This is an interesting investigation which serves to better inform healthcare providers in their clinical decision-making surrounding transfusion thresholds in critically ill patients with and without comorbidity.

The authors analysed data from a large cohort of 258,826 Veterans Affairs ICU patients spanning a 5-year period, of whom approximately 12% were transfused and 11.6% suffered in-hospital mortality. Their findings support many of our clinical suspicions that lower haemoglobin thresholds or ‘triggers’ put forth by a number of transfusion guidelines may not be a one-size-fits-all proposition.

They understand the complex interplay between negative patient exposures to lower levels of anaemia, red blood cell transfusions and patient comorbidity. A goal of this study was to better understand the haemoglobin threshold beneath which a red blood cell transfusion conferred benefit in terms of reduced mortality and above which it conferred increased risk.

The authors report that in patients without cardiac comorbidity red blood cell transfusion in the setting of a haemoglobin threshold of less than 7.7 g/dL reduced mortality. Conversely, transfusion in patients without comorbidity and at higher haemoglobin values (7.7 g/dL) increased mortality.

Patients with cardiac comorbidity benefited from a higher transfusion threshold than patients without comorbidity (a haemoglobin threshold of 8.7 g/dL). Finally, if patients were admitted to the ICU with the diagnosis of acute myocardial infarction, the haemoglobin threshold beneath which a red blood cell transfusion was beneficial was even higher (a haemoglobin threshold of 10 g/dL).

There is emerging evidence supporting a more patient-specific / patient-centric approach rather than a uniformly restrictive approach to red blood cell transfusion. These authors should be commended for their excellent and informative investigation.

– Colleen G. Koch