| Postoperative Bacterial Infection(POBI) is a common postoperative complication in neurosurgery department.The morbidity of which is approximately31%.The infection type includes surgical site infection, respiratory tract infection, urinary tract infection etc. Among these, infection of the respiratory tract are most frequent with an incidence rate of33.6%. Once the postoperative infection occured, It will lead to illness severity and poor prognosis, and definetly affecting the operation effect and enhance hospitalization and cost. thus early, accurate diagnosis of postoperative infection has important significance.Bacterial culture is " gold standard " diagnostic evidence of postoperative bacterial infection. But most types of POBIs have low positive rate of bacterial culture, and moreover, the time of germiculture is too long to achieve.Thus it is not conducive to the early postoperative infection diagnosis. The postoperative infection diagnosis mainly depends on the clinician’s experience, through the combination of clinical symptoms, clinical signs, laboratory examination and postoperative infection risk factors. How to make the postoperative infection diagnosis more convenient, earlier, more effective is still being the world scope of surgical research problem in the world. Body temperature, WBC, CRP and PCT are important parameters to evaluate the inflammatory reaction. Many studies have indicated that, in infectious disease, the changes of these parameters have important clinical significance. However, after operation or the trauma, due to a stress response, these parameters will be a certain degree of change. And as a result of these non-specific increase, the postoperative infection diagnostic value of these parameters is in doubt.CRP is an acute infection protein, mainly create by the liver cells stimulates by interleukin6, interleukin1.Tumor necrosis factor A may also produce a small amount of CRP while it stimulates the synthesis of inflammatory reaction. Normal synthesis rate of CRP is about1-10mg/d, acute inflammatory reaction will be increase to more than1G day. PCT is mainly composed of medullary thyroid cell secretion, while plasma procalcitonin levels is minimal(less than0.02ng/l). On bacterial endotoxin or operation trauma stimuli, plasmatic PCT can be detected in2hour, in6-8hours PCT concentration increased rapidly, and reaching a peak at12-48hours,2-3days will be restoration of normal. In the Department of Neurosurgery, the changes of these parameters and the degree of changes it is still not entirely clear. How to exclude the interference of operation or trauma has a important research value.The purpose of this research is based on the dynamic changes of BT, WBC, CRP, PCT of postoperative patients in Department of Neurosurgery, to explore a better way of using these paremeters in the early prediction of postoperative infection, thereby to improve the clinician’s diagnostic ability.Hence, to improve the postoperative prognosis of patients in Department of neurosurgery and reduce the hospital stay and antibiotics use rate. Therefore, study of the dynamic changes of BT, WBC, CRP and PCT has important clinical significance. Method and clinical data1.1clinical casesIn2011July to2012February,102patients without preoperative infection which underwent craniotomy or spinal operation are as the object of this study, including47men and55women. Age16to78years old, mean41.2±14.7years. Case inclusion criteria:(Dpreoperatively no occurrence of infection;②all operation are elective operation, all the patients received two generation cephalosporin antibiotic prophylaxis30min before the operation.1.2grouping methodA temperature above38℃defined as fever, WBC levels higher than10109/1defined as elevated, CRP levels higher than that of5mg/1defined as elevated. All PCT semi quantitative and quantitative data are divided into3levels:①<0.5ng/ml,②≥0.5and<2ng/ml,③≥2ng/ml.>0.5and<2ng/ml defined as elevated,≥2ng/ml defined as increased significantly. Records of body temperature include1day before operation and1,3,5,7days after operation, body temperature measurement rely on maximum temperature.Blood drawing is arranged in the preoperative1day and postoperative1,3,5,7days. Parameters include CRP, PCT and WBC.CRP detection using automated immunoturbidimetric assay (Olympus AU5400chemistry system instrument type:). In46cases of PCT detection using semi quantitative layer analysis method (instrument type:B.R.A.H.M.S.-Diagnostica GmbH, Henningsdorf),56cases of total quantitative indices using double antibody sandwich immunoassay chemiluminescence method.1.3statatical processingData statatical evaluate by SPSS13. Data expressed as mean±standard deviation. Different groups of the same parameter at the same time were analysis by independent samples t test. Levene’s test of homogeneity of variance was used to evaluate the same parameter at different time points for repeated measurement data. Fisher exact test was used to evaluate categorical variables.A Logistic regression models was used to evaluate the diagnostic value of dynamic changes of BT, WBC, CRP relavant to postoperative bacterial infection. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were determined for fever, CRP, and WBC count alone and in combinations. AUC values were reported with95%confidence interval (95%CI). P≤0.05that was statistically significant.Result3.1In102cases, the incidence rate of postoperative infection were17.6%. Pulmonary infection have the highest ratio of POBIs which were66.7%(12/18), followed by intracranial infection,22.2%(4/18). In this study, It was not significant of comparison of infection group and no infection group between age, type of operation, operation time, gender and pathologic types.(P>0.05). Diagnostic date of Postoperative pulmonary infection was in average of11.6days, postoperative intracranial infection was11days. Urinary tract infection and incision infection were only1cases, diagnosed date for12days and13days after surgery.3.2All patients’ preoperative body temperature were within normal range. Average BT level reached the peaked at first days after operation in non-infection group (38.05±0.68℃), afterwards which were showing a downward trend, on the third day after operation, it is below38℃(37.62±0.51℃), and continued to decline, to seventh days after operation, droped to37.36±0.51℃. The average BT level in the infection group after operation was always higher than38℃, on the first day after operation (38.66±1.05℃) reached the peak, and then decreased slightly, on third days after operation, it is38.23±0.53℃, and fifth days after operation increased again, and reached the peak value(38.67±0.62℃). 3.3Average BT level between the infection group and non-infection group are significant difference (F=53.97, P=0.000). In comparison of different time points, Average BT levels in the infection group are higher than which in the non-infection group in both postoperative4measuring point. In the third, fifth, seventh day after operation, the P values were:P=0.000<0.01, P=0.000<0.01, P=0.000<0.01, which are both significant difference. But in the first day after operation, the P value is0.358, which is no significant difference.3.4All patients’ preoperative WBC levels were within normal range. In non-infection group, average WBC level began to increase and reached the peak value (13.66±4.71109/1) at first day after operation, and then which were showing a continued downward trend, and after fifth day after operation, reduced to within normal range (9.56±2.65109/1). The average postoperative WBC level in infection group was higher than the normal level at all time, however the dynamic changes of which was similar to the BT level which were in infection group. On the first day after operation, it (13.98±2.56109/1) reached the peak, and decreased slightly, to seventh days after operation it increased again, and reached another peak value (14.55±5.76×109/1).3.5There are significant difference between average WBC level in infection groups and those in non-infection group(F=10.71, P=0.001). In both4postoperative measuring point, average WBC levels in infection group were higher than those in non-infection group. On Third day, fifth day, seventh day, the P values were: P=0.024<0.05, P=0.003<0.01, P=0.005<0.01, fifth and seventh day were significantly different. But after first day, the P value is0.684, no significant difference.3.6Average CRP levels of non-infectin cases at first day after operation started to increase(28.87±29.75mg/1), and reached the peak at third day after operation (64.08±43.62mg/1), and then which were showing a downward trend (31.65±35.68mg/1) to fifth day after operation, and continued to decline. But after seventh day, the average level of CRP is still much higher than the normal value (5mg/1). Average postoperative CRP level of infection cases on the first postoperative day began to rise (25.79±28.07mg/1), on the third day after operation (76.10±44.91mg/1) reached the peak, then presents a not too obvious decline trend, and after fifth day and seventh day which remained at a high level. Comparison of two groups of trend overall, downward trend of average level of CRP in non-infection group is still more obvious than those in infection group.3.7There are significant differences between Average CRP level in infection group and those in non-infection group(F=10.71, P=0.001). The average CRP level in infection group in4postoperative measuring point are both higher than those in non-infection group. P value of Fifth day, seventh day were:P=0.001<0.01, P=0.047<0.05. First day and third day after operation, the P values were0.675and0.249, there were no statistically difference.3.8The positive rate of serum PCT level was11.7%on first day after operation. On third day, it raised to21.1%. On fifth day and seventh day after operation, there are no signifivant changes compared with which on the first day after operation. These increases were all mild elevation (≥0.5<2ng/ml). In non-infection group, The positive rate increased on first days after operation to25.0%. But on third day, fifth day and seventh day, the PCT positive rate were higher and higher, respectively:62.5%,87.5%and87.5%. The significantly increased cases are more common in infection group rather than those in non-infection group.(≥2ng/ml). With the passage of time, the proportion of significantly increased cases were enhanced, on third day after operation which was25.0%(2/8), fifth day after operation which was up to50%(4/8), on seventh day after operation which was62.5%(5/8). 3.9Positive rate between each time point were not statistically different in non-infection group (X2=2.745, P=0.433>0.05). There are significant differences between each time point in infection group (X2=10.920, P=0.012<0.05). The positive rate of serum PCT are higher than those in non-infection group in both4postoperative measuring points. On Third day, P value was0.039<0.05. On fifth day and seventh day, the P values were respectively:P=0.000<0.01, which were significant difference. But on first day, the P value was0.982, which was no significant difference.3.10positive rate of PCT serum concentration which underwent by half quantitative method was62.5%, in comparison, quantitative method was36.9%, there was significant differences between two groups, X2=14.33, P=0.000<0.01.3.11If the peak BT level was within the first3days after surgery, droped,to normal and no rebound, value of0, otherwise, value of1. The peak WBC level was within first3days after surgery, droped to normal and no rebound in fifth day postoperatively, value of0, otherwise, value of1. The peak CRP level was within the first3days after surgery, and decreased to below35mg/1, and no rebound, value of0, otherwise, value of1, The Logistic analysis indicated that both the dynamic changes of BT (OR=10.113),WBC (OR=6.438) and CRP (OR=6.797) are the major risk factor relevant to POBIs. In102cases, the total positive rate was88.2%.3.12ROC curve to evaluate the diagnostic value of BT, CRP and WBC, Better performance (AUC>0.8) is seen if the parameters are used in combination Predictive value of combined of BT, WBC, CRP showed a high postoperative, area under ROC curve was0.907, sensitivity and specificity were90%and76.1%. ConclusionThis research shows that:1.In the first3days after operation, elevation of BT, WBC, CRP, PCT are common to those cases with or without POBIs.2.There are certain dynamic changes of BT, WBC, CRP after neurosurgical operation, the logistic analysis indicated that both the dynamic changes of these parameters are the major risk factor relevant to POBIs.3.The positive rate was statistically difference between PCT semi quantitative method and quantitative method.The positive rate of semi quantitative method was higher than the quantitative method. |
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