[Selected novelties for hospital based internal medicine]

In this selective overview of articles, we describe new concepts, therapeutic measures and pharmacological agents that may modify current practice in clinical internal medicine. Novelties for the management of cardiovascular disease, such as heart failure, hypoxemic respiratory failure, nosocomial pneumonia and certain allergies are discussed.

Reliability and Accuracy of the Pediatric Swiss Emergency Triage Scale-the SETSped Study

BACKGROUND AND IMPORTANCE

The Swiss Emergency Triage Scale (SETS) is an adult triage tool used in several emergency departments. It has been recently adapted to the pediatric population but, before advocating for its use, performance assessment of this tool is needed.

OBJECTIVES

The purpose of this study was to assess the reliability and the accuracy of the pediatric version of the SETS for the triage of pediatric patients.

DESIGN, SETTING, AND PARTICIPANTS

This study was a cross-sectional study among a sample of emergency triage nurses (ETNs) exposed to 17 clinical scenarios using a computerized simulator.

OUTCOME MEASURES AND ANALYSIS

The primary outcome was the reliability of the triage level performed by the ETNs. It was assessed using an intraclass correlation coefficient.Secondary outcomes included accuracy of triage compared with expert-based triage levels and factors associated with accurate triage.

MAIN RESULTS

Eighteen ETNs participated in the study and completed the evaluation of all scenarios, for a total of 306 triage decisions. The intraclass correlation coefficient was 0.80 (95% confidence interval, 0.69-0.91), with an agreement by scenario ranging from 61.1% to 100%. The overall accuracy was 85.8%, and nurses were more likely to undertriage (16.0%) than to overtriage (4.3%). No factor for accurate triage was identified.

CONCLUSIONS

This simulator-based study showed that the SETS is reliable and accurate among a pediatric population. Future research is needed to confirm these results, compare this triage scale head-to-head with other recognized international tools, and study the SETSped in real-life setting.

[POCUS : diagnosis of pneumonia by lung ultrasonography]

Point-Of-Care Ultrasonography (POCUS) has emerged to support the diagnosis process and management strategies. Its use for the diagnosis of pneumonia has been shown to be reliable and effective over the past decade. Various ultrasonography patterns exist, none of which are pathognomonic for pneumonia. Therefore, POCUS findings must be interpreted in association with the clinical setting. POCUS enables early identification of complications such as parapneumonic effusion and pulmonary abscess. It also provides guidance for invasive procedure such as thoracocentesis and pleural drainage. The forthcoming results of the Swiss OCTOPLUS study will provide data on the clinical and economic impact of a diagnostic strategy based on targeted lung ultrasonography.

[Duration of antibiotic therapy in febrile neutropenia]

Febrile neutropenia is a frequent complication of cancer treatment and is associated with an increased risk of morbidity and mortality. However, standardization in the management of neutropenic fever has led to a reduction in its complications. The duration and type of antibiotic therapy differ according to guidelines, particularly in cases of febrile neutropenia of unknown origin. Continuation of antibiotic treatment until resolution of neutropenia has historically been recommended but exposes patients to prolonged periods of broad-spectrum antibiotic therapy. In a context of growing resistance to antibiotics, optimization of antibiotic use is necessary, particularly in this frail patient population, faced with the consequences of repeated exposure to broad-spectrum antibiotic therapy.

Trends in management and outcomes of COVID patients admitted to a Swiss tertiary care hospital

Two successive COVID-19 flares occurred in Switzerland in spring and autumn 2020. During these periods, therapeutic strategies have been constantly adapted based on emerging evidence. We aimed to describe these adaptations and evaluate their association with patient outcomes in a cohort of COVID-19 patients admitted to the hospital. Consecutive patients admitted to the Geneva Hospitals during two successive COVID-19 flares were included. Characteristics of patients admitted during these two periods were compared as well as therapeutic management including medications, respiratory support strategies and admission to the ICU and intermediate care unit (IMCU). A mutivariable model was computed to compare outcomes across the two successive waves adjusted for demographic characteristics, co-morbidities and severity at baseline. The main outcome was in-hospital mortality. Secondary outcomes included ICU admission, Intermediate care (IMCU) admission, and length of hospital stay. A total of 2'983 patients were included. Of these, 165 patients (16.3%, n = 1014) died during the first wave and 314 (16.0%, n = 1969) during the second (p = 0.819). The proportion of patients admitted to the ICU was lower in second wave compared to first (7.4 vs. 13.9%, p < 0.001) but their mortality was increased (33.6% vs. 25.5%, p < 0.001). Conversely, a greater proportion of patients was admitted to the IMCU in second wave compared to first (26.6% vs. 22.3%, p = 0.011). A third of patients received lopinavir (30.7%) or hydroxychloroquine (33.1%) during the first wave and none during second wave, while corticosteroids were mainly prescribed during second wave (58.1% vs. 9.1%, p < 0.001). In the multivariable analysis, a 25% reduction of mortality was observed during the second wave (HR 0.75; 95% confidence interval 0.59 to 0.96). Among deceased patients, 82.3% (78.2% during first wave and 84.4% during second wave) died without beeing admitted to the ICU. The proportion of patients with therapeutic limitations regarding ICU admission increased during the second wave (48.6% vs. 38.7%, p < 0.001). Adaptation of therapeutic strategies including corticosteroids therapy and higher admission to the IMCU to receive non-invasive respiratory support was associated with a reduction of hospital mortality in multivariable analysis, ICU admission and LOS during the second wave of COVID-19 despite an increased number of admitted patients. More patients had medical decisions restraining ICU admission during the second wave which may reflect better patient selection or implicit triaging.

Development and retrospective evaluation of a clinical decision support system for the efficient detection of drug-related problems by clinical pharmacists

BACKGROUND

Clinical decision support systems (CDSS) can help identify drug-related problems (DRPs). However, the alert specificity remains variable. Defining more relevant alerts for detecting DRPs would improve CDSS.

AIM

Develop electronic queries that assist pharmacists in conducting medication reviews and an assessment of the performance of this model to detect DRPs.

METHOD

Electronic queries were set up in CDSS using "triggers" from electronic health records: drug prescriptions, laboratory values, medical problems, vital signs, demographics. They were based on a previous study where 315 patients admitted in internal medicine benefited from a multidisciplinary medication review (gold-standard) to highlight potential DRPs. Electronic queries were retrospectively tested to assess performance in detecting DRPs revealed with gold-standard. For each electronic query, sensitivity, specificity, positive and negative predictive value were computed.

RESULTS

Of 909 DRPs, 700 (77.8%) were used to create 366 electronic queries. Electronic queries correctly detected 77.1% of DRPs, median sensitivity and specificity reached 100.0% (IQRs, 100.0%-100.0%) and 99.7% (IQRs, 97.0%-100.0%); median positive predictive value and negative predictive value reached 50.0% (IQRs, 12.5%-100.0%) and 100.0% (IQRs, 100.0%-100.0%). Performances varied according to "triggers" (p < 0.001, best performance in terms of predictive positive value when exclusively involving drug prescriptions).

CONCLUSION

Electronic queries based on electronic heath records had high sensitivity and negative predictive value and acceptable specificity and positive predictive value and may contribute to facilitate medication review. Implementing some of these electronic queries (the most effective and clinically relevant) in current practice will allow a better assessment of their impact on the efficiency of the clinical pharmacist.

[Advances in hospital based internal medicine]

Hospital based internal medicine has been strongly solicited for over two years with the SARS-CoV-2 epidemic. This epidemic continues to evolve and represents a strain for public health. Numerous studies have addressed issues concerning this epidemic, and multiple novelties concerning other frequent pathologies have also been published. Management strategies of cardiovascular, pulmonary, gastro-intestinal and metabolic diseases are discussed.

High-flow nasal oxygen in acute hypoxemic respiratory failure: A narrative review of the evidence before and after the COVID-19 pandemic

High-flow nasal oxygen (HFNO) is a type of non-invasive advanced respiratory support that allows the delivery of high-flow and humidified air through a nasal cannula. It can deliver a higher inspired oxygen fraction than conventional oxygen therapy (COT), improves secretion clearance, has a small positive end-expiratory pressure, and exhibits a washout effect on the upper air space that diminishes dead space ventilation. HFNO has been shown to reduce the work of breathing in acute hypoxemic respiratory failure (AHRF) and has become an interesting option for non-invasive respiratory support. Evidence published before the COVID-19 pandemic suggested a possible reduction of the need for invasive mechanical ventilation compared to COT. The COVID-19 pandemic has resulted in a substantial increase in AHRF worldwide, overwhelming both acute and intensive care unit capacity in most countries. This triggered new trials, adding to the body of evidence on HFNO in AHRF and its possible benefits compared to COT or non-invasive ventilation. We have summarized and discussed this recent evidence to inform the best supportive strategy in AHRF both related and unrelated to COVID-19.

Atypical Pathogens in Adult Community-Acquired Pneumonia and Implications for Empiric Antibiotic Treatment: A Narrative Review

Atypical pathogens are intracellular bacteria causing community-acquired pneumonia (CAP) in a significant minority of patients. Legionella spp., Chlamydia pneumoniae and psittaci, Mycoplasma pneumoniae, and Coxiella burnetii are commonly included in this category. M. pneumoniae is present in 5-8% of CAP, being the second most frequent pathogen after Streptococcus pneumoniae. Legionella pneumophila is found in 3-5% of inpatients. Chlamydia spp. and Coxiella burnetii are present in less than 1% of patients. Legionella longbeachae is relatively frequent in New Zealand and Australia and might also be present in other parts of the world. Uncertainty remains on the prevalence of atypical pathogens, due to limitations in diagnostic means and methodological issues in epidemiological studies. Despite differences between CAP caused by typical and atypical pathogens, the clinical presentation alone does not allow accurate discrimination. Hence, antibiotics active against atypical pathogens (macrolides, tetracyclines and fluoroquinolones) should be included in the empiric antibiotic treatment of all patients with severe CAP. For patients with milder disease, evidence is lacking and recommendations differ between guidelines. Use of clinical prediction rules to identify patients most likely to be infected with atypical pathogens, and strategies of narrowing the antibiotic spectrum according to initial microbiologic investigations, should be the focus of future investigations.

[Osmotic demyelination syndrome and overly rapid correction of hyponatremia]

Hyponatremia is a frequent condition in hospitalized patients and is associated with significant morbidity and mortality. An association between rapid correction of hyponatremia and the occurrence of osmotic demyelination syndrome has been reported. Osmotic demyelination syndrome may present with severe neurologic symptoms, including in rare cases locked-in. Therefore, rapid correction of hyponatremia is recommended only in the presence of severe symptoms. In those cases, hypertonic saline (NaCl 3% 2 ml/Kg over 20 minutes) is recommended with close plasma sodium monitoring. After symptoms improvement, increases in sodium concentration should not exceed 8 mmol/l/24h. In cases without severe neurologic symptoms, the use of 3% NaCl solution should be avoided, and management should target the underlying causes of hyponatremia.

Impact of interactive computerised decision support for hospital antibiotic use (COMPASS): an open-label, cluster-randomised trial in three Swiss hospitals

Background

Computerised decision-support systems (CDSSs) for antibiotic stewardship could help to assist physicians in the appropriate prescribing of antibiotics. However, high-quality evidence for their effect on the quantity and quality of antibiotic use remains scarce. The aim of our study was to assess whether a computerised decision support for antimicrobial stewardship combined with feedback on prescribing indicators can reduce antimicrobial prescriptions for adults admitted to hospital.

Methods

The Computerised Antibiotic Stewardship Study (COMPASS) was a multicentre, cluster-randomised, parallel-group, open-label superiority trial that aimed to assess whether a multimodal computerised antibiotic-stewardship intervention is effective in reducing antibiotic use for adults admitted to hospital. After pairwise matching, 24 wards in three Swiss tertiary-care and secondary-care hospitals were randomised (1:1) to the CDSS intervention or to standard antibiotic stewardship measures using an online random sequence generator. The multimodal intervention consisted of a CDSS providing support for choice, duration, and re-evaluation of antimicrobial therapy, and feedback on antimicrobial prescribing quality. The primary outcome was overall systemic antibiotic use measured in days of therapy per admission, using adjusted-hurdle negative-binomial mixed-effects models. The analysis was done by intention to treat and per protocol. The study was registered with ClinicalTrials.gov (identifier NCT03120975).

Findings

24 clusters (16 at Geneva University Hospitals and eight at Ticino Regional Hospitals) were eligible and randomly assigned to control or intervention between Oct 1, 2018, and Dec 31, 2019. Overall, 4578 (40·2%) of 11 384 admissions received antibiotic therapy in the intervention group and 4142 (42·8%) of 9673 in the control group. The unadjusted overall mean days of therapy per admission was slightly lower in the intervention group than in the control group (3·2 days of therapy per admission, SD 6·2, vs 3·5 days of therapy per admission, SD 6·8; p<0·0001), and was similar among patients receiving antibiotics (7·9 days of therapy per admission, SD 7·6, vs 8·1 days of therapy per admission, SD 8·4; p=0·50). After adjusting for confounders, there was no statistically significant difference between groups for the odds of an admission receiving antibiotics (odds ratio [OR] for intervention vs control 1·12, 95% CI 0·94–1·33). For admissions with antibiotic exposure, days of therapy per admission were also similar (incidence rate ratio 0·98, 95% CI 0·90–1·07). Overall, the CDSS was used at least once in 3466 (75·7%) of 4578 admissions with any antibiotic prescription, but from the first day of antibiotic treatment for only 1602 (58·9%) of 2721 admissions in Geneva. For those for whom the CDSS was not used from the first day, mean time to use of CDSS was 8·9 days. Based on the manual review of 1195 randomly selected charts, transition from intravenous to oral therapy was significantly more frequent in the intervention group after adjusting for confounders (154 [76·6%] of 201 vs 187 [87%] of 215, +10·4%; OR 1·9, 95% CI 1·1–3·3). Consultations by infectious disease specialists were less frequent in the intervention group (388 [13·4%] of 2889) versus the control group (405 [16·9%] of 2390; OR 0·84, 95% CI 0·59–1·25).

Interpretation

An integrated multimodal computerised antibiotic stewardship intervention did not significantly reduce overall antibiotic use, the primary outcome of the study. Contributing factors were probably insufficient uptake, a setting with relatively low antibiotic use at baseline, and delays between ward admission and first CDSS use.

Funding

Swiss National Science Foundation.

Translations

For the French and Italian translations of the abstract see Supplementary Materials section.

[Interprofessional simulation in emergency medicine]

Teamwork is essential in emergency medicine, but in practice it can be polluted by communication difficulties, a lack of understanding of everyone's roles and responsibilities, and a discordant definition of operating methods and objectives. Today, there is a strong awareness of the need to train medical and healthcare teams in interprofessional collaborative practice to learn how to work as a team, reduce medical errors and improve patient safety. Simulation is a recognized and effective pedagogical modality for achieving these objectives. It is now permanently established in pre- and postgraduate medical-nursing training courses in emergency medicine.

Comparison of prognostic scores for inpatients with COVID-19: a retrospective monocentric cohort study

Background

The SARS-CoV-2 pandemic led to a steep increase in hospital and intensive care unit (ICU) admissions for acute respiratory failure worldwide. Early identification of patients at risk of clinical deterioration is crucial in terms of appropriate care delivery and resource allocation. We aimed to evaluate and compare the prognostic performance of Sequential Organ Failure Assessment (SOFA), Quick Sequential Organ Failure Assessment (qSOFA), Confusion, Uraemia, Respiratory Rate, Blood Pressure and Age ≥65 (CURB-65), Respiratory Rate and Oxygenation (ROX) index and Coronavirus Clinical Characterisation Consortium (4C) score to predict death and ICU admission among patients admitted to the hospital for acute COVID-19 infection.

Methods and analysis

Consecutive adult patients admitted to the Geneva University Hospitals during two successive COVID-19 flares in spring and autumn 2020 were included. Discriminative performance of these prediction rules, obtained during the first 24 hours of hospital admission, were computed to predict death or ICU admission. We further exluded patients with therapeutic limitations and reported areas under the curve (AUCs) for 30-day mortality and ICU admission in sensitivity analyses.

Results

A total of 2122 patients were included. 216 patients (10.2%) required ICU admission and 303 (14.3%) died within 30 days post admission. 4C score had the best discriminatory performance to predict 30-day mortality (AUC 0.82, 95% CI 0.80 to 0.85), compared with SOFA (AUC 0.75, 95% CI 0.72 to 0.78), qSOFA (AUC 0.59, 95% CI 0.56 to 0.62), CURB-65 (AUC 0.75, 95% CI 0.72 to 0.78) and ROX index (AUC 0.68, 95% CI 0.65 to 0.72). ROX index had the greatest discriminatory performance (AUC 0.79, 95% CI 0.76 to 0.83) to predict ICU admission compared with 4C score (AUC 0.62, 95% CI 0.59 to 0.66), CURB-65 (AUC 0.60, 95% CI 0.56 to 0.64), SOFA (AUC 0.74, 95% CI 0.71 to 0.77) and qSOFA (AUC 0.59, 95% CI 0.55 to 0.62).

Conclusion

Scores including age and/or comorbidities (4C and CURB-65) have the best discriminatory performance to predict mortality among inpatients with COVID-19, while scores including quantitative assessment of hypoxaemia (SOFA and ROX index) perform best to predict ICU admission. Exclusion of patients with therapeutic limitations improved the discriminatory performance of prognostic scores relying on age and/or comorbidities to predict ICU admission.

Eight versus 28-point lung ultrasonography in moderate acute heart failure: a prospective comparative study

Lung ultrasonography (LUS) is an accurate method of estimating lung congestion but there is ongoing debate on the optimal number of scanning points. The aim of the present study was to compare the reproducibility (i.e. interobserver agreement) and the feasibility (i.e. time consumption) of the two most practiced protocols in patients hospitalized for acute heart failure (AHF). This prospective trial compared 8- and 28-point LUS protocols. Both were performed by an expert-novice pair of sonographers at admission and after 4 to 6 days on patients admitted for AHF. A structured bio-clinical evaluation was simultaneously carried out by the treating physician. The primary outcome was expert-novice interobserver agreement estimated by kappa statistics. Secondary outcomes included time spent on image acquisition and interpretation. During the study period, 43 patients underwent a total of 319 LUS exams. Expert-novice interobserver agreement was moderate at admission and substantial at follow-up for 8-point protocol (weighted kappa of 0.54 and 0.62, respectively) with no significant difference for 28-point protocol (weighted kappa of 0.51 and 0.41; P value for comparison 0.74 at admission and 0.13 at follow-up). The 8-point protocol required significantly less time for image acquisition at admission (mean time difference - 3.6 min for experts, - 5.1 min for novices) and interpretation (- 6.0 min for experts and - 6.3 min for novices; P value < 0.001 for all time comparisons). Similar differences were observed at follow-up. In conclusion, an 8-point LUS protocol was shown to be timesaving with similar reproducibility when compared with a 28-point protocol. It should be preferred for evaluating lung congestion in AHF inpatients.

Effect of body position on the redistribution of regional lung aeration during invasive and non-invasive ventilation of COVID-19 patients

Severe COVID-19-related acute respiratory distress syndrome (C-ARDS) requires mechanical ventilation. While this intervention is often performed in the prone position to improve oxygenation, the underlying mechanisms responsible for the improvement in respiratory function during invasive ventilation and awake prone positioning in C-ARDS have not yet been elucidated. In this prospective observational trial, we evaluated the respiratory function of C-ARDS patients while in the supine and prone positions during invasive (n = 13) or non-invasive ventilation (n = 15). The primary endpoint was the positional change in lung regional aeration, assessed with electrical impedance tomography. Secondary endpoints included parameters of ventilation and oxygenation, volumetric capnography, respiratory system mechanics and intrapulmonary shunt fraction. In comparison to the supine position, the prone position significantly increased ventilation distribution in dorsal lung zones for patients under invasive ventilation (53.3 ± 18.3% vs. 43.8 ± 12.3%, percentage of dorsal lung aeration ± standard deviation in prone and supine positions, respectively; p = 0.014); whereas, regional aeration in both positions did not change during non-invasive ventilation (36.4 ± 11.4% vs. 33.7 ± 10.1%; p = 0.43). Prone positioning significantly improved the oxygenation both during invasive and non-invasive ventilation. For invasively ventilated patients reduced intrapulmonary shunt fraction, ventilation dead space and respiratory resistance were observed in the prone position. Oxygenation is improved during non-invasive and invasive ventilation with prone positioning in patients with C-ARDS. Different mechanisms may underly this benefit during these two ventilation modalities, driven by improved distribution of lung regional aeration, intrapulmonary shunt fraction and ventilation-perfusion matching. However, the differences in the severity of C-ARDS may have biased the sensitivity of electrical impedance tomography when comparing positional changes between the protocol groups.Trial registration: ClinicalTrials.gov (NCT04359407) and Registered 24 April 2020, https://clinicaltrials.gov/ct2/show/NCT04359407 .

Three-Minute Diagnostic Assessment for Delirium using the Confusion Assessment Method (3D-CAM): French translation and cultural adaptation

PURPOSE

The routine use of validated diagnostic instruments is key to identifying delirious patients early and expediting care. The 3-Minute Diagnostic Assessment for Delirium using the Confusion Assessment Method (3D-CAM) instrument is a brief, easy to use, sensitive, and specific delirium assessment tool for hospitalized patients. We aimed to translate the original English version into French, and then adapt it to older high-risk patients.

METHODS

Translation and adaptation of the questionnaire were guided by an expert committee and the 3D-CAM instrument developer. During the translation phase, we achieved semantic and conceptual equivalence of the instrument by conducting forward and backward translations. During the adaptation phase, we assessed the face validity, clarity of wording, and ease of use of the translated questionnaire by administering it to 30 patients and their caregivers in peri-interventional and medical intermediate care units. During both phases, we used qualitative (goal and adequacy of the questionnaire) and quantitative (Sperber score, clarity score) criteria.

RESULTS

Translation: four items were judged inadequate and were revised until all reached a Sperber score of < 3/7. Face validity: 91% of patients thought the questionnaire was designed to assess memory, thoughts, or reasoning. Clarity: eight items required adjustments until all scored ≥ 9/10 for clarity. Ease of use: all bedside caregivers reported that the questionnaire was easy to complete after receiving brief instructions.

CONCLUSIONS

We produced a culturally adapted French version of the 3D-CAM instrument that is well understood and well-received by older high-risk patients and their caregivers.

Risk stratification for hospital-acquired venous thromboembolism in medical patients (RISE): Protocol for a prospective cohort study

Background

Hospital-acquired venous thromboembolism (VTE) is one of the leading preventable causes of in-hospital mortality. However, its risk assessment in medically ill inpatients is complicated due to the patients’ heterogeneity and complexity of currently available risk assessment models (RAMs). The simplified Geneva score provides simplicity but has not yet been prospectively validated. Immobility is an important predictor for VTE in RAMs, but its definition is inconsistent and based on subjective assessment by nurses or physicians. In this study, we aim to prospectively validate the simplified Geneva score and to examine the predictive performance of a novel and objective definition of in-hospital immobilization using accelerometry.

Methods and analysis

RISE is a multicenter prospective cohort study. The goal is to recruit 1350 adult inpatients admitted for medical illness in three Swiss tertiary care hospitals. We collect data on demographics, comorbidities, VTE risk and thromboprophylaxis. Mobility from admission to discharge is objectively measured using a wrist-worn accelerometer. Participants are followed for 90 days for the occurrence of symptomatic VTE (primary outcome). Secondary outcomes are the occurrence of clinically relevant bleeding, and mortality. The evolution of autonomy in the activities of daily living, the length of stay, and the occurrence of readmission are also recorded. Time-dependent area under the curve, sensitivity, specificity, and positive and negative predictive values are calculated for each RAM (i.e. the simplified and original Geneva score, Padua, and IMPROVE score) with and without the objective mobility measures to assess their accuracy in predicting hospital-acquired VTE at 90 days.

Ethics and expected impact

The ethics committee approved the protocol and the study was registered on ClinicalTrials.gov as NCT04439383. RISE has the potential to optimize VTE risk stratification, and thus to improve the quality of care of medically hospitalized patients.

Therapeutic anticoagulation to prevent thrombosis, coagulopathy, and mortality in severe COVID‐19: The Swiss COVID‐HEP randomized clinical trial

Background

Hospitalized patients with COVID‐19 suffered initially from high rates of venous thromboembolism (VTE), with possible associations between therapeutic anticoagulation and better clinical outcomes in observational studies.

Objective

To test whether therapeutic anticoagulation improves clinical outcomes in severe COVID‐19.

Patients/Methods

In this multicenter, open‐label, randomized controlled trial, we recruited acutely ill medical COVID‐19 patients with D‐dimer >1000 ng/ml or critically ill COVID‐19 patients in four Swiss hospitals, from April 2020 until June 2021, with a 30‐day follow‐up. Participants were randomized to in‐hospital therapeutic anticoagulation versus low‐dose anticoagulation in acutely ill participants/intermediate‐dose anticoagulation in critically ill participants, with enoxaparin or unfractionated heparins. The primary outcome was a centrally adjudicated composite of 30‐day all‐cause mortality, VTE, arterial thrombosis, and disseminated intravascular coagulopathy (DIC), with screening for proximal deep vein thrombosis.

Results

Among 159 participants, 55.3% were critically ill and 94.3% received corticosteroids. Before study inclusion, pulmonary embolism had been excluded in 71.7%. The primary outcome occurred in 4/79 participants randomized to therapeutic anticoagulation and 4/80 to low/intermediate anticoagulation (5.4% vs. 5.0%; risk difference +0.4%; adjusted hazard ratio 0.76, 95% confidence interval 0.18–3.21), including three deaths in each group. All primary outcomes and major bleeding (n = 3) occurred in critically ill participants. There was no asymptomatic proximal deep vein thrombosis and no difference in major bleeding.

Conclusions

Among patients with severe COVID‐19 treated with corticosteroids and with exclusion of pulmonary embolism at hospital admission for most, risks of mortality, thrombotic outcomes, and DIC were low at 30 days. The lack of benefit of therapeutic anticoagulation was too imprecise for definite conclusions.

A COVID-19-Related Retinopathy Case Report

The recent outbreak of the severe acute respiratory syndrome coronavirus-2 has been declared a worldwide pandemic by the WHO. Within various multi-organ involvements, several ocular manifestations have been described. We report the case of a patient diagnosed with COVID-19 who presented with a progressive increase of bilateral cotton wool spots over a 1-week period, despite quick and complete recovery of systemic signs of the disease and no ocular symptoms. We followed the evolution of such lesions over a 3-month period. Here, we underline the importance of retinal screening even if no ocular symptom is reported. Furthermore, we demonstrate the essential role of fundus examination as a reflection of systemic vascular changes.

[Latest progress in internal medicine]

Internal medicine continues de evolve as a result of further insight and evidence for the efficacy of given interventions. Although numerous studies have addressed issues concerning the SARS-COV-2 epidemic, multiple novelties concerning other frequent pathologies have also been presented. Management strategies of cardiovascular disease, infectious diseases and venous thromboembolism are particularly concerned.

Early Measurement of ROX Index in Intermediary Care Unit Is Associated with Mortality in Intubated COVID-19 Patients: A Retrospective Study

COVID-19 patients often present with rapidly progressing acute hypoxemic respiratory failure, requiring orotracheal intubation with different prognostic issues. However, ICU specialists lack predictive tools to stratify these patients. We conducted a single-center cross-sectional retrospective study to evaluate if the ROX index, measured under non-invasive oxygenation support, can predict ICU mortality in a COVID-19 intubated patient cohort. This study took place in the division of intensive care at the Geneva University Hospitals (Geneva, Switzerland). We included all consecutive adult patients treated by non-invasive oxygenation support and requiring intubation for acute respiratory failure due to COVID-19 between 9 September 2020 and 30 March 2021, corresponding to the second local surge of COVID-19 cases. Baseline demographic data, comorbidities, median ROX between H0 and H8, and clinical outcomes were collected. Overall, 82 patients were intubated after failing a non-invasive oxygenation procedure. Women represented 25.6% of the whole cohort. Median age and median BMI were 70 (60–75) years and 28 (25–33), respectively. Before intubation, the median ROX between H0 and H8 was 6.3 (5.0–8.2). In a multivariate analysis, the median ROX H0–H8 was associated with ICU mortality as a protective factor with an odds ratio (95% CI) = 0.77 (0.60–0.99); p < 0.05. In intubated COVID-19 patients treated initially by non-invasive oxygenation support for acute respiratory failure, the median ROX H0–H8 could be an interesting predictive factor associated with ICU mortality.

Confidence and use of physical examination and point-of-care ultrasonography for detection of abdominal or pleural free fluid. A cross-sectional survey

Physical examination (PE) has always been a corner stone of medical practice. The recent advances in imaging and fading of doctors' ability in performing it, however, raised doubts on PE usefulness. Point-of-care ultrasonography (POCUS) is gaining ground in medicine with the detection of free fluids being one of its main applications. To estimate physicians' confidence and use of PE and POCUS for the detection of abdominal or pleural free fluid, we conducted a cross-sectional survey. In all, 246 internal and emergency medicine physicians answered to the survey (197 in-hospital physicians and 49 general practitioners; response rate 28.5%). Almost all declared to perform PE in case of suspected ascites or pleural effusion (88% and 90%, respectively). The highest rates of confidence were observed in conventional PE signs (91% for diminished breath sounds, 80% for dullness to thorax percussion, and 66% for abdominal flank dullness). For the remaining signs, rates of confidence were less than 53%. Physicians with > 15 years of experience and POCUS-naïve doctors reported higher confidence in PE. Most of emergency and almost half of internal medicine physicians (78% and 44%, respectively) attended a structured POCUS course. POCUS use was higher among trained physicians for both ascites (84% vs 50%, p < 0.001) and pleural effusion (80% vs 34%, p < 0.001). Similarly, higher POCUS use was observed in younger physicians. In conclusion, PE is frequently performed and rates of confidence are low for most PE signs, especially among young doctors and POCUS users. This detailed inventory suggests an ongoing shift towards POCUS integration in clinical practice.

Symptoms and quality of life at 1-year follow up of patients discharged after an acute COVID-19 episode

AIM OF THE STUDY

Patients surviving COVID-19 have been described as being at risk of developing sequelae. We aimed to investigate and elicit persistent symptoms, emotional status and quality-of-life in patients discharged after an acute COVID-19 episode.

METHODS

Patient-reported outcome measures were collected during a telephone interview 30 days and 1 year after discharge. Patients' general health status was evaluated using questions based on their symptoms, emotional status was assessed using the items 9 to 12 of the HeartQoL questionnaire and quality of life was assessed at 1 year through the EQ-5D-5L. In patients with a history of cardiovascular disease, all 14 items of the HeartQoL questionnaire were completed to derive the HeartQoL global score.

RESULTS

Among 687 patients who survived after being hospitalised for COVID-19 at the University Hospitals of Geneva between 26 February and 26 April 2020, 184 (27%) and 165 (24%), respectively, participated in the follow-up at 30 days and 1 year. Of these 184 participants, 62% were male, median age was 58 years and 21% had a past medical history of cardiovascular disease. At one month after discharge, 61% (113/184) of patients presented fatigue and 28% (52/184) dyspnoea. One year after discharge, the main complaints were persistent fatigue in 27% (45/165) of patients, neurological problems in 17% (28/165) and dyspnoea in 14% (23/165). Eight percent (14/184) of patients declared being significantly worried 1 month after discharge and 5% (9/184) feeling depressed. The number of patients reporting being significantly worried or depressed at 1 year was lower. Regarding the quality of life at 1 year, the median EQ-5D-5L visual analogue scale score was 80 (interquartile range 70-90).

CONCLUSIONS

Approximately half of patients reported some symptoms 1 year after discharge following an acute episode of COVID-19. The predominant symptom was persistent fatigue both at 1-month and at 1-year follow-up. Emotional status and quality of life appeared satisfactory.

[POCUS (Point-of-Care Ultrasonography) in internal general medicine: applications scope and training]

POCUS is a valuable tool for the internist. Its field of application in internal medicine is multisystemic and requires rigorous training. This training includes an initiation phase, followed by a practical training phase for the acquisition of images from patients or simulators. Supervision by experts is vital for mastering the necessary skills for the safe use of POCUS. Although, supervisors are available in French speaking Switzerland, there are too few to meet training needs. Several associations provide training courses to obtain POCUS certification, the content of which has been established since 2018 in Switzerland. In order to maintain a high level of proficiency and to identify tomorrow's supervisors, it is essential to provide the necessary means to allow more internists to obtain POCUS certification.

Prognosis of Laboratory-Confirmed Influenza and Respiratory Syncytial Virus in Acute Heart Failure

Concomitant respiratory viral infections may influence clinical outcomes of acute decompensated heart failure (ADHF) but this association is based on indirect observation. The aim of this study was to evaluate the prevalence and impact of laboratory-confirmed influenza or respiratory syncytial virus (RSV) infection on outcomes in patients hospitalised for ADHF. Prospective cohort of patients hospitalised for ADHF with systematic influenza and RSV screening using real-time PCR on nasopharyngeal swabs. The primary outcome was all-cause mortality or readmission at 90 days. Among 803 patients with ADHF, 196 (24.5%) patients had concomitant flu-like symptoms of influenza. PCR was positive in 45 patients (27 for influenza, 19 for RSV). At 90 days, PCR positive patients had lower rates of all-cause mortality or readmission as compared to patients without flu-like symptoms (HR 0.40, 95% CI 0.18–0.91, p = 0.03), and non-significantly less all-cause mortality (HR 0.30, 95% CI 0.04–2.20, p = 0.24), or HF-related death or readmission (HR 0.36, 95% CI 0.13–0.99, p = 0.05). The prevalence of influenza or RSV infection in patients admitted for ADHF was low and associated with less all-cause mortality and readmission. Concomitant viral infection with ADHF may not in itself be a predictor of poor outcomes. (ClinicalTrials.gov NCT02444416).

Gait speed is associated with death or readmission among patients surviving acute hypercapnic respiratory failure

Objectives

Death or hospital readmission are frequent among patients surviving acute hypercapnic respiratory failure (AHRF). Severity scores are not valid to predict death or readmission after AHRF. Gait speed, a simple functional parameter, has been associated with hospital admission and death in the general population. The purpose of this study is to highlight an association between gait speed at hospital discharge and death or readmission among AHRF survivors.

Design

Secondary analysis of a prospective cohort study.

Settings

Single Swiss tertiary hospital, pulmonary division.

Participants

Patients were prospectively recruited to form a cohort of patients surviving AHRF in the intensive care unit between January 2012 and May 2015.

Outcome measure

Gait speed was derived from a 6 min walking test (6MWT) before hospital discharge. All predictive variables were prospectively collected. Death or hospital readmission were recorded for 6 months. Univariate and multivariate analyses were performed to evaluate the association between predictive variables and death or hospital readmission.

Results

71 patients performed a 6MWT. 34/71 (48%) patients died or were readmitted to the hospital during the observation period. Median gait speed was 0.7 (IQR 0.3–1.0) m/s. At 6 months, 66% (25/38) of slow walkers (gait speed <0.7 m/s) and 27% (9/33) of non-slow walkers died or were readmitted to the hospital (p=0.002). In univariate analysis, gait speed was associated with death or readmission (HR 0.41; 95% CI 0.19 to 0.90, p=0.025). In a multivariate model adjusted for age, gender, body mass index, forced expired volume, heart failure and home mechanical ventilation, gait speed remained the only variable associated with death or readmission (multivariate HR: 0.35; 95% CI 0.14 to 0.88, p=0.025).

Conclusion

This study suggests that a simple functional parameter such as gait speed is associated with death or hospital readmission in patients surviving AHRF.

Trial registration number

NCT02111876.

Role of Intermediate Care Unit Admission and Noninvasive Respiratory Support during the COVID-19 Pandemic: A Retrospective Cohort Study

BACKGROUND

The COVID-19 pandemic has led to shortage of intensive care unit (ICU) capacity. We developed a triage strategy including noninvasive respiratory support and admission to the intermediate care unit (IMCU). ICU admission was restricted to patients requiring invasive ventilation.

OBJECTIVES

The aim of this study is to describe the characteristics and outcomes of patients admitted to the IMCU.

METHOD

Retrospective cohort including consecutive patients admitted between March 28 and April 27, 2020. The primary outcome was the proportion of patients with severe hypoxemic respiratory failure avoiding ICU admission. Secondary outcomes included the rate of emergency intubation, 28-day mortality, and predictors of ICU admission.

RESULTS

One hundred fifty-seven patients with COVID-19-associated pneumonia were admitted to the IMCU. Among the 85 patients admitted for worsening respiratory failure, 52/85 (61%) avoided ICU admission. In multivariate analysis, PaO2/FiO2 (OR 0.98; 95% CI: 0.96-0.99) and BMI (OR 0.88; 95% CI: 0.78-0.98) were significantly associated with ICU admission. No death or emergency intubation occurred in the IMCU.

CONCLUSIONS

IMCU admission including standardized triage criteria, self-proning, and noninvasive respiratory support prevents ICU admission for a large proportion of patients with COVID-19 hypoxemic respiratory failure. In the context of the COVID-19 pandemic, IMCUs may play an important role in preserving ICU capacity by avoiding ICU admission for patients with worsening respiratory failure and allowing early discharge of ICU patients.

Self-proning in COVID-19 patients on low-flow oxygen therapy: a cluster randomised controlled trial

Rationale and objectives

Prone positioning as a complement to oxygen therapy to treat hypoxaemia in coronavirus disease 2019 (COVID-19) pneumonia in spontaneously breathing patients has been widely adopted, despite a lack of evidence for its benefit. We tested the hypothesis that a simple incentive to self-prone for a maximum of 12 h per day would decrease oxygen needs in patients admitted to the ward for COVID-19 pneumonia on low-flow oxygen therapy.

Methods

27 patients with confirmed COVID-19 pneumonia admitted to Geneva University Hospitals were included in the study. 10 patients were randomised to self-prone positioning and 17 to usual care.

Measurements and main results

Oxygen needs assessed by oxygen flow on nasal cannula at inclusion were similar between groups. 24 h after starting the intervention, the median (interquartile range (IQR)) oxygen flow was 1.0 (0.1–2.9) L·min⁻¹ in the prone position group and 2.0 (0.5–3.0) L·min⁻¹ in the control group (p=0.507). Median (IQR) oxygen saturation/fraction of inspired oxygen ratio was 390 (300–432) in the prone position group and 336 (294–422) in the control group (p=0.633). One patient from the intervention group who did not self-prone was transferred to the high-dependency unit. Self-prone positioning was easy to implement. The intervention was well tolerated and only mild side-effects were reported.

Conclusions

Self-prone positioning in patients with COVID-19 pneumonia requiring low-flow oxygen therapy resulted in a clinically meaningful reduction of oxygen flow, but without reaching statistical significance.

This randomised controlled trial analysed the effect of self-prone positioning in #COVID 19-associated pneumonia. Prone positioning was easy to implement and oxygen needs were lower in the self-prone group, although not reaching statistical significance.https://bit.ly/2MdFeyX

Point of care ultrasonography from the emergency department to the internal medicine ward: current trends and perspectives

The advent of portable devices in the early 80s has brought ultrasonography to the patient's bedside. Currently referred to as 'point of care ultrasonography' (POCUS), it has become an essential tool for clinicians. Initially developed in the emergency and critical care settings, POCUS has gained increasing importance in internal medicine wards in the last decade, with both its growing diagnostic accuracy and portability making POCUS an optimal instrument for everyday clinical assessment and procedures. There is large body of evidence to confirm POCUS' superiority when compared to clinical examination and standard X-ray imaging in a variety of clinical situations. On the contrary, only few indications, such as procedural guidance, have a proven additional benefit for patients. Since POCUS is highly user-dependent, pre- and post-graduate curricula are needed and the range of use should be clearly defined. This review focuses on trends and perspectives of POCUS in the management of diseases frequently encountered in emergency and internal medicine. In addition, questions are raised regarding the teaching and supervision of POCUS needing to be addressed in the near future.

Preventing Venous Thromboembolism in Ambulatory Patients with Cancer: A Narrative Review

Venous thromboembolism (VTE) is frequent among patients with cancer. Ambulatory cancer patients starting chemotherapy have a 5% to 10% risk of cancer associated thrombosis (CAT) within the first year after cancer diagnosis. This risk may vary according to patient characteristics, cancer location, cancer stage, or the type of chemotherapeutic regimen. Landmark studies evaluating thrombophrophylaxis with low molecular weight heparin (LMWH) for ambulatory cancer patients have shown a relative reduction in the rate of symptomatic VTE of about one half. However, the absolute risk reduction is modest among unselected patients given a rather low risk of events resulting in a number needed to treat (NNT) of 40 to 50. Moreover, this modest benefit is mitigated by a trend towards an increased risk of bleeding, and the economic and patient burden due to daily injections of LMWH. For these reasons, routine thromboprophylaxis is not recommended by expert societies. Advances in VTE risk stratification among cancer patients, and growing evidence regarding efficacy and safety of direct oral anticoagulants (DOACs) for the treatment and prevention of CAT have led to reconsider the paradigms of this risk–benefit assessment. This narrative review aims to summarize the recent evidence provided by randomized trials comparing DOACs to placebo in ambulatory cancer patients and its impact on expert recommendations and clinical practice.

[Novelties in internal medicine]

This selective overview of articles describes new concepts, therapeutic measures and pharmacological agents that may modify current practice in internal medicine. Implications for management of cardiovascular disease, such as heart failure, diabetes and infectious diseases figure prominently.

[Direct oral anticoagulants in the treatment of cancer-associated thrombosis]

The use of direct oral anticoagulants (DOACs) has been largely -implemented in the management of venous thromboembolic disease in non-cancer patients. In cancer-associated thrombosis, low molecular weight heparins (LMWHs) and especially dalteparin have long been the reference standard therapy. Following the publication of two randomised trials comparing edoxaban and rivaroxaban to -dalteparin, DOACs now represent an alternative with an interesting efficacy and safety profile. Moreover, they offer the comfort of an oral administration and a lower cost. In patients with gastrointestinal or genitourinary cancers however, a higher bleeding risk has been shown with DOACs. LMWHs thus remain the treatment of choice in this group of patients.

[Volemic resuscitation in acute care setting : which intravenous fluid ?]

Crystalloid-type solutions are currently recommended for volume resuscitation. Although historically considered as « physiological saline », NaCl 0.9 % has a high concentration of sodium and chloride that can lead to metabolic acidosis and impaired renal function when large volumes are used. Recent evidence confirms that use of low-chloride crystalloids (so-called balanced solutions) could reduce the occurrence of renal failure and should be preferred during high volume resuscitation.

[First line eradication treatment of Helicobacter pylori in 2019]

Helicobacter pylori infection is associated with chronic gastric inflammation, peptic ulcer and an increased risk of gastric cancer. Helicobacter eradication traditionally consists of an empirical therapy combining clarithromycine, amoxicillin and proton pump inhibitors. However, this classic therapy needs to be reassessed because of the raising prevalence of clarithromycine resistance. Various alternative eradication treatments have been studied. This article aims to review the recommended alternatives and the different factors to guide the most appropriate first line eradication therapy.

Rational Use of CT-Scan for the Diagnosis of Pneumonia: Comparative Accuracy of Different Strategies

Diagnosing pneumonia in emergency departments is challenging because the accuracy of symptoms, signs and laboratory tests is limited. As a confirmation test, chest X-ray has significant limitations and is outperformed by CT-scan. However, obtaining a CT-scan in all cases of suspected pneumonia has significant drawbacks. We used a cohort of 200 consecutive elderly patients admitted to the hospital for suspected pneumonia to build a simple prediction score, which was used to determine indication for performing a CT-scan. The reference diagnosis was adjudicated by experts considering all available data, including evolution until discharge and CT scan in all patients. Results were externally validated in a second cohort of 319 patients. Pneumonia was confirmed in 133 patients (67%). Area under the receiver operator curve (AUROC) of physician evaluation was 0.55 (0.46–0.64). The score incorporated four variables independently predicting confirmed pneumonia: male gender, acute cough, C-reactive protein >70 mg/L, and urea <7 mmol/L. AUROC of the score was 0.68 (95% confidence interval (CI) 0.60–0.76). When a CT-scan was obtained for patients at low or intermediate predicted risk (108 patients, 54% of the cohort), AUROC was 0.71 (0.63–0.80) and 0.69 (0.64–0.74) in the derivation and validation cohort, respectively. A simple prediction score for pneumonia had moderate accuracy and could guide the performance of a CT-scan.

[Contemporary novelties in internal medicine]

Confronted with increasingly complex and interdependent medical situations, targeted clinical answers and recommendations are -increasingly the result of a comprehensive appraisal of existing -evidence. In addition, public health and economic stakes have to be considered and integrated into the decision process, diagnosis and management of numerous clinical entities. This selective overview covers some of these entities and demonstrate the expanding overlap between inpatient and outpatient practice.

Accuracy of comprehensive PCR analysis of nasopharyngeal and oropharyngeal swabs for CT-scan-confirmed pneumonia in elderly patients: a prospective cohort study

OBJECTIVES

We aimed to assess the accuracy of PCR detection of viruses and bacteria on nasopharyngeal and oropharyngeal swabs (NPS) for the diagnosis of pneumonia in elderly individuals.

METHODS

We included consecutive hospitalized elderly individuals suspected of having pneumonia. At inclusion, NPS were collected from all participants and tested by PCR for the presence of viral and bacterial respiratory pathogens (index test, defined as comprehensive molecular testing). Routine diagnostic tests (blood and sputum culture, urine antigen detection) were also performed. The reference standard was the presence of pneumonia on a low-dose CT scan as assessed by two independent expert radiologists.

RESULTS

The diagnosis of pneumonia was confirmed in 127 of 199 (64%) included patients (mean age 83 years, community-acquired pneumonia in 105 (83%)). A pathogen was identified by comprehensive molecular testing in 114 patients (57%) and by routine methods in 22 (11%). Comprehensive molecular testing was positive for viruses in 62 patients (31%) and for bacteria in 73 (37%). The sensitivity and specificity were 61% (95% CI 53%-69%) and 50% (95% CI 39%-61%) for comprehensive molecular testing, and 14% (95% CI 82%-21%) and 94% (95% CI 86%-98%) for routine testing, respectively. Positive likelihood ratio was 2.55 for routine methods and 1.23 for comprehensive molecular testing.

CONCLUSION

Comprehensive molecular testing of NPS increases the number of pathogens detected compared with routine methods, but results are poorly predictive of the presence of pneumonia. Hence, comprehensive molecular testing is unlikely to impact clinical decision-making (NCT02467192).

CLINICAL TRIALS REGISTRATION

NCT02467192.

Impact of a patient-flow physician coordinator on waiting times and length of stay in an emergency department: A before-after cohort study

OBJECTIVE

Overcrowding is common in most emergency departments (ED). Despite the use of validated triage systems, some patients are at risk of delayed medical evaluation. The objective of this study was to assess the impact of a patient-flow physician coordinator (PFPC) on the proportion of patients offered medical evaluation within time limits imposed by the Swiss Emergency Triage Scale (SETS) and on patient flow within the emergency department of a teaching urban hospital.

METHODS

In this before-after retrospective cohort study, we compared the proportions of patients who received their first medical contact within SETS-imposed time limits, mean waiting times before first medical consultation, mean length of stay, and number of patients who left without being seen by a physician, between two periods before and after introducing a PFPC. The PFPC was a senior physician charged with quickly assessing in the waiting area patients who could not immediately be seen and managing patient flow within the department.

RESULTS

Before introducing the PFPC position, 33,605 patients were admitted, versus 36,288 after. Introducing a PFPC enabled the department to increase the proportion of patients seen within the SETS-imposed time limits from 60.1% to 69.0% (p <0.0001). Waiting times until first medical consultation were reduced on average by 27.7 minutes (95% confidence interval [95% CI]: 25.9-29.5, p < .0001). No significant differences were observed as to length of stay or number of patients who left without being seen between the two study periods.

CONCLUSIONS

Introducing a physician dedicated to managing patient flow enabled waiting times until first medical consultation to be reduced, yet had no significant benefit for patient flow within the ED, nor did it reduce the number of patients who left without being seen.

False negative computed tomography scan due to pelvic binder in a patient with pelvic disruption: a case report and review of the literature

Background

Pelvic binders are routinely used in the prehospital setting for stabilization of pelvic injuries in patients with trauma. Emergency department trauma management relies on primary and secondary survey assessment and imaging, most often computed tomography, in hemodynamically stable patients. Maintaining the pelvic binder in situ allows stabilization of pelvic injuries during imaging but may hinder the visualization of some pelvic lesions. We report a very rare case of severe pelvic disruption with an absolutely normal computed tomography scan due to the effective placement of a pelvic binder.

Case presentation

We report the case of a 49-year-old Caucasian man referred to our Emergency Department after a high velocity motorcycle accident. Primary assessment revealed a left wrist deformation and pelvic pain, and a pelvic binder was applied by paramedics. A total body computed tomography scan was performed after arrival in our Emergency Department and did not reveal any pelvic injury. The pelvic binder was removed and because of persisting symphyseal pain, pelvic plain radiography was performed revealing a pelvic disruption with an opening of the pubic symphysis and of the left sacroiliac joint (“open book” type pelvic injury) requiring surgical stabilization.

Conclusions

Pelvic binders may mask pelvic disruption in patients with trauma. Pelvic plain radiography should be repeated after pelvic binder removal in patients with high velocity trauma and pelvic symptoms or neurological alterations limiting the reliability of clinical examination.

Electronic supplementary material

The online version of this article (10.1186/s13256-018-1808-7) contains supplementary material, which is available to authorized users.