The anemic patient in the ICU: How much does the heart tolerate?

Anemia in the critical care setting is a common condition frequently resulting in the use of red cell transfusions. Of particular concern are those anemic, critically ill patients with ischemic heart disease. This critically ill population may be predisposed to the adverse consequences of anemia, by the very nature of their underlying cardiac disease. However, they may also be more predisposed to the adverse consequences of RBC transfusion. Research to date has provided opposing views in terms of the optimal transfusion strategies for use in this "at risk" population. While observational studies have indicated that a liberal strategy is more beneficial, a recent RCT found that a strategy maintaining hemoglobin concentrations between 70 and 90 g/L may result in similar, if not better, outcomes. Further studies are needed, however, to clarify whether the results of this trial can be generalized to patients with cardiovascular disease.

Debate: transfusing to normal haemoglobin levels will not improve outcome.

Recent evidence suggests that critically ill patients are able to tolerate lower levels of haemoglobin than was previously believed. It is our goal to show that transfusing to a level of 100 g/l does not improve mortality and other clinically important outcomes in a critical care setting. Although many questions remain, many laboratory and clinical studies, including a recent randomized controlled trial (RCT), have established that transfusing to normal haemoglobin concentrations does not improve organ failure and mortality in the critically ill patient. In addition, a restrictive transfusion strategy will reduce exposure to allogeneic transfusions, result in more efficient use of red blood cells (RBCs), save blood overall, and decrease health care costs.

Transfusion in the intensive care unit: strategies under scrutiny.

The transfusion of blood products continues to be an important technique for resuscitating patients in intensive care settings. A number of provocative studies have been published in the past year which examine the transfusion of blood products and alternatives. The Transfusion Requirements in Critical Care (TRICC) trial clearly established the safety of a restrictive transfusion strategy, thereby suggesting that physicians could easily minimize exposure to allogeneic red blood cells by lowering their transfusion threshold. The crystalloids versus colloids debate was also fueled by a number of studies this past year, specifically a meta-analysis which reported a 4% increase in absolute risk of mortality associated with resuscitation therapy using colloids. A recent study demonstrated that erythropoietin is a promising therapy in the intensive care. We can anticipate the results of a trial, currently underway, for further evidence of the use of smaller doses of erythropoietin in the ICU setting.