TRICC Trial: A Multicenter, Randomized, Controlled Clinical Trial of Transfusion Requirements in Critical Care

Summary by Brendan McCafferty DO, 2.24.23
https://www.nejm.org/doi/full/10.1056/nejm199902113400601

Clinical Question: In patients admitted to ICU does a restrictive vs. liberal blood transfusion strategy alter mortality.

Take Home Message:

• Patients were randomized to 2 groups

  • Restrictive Group – transfused for a hemoglobin below 7.0 g/dL (Target 7.0-9.0 g/dL)

  • Liberal Group – Transfused for hemoglobin less than 10 g/dL (Target 10-12 g/dL0

• Overall, 30-day mortality was similar in both groups 

• Hospital Mortality was higher in liberal transfusion group compared to restrictive

• The authors suggest their findings can generalized to most critically ill patients with acute blood loss anemia, with the possible exception of patients with active coronary ischemic syndromes.

Summary:

Study Design: 

o   RCT, computer generated randomization, opaque envelopes

o   Stratified by centre and APACHE score

o   Non-blinded 

Population 

o   6541 adult patients were assessed 

o   Euvolemic patients as judged by attending physician

o   Expected stay in ICU >24 hours 

o   Acute anemia with Hb < 9g/dL within 72 hours of admission 

o   Excluded patients with active blood loss; chronic anemia (Hb <9g/dL more than one month prior to admission; admission after routine cardiac surgery

Methods: 

Enrolled 838 critically ill patients with euvolemia after initial treatment who had hemoglobin concentrations of less than 9.0 g per deciliter within 72 hours after admission to the intensive care unit and randomly assigned 418 patients to a restrictive strategy of transfusion, in which red cells were transfused if the hemoglobin concentration dropped below 7.0 g per deciliter and hemoglobin concentrations were maintained at 7.0 to 9.0 g per deciliter, and 420 patients to a liberal strategy, in which transfusions were given when the hemoglobin concentration fell below 10.0 g per deciliter and hemoglobin concentrations were maintained at 10.0 to 12.0 g per deciliter

Primary outcome:

o   Primary outcome: Overall 30-day mortality was similar in both groups. 18.7% in restrictive vs. 23.3% in liberal, (95% C.I. -0.84 to 10.2, P=0.11)

Secondary outcome:

o   Hospital mortality was higher in the liberal transfusion group: 22.2% in restrictive vs. 28.1% in liberal, (95% C.I. -0.3 to 11.7, P=0.05)

o   More than 3 organ failure no difference

Subgroup analyses:

• The mortality rate was significantly lower in the restrictive group in the following circumstances:

  • In the less acutely ill patients (APACHE II score ≤ 20), 30-day mortality was 8.7% vs. 16.1%, 95% C.I. for absolute difference 1-13.6%, P=0.03

  • In the patients who were < 55 years of age (5.7% vs. 13%, P=0.02)

• Mortality was similar in restrictive compared with the liberal groups in patients with known cardiac disease (20.5% vs. 22.9%, p=0.69)

• Cardiac events (MI, pulmonary edema, angina, cardiac arrest) are more common in the liberal (21%) vs. restrictive group (13.2%), P<0.01

Results: 

Overall, 30-day mortality was similar in the two groups (18.7 percent vs. 23.3 percent, P= 0.11). However, the rates were significantly lower with the restrictive transfusion strategy among patients who were less acutely ill — those with an Acute Physiology and Chronic Health Evaluation II score of ≤20 (8.7 percent in the restrictive-strategy group and 16.1 percent in the liberal-strategy group, P=0.03) — and among patients who were less than 55 years of age (5.7 percent and 13.0 percent, respectively; P=0.02), but not among patients with clinically significant cardiac disease (20.5 percent and 22.9 percent, respectively; P=0.69). The mortality rate during hospitalization was significantly lower in the restrictive-strategy group (22.2 percent vs. 28.1 percent, P=0.05).

Discussion: 

o   Restrictive strategy is at least as effective and possibly superior to liberal strategy. The conclusion was that the transfusion threshold could be less than the 9-10g/dl that had been the previous standard of practice. The authors recommended caution and perhaps a higher transfusion threshold in patients with ischaemic heart disease