TRICC trial: critically ill patients5. The TRICC trial was the first major study that compared a liberal transfusion strategy (transfuse when Hb <10 g/dL) to a more conservative approach (transfuse when Hb <7 g/dL). In this multicenter, randomized controlled trial, Hébert et al enrolled 418 critically ill patients and found that there was no significant difference in 30-day all-cause mortality between the restrictive-strategy group (18.7%) and the liberal-strategy group (23.3%).
However, in the pre-determined subgroup analysis, patients who were less severely ill (APACHE II scores of <20) had 30-day all-cause mortality of 8.7%, compared with 16.1% in the liberal-strategy group. Interestingly, there were more cardiac complications (pulmonary edema, angina, MI, and cardiac arrest) in the liberal-strategy group (21%) compared with the restrictive-strategy group (13%). Despite this finding, 30-day mortality was not significantly different in patients with clinically significant cardiac disease (primary or secondary diagnosis of cardiac disease [20.5% restrictive versus 22.9% liberal]).
An average of 2.6 units of RBCs per patient were given in the restrictive group, while 5.6 units were given to patients in the liberal group. This reflects a 54% decrease in the number of transfusions used in the conservative group. All the patients in the liberal group received transfusions, while 33% of the restrictive group’s patients received no blood at all.
The results of this trial suggested that there is no clinical advantage in transfusing ICU patients to Hb values above 9 g/dL, even if they have a history of cardiac disease. In fact, it may be harmful to practice a liberal transfusion strategy in critically ill younger patients (<55 years old) and those who are less severely ill (APACHE II <20).5
FOCUS trial: hip surgery and history of cardiac disease6. The FOCUS trial is a recent study that looked at the optimal hemoglobin level at which an RBC transfusion is beneficial for patients undergoing hip surgery. This study enrolled patients aged 50 or older who had a history or risk factors for cardiovascular disease (clinical evidence of cardiovascular disease: h/o ischemic heart disease, EKG evidence of previous MI, h/o CHF/PVD, h/o stroke/TIA, h/o HTN, DM, hyperlipidemia (TC >200/LDL >130), current tobacco use, or Cr>2.0), who were undergoing primary surgical repair of a hip fracture, and who had Hb <10g/dL within three days after surgery.
More than 2,000 patients were assigned randomly to a liberal-strategy group (transfuse to maintain a Hb >10g/dL) or a restrictive strategy group (transfuse to maintain Hg >8g/dl or for symptoms or signs of anemia). These signs/symptoms included chest pain that was possibly cardiac-related, congestive heart failure, tachycardia, and unresponsive hypotension. The primary outcomes were mortality or inability to walk 10 feet without assistance at 60-day follow-up.
The FOCUS trial found no statistically significant difference in mortality rate (7.6% in the liberal group versus 6.6% in the restrictive group) or in the ability to walk at 60 days (35.2% in the liberal group versus 34.7% in the restrictive group). There were no significant differences in the rates of in-hospital acute MI, unstable angina, or death between the two groups.
Patients in the restrictive-strategy group received 65% fewer units of blood than the liberal group, with 59% receiving no blood after surgery compared with 3% of the liberal group. Overall, the liberal group received 1,866 units of blood, compared with 652 units in the restrictive group.