Réanimation et cytopénies auto-immunes. Diagnostic et modalités de prise en charge

Immune thrombocytopenia (ITP) and autoimmune haemolytic anemia (AIHA) are the two main autoimmune cytopenias in adults. AIHA includes AIHA associated with warm autoantibodies and cold agglutinin-mediated anemia (CAA). Treatment of the most severe forms of ITP is based on high-dose steroids and intravenous immunoglobulins (IVIg). Platelet transfusions are indicated only for life-threatening bleedings. High-dose steroids represent the first-line treatment of warm AIHA. Red blood cell transfusions are effective for symptomatic anemia. Splenectomy should only be performed in the exceptional cases refractory to medical treatment. In CAA, transfusion of warmed packed red blood cells is the unique emergent therapy. Steroids are not effective and should be avoided. Anti-CD20 antibodies represent a promising therapy for warm AIHA and CAA and should be administered if first-line treatment has failed.     

Lipides et poumon en réanimation

Artificial nutrition is an inevitable component of ICU techniques, and usually comes with side effects. Among these, the effects of parenteral lipids on pulmonary function has been described in patients with abnormalities of the ventilation/perfusion ratio. Underlying mechanisms are well-known and involve, under the effect of lipidic infusion, a change in the production of two types of eicosanoids, either vasoconstrictive or vasodilatative for the pulmonary artery. Depending on the rate of the lipidic infusion flow, there will be a more important synthesis of one or the other eicosanoid. A slow flow, eg. 100 g of triglycerids within 10–12 hours, will not change the ventilation/perfusion ratio and will not have any influence on haematosis. TCM-based emulsions hardly interfere with ecosanoids and can be given in adult respiratory distress syndrome. No real benefit was shown compared to a slowly-given soya emulsion. A new aspect of lipidic emulsion is the ability of fish oils and borage oil to modulate pulmonary inflammation and bronchi reactivity. These characteristics are favorable for their use in mucoviscidosis and in patients at risk of, or experiencing, ARDS.     

Transfusion et cardiopathies en réanimation

Critically ill patients with heart disease and especially ischemic heart disease may be predisposed to the adverse consequences of anemia by the nature of their underlying cardiac disease. Research to date has provided opposing views in terms of the optimal transfusion strategies for use in this high risk population. Further studies are needed. In the attempt of such studies results, an increased transfusion threshold of 10 g/dl may be used, based on a professional agreement.     

Fibrinolyse et fibrinogénolyse en réanimation

Fibrinolysis is normally regulated by many activators and inhibitors, in a step-wise sequence. This regulation limits the fibrinolytic process on the blood clot and prevents its systemic dissemination.Specific clinical situations may be followed by an overwhelming primary fibrinolytic process: amniotic fluid embolism, anaphylactic shock and snake bites. In these cases, defibrination is caused by direct proteolysis of plasma fibrinogen. In the most frequent cases, exaggerated fibrinolysis is due to an early activation of plasma and endothelial coagulation. The fibrinolytic process may induce a severe haemorrhagic syndrome in the early post-partum period and in severe liver failure. In these cases, treament with antifibrinolytics must use aprotinin or tranexamic acid to counteract plasmin generation and effects.