Mean platelet volume trend in sepsis: is it a useful parameter?

Sepsis, as an uncontrolled generalized inflammatory response, involves also the haemostatic mechanisms. Mean platelet volume (MPV) measurement has been available since 1970s, but neither its relationship with platelet count nor the clinical meaning of this relation has been understood in sepsis yet. This study aimed to evaluate both the trend and the relationship between platelet count (PC) and their MPV and to explore their significance in the course of sepsis.

Seventy septic patients, were recruited in this prospective study. The PC and MPV were measured repeatedly at the enrollment and, thereafter, whenever patient's sequential organ failure assessment (SOFA) score changed by +/-8% up to 5 samples. Standard correlation test, ANOVA for repeated measures, logistic regression and Wilcoxon test were used.

The relationship between PC and MPV, expressed as means and frequency distributions, showed a negative correlation (95% CI; r -0.34; P<0.0001) with an inverse trend during sepsis course. The logistic regression showed a three times increase in death probability (95% CI; OR=3.04; P<0.05) of patients with a MPV<9.7 fL at the recruitment time.

The behaviour of platelets and their respective MPV could be an indirect sign of disturbance in platelet production and activity, and bone marrow response in sepsis. Our results could suggest that routine concomitant measurement of PC and MPV trend could be considered as a quick and reliable guide in the assessment of bone marrow response to sepsis evolution.