Host transcriptomics and machine learning for secondary bacterial infections in patients with COVID-19: a prospective, observational cohort study

BACKGROUND

Viral respiratory tract infections are frequently complicated by secondary bacterial infections. This study aimed to use machine learning to predict the risk of bacterial superinfection in SARS-CoV-2-positive individuals.

METHODS

In this prospective, multicentre, observational cohort study done in nine centres in six countries (Australia, Indonesia, Singapore, Italy, Czechia, and France) blood samples and RNA sequencing were used to develop a robust model of predicting secondary bacterial infections in the respiratory tract of patients with COVID-19. Eligible participants were older than 18 years, had known or suspected COVID-19, and symptoms of a recent respiratory infection. A control cohort of participants without COVID-19 who were older than 18 years and with no infection symptoms was also recruited from one Australian centre. In the pre-analysis phase, data were filtered to include only individuals with complete blood transcriptomics and patient data (ie, age, sex, location, and WHO severity score at the time of sample collection). The dataset was then divided randomly (4:1) into a training set (80%) and a test set (20%). Gene expression data in the training set and control cohort were used for differential expression analysis. Differentially expressed genes, along with WHO severity score, location, age, and sex, were used for feature selection with least absolute shrinkage and selection operator (LASSO) in the training set. For LASSO analysis, samples were excluded if gene expression data were not obtained at study admission, no longitudinal clinical information was available, a bacterial infection at the time of study admission was present, or a fungal infection in the absence of a bacterial infection was detected. LASSO regression was performed using three subsets of predictor variables: patient data alone, gene expression data alone, or a combination of patient data and gene expression data. The accuracy of the resultant models was tested on data from the test set.

FINDINGS

Between March, 2020, and October, 2021, we recruited 536 SARS-CoV-2-positive individuals and between June, 2013, and January, 2020, we recruited 74 participants into the control cohort. After prefiltering analysis and other exclusions, samples from 158 individuals were analysed in the training set and 47 in the test set. The expression of seven host genes (DAPP1, CST3, FGL2, GCH1, CIITA, UPP1, and RN7SL1) in the blood at the time of study admission was identified by LASSO as predictive of the risk of developing a secondary bacterial infection of the respiratory tract more than 24 h after study admission. Specifically, the expression of these genes in combination with a patient's WHO severity score at the time of study enrolment resulted in an area under the curve of 0·98 (95% CI 0·89-1·00), a true positive rate (sensitivity) of 1·00 (95% CI 1·00-1·00), and a true negative rate (specificity) of 0·94 (95% CI 0·89-1·00) in the test cohort. The combination of patient data and host transcriptomics at hospital admission identified all seven individuals in the training and test sets who developed a bacterial infection of the respiratory tract 5-9 days after hospital admission.

INTERPRETATION

These data raise the possibility that host transcriptomics at the time of clinical presentation, together with machine learning, can forward predict the risk of secondary bacterial infections and allow for the more targeted use of antibiotics in viral infection.

FUNDING

Snow Medical Research Foundation, the National Health and Medical Research Council, the Jack Ma Foundation, the Helmholtz-Association, the A2 Milk Company, National Institute of Allergy and Infectious Disease, and the Fondazione AIRC Associazione Italiana per la Ricerca contro il Cancro.

Pathway and Network Analyses Identify Growth Factor Signaling and MMP9 as Potential Mediators of Mitochondrial Dysfunction in Severe COVID-19

Patients with preexisting metabolic disorders such as diabetes are at a higher risk of developing severe coronavirus disease 2019 (COVID-19). Mitochondrion, the very organelle that controls cellular metabolism, holds the key to understanding disease progression at the cellular level. Our current study aimed to understand how cellular metabolism contributes to COVID-19 outcomes. Metacore pathway enrichment analyses on differentially expressed genes (encoded by both mitochondrial and nuclear deoxyribonucleic acid (DNA)) involved in cellular metabolism, regulation of mitochondrial respiration and organization, and apoptosis, was performed on RNA sequencing (RNASeq) data from blood samples collected from healthy controls and patients with mild/moderate or severe COVID-19. Genes from the enriched pathways were analyzed by network analysis to uncover interactions among them and up- or downstream genes within each pathway. Compared to the mild/moderate COVID-19, the upregulation of a myriad of growth factor and cell cycle signaling pathways, with concomitant downregulation of interferon signaling pathways, were observed in the severe group. Matrix metallopeptidase 9 (MMP9) was found in five of the top 10 upregulated pathways, indicating its potential as therapeutic target against COVID-19. In summary, our data demonstrates aberrant activation of endocrine signaling in severe COVID-19, and its implication in immune and metabolic dysfunction.

Multisite validation of a host response signature for predicting likelihood of bacterial and viral infections in patients with suspected influenza

BACKGROUND

Indiscriminate use of antimicrobials and antimicrobial resistance is a public health threat. IMX-BVN-1, a 29-host mRNA classifier, provides two separate scores that predict likelihoods of bacterial and viral infections in patients with suspected acute infections. We validated the performance of IMX-BVN-1 in adults attending acute health care settings with suspected influenza.

METHOD

We amplified 29-host response genes in RNA extracted from blood by NanoString nCounter. IMX-BVN-1 calculated two scores to predict probabilities of bacterial and viral infections. Results were compared against the infection status (no infection; highly probable/possible infection; confirmed infection) determined by clinical adjudication.

RESULTS

Amongst 602 adult patients (74.9% ED, 16.9% ICU, 8.1% outpatients), 7.6% showed in-hospital mortality and 15.5% immunosuppression. Median IMX-BVN-1 bacterial and viral scores were higher in patients with confirmed bacterial (0.27) and viral (0.62) infections than in those without bacterial (0.08) or viral (0.21) infection, respectively. The AUROC distinguishing bacterial from nonbacterial illness was 0.81 and 0.87 when distinguishing viral from nonviral illness. The bacterial top quartile's positive likelihood ratio (LR) was 4.38 with a rule-in specificity of 88%; the bacterial bottom quartile's negative LR was 0.13 with a rule-out sensitivity of 96%. Similarly, the viral top quartile showed an infinite LR with rule-in specificity of 100%; the viral bottom quartile had a LR of 0.22 and a rule-out sensitivity of 85%.

CONCLUSION

IMX-BVN-1 showed high accuracy for differentiating bacterial and viral infections from noninfectious illness in patients with suspected influenza. Clinical utility of IMX-BVN will be validated following integration into a point of care system.

Blood transcriptome responses in patients correlate with severity of COVID-19 disease

Background

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Infected individuals display a wide spectrum of disease severity, as defined by the World Health Organization (WHO). One of the main factors underlying this heterogeneity is the host immune response, with severe COVID-19 often associated with a hyperinflammatory state.

Aim

Our current study aimed to pinpoint the specific genes and pathways underlying differences in the disease spectrum and outcomes observed, through in-depth analyses of whole blood transcriptomics in a large cohort of COVID-19 participants.

Results

All WHO severity levels were well represented and mild and severe disease displaying distinct gene expression profiles. WHO severity levels 1-4 were grouped as mild disease, and signatures from these participants were different from those with WHO severity levels 6-9 classified as severe disease. Severity level 5 (moderate cases) presented a unique transitional gene signature between severity levels 2-4 (mild/moderate) and 6-9 (severe) and hence might represent the turning point for better or worse disease outcome. Gene expression changes are very distinct when comparing mild/moderate or severe cases to healthy controls. In particular, we demonstrated the hallmark down-regulation of adaptive immune response pathways and activation of neutrophil pathways in severe compared to mild/moderate cases, as well as activation of blood coagulation pathways.

Conclusions

Our data revealed discrete gene signatures associated with mild, moderate, and severe COVID-19 identifying valuable candidates for future biomarker discovery.

Reperfusion strategy and late clinical outcomes of patients with ST-elevation myocardial infarction (STEMI) in the absence of standard modifiable risk factors (SMuRFs)

Introduction

There is growing evidence that patients presenting with STEMI in the absence of standard modifiable cardiovascular risk factors (SMuRFs; smoking, hypertension, hypercholesterolemia, diabetes) have poorer outcomes compared to those with atleast one SMuRF. It has been hypothesised that this may be in part due to decreased administration of pharmacotherapies in the post-infarct period due to perceived low risk. Long term outcomes of patients without SMuRFs based on reperfusion strategy received during the index admission have not been investigated.

Purpose

We sought to analyse late clinical outcomes of STEMI patients with and without SMuRFs based on reperfusion strategy received during the index admission.

Methods

All patients who underwent PCI between 2003 and 2014 were identified from a PCI centre STEMI database. Late clinical outcomes of patients with and without SMuRFs were analysed overall and based on reperfusion strategy [primary PCI (pPCI) vs pharmaco-invasive PCI (PI-PCI)]. Propensity matching was used to account for differences in baseline characteristics between the groups.

Results

Amongst 2,091 STEMI patients, 531 (25%) had no SMuRFs (51% pPCI, 49% PI-PCI) and 1560 (75%) had ≥1 SMuRF (52% pPCI, 48% PI-PCI). Unadjusted late mortality in SMuRF-less patients was 13.4% (18.8% pPCI, 7.7% PI-PCI) and for those with ≥1 SMuRF was 9.7% (11.0% pPCI, 8.4% PI-PCI). After propensity-matching clinical and angiographic characteristics, 5 year mortality rates were significantly higher for patients without SMuRFs compared to those with SMuRFs [HR 1.36, CI: 1.03–1.81, p=0.031]. This difference was attenuated for patients who underwent pPCI [HR 1.72, CI: 1.22–2.43, p=0.002]. Interestingly, this discrepancy was not observed amongst individuals who underwent pharmaco-invasive PCI [HR 1.13, CI: 0.53–1.48, p=0.638], as SMuRF-less patients had similar mortality rates to their counterparts. Long term rates of reinfarction, stent thrombosis and target vessel revascularisation were similar between the groups. Additionally, there was no significant difference in rates of stroke and major bleeding amongst all 4 subgroups.

Conclusion

Patients presenting with STEMI in the absence of SMuRFs have increased overall late mortality compared to those with at least one SMuRF. However, this difference was not observed in patients who underwent a pharmaco-invasive strategy, whereby patients without SMuRFs had similar outcomes to those with SMuRFs after adjusting for confounders. Our findings suggest the use of a pharmaco-invasive strategy in appropriate SMuRF-less patients presenting with STEMI.

Funding Acknowledgement

Type of funding sources: None.

1307 Linking Pre-ST Trainees into The Surgical Profession - An Example from OMFS Of A Structured Introduction to The Speciality

Introduction

Inspiration and support are two of the key principles that enthuse junior trainees to pursue a career in surgery. Exposure to Oral and Maxillofacial Surgery (OMFS) is minimal at undergraduate level and can present a challenge for those postgraduate individuals who wish to gain more experience before applying to further training. This has prompted the formation of a support programme comprised of two stages: Taste of OMFS and Mentoring and Support Programme (MSP).

Method

Feedback was captured from OMFS junior trainees and educational supervisors on the existing junior trainee programme. It was concluded that a new programme was required to create a more structured system to help support trainees achieve their goals within OMFS. Taste in OMFS aims to provoke intrigue in the specialty. Individuals who are inspired to experience more can advance on to the MSP which consists of checklists, carefully designed to help the trainee obtain adequate exposure and achieve the recommended requirements for second-degree and specialty training applications.

Results

The new programme was trialed by existing junior trainee programme members over a six-month period. The results were encouraging with positive feedback on the structure of both sections. This, in combination with ideas generated from a focus group has helped create the final version, now published and accessible on the British Association of Oral and Maxillofacial Surgeons website.

Conclusions

We hope to raise awareness of this dynamic programme which can be tailored to each individual, in the hope that more junior trainees pursue a career within OMFS.

Immunophenotyping of Peripheral Blood Mononuclear Cells in Septic Shock Patients With High-Dimensional Flow Cytometry Analysis Reveals Two Subgroups With Differential Responses to Immunostimulant Drugs

Sepsis is associated with a dysregulated inflammatory response to infection. Despite the activation of inflammation, an immune suppression is often observed, predisposing patients to secondary infections. Therapies directed at restoration of immunity may be considered but should be guided by the immune status of the patients. In this paper, we described the use of a high-dimensional flow cytometry (HDCyto) panel to assess the immunophenotype of patients with sepsis. We then isolated peripheral blood mononuclear cells (PBMCs) from patients with septic shock and mimicked a secondary infection by stimulating PBMCs for 4 h in vitro with lipopolysaccharide (LPS) with or without prior exposure to either IFN-γ, or LAG-3Ig. We evaluated the response by means of flow cytometry and high-resolution clustering cum differential analysis and compared the results to PBMCs from healthy donors. We observed a heterogeneous immune response in septic patients and identified two major subgroups: one characterized by hypo-responsiveness (Hypo) and another one by hyper-responsiveness (Hyper). Hypo and Hyper groups showed significant differences in the production of cytokines/chemokine and surface human leukocyte antigen-DR (HLA-DR) expression in response to LPS stimulation, which were observed across all cell types. When pre-treated with either interferon gamma (IFN-γ) or lymphocyte-activation gene 3 (LAG)-3 recombinant fusion protein (LAG-3Ig) prior to LPS stimulation, cells from the Hypo group were shown to be more responsive to both immunostimulants than cells from the Hyper group. Our results demonstrate the importance of patient stratification based on their immune status prior to any immune therapies. Once sufficiently scaled, this approach may be useful for prescribing the right immune therapy for the right patient at the right time, the key to the success of any therapy.

The UK Mentoring and Support Programme (MSP) for those considering a career in Oral and Maxillofacial Surgery (OMFS). A review of a 'Register Interest in OMFS' website and the MSP as two key resources created by the British Association of Oral and Maxillofacial Surgeons to promote recruitment and retention (2008-2020)

In 2008, to create a rapid route for information transfer in relation training and recruitment for OMFS trainees, the British Association of Oral and Maxillofacial Surgeons (BAOMS) created a website to "Register Your Interest in OMFS" (RYIO). From 2011 a Mentoring and Support Programme (MSP) was created to provide focussed guidance for trainees aiming for specialty training. This paper reviews the effectiveness and cost of these programmes. Between 2008 and 2020, 1744 individuals used RYIO on 2715 occasions. Of these registrations, 1772 were by dentists, 193 dental students, 589 doctors and 161 medical students. 2354 were from UK and Ireland and 351 from the rest of the world. 188 registrants subsequently became UK OMFS trainees or specialists. All registrants valued the information provided. In response to RYIO trainee feedback the new 'Taste of OMFS 2020' programme was created. The MSP was originally called the Junior Trainee Programme (JTP). The MSP scheme provides a layer of mentorship/support which runs parallel to the medical/dental training post or period of study. Of 180 members of MSP, 72 have obtained specialty training posts in OMFS. There are 88 current members. Full information is available on the BAOMS website www.baoms.org.uk. Reviewing both programmes, participant feedback is excellent with tangible results whilst cost effectiveness is high.

The PRICES statement: an ESICM expert consensus on methodology for conducting and reporting critical care echocardiography research studies

PURPOSE

Echocardiography is a common tool for cardiac and hemodynamic assessments in critical care research. However, interpretation (and applications) of results and between-study comparisons are often difficult due to the lack of certain important details in the studies. PRICES (Preferred Reporting Items for Critical care Echocardiography Studies) is a project endorsed by the European Society of Intensive Care Medicine and conducted by the Echocardiography Working Group, aiming at producing recommendations for standardized reporting of critical care echocardiography (CCE) research studies.

METHODS

The PRICE panel identified lists of clinical and echocardiographic parameters (the "items") deemed important in four main areas of CCE research: left ventricular systolic and diastolic functions, right ventricular function and fluid management. Each item was graded using a critical index (CI) that combined the relative importance of each item and the fraction of studies that did not report it, also taking experts' opinion into account.

RESULTS

A list of items in each area that deemed essential for the proper interpretation and application of research results is recommended. Additional items which aid interpretation were also proposed.

CONCLUSION

The PRICES recommendations reported in this document, as a checklist, represent an international consensus of experts as to which parameters and information should be included in the design of echocardiography research studies. PRICES recommendations provide guidance to scientists in the field of CCE with the objective of providing a recommended framework for reporting of CCE methodology and results.

Administration of intravenous iron and tranexamic acid in the management of postoperative iron deficiency anaemia following free flap reconstruction: re-audit

Following free tissue transfer, intravenous iron (IVI) has a role in reducing the rates of blood transfusion and more rapidly restoring haemoglobin (Hb) levels. Anaemia has a detrimental effect on survival, postoperative complications, fatigue, and health-related quality of life, therefore early correction is recommended. The aim of this re-audit is to assess the use of IVI, of tranexamic acid intraoperatively, and of perioperative blood transfusions. A total of 148 consecutive patients who underwent ablative surgery and free flap reconstruction between May 2018 and September 2019 were audited. The median (IQR) age was 66 (59,72) years and 36% were female. For two-thirds, surgery was for cancer located in the oral cavity and two-thirds of the free flaps were soft tissue. Tranexamic acid (TXA) was used intraoperatively for 30%, red blood cells (RBC) were transfused for 20% and 55 patients (37%) received IV iron. This compares with 4%, 26%, and 0, respectively, in the initial audit. Those having IVI were more likely (56%) to have had a composite flap, a lower postoperative haemoglobin and lower discharge Hb. The Hb between four and twelve weeks' follow up, known for 40, was a median (IQR) of 122 (104,138). There were no adverse reactions to IV iron. Although it is straightforward to administer IVI postoperatively, this re-audit demonstrates that it can be a challenge to embed change in protocols. Through raised awareness of the benefits of IVI, lack of adverse events and clarification of selection criteria, it is hoped that rates of IVI use will increase.

Technical considerations when designing a gene expression panel for renal transplant diagnosis

Gene expression analysis is emerging as a new diagnostic tool in transplant pathology, in particular for the diagnosis of antibody-mediated rejection. Diagnostic gene expression panels are defined on the basis of their pathophysiological relevance, but also need to be tested for their robustness across different preservatives and analysis platforms. The aim of this study is the investigate the effect of tissue sampling and preservation on candidate genes included in a renal transplant diagnostic panel. Using the NanoString platform, we compared the expression of 219 genes in 51 samples, split for formalin-fixation and paraffin-embedding (FFPE) and RNAlater preservation (RNAlater). We found that overall, gene expression significantly correlated between FFPE and RNAlater samples. However, at the individual gene level, 46 of the 219 genes did not correlate across the 51 matched FFPE and RNAlater samples. Comparing gene expression results using NanoString and qRT-PCR for 18 genes in the same pool of RNA (RNAlater), we found a significant correlation in 17/18 genes. Our study indicates that, in samples from the same routine diagnostic renal transplant biopsy procedure split for FFPE and RNAlater, 21% of 219 genes of potential biological significance do not correlate in expression. Whether this is due to fixatives or tissue sampling, selection of gene panels for routine diagnosis should take this information into consideration.

Improving systems of care during and after a pregnancy complicated by hyperglycaemia: A protocol for a complex health systems intervention

BACKGROUND

Many women with hyperglycaemia in pregnancy do not receive care during and after pregnancy according to standards recommended in international guidelines. The burden of hyperglycaemia in pregnancy falls disproportionately upon Indigenous peoples worldwide, including Aboriginal and Torres Strait Islander women in Australia. The remote and regional Australian context poses additional barriers to delivering healthcare, including high staff turnover and a socially disadvantaged population with a high prevalence of diabetes.

METHODS

A complex health systems intervention to improve care for women during and after a pregnancy complicated by hyperglycaemia will be implemented in remote and regional Australia (the Northern Territory and Far North Queensland). The Theoretical Domains Framework was used during formative work with stakeholders to identify intervention components: (1) increasing workforce capacity, skills and knowledge and improving health literacy of health professionals and women; (2) improving access to healthcare through culturally and clinically appropriate pathways; (3) improving information management and communication; (4) enhancing policies and guidelines; (5) embedding use of a clinical register as a quality improvement tool. The intervention will be evaluated utilising the RE-AIM framework at two timepoints: firstly, a qualitative interim evaluation involving interviews with stakeholders (health professionals, champions and project implementers); and subsequently a mixed-methods final evaluation of outcomes and processes: interviews with stakeholders; survey of health professionals; an audit of electronic health records and clinical register; and a review of operational documents. Outcome measures include changes between pre- and post-intervention in: proportion of high risk women receiving recommended glucose screening in early pregnancy; diabetes-related birth outcomes; proportion of women receiving recommended postpartum care including glucose testing; health practitioner confidence in providing care, knowledge and use of relevant guidelines and referral pathways, and perception of care coordination and communication systems; changes to health systems including referral pathways and clinical guidelines.

DISCUSSION

This study will provide insights into the impact of health systems changes in improving care for women with hyperglycaemia during and after pregnancy in a challenging setting. It will also provide detailed information on process measures in the implementation of such health system changes.

Recommendations for core critical care ultrasound competencies as a part of specialist training in multidisciplinary intensive care: a framework proposed by the European Society of Intensive Care Medicine (ESICM)

Abstract

Critical care ultrasound (CCUS) is an essential component of intensive care practice. Although existing international guidelines have focused on training principles and determining competency in CCUS, few countries have managed to operationalize this guidance into an accessible, well-structured programme for clinicians training in multidisciplinary intensive care. We seek to update and reaffirm appropriate CCUS scope so that it may be integrated into the international Competency-based Training in Intensive Care Medicine. The resulting recommendations offer the most contemporary and evolved set of core CCUS competencies for an intensive care clinician yet described. Importantly, we discuss the rationale for inclusion but also exclusion of competencies listed.

Background/aim

Critical care ultrasound (CCUS) is an essential component of intensive care practice. The purpose of this consensus document is to determine those CCUS competencies that should be a mandatory part of training in multidisciplinary intensive care.

Methods

A three-round Delphi method followed by face-to-face meeting among 32 CCUS experts nominated by the European Society of Intensive Care Medicine. Agreement of at least 90% of experts was needed in order to enlist a competency as mandatory.

Results

The final list of competencies includes 15 echocardiographic, 5 thoracic, 4 abdominal, deep vein thrombosis diagnosis and central venous access aid.

Conclusion

The resulting recommendations offer the most contemporary and evolved set of core CCUS competencies for an intensive care clinician yet described.

Systematic review and literature appraisal on methodology of conducting and reporting critical-care echocardiography studies: a report from the European Society of Intensive Care Medicine PRICES expert panel

Background

The echocardiography working group of the European Society of Intensive Care Medicine recognized the need to provide structured guidance for future CCE research methodology and reporting based on a systematic appraisal of the current literature. Here is reported this systematic appraisal.

Methods

We conducted a systematic review, registered on the Prospero database. A total of 43 items of common interest to all echocardiography studies were initially listed by the experts, and other “topic-specific” items were separated into five main categories of interest (left ventricular systolic function, LVSF n = 15, right ventricular function, RVF n = 18, left ventricular diastolic function, LVDF n = 15, fluid management, FM n = 7, and advanced echocardiography techniques, AET n = 17). We evaluated the percentage of items reported per study and the fraction of studies reporting a single item.

Results

From January 2000 till December 2017 a total of 209 articles were included after systematic search and screening, 97 for LVSF, 48 for RVF, 51 for LVDF, 36 for FM and 24 for AET. Shock and ARDS were relatively common among LVSF articles (both around 15%) while ARDS comprised 25% of RVF articles. Transthoracic echocardiography was the main echocardiography mode, in 87% of the articles for AET topic, followed by 81% for FM, 78% for LVDF, 70% for LVSF and 63% for RVF. The percentage of items per study as well as the fraction of study reporting an item was low or very low, except for FM. As an illustration, the left ventricular size was only reported by 56% of studies in the LVSF topic, and half studies assessing RVF reported data on pulmonary artery systolic pressure.

Conclusion

This analysis confirmed sub-optimal reporting of several items listed by an expert panel. The analysis will help the experts in the development of guidelines for CCE study design and reporting.

Evaluating the influence of data collector training for predictive risk of death models: an observational study

BACKGROUND

Severity-of-illness scoring systems are widely used for quality assurance and research. Although validated by trained data collectors, there is little data on the accuracy of real-world data collection practices.

OBJECTIVE

To evaluate the influence of formal data collection training on the accuracy of scoring system data in intensive care units (ICUs).

STUDY DESIGN AND METHODS

Quality assurance audit conducted using survey methodology principles. Between June and December 2018, an electronic document with details of three fictitious ICU patients was emailed to staff from 19 Australian ICUs who voluntarily submitted data on a web-based data entry form. Their entries were used to generate severity-of-illness scores and risks of death (RoDs) for four scoring systems. The primary outcome was the variation of severity-of-illness scores and RoDs from a reference standard.

RESULTS

50/83 staff (60.3%) submitted data. Using Bayesian multilevel analysis, severity-of-illness scores and RoDs were found to be significantly higher for untrained staff. The mean (95% high-density interval) overestimation in RoD due to training effect for patients 1, 2 and 3, respectively, were 0.24 (0.16, 0.31), 0.19 (0.09, 0.29) and 0.24 (0.1, 0.38) respectively (Bayesian factor >300, decisive evidence). Both groups (trained and untrained) had wide coefficients of variation up to 38.1%, indicating wide variability. Untrained staff made more errors in interpreting scoring system definitions.

INTERPRETATION

In a fictitious patient dataset, data collection staff without formal training significantly overestimated the severity-of-illness scores and RoDs compared with trained staff. Both groups exhibited wide variability. Strategies to improve practice may include providing adequate training for all data collection staff, refresher training for previously trained staff and auditing the raw data submitted by individual ICUs. The results of this simulated study need revalidation on real patients.

Pathway mapping of leukocyte transcriptome in influenza patients reveals distinct pathogenic mechanisms associated with progression to severe infection

Background

Influenza infections produce a spectrum of disease severity, ranging from a mild respiratory illness to respiratory failure and death. The host-response pathways associated with the progression to severe influenza disease are not well understood.

Methods

To gain insight into the disease mechanisms associated with progression to severe infection, we analyzed the leukocyte transcriptome in severe and moderate influenza patients and healthy control subjects. Pathway analysis on differentially expressed genes was performed using a topology-based pathway analysis tool that takes into account the interaction between multiple cellular pathways. The pathway profiles between moderate and severe influenza were then compared to delineate the biological mechanisms underpinning the progression from moderate to severe influenza.

Results

107 patients (44 severe and 63 moderate influenza patients) and 52 healthy control subjects were included in the study. Severe influenza was associated with upregulation in several neutrophil-related pathways, including pathways involved in neutrophil differentiation, migration, degranulation and neutrophil extracellular trap (NET) formation. The degree of upregulation in neutrophil-related pathways were significantly higher in severely infected patients compared to moderately infected patients. Severe influenza was also associated with downregulation in immune response pathways, including pathways involved in antigen presentation such as CD4+ T-cell co-stimulation, CD8+ T cell and Natural Killer (NK) cells effector functions. Apoptosis pathways were also downregulated in severe influenza patients compare to moderate and healthy controls.

Conclusions

These findings showed that there are changes in gene expression profile that may highlight distinct pathogenic mechanisms associated with progression from moderate to severe influenza infection.

Pre-eclampsia and long-term cardiac dysfunction: A review of asymptomatic cardiac changes existing well beyond the post-partum period

BACKGROUND

Pre-eclampsia is a disease of pregnancy characterised by the manifestations of multi-organ dysfunction. The recent use of transthoracic echocardiography in the assessment of women with pre-eclampsia has allowed the detection of cardiac systolic and diastolic dysfunction in the acute phase. Women with a history of pre-eclampsia also have increased lifelong risks of cardiovascular disease and mortality that persists well beyond the post-partum period. These developments raise the possibility that pre-eclampsia may be an early marker of cardiovascular disease and the potential role for echocardiography in guiding the detection and management of this. This review aims to summarise the existing evidence of echocardiographic cardiac assessment of women with a history of pre-eclampsia performed more than 12 weeks post-partum.

METHODS

A systematic search of PubMed and OVID EMBASE databases was performed to identify studies featuring assessment of cardiac function performed after 12 weeks post-partum in women with a history of pre-eclampsia. Studies without post-partum cardiac assessment or with other documented causes for cardiomyopathy were excluded.

RESULTS

Thirteen studies were identified that measured cardiac function by transthoracic echocardiography between 6 months and 18 years following a pregnancy complicated by pre-eclampsia. Common findings across the studies were of increased diastolic dysfunction, increased left ventricular mass index (LVMI) and concentric hypertrophy in women with a history of pre-eclampsia, as compared to women with uncomplicated pregnancy histories. This was predominantly seen in those with a history of early or preterm pre-eclampsia.

CONCLUSIONS

Women with a history of early or preterm pre-eclampsia have an increased prevalence of diastolic dysfunction. This review demonstrates that the cardiac dysfunction associated with previous pre-eclampsia is quantifiable and persistent. Progression of heart failure from asymptomatic to symptomatic stages carries a fivefold increase in mortality. The use of echocardiography could detect cardiac dysfunction in the asymptomatic stage and guide more intensive risk factor modification in these women.

P333Late mortality after pharmaco-invasive PCI for STEMI

Background

Worldwide, and in Australia, a large proportion of patients with ST-segment elevation myocardial infarction (STEMI) are unable to undergo timely primary percutaneous coronary intervention (PCI), and so are transferred for PCI after receiving fibrinolytic therapy (so-called pharmaco-invasive PCI).

Methods

Our Hospital, the primary PCI centre for Southwest Sydney, Australia receives patients for both primary PCI and transferred post- fibrinolytic therapy for rescue or prognostic PCI. Associations were determined between late outcomes (bleeding according to Bleeding Academic Research Consortium (BARC) criteria and mortality) and reperfusion strategy, either primary PCI, or pharmaco-invasive PCI, in patients undergoing PCI for STEMI during hospitalization.

Results

Among 2083 consecutive patients (80% male) with STEMI who underwent PCI (1076 [52%] primary PCI and 1007 [48%] pharmaco-invasive PCI), mortality at 3 years was 8.7%,11.1% after primary PCI and 6.2% after pharmaco-invasive PCI (9.4% after rescue PCI and 4.6% after prognostic PCI); p<0.001 (Figure). Rates of type 2–5 BARC bleeding post-PCI were 35% after primary PCI and 24% after pharmaco-invasive PCI (42% after rescue PCI and 15% after prognostic PCI); p<0.001. while the rate of major bleeding type 3b-5 were 5% after primary PCI and 3% after pharmaco-invasive PCI (8% after rescue PCI and 1% after prognostic PCI); p=0.112.The independent predictors of 3 year mortality were, pre-PCI cardiogenic shock HR=0.25 [95% CI: 0.16–0.39], p<0.001), age (HR=1.05 [95% CI: 1.03–1.06], p<0.001), TIMI 3 flow post-PCI (HR=5.25 [95% CI: 2.51–11.00], p≤0.001), eGFR<60mL/min/1.73m2 (HR=2.90 [95% CI: 1.93–4.34], p≤0.001), post PCI bleeding (HR=2.17 [95% CI: 1.53–3.08], p≤0.001), anterior infarction (HR=1.76 [95% CI: 1.23–2.51], p=0.002), and female gender (HR=1.56 [95% CI: 1.07–2.27], p=0.022); and primary PCI (HR=1.6 [95% CI: 1.18–2.19; p=0.003]. On multi-variable analysis, age, cardiogenic shock presentation, rescue PCI, intra-aortic balloon pump, Pre-procedural anaemia, (all p<0.001) and eGFR<60mL/min/1.73m2 (p=0.006) were associated with bleeding.

Figure 1. Late survival after primary & PI PCI

Conclusion

Among patients with STEMI who underwent pharmaco-invasive PCI had lower mortality rates than to those who had primary PCI, though procedural selection criteria may have been different; bleeding rates were similar. Among suitable patients pharmaco-invasive PCI should be evaluated in large clinical trials.

Subcostal TAPSE: a retrospective analysis of a novel right ventricle function assessment method from the subcostal position in patients with sepsis

Background

Tricuspid annular plane systolic excursion (TAPSE) is frequently used as an objective measure of right-ventricular dysfunction. Abnormal TAPSE values are associated with poor prognosis in a number of disease states; however, the measure is not always easy to obtain in the critically ill. The purpose of this study is to assess the feasibility and accuracy of using a subcostal view and TAPSE measurement as a measure of right-ventricular dysfunction. A secondary aim was to perform a pilot study to assess whether right-ventricular dysfunction was associated with adverse outcomes including mortality.

Results

Subcostal TAPSE corresponds well with TAPSE obtained from the apical window at low and moderate TAPSE values (mean difference 1.2 mm (CI 0.04–2.36; 100% data pairs < 3-mm difference for TAPSE < 19 mm; 92% had < 3 mm difference at TAPDE < 24 mm). Subcostal TAPSE is able to accurately discriminate between abnormal and normal TAPSE results (sensitivity 97.8%, specificity 87.5%). There was no association between right-ventricular (RV) dysfunction and 90-day mortality.

Conclusions

Subcostal TAPSE is a feasible and accurate alternative to conventional TAPSE from the apical view in critically ill patients. Further research is required to elucidate the relationship between RV dysfunction and outcomes in sepsis.

Neutrophils-related host factors associated with severe disease and fatality in patients with influenza infection

Severe influenza infection has no effective treatment available. One of the key barriers to developing host-directed therapy is a lack of reliable prognostic factors needed to guide such therapy. Here, we use a network analysis approach to identify host factors associated with severe influenza and fatal outcome. In influenza patients with moderate-to-severe diseases, we uncover a complex landscape of immunological pathways, with the main changes occurring in pathways related to circulating neutrophils. Patients with severe disease display excessive neutrophil extracellular traps formation, neutrophil-inflammation and delayed apoptosis, all of which have been associated with fatal outcome in animal models. Excessive neutrophil activation correlates with worsening oxygenation impairment and predicted fatal outcome (AUROC 0.817-0.898). These findings provide new evidence that neutrophil-dominated host response is associated with poor outcomes. Measuring neutrophil-related changes may improve risk stratification and patient selection, a critical first step in developing host-directed immune therapy.

Correction to: A decade of progress in critical care echocardiography: a narrative review

The original version of this article unfortunately contained a mistake.