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Transfusion‑associated circulatory overload (TACO)

2011–12 Data Summary (n=27)
Age Sex Day of Transfusion
0–4 years - Male 10 Week day 16
5–14 years 1 Female 11 Weekend 11
15–24 years 1 Uncategorised 6
25–34 years - Facility Location Time of Transfusion
35–44 years 2 Major City 20 Between 7am and 7pm 3
45–54 years 1 Inner Regional - Between 7pm and 7am 14
55–64 years 3 Outer Regional 1 Unknown 10
65–74 years 6 Remote -
75+ years 13 Very Remote -
Not specified - Uncategorised 6
Clinical Outcome Severity Imputability Blood Component
Death - Excluded/Unlikely - Whole blood -
Life threatening 3 Possible 6 Red cells 25
Severe morbidity 13 Likely/Probable 18 Platelets 1
Minor morbidity 10 Confirmed/Certain 2 Fresh Frozen Plasma 1
No morbidity - Not assessable 1 Cryoprecipitate -
Outcome not available 1 Cryodepleted plasma -
2012–13 Data Summary (n=17)
Age Sex Day of Transfusion
0–4 years - Male 6 Week day 12
5–14 years - Female 8 Weekend 5
15–24 years 2 Uncategorised 3
25–34 years - Facility Location Time of Transfusion
35–44 years - Major City 12 Between 7am and 7pm 4
45–54 years - Inner Regional 1 Between 7pm and 7am 5
55–64 years 1 Outer Regional 1 Unknown 8
65–74 years 1 Remote -
75+ years 13 Very Remote -
Not specified - Uncategorised 3
Clinical Outcome Severity Imputability Blood Component
Death - Excluded/Unlikely - Whole blood -
Life threatening - Possible 6 Red cells 17
Severe morbidity 9 Likely/Probable 10 Platelets -
Minor morbidity 8 Confirmed/Certain - Fresh Frozen Plasma -
No morbidity - Not assessable 1 Cryoprecipitate -
Outcome not available - Cryodepleted plasma -


  1. QLD data is unavailable for 2012–13.
  2. Sex and facility location data is unavailable for NSW.
  3. Time of transfusion data is unavailable for NSW and SA.
  4. Data is unavailable for WA.
  5. Uncategorised refers to those reports where no data was provided.

Over transfusion and rapid transfusion of blood components, especially to patients with reduced cardiopulmonary reserve capacity (children and adults with cardiopulmonary disease) can lead to overload of the circulatory system, termed TACO.

From 2011–12 to 2012–13, there were 44 reports of TACO to the National Haemovigilance Program, accounting for 4.2% of all reports (1,044) for this period. The number of cases rose from 6 in 2008–09 to 27 in 2011–12. The number of reported cases dropped in 2012–13 due to the unavailability of QLD data. One death was reported in 2008–09 and there have been no deaths reported since then. The majority of cases were related to red cell transfusion. The reported figures also indicate that patients aged 65 and above are at high risk of TACO and this is consistent with international findings.

In the period 2011–12 to 2012–13, 30 out of 44 cases were assigned an imputability score of likely/probable or confirmed/certain, including 15 cases with severe morbidity. Three cases with life threatening severity were reported in 2011–12 but none of the cases was confirmed to be related to blood transfusion.

Table 10: TACO clinical outcome severity by imputability, 2011–12 and 2012–13

Clinical Outcome Severity



Excluded / Unlikely


Likely / Probable

Confirmed / Certain

N/A / Not assessable

2011–12 - - - - - -
2012–13 - - - - - -
Life threatening
2011–12 - 1 2 - - 3
2012–13 - - - - - -
Severe morbidity
2011–12 - 2 10 1 - 13
2012–13 - 4 4 - 1 9
Minor morbidity
2011–12 - 3 5 1 1 10
2012–13 - 2 6 - - 8
No morbidity
2011–12 - - - - - -
2012–13 - - - - - -
Outcome not available
2011–12 - - 1 - - 1
2012–13 - - - - - -
Total - 12 28 2 2 44


  1. Outcome severity and imputability data unavailable for QLD for 2012–13.
  2. Outcome severity and imputability data unavailable for WA.

Patients at the highest risk for TACO include those younger than three and those older than 60 years of age, particularly those with underlying cardiac dysfunction.[26] TACO can occur after relatively small volumes of red blood cells (one unit or less) are transfused to these patients. To avoid this complication, transfusion speed and volume must be monitored very carefully.

Published TACO incident estimates have ranged from approximates of 0.0003% to 8% of transfusions depending upon patient population and reporting method.[27] These rates suggest that TACO is as common an adverse event as FNHTR. However, the number of TACO events (44) reported to the National Haemovigilance Program in 2011–12 and 2012–13 is much lower than that of FNHTR (531). The reasons for the under‑reporting of TACO in Australia may relate to a combination of factors:

  • Circulatory overload from fluid infusion (including blood transfusion) is common in elderly patients and patients with heart failure and managed along similar lines—TACO is seen as a complication of fluid infusion rather than blood transfusion.
  • Hospital staff view it as a routine medical management issue (fluids management), rather than an adverse event following transfusion hence do not see the need to report it.
  • It is common but routinely managed, and as such it is unlikely to be reported.

TACO is one of the leading causes of potentially avoidable mortality and major morbidity associated with blood transfusions in many countries including the UK, the Netherlands, the US and Canada (refer to Appendix I: International Context for details).

Increased awareness of TACO by clinical staff is needed as this adverse event is common, potentially lethal and, in many cases, avoidable.

Clinical recommendation

The ANZSBT Guidelines for the Administration of Blood Products recommends that children less than 30kg should have the volume of blood prescribed in mL and the volume should be calculated on the child's weight and the desired haemoglobin to prevent TACO.10

The NBA PBM Guidelines Module 3: Medical has a practice point on the management of TACO.

image of a text table

Text in the above image: PRACTICE POINT — heart failure PP7 - In all patients with heart failure, there is an increased risk of transfusion-associated circulatory overload. This needs to be considered in all transfusion decisions. Where indicated, transfusion should be of a single unit of RBC followed by reassessment of clinical efficacy and fluid status. For further guidance on how to manage patients with heart failure, refer to general medical or ACS sections, as appropriate (R1, R3, PP3—PP6).

The Blood Service provides guidance on the recognition, investigation and management of TACO.[28]

  • When to suspect this adverse reaction?

    The clinical features of TACO can include dyspnoea, orthopnea, cyanosis, tachycardia, increased blood pressure and pulmonary oedema and may develop within 1 to 2 hours of transfusion.

    TACO occurs in less than 1% of patients receiving transfusions. Patients over 60 years of age, infants and severely anaemic patients are particularly susceptible.

  • Usual causes?

    This is usually due to rapid or massive transfusion of blood in patients with diminished cardiac reserve or chronic anaemia.

  • Investigation

    TACO is frequently confused with TRALI as a key feature of both is pulmonary oedema and it is possible for these complications to occur concurrently. Hypertension is a constant feature in TACO whereas it is infrequent and transient in TRALI.

    Perform a chest X-ray and if septal lines, cephalisation and enlarged vascular pedicles (>65 mm) are present, these findings are more consistent with circulatory overload.

    Clinically assess patients for distended neck veins, S3 murmur on cardiac examination and peripheral oedema as these are also consistent with circulatory overload.

  • What to do

    Stop transfusion immediately and follow steps for managing suspected transfusion reactions.

    Place the patient in an upright position and treat symptoms with oxygen, diuretics and other cardiac failure therapy.

    In susceptible patients at risk for TACO (paediatric patients, patients with severe anaemia and patients with congestive heart failure), transfusion should be administered slowly and consideration given to use of a diuretic.