Three dimensional analysis of the exhalation flow in the proximity of the mouth

The human exhalation flow is characterized in this work from the three-dimensional velocimetry results obtained by using the stereo particle image velocimetry (SPIV) measurement technique on the flow emitted from a realistic airway model. For this purpose, the transient exhalation flow through the mouth of a person performing two different breaths corresponding to two metabolic rates, standing relaxed (SR) and walking active (WA), is emulated and studied. To reproduce the flow realistically, a detailed three-dimensional model obtained from computed tomography measurements on real subjects is used. To cope with the variability of the experimental data, a subsequent analysis of the results is performed using the TR-PIV (time resolved particle image velocimetry) technique. Exhalation produces a transient jet that becomes a puff when flow emission ends. Three-dimensional vector fields of the jet velocity are obtained in five equally spaced transverse planes up to a distance of Image 1 from the mouth at equally spaced time instants Image 2 which will be referred to as phases (φ), from the beginning to the end of exhalation. The time evolution during exhalation of the jet area of influence, the velocity field and the jet air entrainment have been characterized for each of the jet cross sections. The importance of the use of realistic airway models for the study of this type of flow and the influence of the metabolic rate on its development are also analyzed. The results obtained contribute to the characterization of the human exhalation as a pathway of the transmission of pathogens such as SARS-CoV-2 virus.

SARS-CoV-2 ORF8 accessory protein is a virulence factor

IMPORTANCE

The relevance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ORF8 in the pathogenesis of COVID-19 is unclear. Virus natural isolates with deletions in ORF8 were associated with wild milder disease, suggesting that ORF8 might contribute to SARS-CoV-2 virulence. This manuscript shows that ORF8 is involved in inflammation and in the activation of macrophages in two experimental systems: humanized K18-hACE2 transgenic mice and organoid-derived human airway cells. These results identify ORF8 protein as a potential target for COVID-19 therapies.

Clinical features and short-term prognosis in the very elderly, >90 year-old, patients hospitalized with heart failure. A population-based study (2016–2019)

Background

Heart failure (HF) is a main health problem in western countries, and a major cause of hospitalizations and death, particularly in older people. Few data are available about clinical features and prognosis of very old patients, those aged 90 or more years.

Purpose

To analyse the clinical features and short-term prognosis (in-hospital mortality and 30-day readmission rate) of patients aged 90 or more years hospitalized with HF in Spain in the last years.

Methods

We conducted a retrospective analysis of patients discharged with an ICD-10 main diagnosis of HF from the Spanish National Health System (SNHS) public hospitals between 2016 and 2019, using as source of data the Minimum Basic Data Set of the SNHS. A comparison of clinical profile, in-hospital mortality and 30-day cardiovascular readmission rate between patients aged 75 to 89 years and those with 90 or more years was performed.

Results

From 2016 to 2019, 354,792 episodes of people older than 74-year and principal diagnosis of HF were included, being 59.2% female. Mean age of the whole population was 85.2±5.5 years, crude in-hospital mortality rate was 12.7% and crude cardiovascular 30-day readmission rate, 11.8%. The very older patients' subgroup (90 or more year-old) comprised 78.777 patients (22.2%). Table 1 shows the differences in clinical features between these patients and those aged 75 to 89 (77.8%). Patients aged 90 or more years were female in a higher proportion and showed a higher prevalence of cognitive impairment and renal failure, but a lower prevalence of most comorbidities (coronary artery revascularization, valve heart disease, cancer, diabetes mellitus, chronic liver disease). The diagnosis of previous myocardial infarction, stroke and systemic hypertension was similar in both groups (Table 1). Crude 30-day cardiovascular readmission rate was slightly but significantly lower in the oldest subgroup (10.9% vs 12%, p<0.001), while crude in-hospital mortality was higher (18.5% vs 11%, p<0.001).

Conclusions

Patients aged 90 or more years represents almost a fourth part of elderly patients hospitalized with HF in Spain within the last years. In general, prevalence of comorbidities and associated heart disease was similar or lower, but in-hospital mortality was twice higher, as compared with less older patients.

Funding Acknowledgement

Type of funding sources: None.

Immune response in breast cancer surgery. A comparative and prospective study of different anesthetic techniques

INTRODUCTION

The main reason for high mortality in breast cancer is local recurrence and metastasis, despite surgery as the first therapeutic option. The anesthesia used in the operation room can determine the immune response.

METHODS

A prospective, comparative and non- randomised study in patients undergoing breast cancer surgery was conducted in our hospital after obtaining approval from the Hospital's Institutional Review Board. Patients were divided in two groups: Group A received general anesthesia with propofol and opioids. Group B, in addition to general anesthesia, three interfascial blocks (Pec I, Pec II and BRILMA) were performed in all patients. Three blood samples were taken 1) previous anesthetic induction; 2) two hours after the end of the surgery and 3) 24-48 h after surgery. Leukocytes, CD3, CD4, CD8 and Natural Killer cells were determined at each time.

RESULTS

103 patients were included. 59 (group A) received general anesthesia and 54 (group B) general anesthesia and interfascial blocks. Regarding baseline characteristics, age was significantly higher in the group that received general anesthesia and mastectomy was more frequent in the group that received interfascial blocks. We observed after surgery an increase in leukocytes level that returns close to baseline levels. On the other hand, a reduction in the immune response was observed that also returns to the previous level 48 h after surgery. Group A and B get similar results and also subgroups of hormonal receptors (HER+, PR and/or ER+).

CONCLUSIONS

Interfascial blocks in chest wall added to general anesthesia in breast cancer surgery has not shown a significant difference in the inflammatory response or immunological depression compared to general anesthesia as the only anesthetic technique. It seems to trend less immunological depression in the interfascial block group.

Soil-transmitted helminth infections in free-ranging non-human primates from Cameroon and Gabon

BACKGROUND

Zoonotic diseases are a serious threat to both public health and animal conservation. Most non-human primates (NHP) are facing the threat of forest loss and fragmentation and are increasingly living in closer spatial proximity to humans. Humans are infected with soil-transmitted helminths (STH) at a high prevalence, and bidirectional infection with NHP has been observed. The aim of this study was to determine the prevalence, genetic diversity, distribution and presence of co-infections of STH in free-ranging gorillas, chimpanzees and other NHP species, and to determine the potential role of these NHP as reservoir hosts contributing to the environmental sustenance of zoonotic nematode infections in forested areas of Cameroon and Gabon.

METHODS

A total of 315 faecal samples from six species of NHPs were analysed. We performed PCR amplification, sequencing and maximum likelihood analysis of DNA fragments of the internal transcribed spacer 2 (ITS2) nuclear ribosomal DNA to detect the presence and determine the genetic diversity of Oesophagostomum spp., Necator spp. and Trichuris spp., and of targeted DNA fragments of the internal transcribed spacer 1 (ITS1) to detect the presence of Ascaris spp.

RESULTS

Necator spp. infections were most common in gorillas (35 of 65 individuals), but also present in chimpanzees (100 of 222 individuals) and in one of four samples from greater spot-nosed monkeys. These clustered with previously described type II and III Necator spp. Gorillas were also the most infected NHP with Oesophagostomum (51/65 individuals), followed by chimpanzees (157/222 individuals), mandrills (8/12 samples) and mangabeys (7/12 samples), with O. stephanostomum being the most prevalent species. Oesophagostomum bifurcum was detected in chimpanzees and a red-capped mangabey, and a non-classified Oesophagostomum species was detected in a mandrill and a red-capped mangabey. In addition, Ternidens deminutus was detected in samples from one chimpanzee and three greater spot-nosed monkeys. A significant relative overabundance of co-infections with Necator and Oesophagostomum was observed in chimpanzees and gorillas. Trichuris sp. was detected at low prevalence in a gorilla, a chimpanzee and a greater spot-nosed monkey. No Ascaris was observed in any of the samples analysed.

CONCLUSIONS

Our results on STH prevalence and genetic diversity in NHP from Cameroon and Gabon corroborate those obtained from other wild NHP populations in other African countries. Future research should focus on better identifying, at a molecular level, the species of Necator and Oesophagostomum infecting NHP and determining how human populations may be affected by increased proximity resulting from encroachment into sylvatic STH reservoir habitats.

Outcome of acute hypoxaemic respiratory failure: insights from the LUNG SAFE Study

BACKGROUND

Current incidence and outcome of patients with acute hypoxaemic respiratory failure requiring mechanical ventilation in the intensive care unit (ICU) are unknown, especially for patients not meeting criteria for acute respiratory distress syndrome (ARDS).

METHODS

An international, multicentre, prospective cohort study of patients presenting with hypoxaemia early in the course of mechanical ventilation, conducted during four consecutive weeks in the winter of 2014 in 459 ICUs from 50 countries (LUNG SAFE). Patients were enrolled with arterial oxygen tension/inspiratory oxygen fraction ratio ≤300 mmHg, new pulmonary infiltrates and need for mechanical ventilation with a positive end-expiratory pressure of ≥5 cmH₂O. ICU prevalence, causes of hypoxaemia, hospital survival and factors associated with hospital mortality were measured. Patients with unilateral versus bilateral opacities were compared.

FINDINGS

12 906 critically ill patients received mechanical ventilation and 34.9% with hypoxaemia and new infiltrates were enrolled, separated into ARDS (69.0%), unilateral infiltrate (22.7%) and congestive heart failure (CHF; 8.2%). The global hospital mortality was 38.6%. CHF patients had a mortality comparable to ARDS (44.1% versus 40.4%). Patients with unilateral-infiltrate had lower unadjusted mortality, but similar adjusted mortality compared to those with ARDS. The number of quadrants on chest imaging was associated with an increased risk of death. There was no difference in mortality comparing patients with unilateral-infiltrate and ARDS with only two quadrants involved.

INTERPRETATION

More than one-third of patients receiving mechanical ventilation have hypoxaemia and new infiltrates with a hospital mortality of 38.6%. Survival is dependent on the degree of pulmonary involvement whether or not ARDS criteria are reached.

Mechanical ventilation in Spain, 1998-2016: changes in the disconnection of mechanical ventilation

PURPOSE

To evaluate changes in the disconnection of mechanical ventilation in Spain from 1998 to 2016.

DESIGN

Post-hoc analysis of four cohort studies.

AMBIT

138 Spanish ICUs.

PATIENTS

2141 patients scheduled extubated.

INTERVENTIONS

None.

VARIABLES OF INTEREST

Demographics, reason for mechanical ventilation, complications, methods for disconnection, failure on the first attempt at disconnection, duration of weaning, reintubation, post-reintubation tracheotomy, ICU stay and mortality.

RESULTS

There was a significant increase (p<0.001) in the use of gradual reduction of support pressure. The adjusted probability of using the gradual reduction in pressure support versus a spontaneous breathing trial has increased over time, both for the first attempt at disconnection (taking the 1998 study as a reference: odds ratio 0.99 in 2004, 0.57 in 2010 and 2.43 in 2016) and for difficult/prolonged disconnection (taking the 1998 study as a reference: odds ratio 2.29 in 2004, 1.23 in 2010 and 2.54 in 2016). The proportion of patients extubated after the first attempt at disconnection has increased over time. There is a decrease in the ventilation time dedicated to weaning (from 45% in 1998 to 36% in 2016). However, the duration in difficult/prolonged weaning has not decreased (median 3 days in all studies, p=0.435).

CONCLUSIONS

There have been significant changes in the mode of disconnection of mechanical ventilation, with a progressive increase in the use of gradual reduction of pressure support. No relevant changes in outcomes have been observed.

Factors associated with impairment in gait speed in older people with clinically normal gait. A cross-sectional study

BACKGROUND

Health professionals commonly use gait speed in the evaluation of functional status in older people. However, only a limited number of studies have assessed gait speed in the absence of disorders of gait, using confounding factors and exclusion criteria coming from studies conducted in younger people. Our study aims to analyse which factors are associated with gait speed in older people with normal clinical gait.

METHODS

An observational cross-sectional study was conducted in 119 community-dwelling residents without relevant comorbidities (Charlson index < 2), preserved function (Barthel > 85) and normal gait by visual exploration. Exclusion criteria included suffering from any illness that could modify the characteristics of gait, terminal status or the presence of an acute medical illness in the past 3 months. We used a stepwise linear regression of several variables (sociodemographic characteristics, cognition, body composition, drugs, falls, sarcopenia, frailty and physical activity) on 6-metre gait speed.

RESULTS

The mean age was 78 years (range 70-96 years) and 71.4% were women. Variables that remained associated with gait speed in the multivariate final model were age (B = - 0.020, p < 0.001); gender (B = - 0.184, p < 0.001); waist-to-height ratio (B = - 0.834, p = 0.002); number of falls (B = - 0.049, p = 0.003) and the number of Fried's frailty criteria (B = - 0.064, p = 0.019).

CONCLUSION

Falls, frailty and the waist-to-height ratio modify gait speed in older people with normal gait. Studies analysing the potential effect of several factors on gait speed should consider them as confounding factors.

Mechanical ventilation in Spain, 1998-2016: Epidemiology and outcomes

PURPOSE

To evaluate changes in the epidemiology of mechanical ventilation in Spain from 1998 to 2016.

DESIGN

A post hoc analysis of four cohort studies was carried out.

SETTING

A total of 138 Spanish ICUs.

PATIENTS

A sample of 4293 patients requiring invasive mechanical ventilation for more than 12h or noninvasive ventilation for more than 1h.

INTERVENTIONS

None.

VARIABLES OF INTEREST

Demographic variables, reason for mechanical ventilation, variables related to ventilatory support (ventilation mode, tidal volume, PEEP, airway pressures), complications during mechanical ventilation, duration of mechanical ventilation, ICU stay and ICU mortality.

RESULTS

There was an increase in severity (SAPSII: 43 points in 1998 vs. 47 points in 2016), changes in the reason for mechanical ventilation (decrease in chronic obstructive pulmonary disease and acute respiratory failure secondary to trauma, and increase in neurological disease and post-cardiac arrest). There was an increase in noninvasive mechanical ventilation as the first mode of ventilatory support (p<0.001). Volume control ventilation was the most commonly used mode, with increased support pressure and pressure-regulated volume-controlled ventilation. A decrease in tidal volume was observed (9ml/kg actual b.w. in 1998 and 6.6ml/kg in 2016; p<0.001) as well as an increase in PEEP (3cmH₂O in 1998 and 6cmH₂O in 2016; p<0.001). In-ICU mortality decreased (34% in 1998 and 27% in 2016; p<0.001), without geographical variability (median OR 1.43; p=0.258).

CONCLUSIONS

A significant decrease in mortality was observed in patients ventilated in Spanish ICUs. These changes in mortality could be related to modifications in ventilation strategy to minimize ventilator-induced lung injury.

P727 Unexpected ventricular aneurysm: further ischemic aetiology

Introduction

Ventricular aneurysm is an infrequent complication of myocardial infarction. In absence of an ischemic event, alternative aetiologies include: thoracic trauma, hypertrophic cardiomyopathy, myocarditis, Chagas disease, cardiac sarcoidosis or arrythmogenic cardiomyopathy. In the absence of any of the previous, congenital aneurysm diagnosis is made.

Case

We present the case of 57-year-old man referred to cardiology department because a new onset of atrial fibrillation with left bundle branch block. Past medical history included high blood pressure and dyslipidaemia without any history or smoking, alcohol consumption or any other toxic abuse. No chest pain, shortness of breath or other significant symptoms were reported. Physical examination was unremarkable except for an arrhythmic pulse at 85-90 bpm.

Echocardiogram showed moderate dilated left ventricle with mild-moderate LV dysfunction (EF 40% ) with a septal aneurysm of 2.4x1cm (Picture A). A coronary CT was performed that ruled out coronary heart disease and confirmed the presence of the septal aneurysm (Picture B). To better characterize this image, a cardiac magnetic resonance (CMR) was performed. Moderate dilated LV with significant dysfunction (EF 31%) was reported. A septal aneurysm of 13 x 22 x 33 mm composed of a 2.8 m thin wall of true myocardial tissue was documented (picture C and D-late gadolinium enhance). No myocardial delayed enhancement was detected in any area of the LV. Moreover, no signs of myocardial non compaction, arrythmogenic cardiomyopathy, hypertrophic cardiomyopathy or myocarditis were seen. Chagas serology as well as sarcoidosis diagnosis work up were negative. Patient denied any thoracic traumatism. Congenital aneurysm diagnosis was finally established.

Electrical cardioversion was performed after 1 month of correct oral anticoagulation and heart failure treatment was started. Case was presented in the Heart Team session and a conservative management was decided based on asymptomatic status and absence of ventricular arrhythmias. After 3 years of clinical follow up, the patients is in good status, asymptomatic and in sinus rhythm. Discussion: Congenital ventricular aneurysm is a rare cardiac malformation that arises during the fourth embryonic week. Most frequently, left ventricular aneurysms are found in the apex and the perivalvular area, being the septal location an atypical one. Most patients are asymptomatic but when symptoms occur, they are mostly related to the presence of ventricular arrhythmias. Aneurysm rupture incidence is variable, ranging from 3.7% to 12 % according to the different series. For this reason, surgery is recommended in symptomatic patients. However, management of asymptomatic patients is not clear since prognosis studies are lacking.

Abstract P727 Figure. A.Echo B.-CT C.-CMR. D.-CMR gadolinium

P1551A genetic risk score predicts recurrent events after myocardial infarction in young adults

Background

To evaluate whether a genetic risk score (GRS) improves the prediction of recurrent events in young non-diabetic patients presenting with an acute myocardial infarction and identifies a more aggressive form of atherosclerosis in this population.

Methods and results

We performed a prospective study including 81 consecutive non-diabetic patients aged below 55 y.o. presenting with an acute myocardial infarction (48±6 y.o., 89% male). A comprehensive study including serum biomarkers, genetic testing and cardiac CT was performed. We studied the association of a GRS composed of 11 genetic variants with a primary composite end-point (all-cause mortality, recurrent acute coronary syndrome, and cardiac re-hospitalisation). After a median follow-up of 4.1 (3.5 - 4.4) years 24 recurrent events were documented. A significantly higher prevalence of 9 out of 11 risk alleles was noted compared with general population. The GRS was significantly associated with recurrent events, especially when baseline LDL-cholesterol levels were elevated. Compared with the low-risk GRS category, the multivariate-adjusted hazard ratio for recurrent events for the intermediate-risk GRS category was 10.2 (95% CI 1.1–100.3, p=0.04) and for the high-risk GRS was 20.7 (2.4–181.0, p=0.006) when LDL-C ≥2.8 mmol/L. Inclusion of the GRS improved the C statistic (ΔC statistic =0.086), the continuous Net Reclassification Index (30%) and the Integrated Discrimination Improvement (0.05) compared with a multivariate clinical risk model. Cardiac CT detected coronary calcified atherosclerosis and numerous plaques but it had a limited value for prediction of recurrences. No association was observed between extracellular matrix metabolism biomarkers and GRS or recurrent events in this population.

Cox regression analysis between GRS terciles and LDL-C Univariate analysis Multivariate analysis* HR (95% CI) p-value HR (95% CI) p-value* Low GRS 1 1 Intermediate GRS 2.0 (0.7–5.8) 0.21 LDL-C≤110 mg/dL (≤2.8 mmol/L) 1.0 (0.3–4.0) >110 mg/dL (>2.8 mmol/L) 10.2 (1.1–100.3) 0.04 High GRS 3.0 (1.0–9.2) 0.05 LDL-C≤110 mg/dL (≤2.8 mmol/L) 0.3 (0.1–1.9) >110 mg/dL (>2.8 mmol/L) 20.7 (2.4–181.0) 0.006 *Multivariate model adjusted for GRACE risk score and LDL-C and interaction. There was a strong interaction between GRS terciles and LDL-C (p<0.01).

Recurrent events based on genetic risk

Conclusions

A multilocus genetic risk score identified non-diabetic young patients at increased risk for recurrent events after a myocardial infarction. The significance of LDL-cholesterol in relation to genetic predisposition for recurrences merits further evaluation.

Acknowledgement/Funding

Instituto de Salud Carlos III (PI12/0564, PI14/01152 and PI15/00667), the CIBERCV and the Spanish Society of Cardiology (2015/CC)

Have there been changes in the application of mechanical ventilation in relation to scientific evidence? A multicenter observational study in Mexico

OBJECTIVE

The main study objectives were to describe the practice of mechanical ventilation over an 18-year period in Mexico, and estimate changes in mortality among critical patients subjected to invasive mechanical ventilation (IMV).

DESIGN

A retrospective subanalysis of a prospective observational study conducted in 1998, 2004, 2010 and 2016 was carried out.

SETTING

Intensive Care Units (ICUs) in Mexico.

PARTICIPANTS

Adult patients consecutively enrolled in the ICU during one month and who underwent IMV for more than 12hours or noninvasive mechanical ventilation for more than one hour. Follow-up was performed up to a maximum of 28 days after inclusion.

INTERVENTIONS

None.

PRINCIPAL VARIABLES OF INTEREST

Age, sex, severity upon admission as estimated by SAPS II, parameters of daily arterial blood gases, treatment and complication variables, date and status at discharge from the ICU and from hospital.

RESULTS

A total of 959 patients were included in 81 ICUs. Tidal volume (vt) decreased significantly both in patients with acute respiratory distress syndrome (ARDS) criteria (estimated 8.5ml/kg b.w. in 1998 to 6ml/kg in 2016; P<0.001) and in patients without ARDS (estimated 9ml/kg b.w. in 1998 to 6ml/kg in 2016; P<0.001). The ventilatory protective strategy (defined as vt < 6ml/kg or < 8ml/kg and a plateau pressure < 30cmH₂O) was: 19% in 1998, 44% in 2004, 58% in 2010 and 75% in 2016 (P<0.001). The adjusted mortality rate in ICU over the 4 periods was: in 2004, odds ratio (OR) 1.05 (95% confidence interval, 95%CI: 0.73-1.72; P=0.764); in 2010, OR 1.68 (95%CI: 1.13-2.48; P=0.009); in 2016, OR 0.85 (95%CI: 0.60-1.20; P=0.368).

CONCLUSIONS

The clinical practice of IMV in Mexican ICUs has been modified over a period of 18 years. The most significant change is the ventilatory strategy based on low vt. These changes have not been associated with significant changes in mortality.

International Analgesia, Sedation, and Delirium Practices: a prospective cohort study

Background

While understanding of critical illness and delirium continue to evolve, the impact on clinical practice is often unknown and delayed. Our purpose was to provide insight into practice changes by characterizing analgesia and sedation usage and occurrence of delirium in different years and international regions.

Methods

We performed a retrospective analysis of two multicenter, international, prospective cohort studies. Mechanically ventilated adults were followed for up to 28 days in 2010 and 2016. Proportion of days utilizing sedation, analgesia, and performance of a spontaneous awakening trial (SAT), and occurrence of delirium were described for each year and region and compared between years.

Results

A total of 14,281 patients from 6 international regions were analyzed. Proportion of days utilizing analgesia and sedation increased from 2010 to 2016 (p < 0.001 for each). Benzodiazepine use decreased in every region but remained the most common sedative in Africa, Asia, and Latin America. Performance of SATs increased overall, driven mostly by the US/Canada region (24 to 35% of days with sedation, p < 0.001). Any delirium during admission increased from 7 to 8% of patients overall and doubled in the US/Canada region (17 to 36%, p < 0.001).

Conclusions

Analgesia and sedation practices varied widely across international regions and significantly changed over time. Opportunities for improvement in care include increasing delirium monitoring, performing SATs, and decreasing use of sedation, particularly benzodiazepines.

Electronic supplementary material

The online version of this article (10.1186/s40560-019-0379-z) contains supplementary material, which is available to authorized users.

Fas activation alters tight junction proteins in acute lung injury

Background:The acute respiratory distress syndrome (ARDS) is characterized by protein-rich oedema in the alveolar spaces, a feature in which Fas-mediated apoptosis of the alveolar epithelium has been involved. Objective:To determine whether Fas activation increases protein permeability by mechanisms involving disruption of the paracellular tight junction (TJ) proteins in the pulmonary alveoli. Methods: Protein permeability and the expression of TJ proteins were assessed in vivo in wild-type and Fas-deficient lpr mice 16 hours after the intratracheal instillation of recombinant human soluble Fas ligand (rh-sFasL), and at different time points in vitro in human pulmonary alveolar epithelial cells (HPAEpiC) exposed to rh-sFasL Results:Activation of the Fas pathway increased protein permeability in mouse lungs and altered the expression of the TJ proteins occludin and zonula occludens-1 in the alveolar-capillary membrane in vivo and in human alveolar epithelial cell monolayers in vitro. Blockade of caspase-3, but not inhibition of tyrosine kinase dependent pathways, prevented the alterations in TJ protein expression and permeability induced by the Fas/FasL system in human alveolar cell monolayers in vitro. We also observed that both the Fas-induced increase of protein permeability and disruption of TJ proteins occurred before cell death could be detected in the cell monolayers in vitro. Conclusion:Targeting caspase pathways could prevent the disruption of TJs and reduce the formation of lung oedema in the early stages of ARDS.

Predictors of diffuse alveolar damage in patients with acute respiratory distress syndrome: a retrospective analysis of clinical autopsies

Background

Although diffuse alveolar damage (DAD) is considered the typical histological pattern of acute respiratory distress syndrome (ARDS), only half of patients exhibit this morphological hallmark. Patients with DAD may have higher mortality than those without DAD. Therefore, we aimed to identify the factors associated with DAD in patients with ARDS.

Methods

We analyzed autopsy samples of 356 patients who had ARDS at the time of death. DAD was assessed by two pathologists, and ARDS criteria were evaluated by two intensivists. Criteria for severe ARDS included the degree of hypoxemia and the ancillary variables of the current Berlin definition assessed within 48 h before death: radiographic severity, high positive end-expiratory pressure (PEEP) level, and physiological variables (i.e., altered respiratory system compliance and large anatomic dead space).

Results

After multivariable analysis, high PEEP levels, physiological variables, and opacities involving only three quadrants on chest radiographs were not associated with DAD. The four markers independently associated with DAD were (1) duration of evolution (OR 3.29 [1.95–5.55] for patients with ARDS ≥ 3 days, p < 0.001), (2) degree of hypoxemia (OR 3.92 [1.48–10.3] for moderate ARDS and 6.18 [2.34–16.3] for severe ARDS, p < 0.01 for both), (3) increased dynamic driving pressure (OR 1.06 [1.04–1.09], p = 0.007), and (4) radiographic severity (OR 2.91 [1.47–5.75] for patients with diffuse opacities involving the four quadrants, p = 0.002). DAD was found in two-thirds of patients with a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen ≤ 100 mmHg and opacities involving the four quadrants.

Conclusions

In addition to severe hypoxemia, diffuse opacities involving the four quadrants were a strong marker of DAD.

Noninvasive Ventilation of Patients with Acute Respiratory Distress Syndrome. Insights from the LUNG SAFE Study

RATIONALE

Noninvasive ventilation (NIV) is increasingly used in patients with acute respiratory distress syndrome (ARDS). The evidence supporting NIV use in patients with ARDS remains relatively sparse.

OBJECTIVES

To determine whether, during NIV, the categorization of ARDS severity based on the Pa_O2/Fi_O2 Berlin criteria is useful.

METHODS

The LUNG SAFE (Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure) study described the management of patients with ARDS. This substudy examines the current practice of NIV use in ARDS, the utility of the Pa_O2/Fi_O2 ratio in classifying patients receiving NIV, and the impact of NIV on outcome.

MEASUREMENTS AND MAIN RESULTS

Of 2,813 patients with ARDS, 436 (15.5%) were managed with NIV on Days 1 and 2 following fulfillment of diagnostic criteria. Classification of ARDS severity based on Pa_O2/Fi_O2 ratio was associated with an increase in intensity of ventilatory support, NIV failure, and intensive care unit (ICU) mortality. NIV failure occurred in 22.2% of mild, 42.3% of moderate, and 47.1% of patients with severe ARDS. Hospital mortality in patients with NIV success and failure was 16.1% and 45.4%, respectively. NIV use was independently associated with increased ICU (hazard ratio, 1.446 [95% confidence interval, 1.159-1.805]), but not hospital, mortality. In a propensity matched analysis, ICU mortality was higher in NIV than invasively ventilated patients with a Pa_O2/Fi_O2 lower than 150 mm Hg.

CONCLUSIONS

NIV was used in 15% of patients with ARDS, irrespective of severity category. NIV seems to be associated with higher ICU mortality in patients with a Pa_O2/Fi_O2 lower than 150 mm Hg. Clinical trial registered with www.clinicaltrials.gov (NCT 02010073).

Geo-economic variations in epidemiology, patterns of care, and outcomes in patients with acute respiratory distress syndrome: insights from the LUNG SAFE prospective cohort study

BACKGROUND

Little information is available about the geo-economic variations in demographics, management, and outcomes of patients with acute respiratory distress syndrome (ARDS). We aimed to characterise the effect of these geo-economic variations in patients enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE).

METHODS

LUNG SAFE was done during 4 consecutive weeks in winter, 2014, in a convenience sample of 459 intensive-care units in 50 countries across six continents. Inclusion criteria were admission to a participating intensive-care unit (including transfers) within the enrolment window and receipt of invasive or non-invasive ventilation. One of the trial's secondary aims was to characterise variations in the demographics, management, and outcome of patients with ARDS. We used the 2016 World Bank countries classification to define three major geo-economic groupings, namely European high-income countries (Europe-High), high-income countries in the rest of the world (rWORLD-High), and middle-income countries (Middle). We compared patient outcomes across these three groupings. LUNG SAFE is registered with ClinicalTrials.gov, number NCT02010073.

FINDINGS

Of the 2813 patients enrolled in LUNG SAFE who fulfilled ARDS criteria on day 1 or 2, 1521 (54%) were recruited from Europe-High, 746 (27%) from rWORLD-High, and 546 (19%) from Middle countries. We noted significant geographical variations in demographics, risk factors for ARDS, and comorbid diseases. The proportion of patients with severe ARDS or with ratios of the partial pressure of arterial oxygen (PaO₂) to the fractional concentration of oxygen in inspired air (F_iO₂) less than 150 was significantly lower in rWORLD-High countries than in the two other regions. Use of prone positioning and neuromuscular blockade was significantly more common in Europe-High countries than in the other two regions. Adjusted duration of invasive mechanical ventilation and length of stay in the intensive-care unit were significantly shorter in patients in rWORLD-High countries than in Europe-High or Middle countries. High gross national income per person was associated with increased survival in ARDS; hospital survival was significantly lower in Middle countries than in Europe-High or rWORLD-High countries.

INTERPRETATION

Important geo-economic differences exist in the severity, clinician recognition, and management of ARDS, and in patients' outcomes. Income per person and outcomes in ARDS are independently associated.

FUNDING

European Society of Intensive Care Medicine, St Michael's Hospital, University of Milan-Bicocca.

Outcome of acute respiratory distress syndrome in university and non-university hospitals in Germany

Background

This study investigates differences in treatment and outcome of ventilated patients with acute respiratory distress syndrome (ARDS) between university and non-university hospitals in Germany.

Methods

This subanalysis of a prospective, observational cohort study was performed to identify independent risk factors for mortality by examining: baseline factors, ventilator settings (e.g., driving pressure), complications, and care settings—for example, case volume of ventilated patients, size/type of intensive care unit (ICU), and type of hospital (university/non-university hospital). To control for potentially confounding factors at ARDS onset and to verify differences in mortality, ARDS patients in university vs non-university hospitals were compared using additional multivariable analysis.

Results

Of the 7540 patients admitted to 95 ICUs from 18 university and 62 non-university hospitals in May 2004, 1028 received mechanical ventilation and 198 developed ARDS. Although the characteristics of ARDS patients were very similar, hospital mortality was considerably lower in university compared with non-university hospitals (39.3% vs 57.5%; p = 0.012). Treatment in non-university hospitals was independently associated with increased mortality (OR (95% CI): 2.89 (1.31–6.38); p = 0.008). This was confirmed by additional independent comparisons between the two patient groups when controlling for confounding factors at ARDS onset. Higher driving pressures (OR 1.10; 1 cmH₂O increments) were also independently associated with higher mortality. Compared with non-university hospitals, higher positive end-expiratory pressure (PEEP) (mean ± SD: 11.7 ± 4.7 vs 9.7 ± 3.7 cmH₂O; p = 0.005) and lower driving pressures (15.1 ± 4.4 vs 17.0 ± 5.0 cmH₂O; p = 0.02) were applied during therapeutic ventilation in university hospitals, and ventilation lasted twice as long (median (IQR): 16 (9–29) vs 8 (3–16) days; p < 0.001).

Conclusions

Mortality risk of ARDS patients was considerably higher in non-university compared with university hospitals. Differences in ventilatory care between hospitals might explain this finding and may at least partially imply regionalization of care and the export of ventilatory strategies to non-university hospitals.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1687-0) contains supplementary material, which is available to authorized users.

Liberation From Mechanical Ventilation in Critically Ill Adults: An Official American College of Chest Physicians/American Thoracic Society Clinical Practice Guideline: Inspiratory Pressure Augmentation During Spontaneous Breathing Trials, Protocols Minimizing Sedation, and Noninvasive Ventilation Immediately After Extubation

BACKGROUND

An update of evidence-based guidelines concerning liberation from mechanical ventilation is needed as new evidence has become available. The American College of Chest Physicians (CHEST) and the American Thoracic Society (ATS) have collaborated to provide recommendations to clinicians concerning liberation from the ventilator.

METHODS

Comprehensive evidence syntheses, including meta-analyses, were performed to summarize all available evidence relevant to the guideline panel's questions. The evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach, and the results were summarized in evidence profiles. The evidence syntheses were discussed and recommendations developed and approved by a multidisciplinary committee of experts in mechanical ventilation.

RESULTS

Recommendations for three population, intervention, comparator, outcome (PICO) questions concerning ventilator liberation are presented in this document. The guideline panel considered the balance of desirable (benefits) and undesirable (burdens, adverse effects, costs) consequences, quality of evidence, feasibility, and acceptability of various interventions with respect to the selected questions. Conditional (weak) recommendations were made to use inspiratory pressure augmentation in the initial spontaneous breathing trial (SBT) and to use protocols to minimize sedation for patients ventilated for more than 24 h. A strong recommendation was made to use preventive noninvasive ventilation (NIV) for high-risk patients ventilated for more than 24 h immediately after extubation to improve selected outcomes. The recommendations were limited by the quality of the available evidence.

CONCLUSIONS

The guideline panel provided recommendations for inspiratory pressure augmentation during an initial SBT, protocols minimizing sedation, and preventative NIV, in relation to ventilator liberation.

Study Skills and Problem-Solving Strategies in Spanish Students

This paper describes an investigation into reported study skills, motivation and creativity and their relation to academic achievement and problem-solving strategies in a sample of Spanish high-school students. The International Study Skills Inventory (Sakamoto, 1983) was administered to 197 students attending two Seville high schools together with a non-verbal cognitive problem (Esteban, 1976). Factor analysis revealed considerable overlap with previous findings in the key factors of study skills, motivation and creativity. Current and, to a lesser extent, projected academic success, and successful problem-solving strategies were found to correlate with specific responses to the ISSI. The Spanish group were found to favour a more passive approach to study which did not relate particularly well to open-ended problem-solving. Further consideration of the whole area of attitudes to study by school psychologists is recommended.

Epidemiology, Patterns of Care, and Mortality for Patients With Acute Respiratory Distress Syndrome in Intensive Care Units in 50 Countries

IMPORTANCE

Limited information exists about the epidemiology, recognition, management, and outcomes of patients with the acute respiratory distress syndrome (ARDS).

OBJECTIVES

To evaluate intensive care unit (ICU) incidence and outcome of ARDS and to assess clinician recognition, ventilation management, and use of adjuncts-for example prone positioning-in routine clinical practice for patients fulfilling the ARDS Berlin Definition.

DESIGN, SETTING, AND PARTICIPANTS

The Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) was an international, multicenter, prospective cohort study of patients undergoing invasive or noninvasive ventilation, conducted during 4 consecutive weeks in the winter of 2014 in a convenience sample of 459 ICUs from 50 countries across 5 continents.

EXPOSURES

Acute respiratory distress syndrome.

MAIN OUTCOMES AND MEASURES

The primary outcome was ICU incidence of ARDS. Secondary outcomes included assessment of clinician recognition of ARDS, the application of ventilatory management, the use of adjunctive interventions in routine clinical practice, and clinical outcomes from ARDS.

RESULTS

Of 29,144 patients admitted to participating ICUs, 3022 (10.4%) fulfilled ARDS criteria. Of these, 2377 patients developed ARDS in the first 48 hours and whose respiratory failure was managed with invasive mechanical ventilation. The period prevalence of mild ARDS was 30.0% (95% CI, 28.2%-31.9%); of moderate ARDS, 46.6% (95% CI, 44.5%-48.6%); and of severe ARDS, 23.4% (95% CI, 21.7%-25.2%). ARDS represented 0.42 cases per ICU bed over 4 weeks and represented 10.4% (95% CI, 10.0%-10.7%) of ICU admissions and 23.4% of patients requiring mechanical ventilation. Clinical recognition of ARDS ranged from 51.3% (95% CI, 47.5%-55.0%) in mild to 78.5% (95% CI, 74.8%-81.8%) in severe ARDS. Less than two-thirds of patients with ARDS received a tidal volume 8 of mL/kg or less of predicted body weight. Plateau pressure was measured in 40.1% (95% CI, 38.2-42.1), whereas 82.6% (95% CI, 81.0%-84.1%) received a positive end-expository pressure (PEEP) of less than 12 cm H2O. Prone positioning was used in 16.3% (95% CI, 13.7%-19.2%) of patients with severe ARDS. Clinician recognition of ARDS was associated with higher PEEP, greater use of neuromuscular blockade, and prone positioning. Hospital mortality was 34.9% (95% CI, 31.4%-38.5%) for those with mild, 40.3% (95% CI, 37.4%-43.3%) for those with moderate, and 46.1% (95% CI, 41.9%-50.4%) for those with severe ARDS.

CONCLUSIONS AND RELEVANCE

Among ICUs in 50 countries, the period prevalence of ARDS was 10.4% of ICU admissions. This syndrome appeared to be underrecognized and undertreated and associated with a high mortality rate. These findings indicate the potential for improvement in the management of patients with ARDS.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02010073.

Ventilator setting in ICUs: comparing a Dutch with a European cohort

BACKGROUND

From data collected during the third International Study on Mechanical Ventilation (ISMV), we compared data from a Dutch cohort with a European cohort. We hypothesised that tidal volumes were smaller and applied positive end-expiratory pressure (PEEP) was higher in the Netherlands, compared with the European cohort. We also compared use of non-invasive ventilation (NIV) and outcomes in both cohorts.

METHODS

A post-hoc analysis of a prospective observational study of patients receiving mechanical ventilation.

RESULTS

Tidal volumes were smaller (7.6 vs. 8.1 ml÷kg predicted bodyweight) in the Dutch cohort and applied PEEP was higher (8 vs. 6 cm H2O). Fewer patients admitted in the Netherlands received NIV as first mode of mechanical ventilation (7.1 vs. 16.7%). Fewer patients in the Dutch cohort developed an ICU-acquired pneumonia (4.5 vs. 12.3%, p < 0.01) and sepsis (5.7 vs. 10.9%, p = 0.03), but more patients were diagnosed as having delirium (15.8 vs. 4.6%, p < 0.01). ICU and in-hospital mortality rates were 19% and 25%, respectively, in Dutch ICUs vs. 26% and 33% in Europe (p = 0.06 and 0.03).

CONCLUSION

Tidal volumes were smaller and applied PEEP was higher in the Dutch cohort compared with international data, but both Dutch and international patients received larger tidal volumes than recommended for prevention or treatment of acute respiratory distress syndrome. NIV as first mode of mechanical ventilation is less commonly used in the Netherlands. The incidence of ICU-acquired pneumonia is lower and of delirium higher in the Netherlands compared with international data.

Streptococcus pneumoniae translocates into the myocardium and forms unique microlesions that disrupt cardiac function

Hospitalization of the elderly for invasive pneumococcal disease is frequently accompanied by the occurrence of an adverse cardiac event; these are primarily new or worsened heart failure and cardiac arrhythmia. Herein, we describe previously unrecognized microscopic lesions (microlesions) formed within the myocardium of mice, rhesus macaques, and humans during bacteremic Streptococcus pneumoniae infection. In mice, invasive pneumococcal disease (IPD) severity correlated with levels of serum troponin, a marker for cardiac damage, the development of aberrant cardiac electrophysiology, and the number and size of cardiac microlesions. Microlesions were prominent in the ventricles, vacuolar in appearance with extracellular pneumococci, and remarkable due to the absence of infiltrating immune cells. The pore-forming toxin pneumolysin was required for microlesion formation but Interleukin-1β was not detected at the microlesion site ruling out pneumolysin-mediated pyroptosis as a cause of cell death. Antibiotic treatment resulted in maturing of the lesions over one week with robust immune cell infiltration and collagen deposition suggestive of long-term cardiac scarring. Bacterial translocation into the heart tissue required the pneumococcal adhesin CbpA and the host ligands Laminin receptor (LR) and Platelet-activating factor receptor. Immunization of mice with a fusion construct of CbpA or the LR binding domain of CbpA with the pneumolysin toxoid L460D protected against microlesion formation. We conclude that microlesion formation may contribute to the acute and long-term adverse cardiac events seen in humans with IPD.

Weaning from mechanical ventilation: why are we still looking for alternative methods?

Most patients who require mechanical ventilation for longer than 24 hours, and who improve the condition leading to the indication of ventilatory support, can be weaned after passing a first spontaneous breathing test. The challenge is to improve the weaning of patients who fail that first test. We have methods that can be referred to as traditional, such as the T-tube, pressure support or synchronized intermittent mandatory ventilation (SIMV). In recent years, however, new applications of usual techniques as noninvasive ventilation, new ventilation methods such as automatic tube compensation (ATC), mandatory minute ventilation (MMV), adaptive support ventilation or automatic weaning systems based on pressure support have been described. Their possible role in weaning from mechanical ventilation among patients with difficult or prolonged weaning remains to be established.