The authors conducted a retrospective study aimed to investigate the relationship between red blood cell transfusion (RBCT) and muscle strength in 124 ventilated, critically ill patients. Seventy tree (59%) received RBCT over their ICU stay. All patients were assessed at a median of 12 days after mechanical ventilation onset.

After adjusting for confounding factors, the authors found that RBCT was associated with decreased muscle strength, as assessed by weaker handgrip and proximal hand muscle strength, but not with ICU-acquired paresis. As far as I know, this is the first study finding a significant association between RBCT and muscle strength.

Although the study was well designed and conducted, its observational nature precludes from drawing firm conclusions, as recognized by the authors. In particular, severity illness scoring, as assessed by APACHE III, was quite different between transfused and non-transfused patients and, despite adjusting for this and other important confounders, the multivariate analysis only demonstrated an association between RBCT and muscle strength loss.

In conclusion, these findings are both novel and hypothesis generating. This putative new adverse effect associated with RBCT should be investigated in prospective studies using a risk-adjusted model.

– Santiago Ramón Leal-Noval