Platelet morphological indices on Intensive Care Unit admission predict mortality in septic but not in non-septic patients.

BACKGROUND: Thrombocytopenia is associated with worse outcomes in critically ill patients. The clinical relevance of other platelets indices is less studied. We investigated the ability of the platelets distribution width (PDW) and the mean platelet volume (MPV) to predict mortality in critically ill patients. We hypothesized that the prognostic values of PDW and MPV could be different in septic and non-septic patients. METHODS: We prospectively analyzed patients with an expected ICU length of stay ≥48 hours. Repeated measurements of PDW and MPV were considered (on ICU admission and up to day 5 thereafter). The primary outcome was to investigate the ability of PDW and MPV to predict 90-day mortality in septic and non-septic patients. RESULTS: We included in the study 234 patients of which 31% patients were septic. 90-day mortality was 39% in septic and 27% non-septic patients. PDW and MPV values on admission were 12.5±2.5% and 10.7±1.1 fL, respectively. The AUROC of PDW values on admission to predict 90-day mortality in septic patients was 0.813, being higher than those in non-septic patients (0.550, P<0.001). Similarly, the AUROC for MPV in septic patients was higher than non-septic patients (0.55, P<0.001). The combined analysis of platelets morphological indices and lactate improved the predictive accuracy (PDW and lactate AUROC=0.870; MPV and lactate AUROC=0.867). CONCLUSIONS: Platelet morphological indices are independent predictor of 90-day mortality in septic patients but not in non-septic patients. A combined analysis of platelets morphological indices and lactate in septic patients resulted in improved prediction of mortality.

Lower airways inflammation in patients with ARDS measured using endotracheal aspirates: a pilot study.

INTRODUCTION: Our knowledge of acute respiratory distress syndrome (ARDS) pathogenesis is incomplete. The goal of this pilot study is to investigate the feasibility of measuring lower airways inflammation in patients with ARDS using repeated endotracheal aspirates (ETAs). METHODS: ETAs were obtained within 24 hours by intensive care unit admission from 25 mechanically ventilated patients with ARDS and 10 of them underwent a second ETA within 96 hours after the first sampling. In each sample, cell viability was assessed using trypan blue exclusion method and the total and differential cell counts were measured using Neubauer-improved cell counting chamber and cytospins stained with Diff-Quik. RESULTS: The median cell viability was 89 (IQR 80-93)%, with a median total cell count of 305 (IQR 130-1270)×103/mL and a median macrophage, neutrophil, lymphocyte and eosinophil count, respectively, of 19.8 (IQR 5.4-71.6)×103/mL; 279 (IQR 109-1213)×103/mL; 0 (IQR 0-0.188)×103/mL; 0 (IQR 0-1.050)×103/mL. Eosinophil count in the ETA correlated with the number of blood eosinophils (r=0.4840, p=0.0142). Cell viability and total and differential cell counts were neither significantly different in the second ETA compared with the first ETA nor were unaffected by the presence or absence of bacteria in the blood and/or ETA, or by the ARDS aetiology, apart from the macrophage count which was significantly increased in patients with ARDS associated with acute pancreatitis compared with those associated with pneumonia (p=0.0143). CONCLUSIONS: ETA can be used to investigate the cellularity of the lower airways in patients with ARDS and it is an easy-to-perform and non-invasive procedure. Eosinophil counts in ETA and blood are significantly correlated. The number of macrophages in ETA may be affected by the aetiology of the ARDS.