Prognostic Significance of Platelet and Mean Platelet Volume Kinetics for Ventilator-Associated Pneumonia

Objective: Platelets play an important role in cases of inflammation and infection, along with in the hemostatic process. The aim of study is to evaluate prognostic efficiency of platelet count (PC), mean platelet volume (MPV) and MPV/PC for mortality prediction in patients with ventilator-associated pneumonia (VAP). Methods: A total of 150 VAP patients were divided into two groups as Survivors (n=98) and Non-survivors (n=52) according to intensive care unit mortality. The PC and MPV on days 1 and 4 of VAP were evaluated. Results: Thirty (31%) patients in the survivors group and 35 (67%) patients in the non-survivor group had thrombocytopenia, respectively (p<0.05). The non-survivor group had higher MPV and a higher MPV/PC on the 1st and 4th days, while the survivor group had higher PC levels, respectively (p<0.05). Platelet count, MPV and MPV/PC had the highest AUC levels at day 4 (0.68, 0.80, 0.73, respectively). The prognostic values of day 4 MPV and MPV/PC measurements were similar (p=0.17). Day 4 PC were found to be negatively correlated with mortality (adjusted hazard ratio (aHR): 0.91, p=0.01). Day 4 MPV and MPV/PC values were the independent mortality predictors (aHR: 2.59, p<0.01 and aHR: 1.63, p=0.01). The survival probability of VAP patients with <9.25 fL of MPV day 4 was significantly higher than those with ≥9.25 fL (p=0.002, log-rank test) Conclusion: In addition to thrombocytopenia, MPV and MPV/PC are useful predictors of poor outcomes. Changes in MPV responses may be a more useful prognostic assessment tool for VAP patients than PC. Keywords: Immune response, mean platelet volume, platelets, prognosis, ventilator-associated pneumonia