 infection as well as of a promising role for functional inhibition with anti-inflammatory agents in SARS-CoV-2 infection as also proposed in independent observational studies. We conclude that large-sized multicenter, interventional trials are now needed to evaluate the potential benefit of functional inhibition of this sphingomyelinase in critically ill patients with COVID-19.

Humoral and Cellular Immune Responses Against Severe Acute Respiratory Syndrome Coronavirus 2 Variants and Human Coronaviruses After Single BNT162b2 Vaccination

BACKGROUND

Vaccine-induced neutralizing antibodies are key in combating the coronavirus disease 2019 (COVID-19) pandemic. However, delays of boost immunization due to limited availability of vaccines may leave individuals vulnerable to infection and prolonged or severe disease courses. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOC)-B.1.1.7 (United Kingdom), B.1.351 (South Africa), and P.1 (Brazil)-may exacerbate this issue, as the latter two are able to evade control by antibodies.

METHODS

We assessed humoral and T-cell responses against SARS-CoV-2 wild-type (WT), VOC, and endemic human coronaviruses (hCoVs) that were induced after single and double vaccination with BNT162b2.

RESULTS

Despite readily detectable immunoglobulin G (IgG) against the receptor-binding domain of the SARS-CoV-2 S protein at day 14 after a single vaccination, inhibition of SARS-CoV-2 S-driven host cell entry was weak and particularly low for the B.1.351 variant. Frequencies of SARS-CoV-2 WT and VOC-specific T cells were low in many vaccinees after application of a single dose and influenced by immunity against endemic hCoV. The second vaccination significantly boosted T-cell frequencies reactive for WT and B.1.1.7 and B.1.351 variants.

CONCLUSIONS

These results call into question whether neutralizing antibodies significantly contribute to protection against COVID-19 upon single vaccination and suggest that cellular immunity is central for the early defenses against COVID-19.

Kinetics of Bilirubin and Ammonia Elimination during Hemadsorption Therapy in Secondary Sclerosing Cholangitis Following ECMO Therapy and Severe COVID-19

In critically ill patients, liver dysfunction often results in coagulopathy and encephalopathy and is associated with high mortality. Extracorporeal clearance of hepatotoxic metabolites, including bilirubin and ammonia, aims to attenuate further hepatocyte damage and liver injury, resulting in decreased mortality. The efficacy of hemadsorption combined with conventional hemodialysis to eliminate bilirubin and ammonia to support the liver's excretory function in acute liver injury has been described previously. However, the optimal use of liver support systems in chronic liver dysfunction due to secondary sclerosing cholangitis in critically ill patients (SSC-CIP) has not been defined yet. We herein describe the kinetics of successful bilirubin and ammonia elimination by hemadsorption in a patient with SSC-CIP after extracorporeal membrane oxygenation (ECMO) therapy for severe acute respiratory distress syndrome (ARDS) in a patient with coronavirus disease 2019 (COVID-19). During the course of the disease, the patient developed laboratory signs of liver injury during ECMO therapy before clinically detectable jaundice or elevated bilirubin levels. A diagnosis of SSC-CIP was confirmed by endoscopic retrograde cholangiopancreatography (ERCP) based on intraductal filling defects in the intrahepatic bile ducts due to biliary casts. The patient showed stable elevations of bilirubin and ammonia levels thereafter, but presented with progressive nausea, vomiting, weakness, and exhaustion. Based on these laboratory findings, hemadsorption was combined with hemodialysis treatment and successfully eliminated bilirubin and ammonia. Moreover, direct comparison revealed that ammonia is more efficiently eliminated by hemadsorption than bilirubin levels. Clinical symptoms of nausea, vomiting, weakness, and exhaustion improved. In summary, bilirubin and ammonia were successfully eliminated by hemadsorption combined with hemodialysis treatment in SSC-CIP following ECMO therapy and severe COVID-19. This observation is particularly relevant since it has been reported that a considerable subset of critically ill patients with COVID-19 suffer from liver dysfunction associated with high mortality.

High class filtering facepiece (FFP) are fundamental and effective in protection of emergency health care workers: an observational cohort study in a German community

Background

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a highly contagious airborne virus inducing pandemic coronavirus disease 2019 (COVID-19). This is most relevant for medical staff working under harmful conditions in emergencies often dealing with patients and an undefined SARS-CoV-2 status. We aimed to measure the effect of high-class filtering facepieces (FFP) in emergency medical service (EMS) staff by analyzing seroprevalence and history of positive polymerase chain reaction (PCR) for SARS-CoV-2.

Method

This observational cohort study included workers in EMS, who were compared with hospital staff (HS) and staff, which was not directly involved in patient care (NPC). All direct patient contacts of EMS workers were protected by FFP2/N95 (filtering face piece protection class 2/non-oil-based particulates filter efficiency 95%) masks, whereas HS was protected by FFP2/N95 exclusively when a patient had a proven or suspected SARS-CoV-2 infection. NPC was not protected by higher FFP. The seroprevalence of SARS-CoV-2 antibodies was analyzed by immunoassay by end of 12/2020 together with the history of a positive PCR. In addition, a self-assessment was performed regarding the quantity of SARS-CoV-2 positive contacts, about flu symptoms and personal belief of previous COVID-19 infections.

Results

The period in which contact to SARS-CoV-2 positive patients has been possible was 10 months (March to December 2020)—with 54,681 patient contacts documented for EMS—either emergencies (n = 33,241) or transportation services (n = 21,440). Seven hundred-thirty (n = 730) participants were included into the study (n = EMS: 325, HS: 322 and NPC: 83). The analysis of the survey showed that the exposure to patients with an unknown and consecutive positive SARS-CoV-2 result was significantly higher for EMS when compared to HS (EMS 55% vs. HS 30%, p = 0.01). The incidence of a SARS-CoV-2 infection in our cohort was 1.2% (EMS), 2.2% (HS) and 2.4% (NPC) within the three groups (ns) and lowest in EMS. Furthermore, the belief of previous COVID-19 was significant higher in EMS (19% vs. 10%),

Conclusion

The consistent use of FFP2/N95 in EMS is able to prevent work-related SARS-CoV-2 infections in emergency situations. The significance of physical airway protection in exposed medical staff is still relevant especially under the aspect of new viral variants and unclear effectiveness of new vaccines.

Graphical Abstract

B.1.617.2 enters and fuses lung cells with increased efficiency and evades antibodies induced by infection and vaccination

The Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), B.1.617.2, emerged in India and has spread to over 80 countries. B.1.617.2 replaced B.1.1.7 as the dominant virus in the United Kingdom, resulting in a steep increase in new infections, and a similar development is expected for other countries. Effective countermeasures require information on susceptibility of B.1.617.2 to control by antibodies elicited by vaccines and used for coronavirus disease 2019 (COVID-19) therapy. We show, using pseudotyping, that B.1.617.2 evades control by antibodies induced upon infection and BNT162b2 vaccination, although to a lesser extent as compared to B.1.351. We find that B.1.617.2 is resistant against bamlanivimab, a monoclonal antibody with emergency use authorization for COVID-19 therapy. Finally, we show increased Calu-3 lung cell entry and enhanced cell-to-cell fusion of B.1.617.2, which may contribute to augmented transmissibility and pathogenicity of this variant. These results identify B.1.617.2 as an immune evasion variant with increased capacity to enter and fuse lung cells.

The COVID-19 puzzle: deciphering pathophysiology and phenotypes of a new disease entity

The zoonotic SARS-CoV-2 virus that causes COVID-19 continues to spread worldwide, with devastating consequences. While the medical community has gained insight into the epidemiology of COVID-19, important questions remain about the clinical complexities and underlying mechanisms of disease phenotypes. Severe COVID-19 most commonly involves respiratory manifestations, although other systems are also affected, and acute disease is often followed by protracted complications. Such complex manifestations suggest that SARS-CoV-2 dysregulates the host response, triggering wide-ranging immuno-inflammatory, thrombotic, and parenchymal derangements. We review the intricacies of COVID-19 pathophysiology, its various phenotypes, and the anti-SARS-CoV-2 host response at the humoral and cellular levels. Some similarities exist between COVID-19 and respiratory failure of other origins, but evidence for many distinctive mechanistic features indicates that COVID-19 constitutes a new disease entity, with emerging data suggesting involvement of an endotheliopathy-centred pathophysiology. Further research, combining basic and clinical studies, is needed to advance understanding of pathophysiological mechanisms and to characterise immuno-inflammatory derangements across the range of phenotypes to enable optimum care for patients with COVID-19.

SARS-CoV-2 variants B.1.351 and P.1 escape from neutralizing antibodies

The global spread of SARS-CoV-2/COVID-19 is devastating health systems and economies worldwide. Recombinant or vaccine-induced neutralizing antibodies are used to combat the COVID-19 pandemic. However, the recently emerged SARS-CoV-2 variants B.1.1.7 (UK), B.1.351 (South Africa), and P.1 (Brazil) harbor mutations in the viral spike (S) protein that may alter virus-host cell interactions and confer resistance to inhibitors and antibodies. Here, using pseudoparticles, we show that entry of all variants into human cells is susceptible to blockade by the entry inhibitors soluble ACE2, Camostat, EK-1, and EK-1-C4. In contrast, entry of the B.1.351 and P.1 variant was partially (Casirivimab) or fully (Bamlanivimab) resistant to antibodies used for COVID-19 treatment. Moreover, entry of these variants was less efficiently inhibited by plasma from convalescent COVID-19 patients and sera from BNT162b2-vaccinated individuals. These results suggest that SARS-CoV-2 may escape neutralizing antibody responses, which has important implications for efforts to contain the pandemic.

Bridging animal and clinical research during SARS-CoV-2 pandemic: A new-old challenge

Many milestones in medical history rest on animal modeling of human diseases. The SARS-CoV-2 pandemic has evoked a tremendous investigative effort primarily centered on clinical studies. However, several animal SARS-CoV-2/COVID-19 models have been developed and pre-clinical findings aimed at supporting clinical evidence rapidly emerge. In this review, we characterize the existing animal models exposing their relevance and limitations as well as outline their utility in COVID-19 drug and vaccine development. Concurrently, we summarize the status of clinical trial research and discuss the novel tactics utilized in the largest multi-center trials aiming to accelerate generation of reliable results that may subsequently shape COVID-19 clinical treatment practices. We also highlight areas of improvement for animal studies in order to elevate their translational utility. In pandemics, to optimize the use of strained resources in a short time-frame, optimizing and strengthening the synergy between the preclinical and clinical domains is pivotal.

Olfactory transmucosal SARS-CoV-2 invasion as a port of central nervous system entry in individuals with COVID-19

The newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a pandemic respiratory disease. Moreover, thromboembolic events throughout the body, including in the CNS, have been described. Given the neurological symptoms observed in a large majority of individuals with COVID-19, SARS-CoV-2 penetrance of the CNS is likely. By various means, we demonstrate the presence of SARS-CoV-2 RNA and protein in anatomically distinct regions of the nasopharynx and brain. Furthermore, we describe the morphological changes associated with infection such as thromboembolic ischemic infarction of the CNS and present evidence of SARS-CoV-2 neurotropism. SARS-CoV-2 can enter the nervous system by crossing the neural-mucosal interface in olfactory mucosa, exploiting the close vicinity of olfactory mucosal, endothelial and nervous tissue, including delicate olfactory and sensory nerve endings. Subsequently, SARS-CoV-2 appears to follow neuroanatomical structures, penetrating defined neuroanatomical areas including the primary respiratory and cardiovascular control center in the medulla oblongata.

S1P lyase inhibition protects against sepsis by promoting disease tolerance via the S1P/S1PR3 axis

Background

One-third of all deaths in hospitals are caused by sepsis. Despite its demonstrated prevalence and high case fatality rate, antibiotics remain the only target-oriented treatment option currently available. Starting from results showing that low-dose anthracyclines protect against sepsis in mice, we sought to find new causative treatment options to improve sepsis outcomes.

Methods

Sepsis was induced in mice, and different treatment options were evaluated regarding cytokine and biomarker expression, lung epithelial cell permeability, autophagy induction, and survival benefit. Results were validated in cell culture experiments and correlated with patient samples.

Findings

Effective low-dose epirubicin treatment resulted in substantial downregulation of the sphingosine 1-phosphate (S1P) degrading enzyme S1P lyase (SPL). Consequent accumulation and secretion of S1P in lung parenchyma cells stimulated the S1P-receptor type 3 (S1PR3) and mitogen-activated protein kinases p38 and ERK, reducing tissue damage via increased disease tolerance. The protective effects of SPL inhibition were absent in S1PR3 deficient mice. Sepsis patients showed increased expression of SPL, stable expression of S1PR3, and increased levels of mucin-1 and surfactant protein D as indicators of lung damage.

Interpretation

Our work highlights a tissue-protective effect of SPL inhibition in sepsis due to activation of the S1P/S1PR3 axis and implies that SPL inhibitors and S1PR3 agonists might be potential therapeutics to protect against sepsis by increasing disease tolerance against infections.

Funding

This study was supported by the Center for Sepsis Control and Care (CSCC), the German Research Foundation (DFG), RTG 1715 (to M. H. G. and I. R.) and the National Institutes of Health, Grant R01GM043880 (to S. S.).

Risk-adjusted strategies in the prevention of early arterial thrombosis following lower extremity arterial reconstruction: a comparison of unfractionated versus low molecular weight heparin

AIM

In vascular surgery postoperative thrombosis prophylaxis must sufficiently prevent arterial thrombosis. This cohort study examines different therapeutic approaches of unfractionated heparin (UFH) or low molecular weight heparin (LMWH) after vascular reconstruction.

METHODS

Four hundred seventy-five patients entered the study between 2005 and 2008. Our clinical routine made a differentiation between low-risk patients (N.=375) and patients with peripheral bypass, which were grouped as high-risk (N.=148). We changed our postoperative anticoagulation management after 24 months in the low-risk and after each 16 months in the high-risk group. The anticoagulation of low-risk patients consisted of either two applications of 7.500 IU UFH subcutaneously (N.=158) or one daily application of 40 mg LMWH each up to discharge (N.=169). High-risk patients received either 25.000 IU UFH i.v. over 24 hours and 4 days (N.=48), 2-times (N.=51) or one-time weight-adjusted LMWH (N.=49) up to discharge (1 mg/kg body weight). Minor complications (bleedings) were differentiated from major early graft occlusion during the postoperative course. Further follow-up was not done for this study.

RESULTS

Low risk: under LMWH, complications could be significantly reduced (P=0.001). Under LMWH significantly fewer occlusion complications occurred (P=0.01) and operation-induced hemorrhages were less frequently observed (P=0.05), this was significant in the complete low-risk group. High-risk: the one-time weight-adjusted LMWH group similarly exhibited many occlusions, like the unfractionated group (NS). The two-time LMWH treatment was significantly superior to the one-time application with respect to occlusion followed by amputations (P=0.03). Minor complications could be minimized overall by administration of LMWH and its dose reduction (NS).

CONCLUSION

The differentiation between patients with high and low risk seems reasonable. An improvement could be achieved by differentiated LMWH application. Synthetic specific antifactor Xa substances (fondaparinux) or other medications could lead in future to other changes in the management of vascular surgery patients and should be further evaluated.

[Overview and evolving strategies of ventral hernia repair]

Incisional hernias occur in 5-10% of patients who have undergone laparotomy and are associated with high morbidity and significant socioeconomic costs. Techniques for reinforcing and/or replacing the abdominal wall with alloplastic meshes have reduced the recurrence rate in comparison to suture techniques from about 40% to less than 10%. A number of mesh types and surgical repair procedures are available, namely the onlay, inlay, sublay, underlay, and intraperitoneal onlay mesh (IPOM) techniques. Evolving strategies include precise criteria for incorporating patient body type, risk factors for recurrence, hernia morphology, and the available biomaterials into the planning of the surgical approach. The authors herein present an overview of the current surgical trends, focusing on mesh reinforcement (sublay technique) and mesh replacement (IPOM technique). Additionally, they review a classification of incisional hernias that is self-explanatory, practicable in routine clinical practice, and based on the cornerstones of morphology, hernia size, and risk factors for recurrence. Evidence for the indications and limitations of the main surgical repair techniques are illustrated and discussed.

An alternative classification of incisional hernias enlisting morphology, body type and risk factors in the assessment of prognosis and tailoring of surgical technique

Incisional hernias occur in 5-10% of patients who have undergone laparotomy and are associated with a high morbidity and significant socioeconomic costs. Better understanding of the anatomy and improved methods for reinforcement of the abdominal wall with alloplastic meshes have reduced the recurrence rate to 1-10% depending on the type of hernia and the technique employed. A number of surgical repair techniques and mesh types are available. However, precise criteria for incorporating patient body type, risk factors for recurrence, hernia morphology, and the available biomaterials into planning of the surgical approach (open versus laparoscopic) have yet to be established. The elaboration of such criteria would require comparative evaluation of long-term results in a sufficiently large number of patients, e.g. in multicentre trials or meta-analyses of standardised data from different centres. Current classifications have the drawback that they fail to take account of prognostically relevant risk factors for recurrence and are not self-explanatory. The authors present a classification of incisional hernias that is self-explanatory and practicable in routine clinical practice. Based on the cornerstones of morphology (M), hernia size in cm (S), and risk factors for recurrence (RF), the scheme enables easy description and documentation of the hernia, and provides evidence for the indications and limitations of the main surgical repair techniques. Since randomised studies can scarcely be conducted on incisional hernias due to the numerous morphological variables, the classification presented here may offer an alternative means for comparative data analysis.