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Transfusion-Associated Circulatory Overload (TACO) Cumulative Data


TACO is defined as acute or worsening respiratory compromise and/or acute or worsening
pulmonary oedema during or up to 12 hours of transfusion, with additional features including
cardiovascular system changes not explained by the patient’s underlying medical condition;
evidence of fluid overload and a relevant biomarker.


Data collection on TACO began in 2008, and although reported numbers have steadily increased since that time, it is thought that TACO remains under-reported.

In 2016 the pre-transfusion TACO checklist was introduced, and has been modified and refined since then. The latest version of this can be found in the most recent Annual Report chapter, and also in the Figures pdf in the Resources section below.


Recent Recommendations

  • Patients who develop respiratory distress during or up to 24 hours following transfusion where transfusion is suspected to be the cause must be reported to SHOT. The TACO definition criteria can be used as guidance, but this should not be restrictive. SHOT experts can transfer cases between categories
  • Action: All staff involved in transfusion
  • A formal pre-transfusion risk assessment for transfusion-associated circulatory overload (TACO) should be undertaken whenever possible for all patients receiving blood transfusion (especially if older than 50 years or weighing less than 50kg) and mitigating actions taken, as TACO is the most commonly reported cause of transfusion-related mortality and major morbidity
  • Action: All staff authorising transfusions
  • A structured incident review should be undertaken for every case of TACO. This will ensure optimal organisational and individual patient safety measures are in place to protect patients from TACO as far as possible (see recommended resources)
  • Action: Trust/Health Board governance and clinical risk departments, all staff investigating transfusion incidents
  • Weight-adjusted red cell dosing should be used to guide the appropriate volume required for all non-bleeding adult patients. Ideally tools which also highlight inappropriate transfusion should be used (Grey et al. 2018, NCA 2017)
  • Action: All staff authorising transfusions

TACO Resources

Please also see the video on pulmonary complications of transfusion. This can be accessed on this page

TACO Annual Report Chapters