From the Guidelines
Transfusion-associated circulatory overload (TACO) is the most common major complication of blood transfusion, and it can be prevented by careful patient monitoring, slow transfusion rates, and avoiding excessive fluid overload. According to the association of anaesthetists guidelines 1, TACO is now the most common cause of transfusion-related mortality and major morbidity. It is broadly defined as acute or worsening respiratory compromise and/or acute or worsening pulmonary oedema during or up to 12 h after transfusion, cardiovascular changes (tachycardia, hypertension) not explained by the patient’s underlying condition, evidence of fluid overload and supportive result of a relevant biomarker (e.g. brain natriuretic peptide) 1.
Risk Factors for TACO
The risk factors for developing TACO include:
- Older, non-bleeding patients (age >70 years)
- Comorbidities (heart failure, renal failure and hypoalbuminaemia)
- Low body weight
- Rapid transfusion
Prevention of TACO
Prevention of TACO can be achieved by:
- Careful patient monitoring, including respiratory rate, pulse, blood pressure, and temperature 1
- Slow transfusion rates
- Avoiding excessive fluid overload
- Identifying patients at high risk of TACO and taking appropriate precautions
Patient Monitoring
Patient monitoring is essential to identify and manage adverse reactions, including TACO 1. Dyspnoea and tachypnoea are typical early symptoms of serious transfusion reactions; therefore, the respiratory rate should be monitored throughout transfusion as recommended by the National Institute for Health and Care Excellence (NICE) 1. Other observations including pulse, blood pressure and temperature should be undertaken and documented for each unit transfused. As a minimum, observations should be completed and recorded before the start of the transfusion (within 60 min), 15 min after the start of each unit and within 60 min of the end of transfusion 1.
From the Research
Most Frequent Major Complication of Blood Transfusion
- The most common major complication of blood transfusion is Transfusion-Associated Circulatory Overload (TACO) 2, 3.
- TACO is characterized by hydrostatic pulmonary edema following blood transfusion and is associated with increased morbidity, length of stay, and hospital costs 3.
Prevention of TACO
- Restrictive transfusion practice may affect the occurrence and severity of TACO in critically ill patients 2.
- The use of diuretics, such as furosemide, has been studied as a potential preventive measure for TACO 4, 5, 6.
- A pilot study found that pre-transfusion furosemide 20 mg or placebo intravenously did not significantly reduce the incidence of TACO, but the study protocol was not feasible as designed 4.
- A retrospective observational study found that furosemide is not routinely ordered for red blood cell transfusion, even in patients with risk factors for TACO 5.
- A dose-finding study aimed to generate a furosemide dose-response curve in TACO-susceptible patients and found that 10-40 mg of furosemide IV would be required to achieve a diuresis volume of 400 mL, which is sufficient to offset 1 red blood cell unit 6.
Risk Factors for TACO
- Cardiovascular comorbidities, acute kidney injury, emergency surgery, pretransfusion diuretic use, and plasma transfusion are independent predictors of TACO 2.
- Renal dysfunction, older age, history of congestive heart failure, low ejection fraction, and diastolic dysfunction are also risk factors for TACO 5.