Massive Blood Loss and Transfusion
- Definition: replacement by transfusion of more than 50% of a patient’s blood volume in 12–24 hours
- Contact blood bank and activate rapid transfusion protocol if available: the blood bank will then always keep a certain number of blood products on hold for this patient
- Acidosis affects coagulation factor involving calcium and phospholipids
- Hypothermia slows any enzymatic activity including coagulation factors and activation of platelets by von Willebrand factor (vWF)
- Not detected by laboratory tests: samples are warmed to 37°C
- Not correctable with plasma and factor concentrates
Check coagulation profiles (including fibrinogen levels) frequently.
- Metabolic alkalosis:
- pH of PRBC at 37°C = 7.10 due to citric acid and production of lactate by red cells during storage; however, metabolism of 1 mmol of citrate generates 3 mEq of bicarbonate (23 mEq of bicarbonate/1 U PRBC)
- Citrate binds ionized calcium: measure calcium frequently and replace generously
- Potassium levels in stored PRBC increase by 1 mEq/L
- Peak K concentration: 90 mEq/L in PRBC
- Measure K concentration frequently
- Treat hyperkalemia aggressively: insulin/glucose, calcium, furosemide, dialysis (continuous venovenous hemodialysis [CVVHD])
- Consider washing PRBC in Cell Saver if plasma K >5 mmol/mL or rapidly rising
- Consider storing 2–3 U washed PRBC prior to surgery in case of massive bleeding and worsening hyperkalemia
- Replace calcium generously
Consider 1:1:1 resuscitation: 1 U PRBC combined with 1 U plasma and 1 U platelets.
Recent studies have shown a survival benefit of 1:1:1 transfusion in combat and civilian trauma.
Dilutional coagulopathy: 500 mL blood loss causes a 10% decrease in clotting factors.
Coagulopathy can occur with a 25% decrease of clotting factors (usually 8–10 U packed red blood cells).
Dose for reversal of anticoagulants:
- Determine current and target INR
- Convert INR to approximate percentage of prothrombin complex:
- INR 1 = 100 (%)
- INR 1.4–1.6 = 40
- INR 1.7–1.8 = 30
- INR 1.9–2.1 = 25
- INR 2.2–2.5 = 20
- INR 2.6–3.2 = 15
- INR 4.0–4.9 = 10
- INR > 5 = 5 (%)
- Amount of FFP (mL) = (target level [%] − current level [%]) × weight (kg)
Fifty percent decrease in platelets with 10–12 U of packed red blood cells.
Transfuse if platelets <50,000 and bleeding or <20,000 without bleeding.
Six units of platelets (=1 “large” unit) increases platelet count by 5–10,000.
Avoid and Treat Disseminated Intravascular Coagulation (DIC)
- Depletion of coagulation factors and release of tissue factor from injured tissue
- Consumptive coagulopathy causes widespread coagulopathy and thrombosis
- Fragmentation of erythrocytes generates ...