Transfusion Associated Circulatory Overload (TACO) Incidence and Risk Factors.
Authors: Piccin Andrea , Cronin Marina , Murphy Ciaran , Eakins Elva , Lawlor Emer 
Published: October 2019

Abstract
Abstract 3157
Poster Board III-94

Introduction
Transfusion circulatory overload (TACO) is a complication of transfusion, often confused with transfusion acute lung injury (TRALI), and is probably under-reported. The pathophysiology is believed to be caused by increased hydrostatic blood pressure leading to fluid leakage in the alveolar space, emulating congestive cardiac failure. We report on a large cohort of TACO cases in Ireland.

Methods
All consecutive TACO cases reported to the National Haemovigilance Office of Ireland between 2000-2008 were retrospectively reviewed. The incidence of TACO was calculated on units issued from the Irish Blood Transfusion Service (IBTS). Comparative analysis of patient demographic and clinical data was made using Fisher's exact test.

Results
179 TACO cases were reviewed. 149 (83%) involved red cell concentrate (RCC), platelets (PLT) n=4 (2%); fresh frozen plasma (FFP) /solvent detergent plasma (SDP) n=16 (8%); multiple components n=10 (6%). During the study period, a total 1,614,973 blood components (RCC, FFP, SDP and PLT) were issued corresponding to a TACO incidence of 1/10.000 of all components issued. TACO incidence per RCC, platelets and plasma issued was 1/8000, 1/48000 and 1/15000 respectively, excluding the cases where multiple components were transfused. While the majority of patients developing TACO were elderly (> 70years)(n= 120, 67%), up to eight cases (4%) were reported in young patients (<30 years). There was no difference in gender. An underlying cardiovascular condition was reported in 73% (131) cases. Patient outcome was specified in 178 cases. One hundred and fifty three (85%) patients recovered post reaction. However, 15 (8%) patients experienced morbidity ranging from prolonged resolution of symptoms, to myocardial infarction (n=2), cancellation of surgery (n=1), and admission to intensive care (n=4). 25 (14%) deaths were reported, and TACO was identified as possible cause of death in n=5 (2%) cases. Four of these patients were male and one patient was female. A total of 158 (88%) patients received diuretics before (n=36), during (n=26) or post (n=124). Nineteen patients (11%) did not receive diuretics; four of these patients died, one of which was possibly attributed to transfusion. Information was unavailable in two cases. Patients treated with diuretics post transfusion were more likely to survive (80% vs. 40%); however statistical significance was not reached (p=0.07). The median transfused volume was 275 mls (range 80-9500 mls). There was no statistical significance between actual time of transfusion and time over which transfusion were prescribed. Approximately 10 % (18) cases involved large volume transfusion most likely in an emergency situation. While only three of these transfusion events met the clinical definition of a massive transfusion (150mls per minute), patients in this cohort received between 300 and 8200 mls per hour. The median volume transfused was 1500mls (range 1000mls – 9500mls). Eleven (61%) patients had underlying cardiovascular conditions. Seven patients were > 70 years, all of whom had underlying cardio–vascular conditions. Four (22%) patients died, one death which was possibly attributed to transfusion, and a further three patients (17%) required admission to intensive care. Four (22%) cases involved young female patients (age < 30 years) who had no underlying cardiovascular condition, but one patient had asthma. These patients were being treated for obstetric bleeding, and all recovered.

Conclusion
This study reports a TACO incidence of 1 /10 000 units issued from the IBTS. Although this incidence is based on units issued rather than transfused, it probably reflects significant underreporting, and perhaps even under-recognition. This study identified TACO has significant impact on patient outcome with approximately 8% (15) of patients suffering significant morbidity and a further 2% (5) of patients dying following onset of TACO. Finally, patients receiving large volume transfusion in emergency situations even young patients are at risk of developing TACO.

Disclosures
No relevant conflicts of interest to declare.