Efficacy and Safety of Early Administration of 4-Factor Prothrombin Complex Concentrate in Patients With Trauma at Risk of Massive Transfusion: The PROCOAG Randomized Clinical Trial.

Importance: Optimal transfusion strategies in traumatic hemorrhage are unknown. Reports suggest a beneficial effect of 4-factor prothrombin complex concentrate (4F-PCC) on blood product consumption. Objective: To investigate the efficacy and safety of 4F-PCC administration in patients at risk of massive transfusion. Design, Setting, and Participants: Double-blind, randomized, placebo-controlled superiority trial in 12 French designated level I trauma centers from December 29, 2017, to August 31, 2021, involving consecutive patients with trauma at risk of massive transfusion. Follow-up was completed on August 31, 2021. Interventions: Intravenous administration of 1 mL/kg of 4F-PCC (25 IU of factor IX/kg) vs 1 mL/kg of saline solution (placebo). Patients, investigators, and data analysts were blinded to treatment assignment. All patients received early ratio-based transfusion (packed red blood cells:fresh frozen plasma ratio of 1:1 to 2:1) and were treated according to European traumatic hemorrhage guidelines. Main Outcomes and Measures: The primary outcome was 24-hour all blood product consumption (efficacy); arterial or venous thromboembolic events were a secondary outcome (safety). Results: Of 4313 patients with the highest trauma level activation, 350 were eligible for emergency inclusion, 327 were randomized, and 324 were analyzed (164 in the 4F-PCC group and 160 in the placebo group). The median (IQR) age of participants was 39 (27-56) years, Injury Severity Score was 36 (26-50 [major trauma]), and admission blood lactate level was 4.6 (2.8-7.4) mmol/L; prehospital arterial systolic blood pressure was less than 90 mm Hg in 179 of 324 patients (59%), 233 patients (73%) were men, and 226 (69%) required expedient hemorrhage control. There was no statistically or clinically significant between-group difference in median (IQR) total 24-hour blood product consumption (12 [5-19] U in the 4F-PCC group vs 11 [6-19] U in the placebo group; absolute difference, 0.2 U [95% CI, -2.99 to 3.33]; P = .72). In the 4F-PCC group, 56 patients (35%) presented with at least 1 thromboembolic event vs 37 patients (24%) in the placebo group (absolute difference, 11% [95% CI, 1%-21%]; relative risk, 1.48 [95% CI, 1.04-2.10]; P = .03). Conclusions and Relevance: Among patients with trauma at risk of massive transfusion, there was no significant reduction of 24-hour blood product consumption after administration of 4F-PCC, but thromboembolic events were more common. These findings do not support systematic use of 4F-PCC in patients at risk of massive transfusion. Trial Registration: ClinicalTrials.gov Identifier: NCT03218722.

Ultrasound guidance for urgent arterial and venous catheterisation: randomised controlled study.

BACKGROUND: Haemodynamically unstable patients often require arterial and venous catheter insertion urgently. We hypothesised that ultrasound-guided arterial and venous catheterisation would reduce mechanical complications. METHODS: We performed a prospective RCT, where patients requiring both urgent arterial and venous femoral catheterisation were randomised to either ultrasound-guided or landmark-guided catheterisation. Complications and characteristics of catheter insertion (procedure duration, number of punctures, and procedure success) were recorded at the time of insertion (immediate complications). Late complications were investigated by ultrasound examination performed between the third and seventh days after randomisation. Primary outcome was the proportion of patients with at least one mechanical complication (immediate or late), by intention-to-treat analysis. Secondary outcomes included success rate, procedure time, and number of punctures. RESULTS: We analysed 136 subjects (102 [75%] male; age range: 27-62 yr) by intention to treat. The proportion of subjects with one or more complications was lower in 22/67 (33%) subjects undergoing ultrasound-guided catheterisation compared with landmark-guided catheterisation (40/69 [58%]; odds ratio: 0.35 [95% confidence interval: 0.18-0.71]; P=0.003). Ultrasound-guided catheterisation reduced both immediate (27%, compared with 51% in the landmark approach group; P=0.004) and late (10%, compared with 23% in the landmark approach group; P=0.047) complications. Ultrasound guidance also reduced the proportion of patients who developed deep vein thrombosis (4%, compared with 22% following landmark approach; P=0.012), and achieved a higher procedural success rate (96% vs 78%; P=0.004). CONCLUSIONS: An ultrasound-guided approach reduced mechanical complications after urgent femoral arterial and venous catheterisation, while increasing procedural success. CLINICAL TRIAL REGISTRATION: NCT02820909.

A Comparison of the Mortality Risk Associated With Ventilator-Acquired Bacterial Pneumonia and Nonventilator ICU-Acquired Bacterial Pneumonia.

OBJECTIVES: To investigate the respective impact of ventilator-associated pneumonia and ICU-hospital-acquired pneumonia on the 30-day mortality of ICU patients. DESIGN: Longitudinal prospective studies. SETTING: French ICUs. PATIENTS: Patients at risk of ventilator-associated pneumonia and ICU-hospital-acquired pneumonia. INTERVENTIONS: The first three episodes of ventilator-associated pneumonia or ICU-hospital-acquired pneumonia were handled as time-dependent covariates in Cox models. We adjusted using the case-mix, illness severity, Simplified Acute Physiology Score II score at admission, and procedures and therapeutics used during the first 48 hours before the risk period. Baseline characteristics of patients with regard to the adequacy of antibiotic treatment were analyzed, as well as the Sequential Organ Failure Assessment score variation in the 2 days before the occurrence of ventilator-associated pneumonia or ICU-hospital-acquired pneumonia. Mortality was also analyzed for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species(ESKAPE) and P. aeruginosa pathogens. MEASUREMENTS AND MAIN RESULTS: Of 14,212 patients who were admitted to the ICUs and who stayed for more than 48 hours, 7,735 were at risk of ventilator-associated pneumonia and 9,747 were at risk of ICU-hospital-acquired pneumonia. Ventilator-associated pneumonia and ICU-hospital-acquired pneumonia occurred in 1,161 at-risk patients (15%) and 176 at-risk patients (2%), respectively. When adjusted on prognostic variables, ventilator-associated pneumonia (hazard ratio, 1.38 (1.24-1.52); p < 0.0001) and even more ICU-hospital-acquired pneumonia (hazard ratio, 1.82 [1.35-2.45]; p < 0.0001) were associated with increased 30-day mortality. The early antibiotic therapy adequacy was not associated with an improved prognosis, particularly for ICU-hospital-acquired pneumonia. The impact was similar for ventilator-associated pneumonia and ICU-hospital-acquired pneumonia mortality due to P. aeruginosa and the ESKAPE group. CONCLUSIONS: In a large cohort of patients, we found that both ICU-hospital-acquired pneumonia and ventilator-associated pneumonia were associated with an 82% and a 38% increase in the risk of 30-day mortality, respectively. This study emphasized the importance of preventing ICU-hospital-acquired pneumonia in nonventilated patients.

Influence of dyskalemia at admission and early dyskalemia correction on survival and cardiac events of critically ill patients.

OBJECTIVES: Our objectives were (1) to characterize the distribution of serum potassium levels at ICU admission, (2) to examine the relationship between dyskalemia at ICU admission and occurrence of cardiac events, and (3) to study both the association between dyskalemia at ICU admission and dyskalemia correction by day 2 on 28-day mortality. DESIGN: Inception cohort study from the longitudinal prospective French multicenter OUTCOMEREA database (1999-2014) SETTING: 22 French OUTCOMEREA network ICUs PATIENTS: Patients were classified into six groups according to their serum potassium level at admission: three groups of hypokalemia and three groups of hyperkalemia defined as serious hypokalemia [K+] < 2.5 and serious hyperkalemia [K+] > 7 mmol/L, moderate hypokalemia 2.5 ≤ [K+] < 3 mmol/L and moderate hyperkalemia 6 < [K+] ≤ 7 mmol/L, and mild hypokalemia 3 ≤ [K+] < 3.5 mmol/L and mild hyperkalemia 5 < [K+] ≤ 6 mmol/L. We sorted evolution at day 2 of dyskalemia into three categories: balanced, not-balanced, and overbalanced. INTERVENTION: None MEASUREMENTS AND MAIN RESULTS: Of 12,090 patients, 2108 (17.4%) had hypokalemia and 1445 (12%) had hyperkalemia. Prognostic impact of dyskalemia and its correction was assessed using multivariate Cox models. After adjustment, hypokalemia and hyperkalemia were independently associated with a greater risk of 28-day mortality. Mild hyperkalemic patients had the highest mortality (hazard ratio (HR) 1.29, 95% confidence interval (CI) [1.13-1.47], p < 0.001). Adjusted 28-day mortality was higher if serum potassium level was not-balanced at day 2 (aHR = 1.51, 95% CI [1.30-1.76], p < 0.0001) and numerically higher but not significantly different if serum potassium level was overbalanced at day 2 (aHR = 1.157, 95% CI [0.84-1.60], p = 0.38). Occurrence of cardiac events was evaluated by logistic regression. Except for patients with serious hypokalemia at admission, the depth of dyskalemia was associated with increased risk of cardiac events. CONCLUSIONS: Dyskalemia is common at ICU admission and associated with increased mortality. Occurrence of cardiac events increased with dyskalemia depth. A correction of serum potassium level by day 2 was associated with improved prognosis.

Association Between Body Weight Variation and Survival and Other Adverse Events in Critically Ill Patients With Shock: A Multicenter Cohort Study of the OUTCOMEREA Network.

OBJECTIVES: This study in critically ill patients with shock assessed the prognostic value of body weight variations occurring each day from day 3 to day 7 on the 30-day outcome in terms of mortality, occurrence of ventilator-associated pneumonia and of bedsore, and occurrence of length of stay. DESIGN: Retrospective analysis of data. Multivariate subdistribution survival models were used at each day, from day 3 to day 7. The impact of body weight variations on length of stay was estimated through a multivariate negative binomial regression model. SETTING: Prospective multicenter cohort study. PATIENTS: Critically ill patients admitted in ICU with shock and requiring mechanical ventilation within 48 hours. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Two-thousand three-hundred seventy-four patients were included. Their median body weight variations increased from 0.4 kg (interquartile range, 0-4.8 kg) on day 3 to 3 kg (interquartile range, -0.4 to 8.2 kg) on day 7. Categories of body weight variations were defined depending on body weight variations interquartiles: weight loss, no weight gain, moderate and severe weight gain. A severe weight gain tended to be associated with death at days 5 and 6 (day 5: subdistribution hazard ratio, 1.27; 95% CI, 0.99-1.63; p = 0.06 and day 6: subdistribution hazard ratio, 1.43; 95% CI, 1.08-1.89; p = 0.01), a weight loss tended to be associated with bedsore, and a severe gain between at days 5 and 6 was associated with ventilator-associated pneumonia. Any body weight variations were associated with an increased length of stay. CONCLUSIONS: In survivors at day 3, body weight variations during the first days of ICU stay might be a clinically relevant tool to prevent weight gain but also for prognostication of 30-day mortality, occurrence of ventilator-associated pneumonia, and occurrence of prolonged ICU stay.

Diabetes was the only comorbid condition associated with mortality of invasive pneumococcal infection in ICU patients: a multicenter observational study from the Outcomerea research group.

PURPOSES: Streptococcus pneumoniae is a leading pathogen of severe community, hospital or nursing facility infections. We sought to describe characteristics of invasive pneumococcal infection (IPI) and pneumonia (due to the high mortality of intensive care-associated pneumonia) and to report outcomes according to various types of comorbidity. METHODS: Multicenter observational cohort study on the prospective Outcomerea database, including adult patients, with a hospital stay < 48 h before ICU admission and a documented IPI within the first 72 h of ICU admission. Comorbid conditions were defined according to the Knaus and Charlson classification. RESULTS: Of the 20,235 patients, 5310 (26.4%) had an invasive infection, including 560/5,310 (10.6%) who had an IPI. The ICU 28-day mortality was 109/560 (19.8%). Four factors were independently associated with mortality: SOFA day 1-2: [hazard ratio (HR) 1.21; 95% confidence interval (95% CI) 1.15-1.27, p < 0.001]; maximum lactate level day 1-2: (HR 1.07, 95% CI 1.02-1.12, p = 0.006); diabetes mellitus: (HR 1.91, 95% CI 1.23-3.03, p = 0.006) and appropriate antibiotics (HR 0.28, 95% CI 0.15-0.50, p < 0.001). Comparable results were obtained when other comorbid conditions were forced into the model. Diabetes impact was more pronounced in case of micro- or macro-angiopathy (HR 4.17, 95%CI 1.68-10.54, p = 0.003), in patients ≥ 65 years old (HR 2.59, 95% CI 1.56-4.28, < 0.001) and in those with body mass index (BMI) < 25 kg/m2 (HR 2.11, 95% CI 1.10-4.06, p = 0.025). CONCLUSIONS: Diabetes mellitus was the only comorbid condition which independently influenced mortality in patients with IPI. Its impact was more pronounced in patients with complications, aged ≥ 65 years and with BMI < 25 kg/m2.

Uncontrolled donation after circulatory death: comparison of two kidney preservation protocols on graft outcomes.

BACKGROUND: Kidney transplantation following uncontrolled donation after circulatory death (uDCD) presents a high risk of delayed graft function due to prolonged warm ischemia time. In order to minimise the effects of ischemia/reperfusion injury during warm ischemia, normothermic recirculation recently replaced in situ perfusion prior to implantation in several institutions. The aim of this study was to compare these preservation methods on kidney graft outcomes. METHODS: The primary endpoint was the one-year measured graft filtration rate (mGFR). We collected retrospective data from 64 consecutive uDCD recipients transplanted over a seven-year period in a single centre. RESULTS: Thirty-two grafts were preserved by in situ perfusion and 32 by normothermic recirculation. The mean ± SD mGFR at 1 year post-transplantation was 43.0 ± 12.8 mL/min/1.73 m2 in the in situ perfusion group and 53.2 ± 12.8 mL/min/1.73 m2 in the normothermic recirculation group (p = 0.01). Estimated GFR levels were significantly higher in the normothermic recirculation group at 12 months (p = 0.01) and 24 months (p = 0.03) of follow-up. We did not find any difference between groups regarding patient and graft survival, delayed graft function, graft rejection, or interstitial fibrosis. CONCLUSIONS: Function of grafts preserved by normothermic recirculation was better at 1 year and the results suggest that this persists at 2 years, although no difference was found in short-term outcomes. Despite the retrospective design, this study provides an additional argument in favour of normothermic recirculation.

Effect of Transfusion on Mortality and Other Adverse Events Among Critically Ill Septic Patients: An Observational Study Using a Marginal Structural Cox Model.

OBJECTIVES: RBC transfusion is often required in patients with sepsis. However, adverse events have been associated with RBC transfusion, raising safety concerns. A randomized controlled trial validated the 7 g/dL threshold, but previously transfused patients were excluded. Cohort studies led to conflicting results and did not handle time-dependent covariates and history of treatment. Additional data are thus warranted to guide patient's management. DESIGN: To estimate the effect of one or more RBC within 1 day on three major outcomes (mortality, ICU-acquired infections, and severe hypoxemia) at day 30, we used marginal structural models. A trajectory modeling, based on hematocrit evolution pattern, allowed identification of subgroups. Secondary analyses were performed into each of them. SETTING: A prospective French multicenter database. PATIENTS: Patients with sepsis at admission. Patients with hemorrhagic shock at admission were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Overall, in our cohort of 6,016 patients, RBC transfusion was not associated with death (hazard ratio, 1.07; 95% CI, 0.88-1.30; p = 0.52). However, RBC transfusion was associated with increased occurrence of ICU-acquired infections (hazard ratio, 2.77; 95% CI, 2.33-3.28; p < 0.01) and of severe hypoxemia (hazard ratio, 1.29; 95% CI, 1.14-1.47; p < 0.01). A protective effect from death by the transfusion was found in the subgroup with the lowest hematocrit level (26 [interquartile range, 24-28]) (hazard ratio, 0.72; 95% CI, 0.55-0.95; p = 0.02). CONCLUSIONS: RBC transfusion did not affect overall mortality in critically ill patients with sepsis. Increased occurrence rate of ICU-acquired infection and severe hypoxemia are expected outcomes from RBC transfusion that need to be weighted with its benefits in selected patients.

Colonization and infection with extended-spectrum ß-lactamase-producing Enterobacteriaceae in ICU patients: what impact on outcomes and carbapenem exposure?

OBJECTIVES: It remains uncertain whether colonization and infection with ESBL-producing Enterobacteriaceae (ESBL-PE) affect the outcomes for ICU patients. Our objectives were to measure the effects of ESBL-PE carriage and infection on mortality, ICU length of stay (LOS) and carbapenem exposure in this population. METHODS: A cause-specific hazard model based on prospectively collected data was built to assess the impact of ESBL-PE colonization and infection on competing risks of death and ICU discharge at day 28 in a multicentre cohort of ICU patients. Carbapenem exposure during the ICU stay was compared between infected carriers, uninfected carriers and non-carriers. RESULTS: Among the 16,734 included patients, 594 (3.5%) were ESBL-PE carriers, including 98 (16.4%) with one or more ESBL-PE infections during the ICU stay. After adjustment for baseline and time-dependent confounders, ESBL-PE infections increased the probability of death at day 28 [adjusted cause-specific hazard ratio (aCSHR), 1.825, 95% CI 1.235-2.699, P = 0.0026] and the ICU LOS (aCSHR for discharge alive at day 28, 0.563, 95% CI 0.432-0.733, P < 0.0001). ESBL-PE carriage without infection extended the LOS (aCSHR, 0.623, 95% CI, 0.553-0.702, P < 0.0001), without affecting mortality (aCSHR, 0.906, 95% CI, 0.722-1.136, P = 0.3916). Carbapenem exposure increased in both infected and uninfected carriers when compared with non-carriers (627, 241 and 69 carbapenem days per 1000 patient days, respectively, P < 0.001). CONCLUSIONS: ESBL-PE infections increased carbapenem consumption, LOS and day 28 mortality. ESBL-PE infections were rather infrequent in carriers; however, even ESBL-PE carriage without infection increased carbapenem exposure and delayed discharge, thereby amplifying the selective pressure and the colonization pressure in the ICU.

Surface-enhanced nitrate photolysis on ice.

Heterogeneous nitrate photolysis is the trigger for many chemical processes occurring in the polar boundary layer and is widely believed to occur in a quasi-liquid layer (QLL) at the surface of ice. The dipole-forbidden character of the electronic transition relevant to boundary layer atmospheric chemistry and the small photolysis/photoproduct yields in ice (and in water) may confer a significant enhancement and interfacial specificity to this important photochemical reaction at the surface of ice. Using amorphous solid water films at cryogenic temperatures as models for the disordered interstitial air-ice interface within the snowpack suppresses the diffusive uptake kinetics, thereby prolonging the residence time of nitrate anions at the surface of ice. This approach allows their slow heterogeneous photolysis kinetics to be studied, providing the first direct evidence that nitrates adsorbed onto the first molecular layer at the surface of ice are photolyzed more effectively than those dissolved within the bulk. Vibrational spectroscopy allows the ∼3-fold enhancement in photolysis rates to be correlated with the nitrates' distorted intramolecular geometry, thereby hinting at the role played by the greater chemical heterogeneity in their solvation environment at the surface of ice than that in the bulk. A simple 1D kinetic model suggests (1) that a 3(6)-fold enhancement in photolysis rate for nitrates adsorbed onto the ice surface could increase the photochemical NO2 emissions from a 5(8) nm thick photochemically active interfacial layer by 30(60)%, and (2) that 25(40)% of the NO2 photochemical emissions to the snowpack interstitial air are released from the topmost molecularly thin surface layer on ice. These findings may provide a new paradigm for heterogeneous (photo)chemistry at temperatures below those required for a QLL to form at the ice surface.

Safety of intrahospital transport in ventilated critically ill patients: a multicenter cohort study*.

OBJECTIVES: To describe intrahospital transport complications in critically ill patients receiving invasive mechanical ventilation. DESIGN: Prospective multicenter cohort study. SETTING: Twelve French ICUs belonging to the OUTCOMEREA study group. PATIENTS: Patients older than or equal to 18 years old admitted in the ICU and requiring invasive mechanical ventilation between April 2000 and November 2010 were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Six thousand two hundred forty-two patients on invasive mechanical ventilation were identified in the OUTCOMEREA database. The statistical analysis included a description of demographic and clinical characteristics of the cohort, identification of risk factors for intrahospital transport and construction of an intrahospital transport propensity score, and an exposed/unexposed study to compare complication of intrahospital transport (excluding transport to the operating room) after adjustment on the propensity score, length of stay, and confounding factors on the day before intrahospital transport. Three thousand and six intrahospital transports occurred in 1,782 patients (28.6%) (1-17 intrahospital transports/patient). Transported patients had higher admission Simplified Acute Physiology Score II values (median [interquartile range], 51 [39-65] vs 46 [33-62], p < 10) and longer ICU stay lengths (12 [6-23] vs 5 [3-11] d, p < 10). Post-intrahospital transport complications were recorded in 621 patients (37.4%). We matched 1,659 intrahospital transport patients to 3,344 nonintrahospital transport patients according to the intrahospital transport propensity score and previous ICU stay length. After adjustment, intrahospital transport patients were at higher risk for various complications (odds ratio = 1.9; 95% CI, 1.7-2.2; p < 10), including pneumothorax, atelectasis, ventilator-associated pneumonia, hypoglycemia, hyperglycemia, and hypernatremia. Intrahospital transport was associated with a longer ICU length of stay but had no significant impact on mortality. CONCLUSIONS: Intrahospital transport increases the risk of complications in ventilated critically ill patients. Continuous quality improvement programs should include specific procedures to minimize intrahospital transport-related risks.

Spectroscopic study of HNO3 dissociation on ice.

A detailed spectroscopic study of HNO(3):H(2)O binary amorphous mixtures, and of the adsorption of HNO(3) onto ice, is reported. Using a classical optics model, the extent of intermixing and of ionic dissociation of adsorbed HNO(3), which forms a strong acid with liquid water, is determined as a function of HNO(3) coverage and temperature. Even at temperatures as low as 45 K, where intermixing is limited to at most a few molecular layers at the interface, ionic dissociation of adsorbed HNO(3) is observed to be extensive. While some amount of molecularly adsorbed HNO(3) is observed at the surface of ice at 45 K, its ionic dissociation occurs irreversibly upon heating the ice substrate to 120 K. The molecularly adsorbed state of HNO(3) is not restored upon cooling, suggesting HNO(3) is a metastable entity at the surface of ice. Therefore, despite ionic dissociation of HNO(3) being thermodynamically favored, it appears to be kinetically inhibited at the surface of amorphous solid water at temperatures below 120 K.

Oil droplet formation and vertical transport in the upper ocean.

The dispersion of oil droplets near ocean surface is important for evaluating the impact to the environment. Under breaking wave conditions, the surface oil experiences mainly two processes: the generation of oil droplets at/near the water surface, and the transport of oil droplets due to ocean dynamics. We investigated the vertical behavior by incorporating the transport equation and the VDROP model. The transport equation adopted the ocean dynamics by K-profile parameterization (KPP) and the impact of additional turbulence by imposing the energy dissipation rate on the ocean surface. The oil droplet distribution was obtained, and the entrained distribution and entrainment rate was computed. The results shows that although the entrained distribution and the entrainment rate shares certain consistency with previous studies, divergences are also noticed. Accordingly, the model that describes the physics should be adopted to avoid incorrect qualification of the oil concentration dispersed in the ocean.

HCl adsorption on ice at low temperature: a combined X-ray absorption, photoemission and infrared study.

The reaction of HCl on water ice provides a simple case for understanding dissociation and proton transfer in this non-optimal, incomplete solvation environment, playing a central role in atmospheric chemistry. This reaction has been repeatedly reported as thermally dependent, whereas the theoretical models predict a spontaneous dissociation. We examine the adsorption of HCl on ice at low temperature (50 K and 90 K) via a combination of near-edge X-ray absorption spectroscopy (NEXAFS) at the chlorine L-edge, photoemission (XPS and UPS), and reflection-adsorption infrared spectroscopy (FT-RAIRS). We show the complete dissociation of HCl into Cl(-) and H(+) through 3 hydrogen bonds, predominantly by direct reaction with water (80%) and by self-solvation (20%), in full agreement with the prediction of a barrierless process.

Strong intermolecular coupling between the HF stretching and H2O bending vibrations in HF:H2O binary amorphous solids: breakdown of the electrostatic description of the hydrogen bond.

The coupling mechanism between the HF stretching and H(2)O bending vibrations observed in the infrared spectra of HF:H(2)O binary amorphous solids is analyzed using a simple cluster model. The intermolecular vibrational coupling derived from electrostatic potentials is one order of magnitude smaller, and of the opposite sign, than that obtained from electronic structure-based potentials. This highlights the distinctively covalent character of strong H-bonds and unveils fundamental weaknesses of electrostatic descriptions of vibrational energy transfer in liquid water and aqueous solutions.

Evolution of Practices in a French Trauma Centre: Decrease in Blood Transfusions and Fresh Frozen Plasma to Red Blood Cell Ratios.

OBJECTIVE: The aim of this study was to describe the evolution of transfusion practices following the introduction of tranexamic acid (TXA) and ROTEMVR in a trauma resuscitation unit (TRU) from a French teaching hospital (FTH). METHODS: This is a single-centre, retrospective study at a TRU from a FTH. All trauma patients aged 18 years or more and transfused with at least 4 red blood cells (RBCs) within 24 hours after trauma, from 2011 to 2016, were included. The primary objective was to analyse transfusion practices over this time period. The secondary objectives aimed at assessing differences between populations according to the fresh frozen plasma (FFP):RBC ratio applied. RESULTS: A total of 122 patients were included. There was a significant decrease in the proportion of patients requiring at least 4 RBCs 24 hours after trauma (9% vs. 3%, P trend < .0001) as well as a decrease in the proportion of patients with a high FFP:RBC ratio (86% vs. 62% at 6 hours, P trend » .0056 and 86% vs. 56% at 24 hours, P trend » .0047). After 2013, fibrinogen was administered to more than 70% of patients and TXA to 100% of them. The observed mortality was lower than the predicted one, irrespective of FFP:RBC ratio. CONCLUSION: An important evolution of practices occurred including a decrease in the proportion of transfusions and use of high FFP:RBC ratios. The origin of these changes is multifactorial, likely including the systematic use of TXA and optimisation of the ROTEM protocol for fibrinogen administration.

Factors Associated with Clostridioides (Clostridium) Difficile Infection and Colonization: Ongoing Prospective Cohort Study in a French University Hospital.

INTRODUCTION: Clostridioides (Clostridium) difficile can be isolated from stool in 3% of healthy adults and in at least 10% of asymptomatic hospitalized patients. C. difficile, the most common cause of hospital-acquired infectious diarrhea in the developed world, has re-emerged in recent years with increasing incidence and severity. In an effort to reduce the spread of the pathogen, published recommendations suggest isolation and contact precautions for patients suffering from C. difficile infection (CDI). However, asymptomatic colonized patients are not targeted by infection control policies, and active surveillance for colonization is not routinely performed. Moreover, given the current changes in the epidemiology of CDI, particularly the emergence of new virulent strains either in the hospital or community settings, there is a need for identification of factors associated with colonization by C. difficile and CDI. Methods and analysis: We are carrying out a prospective, observational, cohort study in Edouard Herriot Hospital, Hospices Civils de Lyon, a 900-bed university hospital in Lyon, France. All consecutive adult patients admitted on selected units are eligible to participate in the study. Stool samples or rectal swabs for C. difficile testing are obtained on admission, every 3-5 days during hospitalization, at the onset of diarrhea (if applicable), and at discharge. Descriptive and logistic regression analyses will be completed to mainly estimate the proportion of asymptomatic colonization at admission, and to evaluate differences between factors associated with colonization and those related to CDI. Ethics: The study is conducted in accordance with the ethical principles of the Declaration of Helsinki, French law, and the Good Clinical Practice guidelines. The study protocol design was approved by the participating units, the ethics committee and the hospital institutional review board (Comité de protection des personnes et Comission Nationale de l'Informatique et des Libertés; N°: 00009118). Dissemination: The results of this study will be disseminated by presenting the findings locally at each participating ward, as well as national and international scientific meetings. Findings will be shared with interested national societies crafting guidelines in CDI.

Life Support Limitations in Mechanically Ventilated Stroke Patients.

OBJECTIVES: The determinants of decisions to limit life support (withholding or withdrawal) in ventilated stroke patients have been evaluated mainly for patients with intracranial hemorrhages. We aimed to evaluate the frequency of life support limitations in ventilated ischemic and hemorrhagic stroke patients compared with a nonbrain-injured population and to determine factors associated with such decisions. DESIGN: Multicenter prospective French observational study. SETTING: Fourteen ICUs of the French OutcomeRea network. PATIENTS: From 2005 to 2016, we included stroke patients and nonbrain-injured patients requiring invasive ventilation within 24 hours of ICU admission. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: We identified 373 stroke patients (ischemic, n = 167 [45%]; hemorrhagic, n = 206 [55%]) and 5,683 nonbrain-injured patients. Decisions to limit life support were taken in 41% of ischemic stroke cases (vs nonbrain-injured patients, subdistribution hazard ratio, 3.59 [95% CI, 2.78-4.65]) and in 33% of hemorrhagic stroke cases (vs nonbrain-injured patients, subdistribution hazard ratio, 3.9 [95% CI, 2.97-5.11]). Time from ICU admission to the first limitation was longer in ischemic than in hemorrhagic stroke (5 [3-9] vs 2 d [1-6] d; p < 0.01). Limitation of life support preceded ICU death in 70% of ischemic strokes and 45% of hemorrhagic strokes (p < 0.01). Life support limitations in ischemic stroke were increased by a vertebrobasilar location (vs anterior circulation, subdistribution hazard ratio, 1.61 [95% CI, 1.01-2.59]) and a prestroke modified Rankin score greater than 2 (2.38 [1.27-4.55]). In hemorrhagic stroke, an age greater than 70 years (2.29 [1.43-3.69]) and a Glasgow Coma Scale score less than 8 (2.15 [1.08-4.3]) were associated with an increased risk of limitation, whereas a higher nonneurologic admission Sequential Organ Failure Assessment score was associated with a reduced risk (per point, 0.89 [0.82-0.97]). CONCLUSIONS: In ventilated stroke patients, decisions to limit life support are more than three times more frequent than in nonbrain-injured patients, with different timing and associated risk factors between ischemic and hemorrhagic strokes.

Clinical and biological clusters of sepsis patients using hierarchical clustering.

BACKGROUND: Heterogeneity in sepsis expression is multidimensional, including highly disparate data such as the underlying disorders, infection source, causative micro-organismsand organ failures. The aim of the study is to identify clusters of patients based on clinical and biological characteristic available at patients' admission. METHODS: All patients included in a national prospective multicenter ICU cohort OUTCOMEREA and admitted for sepsis or septic shock (Sepsis 3.0 definition) were retrospectively analyzed. A hierarchical clustering was performed in a training set of patients to build clusters based on a comprehensive set of clinical and biological characteristics available at ICU admission. Clusters were described, and the 28-day, 90-day, and one-year mortality were compared with log-rank rates. Risks of mortality were also compared after adjustment on SOFA score and year of ICU admission. RESULTS: Of the 6,046 patients with sepsis in the cohort, 4,050 (67%) were randomly allocated to the training set. Six distinct clusters were identified: young patients without any comorbidities, admitted in ICU for community-acquired pneumonia (n = 1,603 (40%)); young patients without any comorbidities, admitted in ICU for meningitis or encephalitis (n = 149 (4%)); elderly patients with COPD, admitted in ICU for bronchial infection with few organ failures (n = 243 (6%)); elderly patients, with several comorbidities and organ failures (n = 1,094 (27%)); patients admitted after surgery, with a nosocomial infection (n = 623 (15%)); young patients with immunosuppressive conditions (e.g., AIDS, chronic steroid therapy or hematological malignancy) (n = 338 (8%)). Clusters differed significantly in early or late mortality (p < .001), even after adjustment on severity of organ dysfunctions (SOFA) and year of ICU admission. CONCLUSIONS: Clinical and biological features commonly available at ICU admission of patients with sepsis or septic shock enabled to set up six clusters of patients, with very distinct outcomes. Considering these clusters may improve the care management and the homogeneity of patients in future studies.

Lack of recovery in monocyte human leukocyte antigen-DR expression is independently associated with the development of sepsis after major trauma.

INTRODUCTION: Major trauma is characterized by an overwhelming pro-inflammatory response and an accompanying anti-inflammatory response that lead to a state of immunosuppression, as observed after septic shock. Diminished monocyte Human Leukocyte Antigen DR (mHLA-DR) is a reliable marker of monocyte dysfunction and immunosuppression. The main objective of this study was to determine the relation between mHLA-DR expression in severe trauma patients and the development of sepsis. METHODS: We conducted a prospective observational study over 23 months in a trauma intensive care unit at a university hospital. Patients with an Injury Severity Score (ISS) over 25 and age over 18 were included. mHLA-DR was assessed by flow cytometry protocol according to standardized protocol. Mann-Whitney U-test for continuous non-parametric variables, independent paired t test for continuous parametric variables and chi-square test for categorical data were used. RESULTS: mHLA-DR was measured three times a week during the first 14 days. One hundred five consecutive severely injured patients were monitored (ISS 38 ± 17, SAPS II 37 ± 16). Thirty-seven patients (35%) developed sepsis over the 14 days post-trauma. At days 1-2, mHLA-DR was diminished in the whole patient population, with no difference with the development of sepsis. At days 3-4, a highly significant difference appeared between septic and non-septic patients. Non- septic patients showed an increase in mHLA-DR levels, whereas septic patients did not (13,723 ± 7,766 versus 9,271 ± 6,029 antibodies per cell, p = .004). Most importantly, multivariate logistic regression analysis, after adjustment for usual clinical confounders (adjusted OR 5.41, 95% CI 1.42-20.52), revealed that a slope of mHLA-DR expression between days1-2 and days 3-4 below 1.2 remained associated with the development of sepsis. CONCLUSIONS: Major trauma induced an immunosuppression, characterized by a decrease in mHLA-DR expression. Importantly, after multivariate regression logistic analysis, persistent decreased expression was assessed to be in relation with the development of sepsis. This is the first study in trauma patients showing a link between the lack of immune recovery and the development of sepsis on the basis of the standardized protocol. Monitoring immune function by mHLA-DR measurement could be useful to identify trauma patients at a high risk of infection.