First paragraph (this article has no abstract)

I read with interest the paper by Sekhon and colleagues, 'Association of hemoglobin concentration in critically ill patients with severe traumatic brain injury' (July edition of Critical Care) [1]. Whilst the conclusion ('mean 7-day haemoglobin concentration < 90 g/L associated with increased hospital mortality in patients with severe traumatic brain injury') is striking, it is plausible, if not likely, that both the haemoglobin deficit and the observed mortality are dependent upon the severity of the initial injury, and therefore an association between these two might be expected.