Nebulized recombinant tissue plasminogen activator (rt-PA) for acute COVID-19-induced severe respiratory failure: an exploratory proof of concept trial (preprint)

Nebulized thrombolysis offers locally targeted therapy with potentially lower bleeding risk than systemic administration for coronavirus disease 2019 (COVID-19) respiratory failure. In a proof-of-concept safety study, adult patients with COVID-19-induced respiratory failure and a <300mmHg PaO2/FiO2 (P/F) ratio, requiring invasive mechanical ventilation (IMV) or non-invasive respiratory support (NIRS) received nebulized rt-PA in two cohorts (C1 and C2), alongside standard of care during the first two UK COVID-19 waves. Matched historical controls (MHC; n=18) were used in C1. Safety co-primary endpoints were treatment-related bleeds and fibrinogen reduction to <1.0–1.5 g/L. A dose escalation strategy for improved efficacy with the least safety concerns was determined in C1 for use in C2; patients were stratified by ventilation type to receive 40–60 mg rt-PA per day for ≤14 days. Nine patients in C1 (IMV, 6/9; NIRS, 3/9) and 26 in C2 (IMV, 12/26; NIRS, 14/26) received nebulized rt-PA for a mean (SD) of 6.7 (4.6) and 9.1(4.6) days, respectively. Four bleeding events (one severe and three mild) in three patients were considered treatment-related. No significant fibrinogen reductions were reported. Greater improvement in mean P/F ratio from baseline to end of study was observed in C1 compared with MHC [C1; 154 to 299 vs MHC; 154 to 212). In C2, there was no difference in the baseline P/F ratio of NIRS and IMV patients. However, a larger improvement in P/F ratio was observed in NIRS patients [NIRS; 126 to 240 vs IMV; 120 to 188) and they required fewer treatment days (NIRS; 7.86 vs IMV; 10.5). Nebulized rt-PA appears to be well-tolerated, showing a trend of improved oxygenation and faster recovery in patients with acute COVID-19-induced respiratory failure requiring respiratory support; this effect was more pronounced in the NIRS group. Further investigation is required to study the potential of this novel treatment approach.

A comparison of long term outcomes in patients managed with VV-ECMO in the first and second waves of the COVID-19 pandemic in the UK (preprint)

BackgroundEarly studies of veno-venous extracorporeal membrane oxygenation (VV-ECMO) in COVID-19 have revealed similar outcomes to historical cohorts. Changes in the disease and treatments has led to differences in the patients supported on VV-ECMO in the 1st and 2nd waves. We aimed to compare these two groups in both the acute and follow-up phase.MethodsIn this retrospective study, we identified the differences between patients supported on ECMO for COVID-19 between wave 1 (17/03/2020-31/08/2020) and wave 2 (01/09/2020-25/05/2021). We examined mortality at censoring date (30/11/2021) and decannulation, patient characteristics, complications and lung function and quality of life (QOL – by EQ5D3L) at first follow-up.FindingsOne-hundred and twenty-three patients were included in our analysis. Survival at censoring date [Chi-sqaured 6.35, p=0.012] and decannulation [90.4% vs 70.0%, p<0.001], was significantly lower in the 2nd wave, whilst duration of ECMO run was longer [12.0(18.0-30.0) days vs. 29.5(15.5-58.3)] days (p=0.005)). Wave 2 patients had longer application of non-invasive ventilation (NIV) prior to ECMO and a higher incidence of barotrauma. Patient age and NIV use were independently associated with increased mortality [OR 1.07(1.01-1.14), p=0.025 and 3.37(1.12–12.60), p=0.043 respectively]. QOL and lung function, apart from KCOc was similar at follow up across the waves.ConclusionMost patients with COVID-19 supported on ECMO in both waves survived in the short and longer term. At follow-up patients had similar lung function and QOL across the 2 waves. This suggests that ECMO has an ongoing role in the management of a carefully selected group of patients with COVID-19.Trial RegistrationResearch Ethics Committee (20/EM/0204)

A persistent neutrophil-associated immune signature characterises post-COVID19 pulmonary sequelae (preprint)

Persistent interstitial lung changes with associated symptoms occur in a proportion of individuals that have recovered from severe acute respiratory syndrome coronavirus-2 (SARS-COV-2) infection through unknown mechanisms. We studied individuals with severe COVID-19 longitudinally following recovery from acute illness. Subjects with interstitial lung changes at 3-6 months post-recovery had an upregulated neutrophil-associated immune signature including increased chemokines, proteases and markers of neutrophil extracellular traps detectable systemically. Similar pathways were enriched in the upper airway with a concomitant augmentation of antiviral type-I interferon signalling. Interaction analysis of the peripheral phosphoproteome identified enriched kinases critical for neutrophil inflammatory pathways. Repeat sampling indicated that full normalisation of radiological and functional changes has not yet been reached in many individuals by 12 months post-recovery. These data provide functional insight into mechanisms driving pulmonary sequelae of COVID-19 and provide a rational basis for development of future targeted approaches to prevent long-term complications.

Organisms causing secondary pneumonias in COVID-19 patients at 5 UK ICUs as detected with the FilmArray test (preprint)

ABSTRACT Introduction. Several viral respiratory infections - notably influenza - are associated with secondary bacterial infection and additional pathology. The extent to which this applies for COVID-19 is unknown. Accordingly, we aimed to define the bacteria causing secondary pneumonias in COVID-19 ICU patients using the FilmArray Pneumonia Panel, and to determine this tests potential in COVID-19 management. Methods. COVID-19 ICU patients with clinically-suspected secondary infection at 5 UK hospitals were tested with the FilmArray at point of care. We collected patient demographic data and compared FilmArray results with routine culture. Results. We report results of 110 FilmArray tests on 94 patients (16 had 2 tests): 69 patients (73%) were male, the median age was 59 yrs; 92 were ventilated. Median hospital stay before testing was 14 days (range 1-38). Fifty-nine (54%) tests were positive, with 141 bacteria detected. Most were Enterobacterales (n=55, including Klebsiella spp. [n= 35]) or Staphylococcus aureus (n=13), as is typical of hospital and ventilator pneumonia. Community pathogens, including Haemophilus influenzae (n=8) and Streptococcus pneumoniae (n=1), were rarer. FilmArray detected one additional virus (Rhinovirus/Enterovirus) and no atypical bacteria. Fewer samples (28 % vs. 54%) were positive by routine culture, and fewer species were reported per sample; Klebsiella species remained the most prevalent pathogens. Conclusion. FilmArray had a higher diagnostic yield than culture for ICU COVID-19 patients with suspected secondary pneumonias. The bacteria found mostly were Enterobacterales, S. aureus and P. aeruginosa, as in typical HAP/VAP, but with Klebsiella spp. more prominent. We found almost no viral co-infection. Turnaround from sample to results is around 1h 15 min compared with the usual 72h for culture, giving prescribers earlier data to inform antimicrobial decisions.

COVID-19 in London, a Case Series Demonstrating Late Improvement in Survivors (preprint)

Objective To determine whether the trajectories of survivors and non-survivors are different in patients admitted to intensive care in London. Design In this case series of 15 survivors and 16 non-survivors, data from admission to discharge was collected and aligned to lowest PaO2/FiO2 ratio where aggregation and trends were demonstrated. Setting Single centre case-series in London, Intensive Care. Participants All non-survivors were included (n=16). A biased set of survivors (n=15) who were demonstrated an unexpected and rapid recovery after a prolonged period of mechanical ventilatory support. Results Respiratory failure trajectories of survivors and non-survivors were similar once aligned indicating, from a respiratory function perspective, it is difficult to identify survivors from non-survivors with some survivors improving late in their disease (day 20 - 30 from symptom onset) Non-survivors are admitted earlier in their disease (p < 0.05) and had worse organ failure requirements prior to the nadir of their respiratory funciton (p < 0.05) compard to survivors. Conclusion Analysis of multiple factors fails to differentiate between survivors and non-survivors. Even when faced with multiorgan failure, perseverance until discharge must be advocated as late improvements do occur in survivors.

Early detection of severe COVID-19 disease patterns define near real-time personalised care, bioseverity in males, and decelerating mortality rates. (preprint)

BACKGROUND: COVID-19 is a global health emergency. Recent data indicate a 50% mortality rate across UK intensive care units. METHODS: A single institution, two-centre retrospective analysis following implementation of a Decision Support tool and real-time data dashboard for early detection of patients requiring personalised enhanced care, focussing particularly on respiratory rate, diastolic blood pressure, oxygenation indices, C-reactive protein, D-dimer and ferritin. Protocols differing from conventional practice included high-dose prophylactic anticoagulation for all COVID-19 positive patients and antioxidant prescription. RESULTS: By 22nd April 2020, 923 patients tested COVID-19 positive. 569 patients (61.7%) were male. The majority presented with advanced disease: interquartile ranges were C-reactive protein 44.9-179mg/L, D-dimer 1070-3802ng/L, and ferritin 261-1208g/L. Completed case fatality rates were 25.1% [95% CI 20.0, 30.0] in females, 40.5% [95% CI 35.9, 45.0] in males. 139 patients were admitted to intensive care where current death rates are 16.2% [95% CI 3.8, 28.7] in females, 38.2% [95% CI 28.6, 47.8] in males with no trends for differences based on ethnicity. A real-time traffic lights dashboard enabled rapid assessment of patients using critical parameters to accelerate adjustments to management protocols. In total 513 (55.6%) of patients were flagged as high risk for thromboembolic disease, exceeding the numbers flagged for respiratory deteriorations (N=391, 42.4%), or cytokine storm (N=68, 7.4%). There was minimal evidence that age was associated with disease severity, but males had higher levels of all dashboard indices, particularly C-reactive protein and ferritin (p<0.0001) which displayed no relationship with age. CONCLUSIONS: Survival rates are encouraging. Protocols employed (traffic light-driven personalised care, protocolised early therapeutic anticoagulation based on D-dimer >1,000ng/L and/or CRP>200 mg/L, personalised ventilatory strategies and antioxidants) are recommended to other units. Males are at greater risk of severe disease, most likely as the obligate SARS-CoV-2 receptor is on the X-chromosome, and require especially close, and early attention.