Ans. is 'c' i.e., Metabolic acidosis The question is most probably about complications of massive blood transfusion.Massive Blood Transfusion * Massive blood transfusion is generally defined as transfusion of one to two volumes of patient's own blood volumes (For most adults that is equivalent to 10-20 units.)Complications of Massive Blood TransfusionCoagulopathyThe most common cause of bleeding following massive blood transfusion is dilutional thrombocytopeniaClinically significant dilution of the coagulation factors is unusual in previously normal individuals.Citrate ToxicityCitrate is used as an anticoagulant in the stored blood.Citrate has a property to bind calcium, this calcium binding by the citrate preservative can become significant following transfusion of large volumes of blood or blood products.Hypocalcemia results in some patients after massive transfusion, to prevent this, the transfusion rate should not exceed 1 unit every 5 minutes.Citrate also has an affinity for magnesium ion and the occurrence of hypomagnesemia in the setting of massive transfusion is seen (rarely).HypothermiaBlood is stored at a temperature of 2degC-6degC. So massive blood transfusion can result in hypothermia.Massive blood transfusion is an absolute indication for warming all blood products and intravenous fluids to normal body temperature.Hypothermia due to massive transfusion can result in ventricular arrhythmia.Acid-Base BalanceThe stored blood is acidic for two reasons.Due to the citric acid (the anticoagulants) Due to release of metabolic products by the anaerobic glycolysis of red cells (CO2 and Lactate).Despite the Stored Blood Being Acidic, Significant metabolic acidosis due to transfusion is not common.- Once the resuscitation is complete and normal perfusion is restored, any metabolic acidosis present, typically resolves, and progressive metabolic alkalosis supervenes as citrate and lactate contained in transfusion and resuscitation fluids are converted to bicarbonate by the liver. The most consistent acid base abnormality after massive blood transfusion is postoperative metabolic alkalosis.Serum Potassium ConcentrationThe extracellular concentration of Potassium in stored blood steadily increases with time due to lysis of RBC's.The amount of extracellular potassium transfused with each unit is typically less than 4m Eq per unit. Hyperkalemia can develop regardless of the age of the blood when transfusion rate exceeded 100ml/min.Oxygen Affinity Changes * 2, 3 DPG is greatly reduced in RBC's after about 3 weeks of storage, this increases hemoglobin's affinity for oxygen and adversely affects oxygen delivery to tissues.Acute Respiration? Distress SyndromeCoagulation Factor Depletion