Transfusion-associated circulatory overload (TACO)

TACO:

Transfusion-associated circulatory overload (TACO) is a complication of blood transfusions that occurs when the volume of transfused blood exceeds the capacity of the recipient's cardiovascular system.

Clinical Features: TACO can present with a range of clinical features, including dyspnea, orthopnea, cough, chest pain, tachycardia, and hypertension. These symptoms typically occur within six hours of the transfusion and may persist for several days. In severe cases, TACO can lead to acute respiratory distress syndrome (ARDS), which requires intensive care management.

Pathophysiology: The pathophysiology of TACO is complex and involves a combination of factors. The transfused blood increases the volume and viscosity of the recipient's blood, leading to increased pressure and strain on the cardiovascular system. This can result in increased pulmonary capillary pressure and decreased cardiac output, leading to pulmonary edema and respiratory distress. Other factors that may contribute to TACO include pre-existing cardiac or renal dysfunction, advanced age, and a history of blood transfusions.

Diagnosis: The diagnosis of TACO is based on clinical features, such as the onset of symptoms within six hours of the transfusion, along with evidence of fluid overload on chest X-ray or ultrasound. It is essential to differentiate TACO from other causes of respiratory distress, such as transfusion-related acute lung injury (TRALI), sepsis, and congestive heart failure (CHF). TRALI is a severe complication of blood transfusions that occurs due to an immune reaction to transfused antibodies, while sepsis and CHF may have similar clinical features to TACO.

Management: The management of TACO involves a combination of supportive measures and specific treatments. Supportive measures may include oxygen therapy, diuretics, and elevation of the head of the bed to reduce fluid overload. Specific treatments for TACO may include slowing the rate of transfusion, reducing the volume of transfused blood, or administering medications, such as vasodilators or inotropic agents, to improve cardiac function. In severe cases, mechanical ventilation may be necessary to manage respiratory distress and prevent the development of ARDS.

Prevention: Prevention of TACO involves careful selection of blood products and monitoring of recipients during and after transfusions. Blood products should be selected based on the recipient's blood type and any pre-existing medical conditions that may increase the risk of TACO. Monitoring during and after transfusions should include measurement of vital signs and assessment for signs of fluid overload or respiratory distress.

In conclusion, TACO is a common complication of blood transfusions that can lead to significant morbidity and mortality. Early recognition and management of TACO are essential to prevent the development of severe respiratory distress and ARDS. Careful selection of blood products and monitoring of recipients can help prevent the development of TACO and improve outcomes for transfusion recipients.

References:

1. Popovsky MA, Whitaker B, Arnold NL. Severe outcomes of transfusion (SHOT) initiative: analysis of the first two annual reports. Transfus Med Rev. 2005;19(4):284-295.
2. Gajic O, Rana R, Winters JL, et al. Transfusion-related acute lung injury in the critically ill: prospective nested case-control study. Am J Respir Crit Care Med. 2007;176(9):886-891.
3. Williamson LM, Lowe S, Love EM, Cohen H, Soldan K, McClelland DB. Serious hazards of transfusion.

- KM