"Management of Massive Transfusion"
Management of Massive Transfusion Massive transfusion Defined as giving greater than one blood volume (8-10 units of blood in an adult) in 24 hrs or less. Practically defined as giving one blood volume in two hrs or less. The replacement of a patient’s total blood volume by stored blood in a relatively short period of time Patients with massive transfusion need close attention to detail and careful monitoring for complications Complications Thrombocytopenia Hypothermia Electrolyte imbalance: Hypocalcaemia Hyperkalaemia Coagulation defects Thrombocytopenia Occur reasonably quickly. Usually results from dilution. Increased consumption may also occur. When the platelet count is less than 50x10 9/l microvascular bleeding and general oozing from wounds or venapuncture sites are likely Hypothermia Most common complication. Red cells stored at 4° C can cool the patient. Core temperatures below 35 ° C have been associated with development of coagulopathies and variety of metabolic disturbances. Hyperkalaemia Rarely seen. A plasma or additive solution K+ in a unit of red cells or whole blood increases with storage period. Presence of acidaemia, hypothermia and hypocalcaemia with hyperkalaemia can lead to cardiac arrest. This problem is best prevented by keeping the patient warm. Hypocalcaemia Due to citrate present in anticoagulant solution. As normal liver can metabolize citrate, this condition is rare. In neonates and hypothermic patients, the combined effects of hypocalcaemia and hyperkalaemia can lead to cardiac arrest. If there is clinical or ECG evidence, treat with IV calcium gluconate (5ml of 10% solution IV) Coagulation defects Common. Due to dilution of plasma. (replacement with packed cells lead to dilutional coagulopathy) Patient may develop coagulopathy due to underlying medical condition or trauma. Hypothermia leads to coagulation defects. Degree of coagulopathy cannot be predicted according to the amount of blood replaced. Management of massive transfusion Replacement therapy according to the five basic tests. Use blood warmers and keeping the patient warm. Five basic tests Haematocrit Platelet count Prothrombin time (INR) Activated partial thromboplastin time (APTT) Fibrinogen level Management Assess need for blood products based on five basic tests. Platelets < 50-75000/L : give platelet concentrates (6-8 packs) Fibrinogen<125 mg/dl, unusually prolonged PT and APTT or evidence of DIC: Give cryoprecipitate 6-8 units of cryoprecipitate PCV below 30%: give red cells INR > 2.0 and aPTT abnormal 2-4 units of FFP Isolated abnormalities of PT: no specific replacement is needed. When laboratory tests are not available Platelet concentrates. FFP 10-15 ml/kg will replace both fibrinogen and coagulation factors. If hypofibrinogenaemia is suspected consider giving cryoprecipitates. Platelets Largest determinant of microvascular bleeding in massively transfused patients. Priority should be directed towards keeping platelet count about 50-75000/ L. Each platelet concentrate will increase platelet count by 5000-7000/L. Either 6-8 platelet concentrates or single donor (apharesis) platelets. Cryoprecipitate If there is evidence of DIC cryoprecipitate transfusion is indicated. Fibrinogen levels below 125mg/dl needs cryoprecipitate. Each unit of cryoprecipitate will increase fibrinogen level by 10 mg/dl. When indicated transfuse at least 7-10 units of cryoprecipitate. Fresh frozen plasma Used only when there is micro-vascular bleeding with laboratory results showing abnormal coagulation. Given 15 ml/kg dosage Ongoing haemostatic treatment should be guided by the patients clinical response and results of repeated laboratory tests Indiscriminate use of blood component therapy can be avoided by routine tests of haemostasis performed early in order to define precise abnormalities Disseminated intravascular coagulation Clinical manifestation of inappropriate thrombin generation Clinically present as asymptomatic, severe bleeding, thrombosis, purpura fulminans Aetiology of DIC Infection Shock Trauma Penetrating brain injury Placental abruption Amniotic fluid embolism Retained fetus Adenocarcinoma Leukaemia Snake bites Burns Diagnosis PT, APTT, Fibrinogen assay (non specific) Specific – FDP – D-Dimers Consequences of excessive thrombin generation Conversion of fibrinogen to fibrin : thrombosis and depletion of fibrinogen