| BackgroundPneumonia after acute stroke is one of the important complications of acute Stroke,the prevalence of it in neurological intensive care units (NICUs) is about 4.1% ～4.1%.Nowadays the impaired level of consciousness and the aspiration caused by swallowing disorder after stroke is thought to be the important pathogenesis of pneumonia after acute stroke, while the severity of stroke is an important independent risk factors for pneumonia after acute stroke.Pseudomonas aeruginosa and staphylococcus aureus are the main pathogenic bacteria of pneumonia after acute stroke, which associated with poor prognosis significantly, early detection and treatment can improve prognosis of patients.Therefore,a relatively specific clinical index is needed for early identification of pneumonia after acute stroke..Serum procalcitonin (PCT) is now considered to be a relatively specific clinical index to judge the bacterial infection.Studies have shown that compared to white blood cell (WBC) and C-Reactive protein (CRP), PCT can be a better indicator of the diagnosis of bacterial infection.Meanwhile, sepsis is caused by systemic inflammatory response syndrome, which progress rapidly and has high case fatality rate.Study found that increased of PCT level is associated with the severity of sepsis.Now there is not much study of the predictive value of the serum PCT level in bacterial pneumonia and sepsis classification with acute stroke, this study aimed to explore the predictive value of the serum PCT level in bacterial pneumonia and sepsis classification.ObjectionThis study will explore risk factors of bacterial pneumonia in patients with acute stroke and to explore the predictive value of the serum PCT level in bacterial pneumonia and sepsis classification.MethodsPatients from the department of Neurology in neurological intensive care units of Nanfang Hospital, from January 2012 to August 2013,with acute stroke within 24 hours of symptom onset were enrolled in this observational study. All patients or their family members signed an informed consent.1. Inclusion criteria were as follows:1) stroke onset within 24 hours;2) stroke diagnostic standards revised in line with the 4th National Cerebrovascular Disease Conference (including cerebral hemorrhage and cerebral infarction);3) age (?)18 years old.2. Exclusion criteria were as follows:1) patients who were not detect PCT as well as the demography and baseline clinical data is not complete;2) combining one of the following conditions:cardiopulmonary resuscitation, trauma, major surger, burns, acute respiratory distress syndrome, shock, heatstroke, neuroendocrine tumors, cardiopulmonary bypass, cirrhosis, pancreatitis, mesenteric infarction, useing proinflammatory cytokine release drugs, renal insufficiency;3) co-infection within 72 hours of admission or any other type of infection besides bacterial pneumonia occurs after admission (including urinary tract infection, catheter-related infection, infectious diarrhea, intracranial infection, bloodstream infection etc.), the diagnosis of infection missed hospital acquired infection diagnostic criteria (for trial implementation) issued by the Ministry of Health of the People’s Republic of China in 2001;3. Collection of general data of all the patientsThe demographic and baseline clinical data of all patients were collected, including gender, age, hypertension, diabetes, type of stroke (cerebral hemorrhage, cerebral infarction)and Glasgow Coma Scale(GCS).The laboratory related indicators of patients recruited in 24 hours were collected, including triglyceride, total cholesterol, high-density lipoprotein cholesterol, low density lipoprotein cholesterol and fasting blood glucose.4. Infection groupPatients were divided into bacterial pneumonia and no infection group according to the presence of bacterial pneumonia after admission, the diagnostic criteria of bacterial pneumonia were based on the guidelines of pneumonia issued in 2005. Then, the patients in bacterial pneumonia group were divided into local infection, sepsis and severe sepsis subgroups according to the diagnostic criteria of sepsis based on international sepsis definitions conference in 2001.5. PCT collectingThe PCT of bacterial pneumonia group was collected when infection occurs, while that of no infection group was collected the time admitted to hospital within 24 h.6. PCT measureingPCT was measured by double-antibody sandwich assay (cobas e 601 electrochemical luminescence automatic immunoassay system, Roche Diagnostics Ltd.). The serum sensitivity was less than 0.02ng/ml, and the upper value of normal range was 0.05ng/ml.7. Statistical analysisNon-normal distribution measurement data was expressed as median (interquatile), rank sum test was used between groups. Normal distribution measurement data was expressed as mean ± standard deviation (x±s), two independent samples t-test was used between groups. Count data was expressed by rate,chi-square test was used between groups. Multivariate logistic regression analysis was used to identify the independent risk factors for bacterial pneumonia. The receiver operator characteristic(ROC) curve was used to analyze the predictive value of serum PCT level in bacterial pneumonia and its sepsis classification. All recorded data were statistically analyzed by SPSS 22.0 statistical software. P<0.05 was considered to be statistically significant.Results1. Baseline characteristics:184 patients with an initial diagnosis of acute stroke missed the inclusion criteria during the study, of which 20 patients were excluded due to the following resones:(1) co-infection before admission(n= 11); (2) renal insufficiency (n= 6); (3) cardiopulmonary resuscitation (n=2);(4) cirrhosis (n= 1). Finally,164 patients were included in the study.There were 114 patients in bacterial pneumonia group,They were 84 males(73.7%) and 30 females (26.3%). The patients had an mean age of 63.21 ± 13.66 years. And there were 50 patients in no infection group,They were 34 males(68%) and 16 females (32%). The patients had an mean age of 56.96 ± 13.45 years.At last, there were 23 patients in local infection subgroup,43 ones in sepsis subgroup,48 ones in severe sepsis subgroup.2. Comparisons of the population statistics and baseline data between the bacterial pneumonia group and no infection groupThere were no significant differences in gender, hypertension, diabetes, type of stroke, triglyceride, total cholesterol, high-density lipoprotein cholesterol and low density lipoprotein cholesterol between the bacterial pneumonia group and the no infection group(P>0.05);on the other hand, there were significant differences in age, fasting blood glucose, GCS score and the PCT level between two groups(P<0.05).3. Independent risk factors for bacterial pneumonia in patients with acute strokeTaking age>60 years old, fasting blood glucose level≥7mmol/L, GCS≤8 points and the PCT level>0.05 ng/mL as independent variable, bacterial pneumonia as dependent variables in multivariable logistic regression analysis, the results showed that the fasting blood glucose level≥7mmol/L (odds ratio[OR]8.488,95% confidence interval[CI]2.739-26.300; P<0.01),the GCS≤8 points(odds ratio[OR]11.361,95% confidence interval[CI]2.175 to 59.352;P<0.01),and the PCT level≥0.05 ng/mL (odds ratio[OR]16.715,95% confidence interval [CI] 5.075 to 55.049; P<0.01) were the independent risk factors for bacterial pneumonia.4. Comparison of the PCT level between the subgroups of bacterial pneumoniaThere were significant differences in the PCT level between local infection subgroup and severe sepsis subgroup, sepsis subgroup and severe sepsis subgroup. (P<0.01).On the other hand, There were no significant differences in the PCT level between local infection subgroup and sepsis subgroup. (P=0.681).Since there were no significant differences in the PCT level between local infection subgroup and sepsis subgroup, we combined the two subgroups into non-severe sepsis subgroup.The PCT level in severe sepsis subgroup was significantly higher than that in the non-severe sepsis subgroup[median(interquatile)] [0.835 (0.164-1.715) ng/mL vs.0.114 (0.073-0.275)ng/mL;Z=-4.818,P<0.01].5. the predictive value of the PCT level in acute stroke patients with bacterial pneumonia and sepsis classificationThe ROC curve analysis showed that it can better predict the occurrence of bacterial pneumonia in acute stroke patients with the PCT level of 0.07 ng/mL, the sensitivity was 84.2%, specificity was 74%;The area under the ROC curve was 0.865(95% CI 0.806-0.924;P<0.01); When the value of PCT was 0.05 ng/mL, the sensitivity was 94.7%, specificity was 54%; When it was 0.1 ng/mL, the sensitivity was 69.3%, specificity was 82%; When it was 0.25 ng/mL, the sensitivity was 43.9%, specificity was 98%.What’s more, the PCT level of 0.669 ng/mL can better predict the occurrence of severe sepsis in acute stroke patients with bacterial pneumonia, the sensitivity was 56.3%, specificity was 92.4%;The area under the ROC curve was 0.765(95% CI 0.672-0.858;P<0.01).Conclusions1. Acute stroke patients with bacterial pneumonia were older, had higher fasting blood glucose and lower GCS score, compared that with no infection, they all had a significant statistically difference(.P<0.05).2. The fasting blood glucose level>7mmol/L,the GCS<8 points and the PCT level≥0.05 ng/mL were the independent risk factors for acute stroke patients with bacterial pneumonia. It suggested that the serious neurologic impairment, higher fasting blood glucose and higher PCT level will increase the risk of bacterial pneumonia in patients with acute stroke.3. Acute stroke patients with bacterial pneumonia had higher PCT level significantly increased, compared that with no infection, it had a significant statistically difference(P<0.05).The PCT level increases gradually form no infection group to severe sepsis subgroup, suggested that acute stroke patients with bacterial pneumonia had higher PCT level,and the PCT level increased with the infection degree.4. Serum PCT level has significant predictive value for acute stroke patients with bacterial pneumonia, the best value point was 0.07 ng/mL, the sensitivity was 84.2%, specificity was 74%.In the actual clinical application, if the value point was 0.05 ng/mL,it has higher sensitivity;if it was 0.1 ng/mL, it has higher specificity; if it was 0.25 ng/mL, the specificity was 98%. It suggested that if the PCT level of acute stroke patients were higer than 0.25 ng/mL, it had the possibility of bacterial pneumonia.5. As for the predictive value of the PCT level in sepsis classification, the best value point was 0.669 ng/mL, the sensitivity was 56.3%, specificity was 92.4%.6. There were no significant differences in the PCT level between local infection subgroup and sepsis subgroup.It may be related to the relatively small sample sizes, the difference between sampling and nervous system lesions of acute stroke patients which effected sepsis judgment.Therefore, wheather the PCT levels could be used as a predictive index to judge the infection and sepsis classification in acute stroke patients, further large sample size and multicenter studies are needed to determine its clinical application value. |
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