The Clinical Significance Of Platelet Parameters In Patients With Sepsis

Background:Sepsis was defined as the presence of infection together with systemic inflammatory response syndrome (SIRS) of infection. It was one of the serious complications of trauma, burns, shock, infection, major operations, and other critical diseases. It also could induce septic shock and multiple organ dysfunction syndrome (MODS). Sepsis was very common, frequently fatal condition, high mortality rate, expensive and consumed considerable healthcare resources. It had became a burning question on the public health. There were over18million cases of severe sepsis in the worldwide per year, while750,000cases in the United States. The number of cases was to increase at1.5%to8.0%per year. And there were about14,000deaths in the worldwide per day.It had costed about$22,000everyone on an average, nearly$20billion per year in the United States, while there was about$10billion per year in Europe. Although there was no complete epidemiological data about sepsis in china, it was not less than4million cases per year according to the statistics, and it could consume huge medical expenses. Even though the rapid development of basic and clinical research and the therapy in the Intensive Care Unit(ICU), the incidence and mortality was still increased, and its deaths were more than those in total of prostate cancer, breast cancer and Acquired Immune Deficiency Syndrome(AIDS). Sepsis had become a threat to human health. Therefore, to monitor and investigate the indicators that could sensitively reflect the severity and prognosis of sepsis seemed very important. The pathogenesis of sepsis was very complex, and it had not been fully clarified yet. It had referred to infection, inflammation, immunology, coagulation, metabolism, tissue damage, nerve-endocrine system-immunoregulatory network and had been considered as a generalized process where every organ and system could be involved. It had been shown that the inflammatory response, coagulation activation and inhibition of fibrinolysis could occur in the early phase of this syndrome. They were proposed to play a major role.in the pathogenesis of multiple organ dysfunction syndrome. It had been proposed that the platelet activation/hyperaggregation played an important role in the exaggerated inflammation and coagulation activation, could occur in a nearly phase of this syndrome in sepsis. It had been reported that the morphology and function were changed when platelet was activated, therefore, to some extent, it could reflect the inflammatory response and the severity of the disease by observing the morphological and functional changes of the platelets. At present, the function of platelet was mainly reflected by detecting the molecules that expressed in the platelet. The study had found that the molecules expressed in platelet which participated in the systemic inflammatory response mainly were:①Platelet activating factor(PAF).②CD40L, CD40.③P-selectin.④Toll-like receptor(TLRs)⑤LIGHT.⑥Other phospholipid metabolites(leukotrienes).⑦Interleukin (Interleukin-1, Interleukin-6)and so on. However, the reagent required especial equipment, and was expensive, those made it difficult to be common. Therefore, to assess the severity and prognosis by monitoring the molecular that expressed in platelet dynamically was not feasible. And the platelet parameters, such as platelet count (shorted for PLT), mean platelet volume (shorted for MPV), platelet distribution width (shorted for PDW), and platelet large cell ratio (shorted for P-LCR) provided some important information about platelet. Platelet count (PLT) showed the number of platelet, mean platelet volume (MPV) showed the volume (or size) of platelet, platelet distribution width (PDW) showed the difference in the volume (or size) of platelet, and the platelet large cell ratio (P-LCR) showed the proportion of the large volume in platelet. To some extent, they could reflect the platelet kinetics and bone marrow compensatory hyperplasia. The domestic and international researches had reported that platelet count had changed in the early phrase of sepsis, and the changes were association with the severity and prognosis. But platelet count was less sensitive than platelet parameters, it was only expressed while there was a large range of changes in platelet count. And the platelet parameters might provide some important information before the change in platelet count. Therefore, to monitor the platelet parameters in the early phrase in sepsis might provide some important information that was association with the severity and prognosis. Recent advances in automated blood cell analyzers had made it possible and common to measure various platelet parameters automatically, and it was not expensive and easy to acquire. These made it feasible to monitor the platelet parameters in the early phrase in sepsis. There were some researches on the platelet count in sepsis, fewer on the platelet parameters in sepsis, but rarely in the relationship between the platelet count and the platelet parameters, for example, the MPV, PDW and P-LCR in patients with thrombocytopenia in sepsis. In the clinical work, we found that the platelet parameters could provide some important information in patients with sepsis, especially the relationship between platelet parameters and platelet count, it might help us to judge when the platelet count would be recovery. However, these were not accepted for routine clinical use in the worldwide. Therefore, to investigate the clinical significance of the platelet parameters in patients with sepsis, we combined the platelet parameters with the APACHE Ⅱ scoring system which had been considered to be an indicator of the severity and prognosis in critically ill disease to have a comprehensive analysis in the research and monitoring the platelet parameters dynamically.Objective:To investigate the clinical significance of the platelet parameters-platelet count, mean platelet volume, platelet distribution width, and platelet large cell ratio in patients with sepsis.Methods:This was a retrospective study. Ninety four patients with sepsis were consecutively included in the study between January2010and July2012in the Intensive Care Unit. All patients were included according to the new diagnostic criteria which was proposed by the International Sepsis Definitions Conference in Washington in2001. There were65males and29females, the median age was68.5years, aged between29to92years. All patients were divided into Survivors(n=71) and non-survivors (n=23) according to the prognosis, the platelet count, mean platelet volume, platelet distribution width, and platelet large cell ratio were detected and Acute Physiology And Chronic Health Evaluation II(shorted for APACHE Ⅱ)score was calculated the day on admission to ICU. All patients were divided into Group A (APACHE II score <10points, n=12), Group B (APACHE II score10to19points, n=39) and Group C (APACHE Ⅱ score>20points, n=43) according to the APACHE II score. The platelet count, mean platelet volume, platelet distribution width, platelet large cell ratio and mortality were analyzed among the three groups. In addition, all patients were divided into thrombocytopenia group (PLT<100x109/L, n=39) and non-thrombocytopenia group (PLT≥100x109/L, n=55) according to the platelet count, the incidence of septic shock, APACHE II score, mortality, days in ICU, mean platelet volume, platelet distribution width, and platelet large cell ratio were analyzed between these two groups. To explore the relationship between platelet count,mean platelet volume, platelet distribution width, platelet large cell ratio with the APACHE II score, and the relationship between platelet count with mean platelet volume, platelet distribution width, platelet large cell ratio in thrombocytopenia, the relationship was performed with correlation analysis.All the results were statistically analyzed. The statistical analysis was performed with the software SPSS13.0, and the significance was set at P value <0.05.Results1.The platelet count was higher in survivors than that in non-survivors (p<0.001), the age was yonger in survivors than that in non-survivors (p=0.007), mean platelet volume, platelet distribution width, platelet large cell ratio and the APACHE II score was lower in survivors than those in non-survivors(p<0.001).2. The higher the APACHE II score was, the lower the platelet count was, and the higher the mortality, mean platelet volume, platelet distribution width, and platelet large cell ratio was (p<0.001).3.The incidence of septic shock, APACHE II score, days in ICU, mean platelet volume, platelet distribution width, and platelet large cell ratio were higher in thrombocytopenia group than those in non-thrombocytopenia group (p<0.01). The mortality was higher in thrombocytopenia group than those in non-thrombocytopenia group(p=0.143).4.The relationship between platelet count and APACHE II score was negatively correlated, and the relationship between mean platelet volume, platelet distribution width, platelet large cell ratio and APACHE II score was positively correlated (p<0.001).5.Platelet count and its parameters:mean platelet volume, platelet distribution width, platelet large cell ratio were detected dynamically, the relationship between mean platelet volume, platelet distribution width, platelet large cell ratio and platelet count was negatively correlated (p<0.001).Conclusion1. Thrombocytopenia could be used as an early warning indicator of severity and prognosis in patients with sepsis the day on admission.2. The change of mean platelet volume, platelet distribution width, platelet large cell ratio could be an indirect sign of the severity and prognosis in patients with sepsis the day on admission. Monitoring the changes of the platelet parameters dynamically could reflect the prognosis in sepsis.3. Mean platelet volume, platelet distribution width, platelet large cell ratio could be indicative of the recovery of the platelet count in sepsis with thrombocytopenia.4. Monitoring the changes of the platelet parameters dynamically might have an important clinical significance on judging whether to have a platelet transfusion in patients with thrombocytopenia in sepsis.