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Evevident
Original paper
1999NEJMPulmonary/Critical Care

TRICC

A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group

RCTTransfusion

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Overview

A restrictive RBC transfusion strategy was at least as effective as a liberal strategy in critically ill patients and may be better in less severely ill/younger patients.

Clinical takeaway

TRICC established that many stable ICU patients do not need transfusion until hemoglobin is around 7 g/dL.

Key result

30-day mortality was 18.7% with restrictive vs 23.3% with liberal transfusion (p=0.11).

Practice impact

Restrictive transfusion thresholds became standard for stable hospitalized/ICU patients.

Evidence

Study design

Multicenter randomized controlled trial.

Enrollment

838

Follow-up

30 days (primary); mortality also reported at 60 days and for the hospital stay.

Geography

Canada

Clinical question

Is a restrictive transfusion threshold safe in critically ill patients?

Population

  • Hemodynamically stable critically ill adults with hemoglobin <9 g/dL after initial resuscitation.

Intervention

Restrictive strategy: transfuse at Hb <7 g/dL, target 7-9 g/dL.

Comparator

Liberal strategy: transfuse at Hb <10 g/dL, target 10-12 g/dL.

Primary outcome

30-day all-cause mortality.

A restrictive transfusion threshold (Hb 7 g/dL) was at least as safe as a liberal threshold and used far less blood in stable critically ill adults.

Absolute difference (restrictive minus liberal) / -4.6 / p=0.11

Key results

  • 30-day mortality: 18.7% restrictive vs 23.3% liberal (p=0.11), meeting the noninferiority criterion.
  • In-hospital mortality was significantly lower with the restrictive strategy (22.2% vs 28.1%; p=0.05).
  • Younger (<55 years) and less acutely ill (APACHE II <=20) patients had significantly lower mortality with the restrictive strategy.
  • The restrictive strategy used roughly half as many red-cell units.

Harms

  • Cardiac events, including pulmonary edema and myocardial infarction, were more frequent with the liberal strategy.
  • The restrictive strategy did not increase mortality or organ dysfunction.

Clinical Use

When to cite

  • When choosing a restrictive transfusion threshold for stable critically ill patients without active bleeding or acute coronary ischemia.

Practice impact

  • Restrictive transfusion thresholds became standard for stable hospitalized/ICU patients.

Applicability

  • Most applicable to hemodynamically stable critically ill adults after initial resuscitation.

Limitations

  • Excluded patients with active bleeding and some acute coronary contexts.
  • Thresholds must be individualized for active ischemia, bleeding, and symptoms.
  • Predates leukoreduction of blood products in some centers.

Common misinterpretations

  • Hb 7 g/dL is a trigger for stable patients, not a mandate to withhold transfusion during active bleeding or acute coronary ischemia.
  • The restrictive strategy was not merely non-inferior; several subgroups did better with less transfusion.

Related evidence

Villanueva UGIB transfusion trial - Similar Question

Citation

Hébert PC, Wells G, Blajchman MA, et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group. N Engl J Med. 1999;340(6):409-417. doi:10.1056/NEJM199902113400601

A restrictive strategy of red-cell transfusion is at least as effective as and possibly superior to a liberal transfusion strategy in critically ill patients, with the possible exception of patients with acute myocardial infarction and unstable angina.