Blood Transfusion - Deranged Physiology：输血-疯狂的生理学.pptVIP

Blood Transfusion Evidence based practice in intensive care [a thorough scraping of the Cochrane database] Alex Yartsev 11/2010 Blood Products Whole blood Packed cells Pooled platelets Fresh frozen plasma (FFP) Cryoprecipitate Immunoglobulin Factor concentrates Albumin Packed Red Blood Cells 500ml whole blood = 1 unit PC good for ~ 42 day in the fridge Store up to 10 yrs in the freezer After the vein “lesions” of collection, due to Anticoagulation Separation Cooling preservation There are consequences to storing RBCs The longer you store the cells, the worse the lesions get Scott KL et al, Biopreservation of red blood cells: past, present and future. Transfus med rev 2005 19:127-42 In the fridge Tinmouth et al; Clinical consequences of red cell storage in the critically ill Transfusion 2006 46:2014-27 RBCs lose their shape and become “echinocytes” Membrane changes: more adhesive in the microcirulation RBCs die and burst; their remains form procoagulant debris Oxygen transport is poor in the first 4-6 hrs Bilirubin increases, pH drops Blood storage lesions implicated in all kinds of problems, eg. ARDS, TRALI Complications of transfusion Gould S et al Packed Red Blood Cell Transfusion in the Intensive Care Unit: Limitations and Consequences American Journal of Critical Care. 2007;16: 39-48 Febrile nonhemolytic reactions (most common) Hemolytic transfusion reaction (type 2 hypersensitivity) Transmission of pathogens TRALI (transfusion-associated lung injury) Biochemical (products of degradation) Cardiovascular (APO) When is transfusion appropriate? Irbister JP, Blood transfusion in Ohs Intensive Care Manual 6th ed. Theoretically: Lowest safe hematocrit? Lowest safe hemoglobin? How much bleeding is too much? Practically: do what is best for the patient, not what is best for the laboratory Ongoing bleeding Give blood if Hb is less than 90 or 100 and there are concomitant oxygen transport problems If there is symptomatic anaemia with Hb below