Ans. (b) Transfusion related circulatory overload (TACO)Ref: Robbins and Cotran Pathologic Basis of Disease 9th Ed; Page No-666* The ISBT criteria for diagnosis of TACO states that it is characterized by any of the 4 of the following within 6 hours of transfusion:# Acute respiratory distress# Tachycardia# Raised blood pressure# Acute of worsening pulmonary oedema on CXR# Evidence of positive fluid balance.* This is usually due to rapid or massive transfusion of blood in patients with diminished cardiac reserve or chronic anemia. Patients over 60 years age, infants, and severely anemic patients are particularly susceptible.* Transfusion R elated Acute Lung Injury (TRALI):# It is most common cause of major morbidity and death after transfusion.# It is most commonly associated with FFP (Fresh Frozen Plasma) transfusion.# It presents as an acute respiratory distress syndrome (ARDS) within 6 hour of transfusion.# Transfusion-Related Acute Lung Injury (TRALI) is a severe, frequently fatal complication in which factors in a transfused blood product trigger the activation of neutrophils in the lung microvasculature.# Current models favor a "two hit" hypothesis for TRALI.# The priming event that leads to increased sequestration and sensitization of neutrophils in the microvasculature of the lung.# The most common antibodies associated with TRALI are those that bind major histocompatibility complex (MHC) antigens, particularly MHC class I antigens.# These antibodies are often found in multiparous women, who generate such antibodies in response to foreign MHC antigens expressed by the fetus.