Transfusion Associated Circulatory Overload
Plasma is most often transfused to reverse a coagulopathy in a patient who is bleeding or scheduled to undergo an invasive procedure. It is also used as a replacement fluid during plasma exchange for treatment of diseases such as TTP or myasthenia gravis.
The most common risks associated with plasma transfusion include allergic reactions, transfusion related acute lung injury (TRALI) and transfusion associated circulatory overload (TACO). The incidence of TRALI has declined significantly in the past 2 years following the introduction of male-only plasma, but the incidence of TACO appears to be increasing both locally and nationally.
Active surveillance of plasma recipients indicates that TACO is a relatively common, but often unreported, occurrence. Between 4 and 5% of plasma recipients experience symptoms consistent with TACO. The estimated risk is 1 reaction per 70 units of plasma transfused. TACO reactions can be life threatening. Published mortality rates range from 5 to 15%. The latest Food and Drug Administration transfusion related mortality report indicated that TACO accounted for 20% of reported deaths.
TACO usually occurs when plasma is infused too quickly or in high volume. Generally, it is recommended that plasma be infused at a rate of 250 to 500 mL per hour. This is equivalent to one bag in 30 to 60 minutes. More than 50% of patients who develop TACO were transfused at a higher rate.
TACO cases occur most commonly in ICU patients. These patients may be predisposed to volume overload due to their comorbidities including congestive heart failure, renal failure, respiratory failure and positive fluid balance.
Signs and symptoms include dyspnea, orthopnea, wheezing, tightness in the chest, cough, cyanosis, tachypnea, rapid increase in blood pressure, distended neck veins, and S3 on auscultation. Peripheral and pulmonary edema may also develop. Chest x-ray demonstrates bilateral infiltrates and possibly an enlarged heart. BNP is usually elevated. If a pre and post BNP level are available, the post BNP level usually increased by at least 50%.
The National Healthcare Safety Network (NHSN) hemovigilance protocol defines TACO as the new onset or exacerbation of 3 or more of the following symptoms within 6 hours of cessation of transfusion:
- Acute respiratory distress such as dyspnea, orthopnea or cough
- Elevated brain natriuretic peptide (BNP or proBNP)
- Elevated central venous pressure (CVP)
- Evidence of left heart failure
- Evidence of positive fluid balance
- Radiographic evidence of pulmonary edema
At the first indication of TACO, the patient should be placed in a sitting position and the transfusion stopped. If symptoms progress oxygen support and IV administration of a rapid acting diuretic may be necessary. Unlike TRALI, most patients with TACO will rapidly improve with diuresis. If symptoms are severe and urgent, a therapeutic phlebotomy of 200 to 400 mL may be warranted.
TACO can be prevented by limiting the total volume of crystalloid and colloid infused as well as the rate of infusion. Patients with risk factors for circulatory overload should probably have their plasma infusion rate reduced to 1 mL per kg body weight per hour. Diuretics can also be given prior to transfusion.
