Transfusion of fresh washed platelets does not prevent experimental polymicrobial-induced septic shock in mice.

INTRODUCTION: The specific role of platelets during sepsis is not yet fully understood, probably related to the paradox of platelets being potentially beneficial but also deleterious via their thrombotic functions. OBJECTIVE: To evaluate the impact of thrombocytopenia on septic shock in mice and to investigate whether transfusion of fresh washed platelets, either fully functional or with impaired hemostatic properties, might have beneficial effects. METHODS: Septic shock was induced by cecal ligation and puncture (CLP). Experimental depletion of circulating platelets was induced with a rat anti-mouse GPIbα monoclonal antibody. Transfusion of either wild-type washed platelets, platelets treated with the antiplatelet drugs acetylsalicylic acid (ASA) and clopidogrel, or GPIIbIIIa-deficient washed platelets treated with ASA and clopidogrel was performed 4 h after CLP surgery. RESULTS: Depletion of circulating platelets negatively affected septic shock, worsening systemic inflammation, coagulopathy, organ damage, and mortality, raising the question of whether a higher platelet count could be protective. Transfusion of fully functional platelets or platelets with combined treatment with ASA and clopidogrel, with or without additional GPIIbIIIa deficiency, afforded an immediate return of circulating platelet counts to their initial values before surgery. However, transfusion of each of the three types of platelets did not prevent arterial hypotension, inflammatory response, coagulopathy, and organ damage during septic shock. CONCLUSION: Depletion of circulating platelets negatively affects septic shock, while transfusion of washed platelets has no significant beneficial effect in mice.

Impact of COVID-19 and lockdown regarding blood transfusion.

BACKGROUND: The outbreak of a SARS-CoV-2 resulted in a massive afflux of patients in hospital and intensive care units with many challenges. Blood transfusion was one of them regarding both blood banks (safety, collection, and stocks) and consumption (usual care and unknown specific demand of COVID-19 patients). The risk of mismatch was sufficient to plan blood transfusion restrictions if stocks became limited. STUDY DESIGN AND METHODS: Analyses of blood transfusion in a tertiary hospital and blood collection in the referring blood bank between February 24 and May 31, 2020. RESULTS: Withdrawal of elective surgery and non-urgent care and admission of 2291 COVID-19 patients reduced global activity by 33% but transfusion by 17% only. Only 237 (10.3) % of COVID-19 patients required blood transfusion, including 45 (2.0%) with acute bleeding. Lockdown and cancellation of mobile collection resulted in an 11% reduction in blood donation compared to 2019. The ratio of reduction in blood transfusion to blood donation remained positive and stocks were slightly enhanced. DISCUSSION: Reduction of admissions due to SARS-CoV-2 pandemic results only in a moderate decrease of blood transfusion. Incompressible blood transfusions concern urgent surgery, acute bleeding (including some patients with COVID-19, especially under high anticoagulation), or are supportive for chemotherapy-induced aplasia or chronic anemia. Lockdown results in a decrease of blood donation by cancellation of mobile donation but with little impact on a short period by mobilization of usual donors. No mismatch between demand and donation was evidenced and no planned restriction to blood transfusion was necessary.

Immunohaemostasis: a new view on haemostasis during sepsis.

Host infection by a micro-organism triggers systemic inflammation, innate immunity and complement pathways, but also haemostasis activation. The role of thrombin and fibrin generation in host defence is now recognised, and thrombin has become a partner for survival, while it was seen only as one of the "principal suspects" of multiple organ failure and death during septic shock. This review is first focused on pathophysiology. The role of contact activation system, polyphosphates and neutrophil extracellular traps has emerged, offering new potential therapeutic targets. Interestingly, newly recognised host defence peptides (HDPs), derived from thrombin and other "coagulation" factors, are potent inhibitors of bacterial growth. Inhibition of thrombin generation could promote bacterial growth, while HDPs could become novel therapeutic agents against pathogens when resistance to conventional therapies grows. In a second part, we focused on sepsis-induced coagulopathy diagnostic challenge and stratification from "adaptive" haemostasis to "noxious" disseminated intravascular coagulation (DIC) either thrombotic or haemorrhagic. Besides usual coagulation tests, we discussed cellular haemostasis assessment including neutrophil, platelet and endothelial cell activation. Then, we examined therapeutic opportunities to prevent or to reduce "excess" thrombin generation, while preserving "adaptive" haemostasis. The fail of international randomised trials involving anticoagulants during septic shock may modify the hypothesis considering the end of haemostasis as a target to improve survival. On the one hand, patients at low risk of mortality may not be treated to preserve "immunothrombosis" as a defence when, on the other hand, patients at high risk with patent excess thrombin and fibrin generation could benefit from available (antithrombin, soluble thrombomodulin) or ongoing (FXI and FXII inhibitors) therapies. We propose to better assess coagulation response during infection by an improved knowledge of pathophysiology and systematic testing including determination of DIC scores. This is one of the clues to allocate the right treatment for the right patient at the right moment.

Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome After Pneumonectomy.

BACKGROUND: Postpneumonectomy acute respiratory distress syndrome (ppARDS) is a life-threatening condition with a disastrous prognosis. This study assessed the efficacy of venovenous extracorporeal membrane oxygenation (VV-ECMO) in adult patients with unresponsive severe ppARDS. METHODS: We retrospectively reviewed data of all patients treated with VV-ECMO for ppARDS from January 2009 to December 2015. We calculated the Sequential Organ Failure Assessment score before ECMO insertion and monitored the subsequent mechanical ventilation settings. The primary end point was hospital survival. The secondary end point was the ability to achieve a protective ventilatory strategy allowing lung recovery on ECMO. RESULTS: VV-ECMO was indicated in 8 ppARDS patients for refractory hypoxemia (median partial pressure of arterial oxygen/fraction of inspired oxygen: 68 [range, 60 to 75] mm Hg). Median Sequential Organ Failure Assessment before ECMO was 15 (range, 12 to 17), predicting a mortality rate greater than 80%. Median duration of ECMO was 9.5 (range, 5 to 16) days. Tidal volumes and plateau pressures both decreased on ECMO (pre-ECMO tidal volume: 412 [range, 250 to 450 mL] vs ECMO tidal volume: 277 [range, 105 to 367 mL], p = 0.0156; pre-ECMO plateau pressure: 34 [range, 32 to 40] cm H2O vs ECMO plateau pressure: 24.5 [range, 23.3 to 27.3] cm H2O, p = 0.0195). ECMO could be weaned in 7 patients (87.5%). Hospital survival was 50%. CONCLUSIONS: Hospital survival was better than predicted before ECMO insertion. In severe and refractory ppARDS, VV-ECMO allows lung recovery and therefore increased survival.

Lipid emulsions differentially affect LPS-induced acute monocytes inflammation: in vitro effects on membrane remodeling and cell viability.

The aim of this study was to assess how lipid emulsions for parenteral nutrition affect lipopolysaccharide (LPS)-induced acute monocyte inflammation in vitro. An 18 h long LPS induced human monocyte leukemia cell stimulation was performed and the cell-growth medium was supplemented with three different industrial lipid emulsions: Intralipid(®), containing long-chain triglycerides (LCT--soybean oil); Medialipid(®), containing LCT (soybean oil) and medium-chain triglycerides (MCT--coconut oil); and SMOFlipid(®), containing LCT, MCT, omega-9 and -3 (soybean, coconut, olive and fish oils). Cell viability and apoptosis were assessed by Trypan blue exclusion and flow cytometry respectively. Monocyte composition and membrane remodeling were studied using gas chromatography and NR12S staining. Microparticles released in supernatant were measured by prothrombinase assay. After LPS challenge, both cellular necrosis and apoptosis were increased (threefold and twofold respectively) and microparticle release was enhanced (sevenfold) after supplementation with Medialipid(®) compared to Intralipid(®), SMOFlipid(®) and monocytes in the standard medium. The monocytes differentially incorporated fatty acids after lipid emulsion challenge. Finally, lipid-treated cells displayed microparticles characterized by disrupted membrane lipid order, reflecting lipid remodeling of the parental cell plasma membrane. Our data suggest that lipid emulsions differentially alter cell viability, monocyte composition and thereby microparticle release. While MCT have deleterious effects, we have shown that parenteral nutrition emulsion containing LCT or LCT and MCT associated to n-3 and n-9 fatty acids have no effect on endotoxin-induced cell death and inflammation.

Left ventricular rupture after embolic myocardial infarction due to mitral valve endocarditis.

We report a very rare case of a 43-year-old patient with fatal left ventricular subepicardial aneurysm rupture complicating embolic myocardial infarction due to mitral valve infective endocarditis.