Comment on 'control' arm of the study Tim Coats, University of Leicester 6 April 2011 I think that it is not good to regard the 0.9% saline dilution as a "control" - this terminology implies that normal saline has no effect on coagulation, which is incorrect. Different resuscitation fluids (including saline) have different effects on the coagulation system, see: Impairment of coagulation by commonly used resuscitation fluids in human volunteers. Coats TJ, Brazil E, Heron M, MacCallum PK. Emerg Med J. 2006 Nov;23(11):846-9). Resuscitation. 2004 Jan;60(1):101-4. The effect of hypertonic saline dextran on whole blood coagulation Coats TJ, Heron M The effects of commonly used resuscitation fluids on whole blood coagulation. Coats TJ, Brazil E, Heron M. Emerg Med J. 2006 Jul;23(7):546-9. Does calcium cause the different effects of Gelofusine and Haemaccel on coagulation? Coats TJ, Heron M. Emerg Med J. 2006 Mar;23(3):193-4. What is presented in the current paper is actually "The difference between the effects of saline and Hypertonic Saline Hydroxyethyl Starch on coagulation" not "the effect of Hypertonic Saline Hydroxyethyl Starch". The literature in this area is confusing partly because different investigators have used different 'control' fluids, but not taken into account the effect of the control on coagulation. So it may appear pedantic to object to the word 'control' - but I think that it is an important point if we are to understand the effects of our resuscitation fluids on blood coagulation. Competing interests No competing interests.