Biogeographical patterns of the soil fungal:bacterial ratio across France.

Soils are one of the major reservoirs of biological diversity on our planet because they host a huge richness of microorganisms. The fungal:bacterial (F:B) ratio targets two major functional groups of organisms in soils and can improve our understanding of their importance and efficiency for soil functioning. To better decipher the variability of this ratio and rank the environmental parameters involved, we used the French Soil Quality Monitoring Network (RMQS)-one of the most extensive and a priori-free soil sampling surveys, based on a systematic 16 km × 16 km grid and including more than 2,100 samples. F:B ratios, measured by quantitative PCR targeting the 18S and 16S rDNA genes, turned out to be heterogenously distributed and spatially structured in geographical patterns across France. These distribution patterns differed from bacterial or fungal densities taken separately, supporting the hypothesis that the F:B ratio is not the mere addition of each density but rather results from the complex interactions of the two functional groups. The F:B ratios were mainly influenced by soil characteristics and land management. Among soil characteristics, the pH and, to a lesser extent, the organic carbon content and the carbon:nitrogen (C:N) ratio were the main drivers. These results improved our understanding of soil microbial communities, and from an operational point of view, they suggested that the F:B ratio should be a useful new bioindicator of soil status. The resulting dataset can be considered as a first step toward building up a robust repository essential to any bioindicator and aimed at guiding and helping decision making. IMPORTANCE In the face of human disturbances, microbial activity can be impacted and, e.g., can result in the release of large amounts of soil carbon into the atmosphere, with global impacts on temperature. Therefore, the development and the regular use of soil bioindicators are essential to (i) improve our knowledge of soil microbial communities and (ii) guide and help decision makers define suitable soil management strategies. Bacterial and fungal communities are key players in soil organic matter turnover, but with distinct physiological and ecological characteristics. The fungal:bacterial ratio targets these two major functional groups by investigating their presence and their equilibrium. The aim of our study is to characterize this ratio at a territorial scale and rank the environmental parameters involved so as to further develop a robust repository essential to the interpretation of any bioindicator of soil quality.

Potential of Meta-Omics to Provide Modern Microbial Indicators for Monitoring Soil Quality and Securing Food Production.

Soils are fundamental resources for agricultural production and play an essential role in food security. They represent the keystone of the food value chain because they harbor a large fraction of biodiversity-the backbone of the regulation of ecosystem services and "soil health" maintenance. In the face of the numerous causes of soil degradation such as unsustainable soil management practices, pollution, waste disposal, or the increasing number of extreme weather events, it has become clear that (i) preserving the soil biodiversity is key to food security, and (ii) biodiversity-based solutions for environmental monitoring have to be developed. Within the soil biodiversity reservoir, microbial diversity including Archaea, Bacteria, Fungi and protists is essential for ecosystem functioning and resilience. Microbial communities are also sensitive to various environmental drivers and to management practices; as a result, they are ideal candidates for monitoring soil quality assessment. The emergence of meta-omics approaches based on recent advances in high-throughput sequencing and bioinformatics has remarkably improved our ability to characterize microbial diversity and its potential functions. This revolution has substantially filled the knowledge gap about soil microbial diversity regulation and ecology, but also provided new and robust indicators of agricultural soil quality. We reviewed how meta-omics approaches replaced traditional methods and allowed developing modern microbial indicators of the soil biological quality. Each meta-omics approach is described in its general principles, methodologies, specificities, strengths and drawbacks, and illustrated with concrete applications for soil monitoring. The development of metabarcoding approaches in the last 20 years has led to a collection of microbial indicators that are now operational and available for the farming sector. Our review shows that despite the recent huge advances, some meta-omics approaches (e.g., metatranscriptomics or meta-proteomics) still need developments to be operational for environmental bio-monitoring. As regards prospects, we outline the importance of building up repositories of soil quality indicators. These are essential for objective and robust diagnosis, to help actors and stakeholders improve soil management, with a view to or to contribute to combining the food and environmental quality of next-generation farming systems in the context of the agroecological transition.

Impact of early nutrition route in patients receiving extracorporeal membrane oxygenation: A retrospective cohort study.

BACKGROUND: Early nutrition management in patients receiving extracorporeal membrane oxygenation (ECMO) remains controversial. Despite its potentially beneficial effect, enteral nutrition (EN) could be associated with gastrointestinal (GI) complications. Total daily energy requirements remain difficult to achieve with ECMO support. Analysis of nutrition practices could improve nutrition management of this particular population. METHODS: A monocentric retrospective study of patients requiring ECMO in a cardiac surgery intensive care unit (ICU) between 2010 and 2014 with follow-up ≥6 days. Nutrition support was monitored daily until ECMO weaning. We compared patients exposed (EN group, n = 49) and unexposed (No EN group (NEN), n = 63) with EN, as well as the energy and protein intakes within 4 days after initiation of ECMO. Vital status and nosocomial infections were followed up until ICU discharge. Primary outcome was the incidence of GI intolerance and risk-factor identification. Secondary outcomes included impact of nutrition inadequacy and clinical outcome. RESULTS: A total 112 patients were analyzed, representing 969 nutrition days. Median ratio of energy and protein prescribed/required daily was 81% (58-113) and 56% (36-86), respectively. GI intolerance was experienced by 53% (26 of 49) of patients in the EN group and was only associated with ECMO duration (odds ratio, 1.14: 95% CI, 1.00-1.31; P = .05). Low-energy and protein days were not associated with clinical outcomes such as nosocomial infections. CONCLUSION: EN is associated with almost 50% GI intolerance without clinical benefit for patients receiving ECMO. Adequacy in energy and protein amounts did not affect clinical outcome.

Evaluation of the impact of HMS Plus on postoperative blood loss compared with ACT Plus in cardiac surgery.

BACKGROUND: The standardized management of anticoagulation during the cardiopulmonary bypass seems inaccurate because of patients and surgeries variability. This study evaluates if an individualized management of heparin and protamine guided by the HMS Plus system during cardiopulmonary bypass could reduce postoperative blood loss. METHODS: We conducted a prospective, controlled, unblinded, single-center study. One-hundred and eighthy-eight patients operated for cardiac surgery were included. Patients were divided in ACT Plus group (standardized approach) and HMS Plus group (individualized approach). The primary outcome was blood-loss volume during the first 24 postoperative hours. The main secondary outcomes were the need for allogeneic blood transfusions and the final protamine/heparin ratio. RESULTS: There was no difference between the two groups for baseline characteristics. Medium blood-loss volume in the ACT Plus group was 522±260 mL vs. 527±255 mL in the HMS Plus group (P=0.58). The final protamine/heparin ratio in the ACT Plus group was 0.94±0.1 vs. 0.58±0.1 in the HMS Plus group (P<0.0001). The transfusion rate during surgery in the ACT Plus group was 25% vs. 14% in the HMS Plus group (P=0.09). CONCLUSIONS: HMS Plus did not reduce the mean blood-loss volume during the first 24 postoperative hours compared with ACT Plus. Its utility for potential transfusion rate reduction remains to be proven.

Compared Efficacy of Four Preoxygenation Methods for Intubation in the ICU: Retrospective Analysis of McGrath Mac Videolaryngoscope Versus Macintosh Laryngoscope (MACMAN) Trial Data.

OBJECTIVES: Severe hypoxemia is the most common serious adverse event during endotracheal intubation. Preoxygenation is performed routinely as a preventive measure. The relative efficacy of the various available preoxygenation devices is unclear. Here, our objective was to assess associations between preoxygenation devices and pulse oximetry values during endotracheal intubation. DESIGN: Post hoc analysis of data from a multicenter randomized controlled superiority trial (McGrath Mac Videolaryngoscope Versus Macintosh Laryngoscope [MACMAN]) comparing videolaryngoscopy to Macintosh laryngoscopy for endotracheal intubation in critical care. SETTING: Seven French ICUs. PATIENTS: Three-hundred nineteen of the 371 critically ill adults requiring endotracheal intubation who were included in the MACMAN trial. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Minimal pulse oximetry value during endotracheal intubation was the primary endpoint. We also sought risk factors for pulse oximetry below 90%. Of 319 patients, 157 (49%) had bag-valve-mask, 71 (22%) noninvasive ventilation, 71 (22%) non-rebreathing mask, and 20 (7%) high-flow nasal oxygen for preoxygenation. Factors independently associated with minimal pulse oximetry value were the Simplified Acute Physiology Score II severity score (p = 0.03), baseline pulse oximetry (p < 0.001), baseline PaO2/FIO2 ratio (p = 0.02), and number of laryngoscopies (p = 0.001). The only independent predictors of pulse oximetry less than 90% were baseline pulse oximetry (odds ratio, 0.71; 95% CI, 0.64-0.79; p < 0.001) and preoxygenation device: with bag-valve-mask as the reference, odds ratios were 1.10 (95% CI, 0.25-4.92) with non-rebreathing mask, 0.10 (95% CI, 0.01-0.80) with noninvasive ventilation, and 5.75 (95% CI, 1.15-28.75) with high-flow nasal oxygen. CONCLUSIONS: Our data suggest that the main determinants of hypoxemia during endotracheal intubation may be related to critical illness severity and to preexisting hypoxemia. The differences across preoxygenation methods suggest that noninvasive ventilation may deserve preference in patients with marked hypoxemia before endotracheal intubation. Ongoing studies will provide further clarification about the optimal preoxygenation method for endotracheal intubation in critically ill patients.

Video Laryngoscopy vs Direct Laryngoscopy on Successful First-Pass Orotracheal Intubation Among ICU Patients: A Randomized Clinical Trial.

Importance: In the intensive care unit (ICU), orotracheal intubation can be associated with increased risk of complications because the patient may be acutely unstable, requiring prompt intervention, often by a practitioner with nonexpert skills. Video laryngoscopy may decrease this risk by improving glottis visualization. Objective: To determine whether video laryngoscopy increases the frequency of successful first-pass orotracheal intubation compared with direct laryngoscopy in ICU patients. Design, Setting, and Participants: Randomized clinical trial of 371 adults requiring intubation while being treated at 7 ICUs in France between May 2015 and January 2016; there was 28 days of follow-up. Interventions: Intubation using a video laryngoscope (n = 186) or direct laryngoscopy (n = 185). All patients received general anesthesia. Main Outcomes and Measures: The primary outcome was the proportion of patients with successful first-pass intubation. The secondary outcomes included time to successful intubation and mild to moderate and severe life-threatening complications. Results: Among 371 randomized patients (mean [SD] age, 62.8 [15.8] years; 136 [36.7%] women), 371 completed the trial. The proportion of patients with successful first-pass intubation did not differ significantly between the video laryngoscopy and direct laryngoscopy groups (67.7% vs 70.3%; absolute difference, -2.5% [95% CI, -11.9% to 6.9%]; P = .60). The proportion of first-attempt intubations performed by nonexperts (primarily residents, n = 290) did not differ between the groups (84.4% with video laryngoscopy vs 83.2% with direct laryngoscopy; absolute difference 1.2% [95% CI, -6.3% to 8.6%]; P = .76). The median time to successful intubation was 3 minutes (range, 2 to 4 minutes) for both video laryngoscopy and direct laryngoscopy (absolute difference, 0 [95% CI, 0 to 0]; P = .95). Video laryngoscopy was not associated with life-threatening complications (24/180 [13.3%] vs 17/179 [9.5%] for direct laryngoscopy; absolute difference, 3.8% [95% CI, -2.7% to 10.4%]; P = .25). In post hoc analysis, video laryngoscopy was associated with severe life-threatening complications (17/179 [9.5%] vs 5/179 [2.8%] for direct laryngoscopy; absolute difference, 6.7% [95% CI, 1.8% to 11.6%]; P = .01) but not with mild to moderate life-threatening complications (10/181 [5.4%] vs 14/181 [7.7%]; absolute difference, -2.3% [95% CI, -7.4% to 2.8%]; P = .37). Conclusions and Relevance: Among patients in the ICU requiring intubation, video laryngoscopy compared with direct laryngoscopy did not improve first-pass orotracheal intubation rates and was associated with higher rates of severe life-threatening complications. Further studies are needed to assess the comparative effectiveness of these 2 strategies in different clinical settings and among operators with diverse skill levels. Trial Registration: clinicaltrials.gov Identifier: NCT02413723.

McGRATH MAC videolaryngoscope versus Macintosh laryngoscope for orotracheal intubation in intensive care patients: the randomised multicentre MACMAN trial study protocol.

INTRODUCTION: Critically ill patients with acute respiratory, neurological or cardiovascular failure requiring invasive mechanical ventilation are at high risk of difficult intubation and have organ dysfunctions associated with complications of intubation and anaesthesia such as hypotension and hypoxaemia. The complication rate increases with the number of intubation attempts. Videolaryngoscopy improves elective endotracheal intubation. McGRATH MAC is the lightest videolaryngoscope and the most similar to the Macintosh laryngoscope. The primary goal of this trial was to determine whether videolaryngoscopy increased the frequency of successful first-pass intubation in critically ill patients, compared to direct view Macintosh laryngoscopy. METHODS AND ANALYSIS: MACMAN is a multicentre, open-label, randomised controlled superiority trial. Consecutive patients requiring intubation are randomly allocated to either the McGRATH MAC videolaryngoscope or the Macintosh laryngoscope, with stratification by centre and operator experience. The expected frequency of successful first-pass intubation is 65% in the Macintosh group and 80% in the videolaryngoscope group. With α set at 5%, to achieve 90% power for detecting this difference, 185 patients are needed in each group (370 in all). The primary outcome is the proportion of patients with successful first-pass orotracheal intubation, compared between the two groups using a generalised mixed model to take the stratification factors into account. ETHICS AND DISSEMINATION: The study project has been approved by the appropriate ethics committee (CPP Ouest 2, # 2014-A00674-43). Informed consent is not required, as both laryngoscopy methods are considered standard care in France; information is provided before study inclusion. If videolaryngoscopy proves superior to Macintosh laryngoscopy, its use will become standard practice, thereby decreasing first-pass intubation failure rates and, potentially, the frequency of intubation-related complications. Thus, patient safety should benefit. Further studies would be warranted to determine whether videolaryngoscopy is also beneficial in the emergency room and for prehospital emergency care. TRIAL REGISTRATION NUMBER: NCT02413723; Pre-results.