Tranexamic acid: a narrative review of its current role in perioperative medicine and acute medical bleeding.

Purpose: Tranexamic acid (TXA) is the most widely prescribed antifibrinolytic for active bleeding or to prevent surgical bleeding. Despite numerous large multi-center randomized trials involving thousands of patients being conducted, TXA remains underutilized in indications where it has demonstrated efficacy and a lack of harmful effects. This narrative review aims to provide basic concepts about fibrinolysis and TXA's mode of action and is focused on the most recent and important trials evaluating this drug in different hemorrhagic situations. Methods: We selected every low bias RCT, and we highlighted their strengths and limitations throughout this review. Principal findings: While TXA appears to have a favorable benefit-risk ratio in most situations (trauma, obstetrics, at-risk for bleeding surgeries) evidence of benefit is lacking in certain medical settings (SAH, digestive bleeding). Conclusion: Although in some situations the drug's effect on significant outcomes is modest, its favorable safety profile allows it to be recommended for trauma patients, in obstetrics, and in scheduled surgeries at risk of bleeding. However, it cannot be recommended in cases of spontaneous intracranial bleeding, subarachnoid hemorrhage (SAH), or gastrointestinal bleeding.

Sepsis-trained macrophages promote antitumoral tissue-resident T cells.

Sepsis induces immune alterations, which last for months after the resolution of illness. The effect of this immunological reprogramming on the risk of developing cancer is unclear. Here we use a national claims database to show that sepsis survivors had a lower cumulative incidence of cancers than matched nonsevere infection survivors. We identify a chemokine network released from sepsis-trained resident macrophages that triggers tissue residency of T cells via CCR2 and CXCR6 stimulations as the immune mechanism responsible for this decreased risk of de novo tumor development after sepsis cure. While nonseptic inflammation does not provoke this network, laminarin injection could therapeutically reproduce the protective sepsis effect. This chemokine network and CXCR6 tissue-resident T cell accumulation were detected in humans with sepsis and were associated with prolonged survival in humans with cancer. These findings identify a therapeutically relevant antitumor consequence of sepsis-induced trained immunity.

Cost effectiveness and long-term outcomes of dexamethasone administration in major non-cardiac surgery.

STUDY OBJECTIVES: Postoperative administration of dexamethasone has been proposed to reduce morbidity and mortality in patients undergoing major non-cardiac surgery. In this ancillary study of the PACMAN trial, we aimed to evaluate the cost effectiveness of dexamethasone in patients undergoing major non-cardiac surgery. METHODS: Patients included in the multicentric randomized double-blind, placebo-controlled PACMAN trial were followed up for 12 months after their surgical procedure. Patients were randomized to receive either dexamethasone (0.2 mg/kg immediately after the surgical procedure, and on day 1) or placebo. Cost effectiveness between the dexamethasone and placebo groups was assessed for the 12-month postoperative period from a health payer perspective. RESULTS: Of 1222 randomized patients in PACMAN, 137 patients (11%) were followed up until 12 months after major surgery (71 in the DXM group and 66 in the placebo group). Postoperative dexamethasone administration reduced costs per patient at 1 year by €358.06 (95%CI -€1519.99 to €803.87). The probability of dexamethasone being cost effective was between 12% and 22% for a willingness to pay of €100,000 to €150,000 per life-year, which is the threshold that is usually used in France and was 52% for willingness to pay of €50,000 per life-year (threshold in USA). At 12 months, 9 patients (13.2%) in the DXM group and 10 patients (16.1%) in the placebo group had died. In conclusion, our study does not demonstrate the cost effectiveness of perioperative administration of DXM in major non-cardiac surgery.

Mechanical ventilation in patients with acute brain injury: a systematic review with meta-analysis.

OBJECTIVE: To describe the potential effects of ventilatory strategies on the outcome of acute brain-injured patients undergoing invasive mechanical ventilation. DESIGN: Systematic review with an individual data meta-analysis. SETTING: Observational and interventional (before/after) studies published up to August 22nd, 2022, were considered for inclusion. We investigated the effects of low tidal volume Vt < 8 ml/Kg of IBW versus Vt > = 8 ml/Kg of IBW, positive end-expiratory pressure (PEEP) < or > = 5 cmH2O and protective ventilation (association of both) on relevant clinical outcomes. POPULATION: Patients with acute brain injury (trauma or haemorrhagic stroke) with invasive mechanical ventilation for ≥ 24 h. MAIN OUTCOME MEASURES: The primary outcome was mortality at 28 days or in-hospital mortality. Secondary outcomes were the incidence of acute respiratory distress syndrome (ARDS), the duration of mechanical ventilation and the partial pressure of oxygen (PaO2)/fraction of inspired oxygen (FiO2) ratio. RESULTS: The meta-analysis included eight studies with a total of 5639 patients. There was no difference in mortality between low and high tidal volume [Odds Ratio, OR 0.88 (95%Confidence Interval, CI 0.74 to 1.05), p = 0.16, I2 = 20%], low and moderate to high PEEP [OR 0.8 (95% CI 0.59 to 1.07), p = 0.13, I2 = 80%] or protective and non-protective ventilation [OR 1.03 (95% CI 0.93 to 1.15), p = 0.6, I2 = 11]. Low tidal volume [OR 0.74 (95% CI 0.45 to 1.21, p = 0.23, I2 = 88%], moderate PEEP [OR 0.98 (95% CI 0.76 to 1.26), p = 0.9, I2 = 21%] or protective ventilation [OR 1.22 (95% CI 0.94 to 1.58), p = 0.13, I2 = 22%] did not affect the incidence of acute respiratory distress syndrome. Protective ventilation improved the PaO2/FiO2 ratio in the first five days of mechanical ventilation (p < 0.01). CONCLUSIONS: Low tidal volume, moderate to high PEEP, or protective ventilation were not associated with mortality and lower incidence of ARDS in patients with acute brain injury undergoing invasive mechanical ventilation. However, protective ventilation improved oxygenation and could be safely considered in this setting. The exact role of ventilatory management on the outcome of patients with a severe brain injury needs to be more accurately delineated.

High-flow oxygen therapy versus facemask preoxygenation in anticipated difficult airway management (PREOPTI-DAM): an open-label, single-centre, randomised controlled phase 3 trial.

Background: Difficult airway management remains a critical procedure with life-threatening adverse events. Current guidelines suggest high-flow therapy by nasal cannulae (HFNC) as a preoxygenation device in this setting. However, there is an evidence gap to support this recommendation. Methods: The PREOPTI-DAM study is an open-label, single-centre, randomised controlled phase 3 trial done at Nantes University Hospital, France. Patients were aged 18-90 years with one major or two minor criteria of anticipated difficult airway management, and requiring intubation for scheduled surgery, were eligible. Patients with body mass index >35 kg/m2 were excluded. Patients were randomly allocated (1:1) to receive 4-min preoxygenation by HFNC or facemask. Randomisation was stratified according to the intubation strategy (laryngoscopic versus fiberoptic intubation). The primary outcome was the incidence of oxygen desaturation ≤94% or of bag-mask ventilation during intubation. The primary and safety analyses included the intention to treat population. This trial is registered with ClinicalTrials.gov (NCT03604120) and EudraCT (2018-A00434-51). Findings: From September 4 2018 to March 31 2021, 186 patients were enrolled and randomly assigned. One participant withdrew consent and 185 (99.5%) were included in the primary analysis (HFNC, N = 95; Facemask, N = 90). The incidence of the primary outcome was not significantly different between the HFNC and the facemask groups, respectively 2 (2%) versus 7 (8%); adjusted difference, -5.6 [95% confidence interval (CI), -11.8 to 0.6], P = 0.10. In the HFNC group, 76 patients (80%) versus 53 (59%) in the facemask group, reported good or excellent intubation experiences; adjusted difference 20.5 [95% CI, 8.3-32.8], P = 0.016. Comparing HFNC with facemask, severe complication occurred in 22 (23%) versus 27 (30%) patients (P = 0.29), and moderate complication in 14 (15%) versus 18 (20%) patients (P = 0.35). No death or cardiac arrest occurred during the study. Interpretation: Compared with facemask, HFNC did not significantly reduce the incidence of desaturation ≤94% or bag-mask ventilation during anticipated difficult intubation but the trial was underpowered to rule out a clinically significant benefit. Patient satisfaction was improved with HFNC. Funding: Nantes University Hospital and Fisher & Paykel Healthcare.

Transfusion-Related Renal Dysfunction After Cardiac Surgery: The Role of Myeloid-Related Protein_14 in Neutrophil-Mediated Tubular Damage.

Transfusion is a specific cause of acute kidney injury (AKI) after cardiac surgery. Whether there is an association between the composition of blood products and the onset of AKI is unknown. The present study suggests that the transfusion of packed red blood cells containing a high amount of myeloid-related protein 14 (MRP_14) could increase the incidence of AKI after cardiac surgery. In a mouse model, MRP_14 increased the influx of neutrophils in the kidney after ischemia-reperfusion and their ability to damage tubular cells. Higher concentrations of MRP_14 were found in packed red blood cells from female donors or prepared by whole blood filtration.

Ruxolitinib in addition to standard of care for the treatment of patients admitted to hospital with COVID-19 (RUXCOVID): a randomised, double-blind, placebo-controlled, phase 3 trial.

Background: COVID-19 is associated with acute respiratory distress and cytokine release syndrome. The Janus kinase (JAK)1/JAK2 inhibitor ruxolitinib reduces inflammatory cytokine concentrations in disorders characterised by cytokine dysregulation, including graft-versus-host disease, myelofibrosis, and secondary hemophagocytic lymphohistiocytosis. We assessed whether treatment with the JAK1/JAK2 inhibitor ruxolitinib would be beneficial in patients with COVID-19 admitted to hospital. Methods: RUXCOVID was an international, randomised, double-blind, phase 3 trial of ruxolitinib plus standard of care versus placebo plus standard of care in patients with COVID-19. Patients who were hospitalised but not on mechanical ventilation or in the intensive care unit [ICU] were randomly assigned (2:1) to oral ruxolitinib 5 mg twice per day or placebo for 14 days (14 additional days were allowed if no improvement). The primary endpoint was a composite of death, respiratory failure (invasive ventilation), or ICU care by day 29, analysed by logistic regression including region, treatment, baseline clinical status, age, and sex as covariates. This trial is registered with ClinicalTrials.gov, NCT04362137. Findings: Between May 4 and Sept 19, 2020, 432 patients were randomly assigned to ruxolitinib (n=287) or placebo (n=145) plus standard of care; the mean age was 56·5 years (SD 13·3), 197 (46%) were female, and 235 (54%) were male. The primary objective was not met: the composite endpoint occurred in 34 (12%) of 284 ruxolitinib-treated patients versus 17 (12%) of 144 placebo-treated patients (odds ratio 0·91, 95% CI 0·48-1·73; p=0·77). By day 29, nine (3%) of 286 ruxolitinib-treated patients had died compared with three (2%) of 145 placebo-treated patients; 22 (8%) of 286 ruxolitinib-treated patients had received invasive ventilation compared with ten (7%) of 145 placebo-treated patients; and 30 (11%) of 284 ruxolitinib-treated patients had received ICU care compared with 17 (12%) of 144 placebo-treated patients. In an exploratory analysis, median time to recovery was 1 day faster with ruxolitinib versus placebo (8 days vs 9 days; hazard ratio 1·10, 95% CI 0·89-1·36). Adverse events included headache (23 [8%] of 281 on ruxolitinib vs 11 [8%] of 143 on placebo) and diarrhoea (21 [7%] vs 12 [8%]). Interpretation: Ruxolitinib 5 mg twice per day showed no benefit in the overall study population. A larger sample is required to determine the clinical importance of trends for increased efficacy in patient subgroups. Funding: Novartis and Incyte.

Spatiotemporal Adaptations of Macrophage and Dendritic Cell Development and Function.

Macrophages and conventional dendritic cells (cDCs) are distributed throughout the body, maintaining tissue homeostasis and tolerance to self and orchestrating innate and adaptive immunity against infection and cancer. As they complement each other, it is important to understand how they cooperate and the mechanisms that integrate their functions. Both are exposed to commensal microbes, pathogens, and other environmental challenges that differ widely among anatomical locations and over time. To adjust to these varying conditions, macrophages and cDCs acquire spatiotemporal adaptations (STAs) at different stages of their life cycle that determine how they respond to infection. The STAs acquired in response to previous infections can result in increased responsiveness to infection, termed training, or in reduced responses, termed paralysis, which in extreme cases can cause immunosuppression. Understanding the developmental stage and location where macrophages and cDCs acquire their STAs, and the molecular and cellular players involved in their induction, may afford opportunities to harness their beneficial outcomes and avoid or reverse their deleterious effects. Here we review our current understanding of macrophage and cDC development, life cycle, function, and STA acquisition before, during, and after infection.We propose a unified framework to explain how these two cell types adjust their activities to changing conditions over space and time to coordinate their immunosurveillance functions.

Empiric antimicrobial therapy for early-onset pneumonia in severe trauma patients.

PURPOSE: The bacterial ecology involved in early pneumonia of severe trauma patients is mostly commensal and would allow wide use of narrow-spectrum antibiotics. We describe risk factors for treatment failure of severe trauma patients' pneumonia with the use of narrow-spectrum antimicrobial therapy in order to develop a score that could help clinicians to determine which patients might be treated with narrow-spectrum antibiotics. METHODS: A retrospective, observational, monocentric cohort study was conducted of severe trauma patients requiring mechanical ventilation for > 48 h and developing a first episode of microbiologically confirmed pneumonia occurring within the first 10 days after admission. RESULTS: Overall, 370 patients were included. The resistance rate against narrow-spectrum antibiotics (amoxicillin/clavulanic acid) was 22.7% (84 pneumonia). In a multivariate analysis, two independent risk factors were associated with this resistance: prior antimicrobial therapy ≥ 48 h (OR 4.00; 95 CI [2.39; 6.75]) and age ≥ 30y (OR 2.10; 95 CI [1.21; 3.78]). We created a prediction score that defined patient with one or two risk factors at high risk of resistance. This score presented a sensitivity of 0.92 [0.88; 0.94], a specificity of 0.33 [0.28; 0.38], a positive predictive value of 0.29 [0.24; 0.33] and a negative predictive value of 0.93 [0.90; 0.95]. CONCLUSION: Simple risk factors may help clinicians to identify severe trauma patients at high risk of pneumonia treatment failure with the use of narrow-spectrum antimicrobial therapy and, thus, use better tailored empiric therapy and limit the use of unnecessary broad-spectrum antimicrobial therapy.

Effect of dexamethasone on complications or all cause mortality after major non-cardiac surgery: multicentre, double blind, randomised controlled trial.

OBJECTIVE: To assess the effect of dexamethasone on complications or all cause mortality after major non-cardiac surgery. DESIGN: Phase III, randomised, double blind, placebo controlled trial. SETTING: 34 centres in France, December 2017 to March 2019. PARTICIPANTS: 1222 adults (>50 years) requiring major non-cardiac surgery with an expected duration of more than 90 minutes. The anticipated time frame for recruitment was 24 months. INTERVENTIONS: Participants were randomised to receive either dexamethasone (0.2 mg/kg immediately after the surgical procedure, and on day 1) or placebo. Randomisation was stratified on the two prespecified criteria of cancer and thoracic procedure. MAIN OUTCOMES MEASURES: The primary outcome was a composite of postoperative complications or all cause mortality within 14 days after surgery, assessed in the modified intention-to-treat population (at least one treatment administered). RESULTS: Of the 1222 participants who underwent randomisation, 1184 (96.9%) were included in the modified intention-to-treat population. 14 days after surgery, 101 of 595 participants (17.0%) in the dexamethasone group and 117 of 589 (19.9%) in the placebo group had complications or died (adjusted odds ratio 0.81, 95% confidence interval 0.60 to 1.08; P=0.15). In the stratum of participants who underwent non-thoracic surgery (n=1038), the primary outcome occurred in 69 of 520 participants (13.3%) in the dexamethasone group and 93 of 518 (18%) in the placebo group (adjusted odds ratio 0.70, 0.50 to 0.99). Adverse events were reported in 288 of 613 participants (47.0%) in the dexamethasone group and 296 of 609 (48.6%) in the placebo group (P=0.46). CONCLUSIONS: Dexamethasone was not found to significantly reduce the incidence of complications and death in patients 14 days after major non-cardiac surgery. The 95% confidence interval for the main result was, however, wide and suggests the possibility of important clinical effectiveness. TRIAL REGISTRATION: ClinicalTrials.gov NCT03218553.

Circulating Regulatory T Cells Expressing Tumor Necrosis Factor Receptor Type 2 Contribute to Sepsis-Induced Immunosuppression in Patients During Septic Shock.

BACKGROUND: Septic shock remains a major cause of death that can be complicated by long-term impairment in immune function. Among regulatory T (Treg) cells, the tumor necrosis factor receptor 2 positive (TNFR2pos) Treg-cell subset endorses significant immunosuppressive functions in human tumors and a sepsis mouse model but has not been investigated during septic shock in humans. METHODS: We prospectively enrolled patients with septic shock hospitalized in intensive care units (ICU). We performed immunophenotyping and functional tests of CD4+ T cells, Treg cells, and TNFR2pos Treg cells on blood samples collected 1, 4, and 7 days after admission to ICU. RESULTS: We investigated 10 patients with septic shock compared to 10 healthy controls. Although the proportions of circulating Treg cells and TNFR2pos Treg-cell subsets were not increased, their CTLA4 expression and suppressive functions in vitro were increased at 4 days of septic shock. Peripheral blood mononuclear cells from healthy donors cultured with serum from septic shock patients had increased CTLA4 expression in TNFR2pos Treg cells compared to TNFR2neg Treg cells. CONCLUSIONS: In patients with septic shock, CTLA4 expression and suppressive function were increased in circulating TNFR2pos Treg cells. We identify TNFR2pos Treg cells as a potential attractive target for therapeutic intervention.

Could Azithromycin Be Part of Pseudomonas aeruginosa Acute Pneumonia Treatment?

Azithromycin (AZM) is a 15-membered-ring macrolide that presents a broad-spectrum antimicrobial activity against Gram-positive bacteria and atypical microorganisms but suffers from a poor diffusion across the outer-membrane of Gram-negative bacilli, including Pseudomonas aeruginosa (PA). However, AZM has demonstrated clinical benefits in patients suffering from chronic PA respiratory infections, especially cystic fibrosis patients. Since the rise of multidrug-resistant PA has led to a growing need for new therapeutic options, this macrolide has been proposed as an adjunctive therapy. Clinical trials assessing AZM in PA acute pneumonia are scarce. However, a careful examination of the available literature provides good rationales for its use in that context. In fact, 14- and 15-membered-ring macrolides have demonstrated immunomodulatory and immunosuppressive effects that could be of major interest in the management of acute illness. Furthermore, growing evidence supports a downregulation of PA virulence dependent on direct interaction with the ribosomes, and based on the modulation of several key regulators from the Quorum Sensing network. First highlighted in vitro, these interesting properties of AZM have subsequently been confirmed in the animal models. In this review, we systematically analyzed the literature regarding AZM immunomodulatory and anti-PA effects. In vitro and in vivo studies, as well as clinical trials were reviewed, looking for rationales for AZM use in PA acute pneumonia.

Balanced Opioid-free Anesthesia with Dexmedetomidine versus Balanced Anesthesia with Remifentanil for Major or Intermediate Noncardiac Surgery.

BACKGROUND: It is speculated that opioid-free anesthesia may provide adequate pain control while reducing postoperative opioid consumption. However, there is currently no evidence to support the speculation. The authors hypothesized that opioid-free balanced anesthetic with dexmedetomidine reduces postoperative opioid-related adverse events compared with balanced anesthetic with remifentanil. METHODS: Patients were randomized to receive a standard balanced anesthetic with either intraoperative remifentanil plus morphine (remifentanil group) or dexmedetomidine (opioid-free group). All patients received intraoperative propofol, desflurane, dexamethasone, lidocaine infusion, ketamine infusion, neuromuscular blockade, and postoperative lidocaine infusion, paracetamol, nefopam, and patient-controlled morphine. The primary outcome was a composite of postoperative opioid-related adverse events (hypoxemia, ileus, or cognitive dysfunction) within the first 48 h after extubation. The main secondary outcomes were episodes of postoperative pain, opioid consumption, and postoperative nausea and vomiting. RESULTS: The study was stopped prematurely because of five cases of severe bradycardia in the dexmedetomidine group. The primary composite outcome occurred in 122 of 156 (78%) dexmedetomidine group patients compared with 105 of 156 (67%) in the remifentanil group (relative risk, 1.16; 95% CI, 1.01 to 1.33; P = 0.031). Hypoxemia occurred 110 of 152 (72%) of dexmedetomidine group and 94 of 155 (61%) of remifentanil group patients (relative risk, 1.19; 95% CI, 1.02 to 1.40; P = 0.030). There were no differences in ileus or cognitive dysfunction. Cumulative 0 to 48 h postoperative morphine consumption (11 mg [5 to 21] versus 6 mg [0 to 17]) and postoperative nausea and vomiting (58 of 157 [37%] versus 37 of 157 [24%]; relative risk, 0.64; 95% CI, 0.45 to 0.90) were both less in the dexmedetomidine group, whereas measures of analgesia were similar in both groups. Dexmedetomidine patients had more delayed extubation and prolonged postanesthesia care unit stay. CONCLUSIONS: This trial refuted the hypothesis that balanced opioid-free anesthesia with dexmedetomidine, compared with remifentanil, would result in fewer postoperative opioid-related adverse events. Conversely, it did result in a greater incidence of serious adverse events, especially hypoxemia and bradycardia.

Study protocol for a multicentre, 2×2 factorial, randomised, controlled trial evaluating the interest of intravenous iron and tranexamic acid to reduce blood transfusion in hip fracture patients (the HiFIT study).

INTRODUCTION: Blood transfusion and anaemia are frequent and are associated with poor outcomes in patients with hip fracture (HF). We hypothesised that preoperative intravenous iron and tranexamic acid (TXA) may reduce the transfusion rate in these patients. METHODS AND ANALYSIS: The HiFIT study is a multicentre, 2×2 factorial, randomised, double-blinded, controlled trial evaluating the effect of iron isomaltoside (IIM) (20 mg/kg) vs placebo and of TXA (intravenously at inclusion and topically during surgery) versus placebo on transfusion rate during hospitalisation, in patients undergoing emergency surgery for HF and having a preoperative haemoglobin between 95 and 130 g/L. 780 patients are expected. The primary endpoint is the proportion of patients receiving an allogenic blood transfusion of packed red blood cells from the day of surgery until hospital discharge (or until D30 if patient is still hospitalised). Enrolment started on March 2017 in 11 French hospitals. The study was stopped between July 2017 and August 2018 (because of investigation of serious AEs with IIM in Spain) and slowed down since March 2020 (COVID-19 crisis). The expected date of final follow-up is May 2022. Analyses of the intent-to-treat and per-protocol populations are planned. ETHICS AND DISSEMINATION: The HiFIT trial protocol has been approved by the Ethics Committee of Comité de Protection des Personnes Ouest II and the French authorities (ANSM). It will be carried out according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines. The results will be disseminated through presentation at scientific conferences and publication in peer-reviewed journals. The HiFIT trial will be the largest study evaluating iron and TXA in patients with HF. TRIAL REGISTRATION NUMBER: clinicalTrials.gov identifier: NCT02972294; EudraCT Number 2016-003087-40.

Monocytic Human Leukocyte Antigen DR Expression in Young Infants Undergoing Cardiopulmonary Bypass.

BACKGROUND: Monocytic human leukocyte antigen DR (mHLA-DR) expression levels have been reported to be a marker of immunosuppression and a predictor of sepsis and mortality. There are, however, scant data regarding mHLA-DR monitoring in young infants after cardiopulmonary bypass. Our objectives were to investigate the kinetics of mHLA-DR expression and to determine whether mHLA-DR levels are associated with healthcare-associated infection (HAI) after cardiopulmonary bypass in young infants. METHODS: mHLA-DR levels were analyzed by flow cytometry using a standardized method in 49 infants (<3 months old) with congenital heart disease before and after cardiopulmonary bypass. Results are expressed as the number of anti-HLA-DR antibodies per cell (AB/c). RESULTS: Postoperative mHLA-DR expression was reduced in all infants. Eleven patients (22%) developed HAI, and 4 patients (8%) died during the 30-day follow-up. mHLA-DR expression was significantly lower on postoperative day 4 in the HAI group compared with those who without HAI (3768 AB/c [range, 1938-6144] vs 13,230 AB/c [range, 6152-19,130], P = .014). Although mHLA-DR expression was associated with postoperative severity, mHLA-DR ≤4500 AB/c in the first 72 hours among patients with higher postoperative severity (extracorporeal membrane oxygenation and/or corticoids and/or delayed closure of sternum) was associated with occurrence of HAI in the univariate analysis (odds ratio, 6.3; 95% confidence interval, 1.0-38.7; P = .037). CONCLUSIONS: Cardiopulmonary bypass induces a profound decrease in mHLA-DR expression in young infants. Among patients with higher postoperative severity, low level of mHLA-DR in the early postoperative period is associated with the development of HAI.

The A2B trial, antibiotic prophylaxis for excision-graft surgery in burn patients: a multicenter randomized double-blind study.

BACKGROUND: The indication for antibiotic prophylaxis in burn patients remains highly controversial, with no consensus having been reached. The objective of antibiotic prophylaxis is to reduce the risk of postoperative local and systemic infections. Burn surgery is associated with a high incidence of bacteremia, postoperative infections, and sepsis. However, antibiotic prophylaxis exposes patients to the risk of selecting drug-resistant pathogens as well as to the adverse effects of antibiotics (i.e., Clostridium difficile colitis). The lack of data precludes any strong international recommendations regarding perioperative prophylaxis using systemic antibiotics in this setting. The goal of this project is therefore to determine whether perioperative systemic antibiotic prophylaxis can reduce the incidence of postoperative infections in burn patients. METHODS: The A2B trial is a multicenter (10 centers), prospective, randomized, double-blinded, placebo-controlled study. The trial will involve the recruitment of 506 adult burn patients with a total body surface area (TBSA) burn of between 5 and 40% and requiring at least one excision-graft surgery for deep burn injury. Participants will be randomized to receive antibiotic prophylaxis (antibiotic prophylaxis group) or a placebo (control group) 30 min before the incision of the first two surgeries. The primary outcome will be the occurrence of postoperative infections defined as postoperative sepsis and/or surgical site infection and/or graft lysis requiring a new graft within 7 days after surgery. Secondary outcomes will include mortality at day 90 postrandomization, skin graft lysis requiring a new graft procedure, postoperative bacteremia (within 48 h of surgery), postoperative sepsis, postoperative surgical site infection, number of hospitalizations until complete healing (> 95% TBSA), number of hospitalization days living without antibiotic therapy at day 28 and day 90, and multiresistant bacterial colonization or infection at day 28 and day 90. DISCUSSION: The trial aims to provide evidence on the efficacy and safety of antibiotic prophylaxis for excision-graft surgery in burn patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT04292054 . Registered on 2 March 2020.

Pseudomonas aeruginosa Infection Impairs NKG2D-Dependent NK Cell Cytotoxicity through Regulatory T-Cell Activation.

Natural killer (NK) cells play a key role in both antibacterial and antitumor immunity. Pseudomonas aeruginosa infection has already been reported to alter NK cell functions. We studied in vitro the effect of P. aeruginosa on NK cell cytotoxic response (CD107a membrane expression) to a lymphoma cell line. Through positive and negative cell sorting and adoptive transfer, we determined the influence of monocytes, lymphocytes, and regulatory T cells (Treg) on NK cell function during P. aeruginosa infection. We also studied the role of the activating receptor natural killer group 2D (NKG2D) in NK cell response to B221. We determined that P. aeruginosa significantly altered both cytotoxic response to B221 and NKG2D expression on NK cells in a Treg-dependent manner and that the NKG2D receptor was involved in NK cell cytotoxic response to B221. Our results also suggested that during P. aeruginosa infection, monocytes participated in Treg-mediated NK cell alteration. In conclusion, P. aeruginosa infection impairs NK cell cytotoxicity and alters antitumor immunity. These results highlight the strong interaction between bacterial infection and immunity against cancer.

Regulatory T Cells Expressing Tumor Necrosis Factor Receptor Type 2 Play a Major Role in CD4+ T-Cell Impairment During Sepsis.

Sepsis causes inflammation-induced immunosuppression with lymphopenia and alterations of CD4+ T-cell functions that renders the host prone to secondary infections. Whether and how regulatory T cells (Treg) are involved in this postseptic immunosuppression is unknown. We observed in vivo that early activation of Treg during Staphylococcus aureus sepsis induces CD4+ T-cell impairment and increases susceptibility to secondary pneumonia. The tumor necrosis factor receptor 2 positive (TNFR2pos) Treg subset endorsed the majority of effector immunosuppressive functions, and TNRF2 was particularly associated with activation of genes involved in cell cycle and replication in Treg, probably explaining their maintenance. Blocking or deleting TNFR2 during sepsis decreased the susceptibility to secondary infection. In humans, our data paralleled those in mice; the expression of CTLA-4 was dramatically increased in TNFR2pos Treg after culture in vitro with S. aureus. Our findings describe in vivo mechanisms underlying sepsis-induced immunosuppression and identify TNFR2pos Treg as targets for therapeutic intervention.