High Airway Occlusion Pressure Is Associated with Dyspnea and Increased Mortality in Critically Ill Mechanically Ventilated Patients.

RATIONALE: 100 ms airway occlusion pressure (P0.1) reflects central respiratory drive. We aimed to assess factors associated with P0.1 and whether an abnormally low or high P0.1 value is associated with higher mortality and longer duration of mechanical ventilation (MV). METHODS: Secondary analysis of a prospective cohort study conducted in 10 intensive care units in France to evaluate dyspnea in communicative MV patients. In patients intubated for more than 24 hours, P0.1 was measured with dyspnea as soon as patients could communicate and the following day. RESULTS: 260 patients were assessed after a median time of ventilation of 4 days. P0.1 was 1.9 (1 - 3.5) cmH2O on enrollment, 24% had a P0.1 >3.5 cmH2O, 37% had a P0.1 between 1.5 and 3.5 cmH2O, and 39% had a P0.1 <1.5 cmH2O. In multivariable linear regression, independent factors associated with P0.1 level were presence of dyspnea (p=0.037), respiratory rate (p<0.001), and PaO2 (p=0.008). 90-day mortality was 33% in patients with P0.1 >3.5 cmH2O vs. 19% in those with a P0.1 between 1.5 and 3.5 cmH2O and 17% in patients with P0.1 <1.5 cmH2O (p=0.046). After adjustment for the main risk factors, P0.1 was associated with 90-day mortality (per cmH2O of P0.1, Hazard ratio 1.19, 95% Confidence interval 1.04 - 1.37, p=0.011). P0.1 was also independently associated with a longer duration of MV (per cmH2O of P0.1, Hazard ratio 1.10, 95% Confidence interval 1.02-1.19, p=0.016). CONCLUSIONS: In patients receiving invasive mechanical ventilation, abnormally high P0.1 values may suggest dyspnea and is associated with higher mortality and prolonged duration of MV.

Oesophageal pressure monitoring in intubated patients by intensive care units' nurses: An educational study.

BACKGROUND: Trained ICU nurses may perform oesophageal pressure measurements which may help facilitate its implementation in the usual patient care to better assess lung and chest wall mechanics and easily detect patient-ventilator asynchronies. AIM AND STUDY DESIGN: We thus conducted a prospective educational study aiming to assess the ability of ICU nurses to perform reliable oesophageal pressure measurements after a short dedicated training program. RESULTS: All the 11 nurses who completed the program succeeded their practical evaluation (nine (82%) at the first evaluation and two (18%) at their second attempt). CONCLUSION: These results show that this training program is feasible and that trained ICU nurses can perform accurate oesophageal pressure measurements in mechanically ventilated patients. RELEVANCE TO CLINICAL PRACTICE: Such training program may help to implement this technique in routine ICU care.

Bedside personalized methods based on electrical impedance tomography or respiratory mechanics to set PEEP in ARDS and recruitment-to-inflation ratio: a physiologic study.

BACKGROUND: Various Positive End-Expiratory Pressure (PEEP) titration strategies have been proposed to optimize ventilation in patients with acute respiratory distress syndrome (ARDS). We aimed to compare PEEP titration strategies based on electrical impedance tomography (EIT) to methods derived from respiratory system mechanics with or without esophageal pressure measurements, in terms of PEEP levels and association with recruitability. METHODS: Nineteen patients with ARDS were enrolled. Recruitability was assessed by the estimated Recruitment-to-Inflation ratio (R/Iest) between PEEP 15 and 5 cmH2O. Then, a decremental PEEP trial from PEEP 20 to 5 cmH2O was performed. PEEP levels determined by the following strategies were studied: (1) plateau pressure 28-30 cmH2O (Express), (2) minimal positive expiratory transpulmonary pressure (Positive PLe), (3) center of ventilation closest to 0.5 (CoV) and (4) intersection of the EIT-based overdistension and lung collapse curves (Crossing Point). In addition, the PEEP levels determined by the Crossing Point strategy were assessed using different PEEP ranges during the decremental PEEP trial. RESULTS: Express and CoV strategies led to higher PEEP levels than the Positive PLe and Crossing Point ones (17 [14-17], 20 [17-20], 8 [5-11], 10 [8-11] respectively, p < 0.001). For each strategy, there was no significant association between the optimal PEEP level and R/Iest (Crossing Point: r2 = 0.073, p = 0.263; CoV: r2 < 0.001, p = 0.941; Express: r2 < 0.001, p = 0.920; Positive PLe: r2 = 0.037, p = 0.461). The PEEP level obtained with the Crossing Point strategy was impacted by the PEEP range used during the decremental PEEP trial. CONCLUSIONS: CoV and Express strategies led to higher PEEP levels than the Crossing Point and Positive PLe strategies. Optimal PEEP levels proposed by these four methods were not associated with recruitability. Recruitability should be specifically assessed in ARDS patients to optimize PEEP titration.

A New Global Definition of Acute Respiratory Distress Syndrome.

Background: Since publication of the 2012 Berlin definition of acute respiratory distress syndrome (ARDS), several developments have supported the need for an expansion of the definition, including the use of high-flow nasal oxygen, the expansion of the use of pulse oximetry in place of arterial blood gases, the use of ultrasound for chest imaging, and the need for applicability in resource-limited settings. Methods: A consensus conference of 32 critical care ARDS experts was convened, had six virtual meetings (June 2021 to March 2022), and subsequently obtained input from members of several critical care societies. The goal was to develop a definition that would 1) identify patients with the currently accepted conceptual framework for ARDS, 2) facilitate rapid ARDS diagnosis for clinical care and research, 3) be applicable in resource-limited settings, 4) be useful for testing specific therapies, and 5) be practical for communication to patients and caregivers. Results: The committee made four main recommendations: 1) include high-flow nasal oxygen with a minimum flow rate of ⩾30 L/min; 2) use PaO2:FiO2 ⩽ 300 mm Hg or oxygen saturation as measured by pulse oximetry SpO2:FiO2 ⩽ 315 (if oxygen saturation as measured by pulse oximetry is ⩽97%) to identify hypoxemia; 3) retain bilateral opacities for imaging criteria but add ultrasound as an imaging modality, especially in resource-limited areas; and 4) in resource-limited settings, do not require positive end-expiratory pressure, oxygen flow rate, or specific respiratory support devices. Conclusions: We propose a new global definition of ARDS that builds on the Berlin definition. The recommendations also identify areas for future research, including the need for prospective assessments of the feasibility, reliability, and prognostic validity of the proposed global definition.

Advanced respiratory mechanics assessment in mechanically ventilated obese and non-obese patients with or without acute respiratory distress syndrome.

BACKGROUND: Respiratory mechanics is a key element to monitor mechanically ventilated patients and guide ventilator settings. Besides the usual basic assessments, some more complex explorations may allow to better characterize patients' respiratory mechanics and individualize ventilation strategies. These advanced respiratory mechanics assessments including esophageal pressure measurements and complete airway closure detection may be particularly relevant in critically ill obese patients. This study aimed to comprehensively assess respiratory mechanics in obese and non-obese ICU patients with or without ARDS and evaluate the contribution of advanced respiratory mechanics assessments compared to basic assessments in these patients. METHODS: All intubated patients admitted in two ICUs for any cause were prospectively included. Gas exchange and respiratory mechanics including esophageal pressure and end-expiratory lung volume (EELV) measurements and low-flow insufflation to detect complete airway closure were assessed in standardized conditions (tidal volume of 6 mL kg-1 predicted body weight (PBW), positive end-expiratory pressure (PEEP) of 5 cmH2O) within 24 h after intubation. RESULTS: Among the 149 analyzed patients, 52 (34.9%) were obese and 90 (60.4%) had ARDS (65.4% and 57.8% of obese and non-obese patients, respectively, p = 0.385). A complete airway closure was found in 23.5% of the patients. It was more frequent in obese than in non-obese patients (40.4% vs 14.4%, p < 0.001) and in ARDS than in non-ARDS patients (30% vs. 13.6%, p = 0.029). Respiratory system and lung compliances and EELV/PBW were similarly decreased in obese patients without ARDS and obese or non-obese patients with ARDS. Chest wall compliance was not impacted by obesity or ARDS, but end-expiratory esophageal pressure was higher in obese than in non-obese patients. Chest wall contribution to respiratory system compliance differed widely between patients but was not predictable by their general characteristics. CONCLUSIONS: Most respiratory mechanics features are similar in obese non-ARDS and non-obese ARDS patients, but end-expiratory esophageal pressure is higher in obese patients. A complete airway closure can be found in around 25% of critically ill patients ventilated with a PEEP of 5 cmH2O. Advanced explorations may allow to better characterize individual respiratory mechanics and adjust ventilation strategies in some patients. Trial registration NCT03420417 ClinicalTrials.gov (February 5, 2018).

A new reservoir-based CPAP with low oxygen consumption: the Bag-CPAP.

BACKGROUND: Several noninvasive ventilatory supports rely in their design on high oxygen consumption which may precipitate oxygen shortage, as experienced during the COVID-19 pandemic. In this bench-to-bedside study, we assessed the performance of a new continuous positive airway pressure (CPAP) device integrating a large reservoir ("Bag-CPAP") designed to minimize oxygen consumption, and compared it with other CPAP devices. METHODS: First, a bench study compared the performances of Bag-CPAP and four CPAP devices with an intensive care unit ventilator. Two FiO2 targets (40-60% and 80-100%) at a predefined positive end expiratory pressure (PEEP) level between 5 and 10 cm H2O were tested and fraction of inspired oxygen (FiO2) and oxygen consumption were measured. Device-imposed work of breathing (WOB) was also evaluated. Second, an observational clinical study evaluated the new CPAP in 20 adult patients with acute respiratory failure in two hospitals in France. Actual FiO2, PEEP, peripheral oxygen saturation, respiratory rate, and dyspnea score were assessed. RESULTS: All six systems tested in the bench study reached the minimal FiO2 target of 40% and four reached at least 80% FiO2 while maintaining PEEP in the predefined range. Device-delivered FiO2/consumed oxygen ratio was the highest with the new reservoir-based CPAP irrespective of FiO2 target. WOB induced by the device was higher with Bag-CPAP. In the clinical study, Bag-CPAP was well tolerated and could reach high (> 90%) and moderate (> 50%) FiO2 with an oxygen flow rate of 15 [15-16] and 8 [7-9] L/min, respectively. Dyspnea score improved significantly after introduction of Bag-CPAP, and SpO2 increased. CONCLUSIONS: In vitro, Bag-CPAP exhibited the highest oxygen saving properties albeit had increased WOB. It was well accepted clinically and reduced dyspnea. Bag-CPAP may be useful to treat patients with acute respiratory failure in the field, especially when facing constraints in oxygen delivery.

A novel method for assessment of airway opening pressure without the need for low-flow insufflation.

BACKGROUND: Airway opening pressure (AOP) detection and measurement are essential for assessing respiratory mechanics and adapting ventilation. We propose a novel approach for AOP assessment during volume assist control ventilation at a usual constant-flow rate of 60 L/min. OBJECTIVES: To validate the conductive pressure (Pcond) method, which compare the Pcond-defined on the airway pressure waveform as the difference between the airway pressure level at which an abrupt change in slope occurs at the beginning of insufflation and PEEP-to resistive pressure for AOP detection and measurement, and to compare its respiratory and hemodynamic tolerance to the standard low-flow insufflation method. METHODS: The proof-of-concept of the Pcond method was assessed on mechanical (lung simulator) and physiological (cadavers) bench models. Its diagnostic performance was evaluated in 213 patients, using the standard low-flow insufflation method as a reference. In 45 patients, the respiratory and hemodynamic tolerance of the Pcond method was compared with the standard low-flow method. MEASUREMENTS AND MAIN RESULTS: Bench assessments validated the Pcond method proof-of-concept. Sensitivity and specificity of the Pcond method for AOP detection were 93% and 91%, respectively. AOP obtained by Pcond and standard low-flow methods strongly correlated (r = 0.84, p < 0.001). Changes in SpO2 were significantly lower during Pcond than during standard method (p < 0.001). CONCLUSION: Determination of Pcond during constant-flow assist control ventilation may permit to easily and safely detect and measure AOP.

ESICM guidelines on acute respiratory distress syndrome: definition, phenotyping and respiratory support strategies.

The aim of these guidelines is to update the 2017 clinical practice guideline (CPG) of the European Society of Intensive Care Medicine (ESICM). The scope of this CPG is limited to adult patients and to non-pharmacological respiratory support strategies across different aspects of acute respiratory distress syndrome (ARDS), including ARDS due to coronavirus disease 2019 (COVID-19). These guidelines were formulated by an international panel of clinical experts, one methodologist and patients' representatives on behalf of the ESICM. The review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. We followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence and grade recommendations and the quality of reporting of each study based on the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) network guidelines. The CPG addressed 21 questions and formulates 21 recommendations on the following domains: (1) definition; (2) phenotyping, and respiratory support strategies including (3) high-flow nasal cannula oxygen (HFNO); (4) non-invasive ventilation (NIV); (5) tidal volume setting; (6) positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM); (7) prone positioning; (8) neuromuscular blockade, and (9) extracorporeal life support (ECLS). In addition, the CPG includes expert opinion on clinical practice and identifies the areas of future research.

Inhaled nitric oxide in patients with acute respiratory distress syndrome caused by COVID-19: treatment modalities, clinical response, and outcomes.

BACKGROUND: Inhaled nitric oxide (iNO) has been widely used in patients with COVID-19-related acute respiratory distress syndrome (C-ARDS), though its physiological effects and outcome are debated in this setting. The objective of this cohort study was to describe the modalities of iNO use, clinical response, and outcomes in a large cohort of C-ARDS patients. METHODS: Multicentre, retrospective cohort study conducted in France. RESULTS: From end February to December 2020, 300 patients (22.3% female) were included, 84.5% were overweight and 69.0% had at least one comorbidity. At ICU admission, their median (IQR) age, SAPS II, and SOFA score were 66 (57-72) years, 37 (29-48), and 5 (3-8), respectively. Patients were all ventilated according to a protective ventilation strategy, and 68% were prone positioned before iNO initiation. At iNO initiation, 2%, 37%, and 61% of patients had mild, moderate, and severe ARDS, respectively. The median duration of iNO treatment was 2.8 (1.1-5.5) days with a median dosage of 10 (7-13) ppm at initiation. Responders (PaO2/FiO2 ratio improving by 20% or more) represented 45.7% of patients at 6 h from iNO initiation. The severity of ARDS was the only predictive factor associated with iNO response. Among all evaluable patients, the crude mortality was not significantly different between responders at 6 h and their counterparts. Of the 62 patients with refractory ARDS (who fulfilled extracorporeal membrane oxygenation criteria before iNO initiation), 32 (51.6%) no longer fulfilled these criteria after 6 h of iNO. The latter showed significantly lower mortality than the other half (who remained ECMO eligible), including after confounder adjustment (adjusted OR: 0.23, 95% CI 0.06, 0.89, p = 0.03). CONCLUSIONS: Our study reports the benefits of iNO in improving arterial oxygenation in C-ARDS patients. This improvement seems more relevant in the most severe cases. In patients with ECMO criteria, an iNO-driven improvement in gas exchange was associated with better survival. These results must be confirmed in well-designed prospective studies.

Differences in clinical characteristics and outcomes between COVID-19 and influenza in critically ill adult patients: A national database study.

OBJECTIVE: Prior to the coronavirus disease 2019 (COVID-19) pandemic, influenza was the most frequent cause of viral respiratory pneumonia requiring intensive care unit (ICU) admission. Few studies have compared the characteristics and outcomes of critically ill patients with COVID-19 and influenza. METHODS: This was a French nationwide study comparing COVID-19 (March 1, 2020-June 30, 2021) and influenza patients (January 1, 2014-December 31, 2019) admitted to an ICU during pre-vaccination era. Primary outcome was in-hospital death. Secondary outcome was need for mechanical ventilation. RESULTS: 105,979 COVID-19 patients were compared to 18,763 influenza patients. Critically ill patients with COVID-19 were more likely to be men with more comorbidities. Patients with influenza required more invasive mechanical ventilation (47 vs. 34%, p < 0·001), vasopressors (40% vs. 27, p < 0·001) and renal-replacement therapy (22 vs. 7%, p < 0·001). Hospital mortality was 25% and 21% (p < 0·001) in patients with COVID-19 and influenza, respectively. In the subgroup of patients receiving invasive mechanical ventilation, ICU length of stay was significantly longer in patients with COVID-19 (18 [10-32] vs. 15 [8-26] days, p < 0·001). Adjusting for age, gender, comorbidities, and modified SAPS II score, in-hospital death was higher in COVID-19 patients (adjusted sub-distribution hazard ratio [aSHR]=1.69; 95%CI=1.63-1.75) compared with influenza patients. COVID-19 was also associated with less invasive mechanical ventilation (aSHR=0.87; 95%CI=0.85-0.89) and a higher likelihood of death without invasive mechanical ventilation (aSHR=2.40; 95%CI=2.24-2.57). CONCLUSION: Despite younger age and lower SAPS II score, critically ill COVID-19 patients had a longer hospital stay and higher mortality than patients with influenza.

Clusterin Neutralizes the Inflammatory and Cytotoxic Properties of Extracellular Histones in Sepsis.

Rationale: Extracellular histones, released into the surrounding environment during extensive cell death, promote inflammation and cell death, and these deleterious roles have been well documented in sepsis. Clusterin (CLU) is a ubiquitous extracellular protein that chaperones misfolded proteins and promotes their removal. Objectives: We investigated whether CLU could protect against the deleterious properties of histones. Methods: We assessed CLU and histone expression in patients with sepsis and evaluated the protective role of CLU against histones in in vitro assays and in vivo models of experimental sepsis. Measurements and Main Results: We show that CLU binds to circulating histones and reduces their inflammatory, thrombotic, and cytotoxic properties. We observed that plasma CLU levels decreased in patients with sepsis and that the decrease was greater and more durable in nonsurvivors than in survivors. Accordingly, CLU deficiency was associated with increased mortality in mouse models of sepsis and endotoxemia. Finally, CLU supplementation improved mouse survival in a sepsis model. Conclusions: This study identifies CLU as a central endogenous histone-neutralizing molecule and suggests that, in pathologies with extensive cell death, CLU supplementation may improve disease tolerance and host survival.

Impact of a strategy based on unique blood culture sampling on contamination rate and detection of bloodstream infections in critically ill patients.

BACKGROUND: Unique blood culture (UBC) has been proposed to limit the number of venipuncture and to decrease the risk of BC contaminations (BCC) without affecting their yield. We hypothesized that a multi-faceted program based on UBC in the ICU may reduce the rate of contaminants with a similar performance for bloodstream infections (BSI) identification. METHODS: In a before and after design, we compared the proportion of BSI and BCC. A first 3-year period with multi-sampling (MS) strategy followed by a 4-month washout period, where staff received education and training for using UBC, and a 32-month period, where UBC was routinely used, while education and feedback were maintained. During the UBC period, a large volume of blood (40 mL) was sampled through a unique venipuncture with additional BC collections discouraged for 48 h. RESULTS: Of the 4,491 patients included (35% female patients, mean age 62 years) 17,466 BC were collected. The mean volume of blood per bottle collected increased from 2.8 ± 1.8 mL to 8.2 ± 3.9 mL between the MS and UBC periods, P < 0.01. A 59.6% reduction (95% CI 56.7-62.3; P < 0.001) of BC bottles collected per week was observed between the MS and UBC periods. The rate of BCC per patient decreased between the two periods from 11.2% to 3.8% (73.4% reduction; P < 0.001) for the MS and UBC periods, P < 0.001. Meanwhile, the rate of BSI per patient remained stable at 13.2% and 13.2% for the MS and UBC periods, P = 0.98. CONCLUSIONS: In ICU patients, a strategy based on UBC reduces the contamination rate of cultures without affecting their yield.

Study protocol for a randomized controlled trial of Proportional Assist Ventilation for Minimizing the Duration of Mechanical Ventilation: the PROMIZING study.

BACKGROUND: Proportional assist ventilation with load-adjustable gain factors (PAV+) is a mechanical ventilation mode that delivers assistance to breathe in proportion to the patient's effort. The proportional assistance, called the gain, can be adjusted by the clinician to maintain the patient's respiratory effort or workload within a normal range. Short-term and physiological benefits of this mode compared to pressure support ventilation (PSV) include better patient-ventilator synchrony and a more physiological response to changes in ventilatory demand. METHODS: The objective of this multi-centre randomized controlled trial (RCT) is to determine if, for patients with acute respiratory failure, ventilation with PAV+ will result in a shorter time to successful extubation than with PSV. This multi-centre open-label clinical trial plans to involve approximately 20 sites in several continents. Once eligibility is determined, patients must tolerate a short-term PSV trial and either (1) not meet general weaning criteria or (2) fail a 2-min Zero Continuous Positive Airway Pressure (CPAP) Trial using the rapid shallow breathing index, or (3) fail a spontaneous breathing trial (SBT), in this sequence. Then, participants in this study will be randomized to either PSV or PAV+ in a 1:1 ratio. PAV+ will be set according to a target of muscular pressure. The weaning process will be identical in the two arms. Time to liberation will be the primary outcome; ventilator-free days and other outcomes will be measured. DISCUSSION: Meta-analyses comparing PAV+ to PSV suggest PAV+ may benefit patients and decrease healthcare costs but no powered study to date has targeted the difficult to wean patient population most likely to benefit from the intervention, or used consistent timing for the implementation of PAV+. Our enrolment strategy, primary outcome measure, and liberation approaches may be useful for studying mechanical ventilation and weaning and can offer important results for patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT02447692 . Prospectively registered on May 19, 2015.

Trends in clinical characteristics and outcomes of all critically ill COVID-19 adult patients hospitalized in France between March 2020 and June 2021: a national database study.

INTRODUCTION: Studies regarding coronavirus disease 2019 (COVID-19) were mainly performed in the initial wave, but some small-scale data points to prognostic differences for patients in successive waves. We therefore aimed to study the impact of time on prognosis of ICU-admitted COVID-19 patients. METHOD: We performed a national retrospective cohort study, including all adult patients hospitalized in French ICUs from March 1, 2020 to June 30, 2021, and identified three surge periods. Primary and secondary outcomes were in-hospital mortality and need for invasive mechanical ventilation, respectively. RESULTS: 105,979 critically ill ICU-admitted COVID-19 patients were allocated to the relevant three surge periods. In-hospital mortality for surges 1, 2, and 3 was, respectively, 24%, 27%, and 24%. Invasive mechanical ventilation was the highest level of respiratory support for 42%, 32%, and 31% (p < 0.001) over the whole period, with a decline in the use of vasopressors over time. Adjusted for age, sex, comorbidities, and modified Simplified Acute Physiology Score II at ICU admission, time period was associated with less invasive mechanical ventilation and a high risk of in-hospital death. Vaccination against COVID-19 was associated with a lower likelihood of invasive mechanical ventilation (adjusted sub-hazard ratio [aSHR] = 0.64 [0.53-0.76]) and intra-hospital death (aSHR = 0.80, [0.68-0.95]). CONCLUSION: In this large database of ICU patients admitted for COVID-19, we observed a decline in invasive mechanical ventilation, vasopressors, and RRT use over time but a high risk of in-hospital death. Vaccination was identified as protective against the risk of invasive mechanical ventilation and in-hospital death.

Continued enteral nutrition until extubation compared with fasting before extubation in patients in the intensive care unit: an open-label, cluster-randomised, parallel-group, non-inferiority trial.

BACKGROUND: Fasting is frequently imposed before extubation in patients in intensive care units, with the aim to reduce risk of aspiration. This unevaluated practice might delay extubation, increase workload, and reduce caloric intake. We aimed to compare continued enteral nutrition until extubation with fasting before extubation in patients in the intensive care unit. METHODS: We conducted an open-label, cluster-randomised, parallel-group, non-inferiority trial in 22 intensive care units in France. Patients aged 18 years or older were eligible for enrolment if they had received invasive mechanical ventilation for at least 48 h in the intensive care unit and received prepyloric enteral nutrition for at least 24 h at the time of extubation decision. Centres were randomly assigned (1:1) to continued enteral nutrition until extubation or 6-h fasting with concomitant gastric suctioning before extubation, to be applied for all patients within the unit. Masking was not possible because of the nature of the trial. The primary outcome was extubation failure (composite criteria of reintubation or death) within 7 days after extubation, assessed in both the intention-to-treat and per-protocol populations. The non-inferiority margin was set at 10%. Pneumonia within 14 days of extubation was a key secondary endpoint. This trial is now complete and is registered with ClinicalTrials.gov, NCT03335345. FINDINGS: Between April 1, 2018, and Oct 31, 2019, 7056 patients receiving enteral nutrition and mechanical ventilation were admitted to the intensive care units and 4198 were assessed for eligibility. 1130 patients were enrolled and included in the intention-to-treat population and 1008 were included in the per-protocol population. In the intention-to-treat population, extubation failure occurred in 106 (17·2%) of 617 patients assigned to receive continued enteral nutrition until extubation versus 90 (17·5%) of 513 assigned to fasting, meeting the a priori defined non-inferiority criterion (absolute difference -0·4%, 95% CI -5·2 to 4·5). In the per-protocol population, extubation failure occurred in 101 (17·0%) of 595 patients assigned to receive continued enteral nutrition versus 74 (17·9%) of 413 assigned to fasting (absolute difference -0·9%, 95% CI -5·6 to 3·7). Pneumonia within 14 days of extubation occurred in ten (1·6%) patients assigned to receive continued enteral nutrition and 13 (2·5%) assigned to fasting (rate ratio 0·77, 95% CI 0·22 to 2·69). INTERPRETATION: Continued enteral nutrition until extubation in critically ill patients in the intensive care unit was non-inferior to a 6-h fasting maximum gastric vacuity strategy comprising continuous gastric tube suctioning, in terms of extubation failure within 7 days (a patient-centred outcome), and thus represents a potential alternative in this population. FUNDING: French Ministry of Health. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

A novel capnogram analysis to guide ventilation during cardiopulmonary resuscitation: clinical and experimental observations.

BACKGROUND: Cardiopulmonary resuscitation (CPR) decreases lung volume below the functional residual capacity and can generate intrathoracic airway closure. Conversely, large insufflations can induce thoracic distension and jeopardize circulation. The capnogram (CO2 signal) obtained during continuous chest compressions can reflect intrathoracic airway closure, and we hypothesized here that it can also indicate thoracic distension. OBJECTIVES: To test whether a specific capnogram may identify thoracic distension during CPR and to assess the impact of thoracic distension on gas exchange and hemodynamics. METHODS: (1) In out-of-hospital cardiac arrest patients, we identified on capnograms three patterns: intrathoracic airway closure, thoracic distension or regular pattern. An algorithm was designed to identify them automatically. (2) To link CO2 patterns with ventilation, we conducted three experiments: (i) reproducing the CO2 patterns in human cadavers, (ii) assessing the influence of tidal volume and respiratory mechanics on thoracic distension using a mechanical lung model and (iii) exploring the impact of thoracic distension patterns on different circulation parameters during CPR on a pig model. MEASUREMENTS AND MAIN RESULTS: (1) Clinical data: 202 capnograms were collected. Intrathoracic airway closure was present in 35%, thoracic distension in 22% and regular pattern in 43%. (2) Experiments: (i) Higher insufflated volumes reproduced thoracic distension CO2 patterns in 5 cadavers. (ii) In the mechanical lung model, thoracic distension patterns were associated with higher volumes and longer time constants. (iii) In six pigs during CPR with various tidal volumes, a CO2 pattern of thoracic distension, but not tidal volume per se, was associated with a significant decrease in blood pressure and cerebral perfusion. CONCLUSIONS: During CPR, capnograms reflecting intrathoracic airway closure, thoracic distension or regular pattern can be identified. In the animal experiment, a thoracic distension pattern on the capnogram is associated with a negative impact of ventilation on blood pressure and cerebral perfusion during CPR, not predicted by tidal volume per se.

Effects of mean arterial pressure target on mottling and arterial lactate normalization in patients with septic shock: a post hoc analysis of the SEPSISPAM randomized trial.

BACKGROUND: In patients with septic shock, the impact of the mean arterial pressure (MAP) target on the course of mottling remains uncertain. In this post hoc analysis of the SEPSISPAM trial, we investigated whether a low-MAP (65 to 70 mmHg) or a high-MAP target (80 to 85 mmHg) would affect the course of mottling and arterial lactate in patients with septic shock. METHODS: The presence of mottling was assessed every 2 h from 2 h after inclusion to catecholamine weaning. We compared mottling and lactate time course between the two MAP target groups. We evaluated the patient's outcome according to the presence or absence of mottling. RESULTS: We included 747 patients, 374 were assigned to the low-MAP group and 373 to the high-MAP group. There was no difference in mottling and lactate evolution during the first 24 h between the two MAP groups. After adjustment for MAP and confounding factors, the presence of mottling ≥ 6 h during the first 24 h was associated with a significantly higher risk of death at day 28 and 90. Patients without mottling or with mottling < 6 h and lactate ≥ 2 mmol/L have a higher probability of survival than those with mottling ≥ 6 h and lactate < 2 mmol/L. CONCLUSION: Compared with low MAP target, higher MAP target did not alter mottling and lactate course. Mottling lasting for more than 6 h was associated with higher mortality. Compared to arterial lactate, mottling duration appears to be a better marker of mortality.