Compare Reliability Of Different Inflammation-related Hematological Parameters In Infering Surgical Site Infection After Operation

ObjectiveTo compare the reliability of White Blood Cell(WBC)?Neutrophils(N)?Lymphocyte(L)and C-reactive protein(CRP)in inferring Surgical Site Infection after operation.MethodsChoose the patients of lumbar posterior operation from January 1st 2011 to December 31 st 2016 in first affiliated hospital of Soochow University.There were a total of 535 patients who had complete clinical statistics.Retrospective analysis of the change of inflammation-related hematological parameters were did during perioperative period.All patients satisfied the following conditions:(1)Diagnosis were explicit,and they all had explicit indication to surgery.All patients were operated in first affiliated hospital of Soochow University.(2)No infection in other systems and no history of malignant tumor.In addition,inflammation of digestive tract and Rheumatoid arthritis were ruled out.535 patients were divided into four groups(A,B,C,D).Group A: lumbar discectomy group(n=93);Group B: single or two-level fusion group(n=215);Group C: multi-level fusion(?3)or revision surgery group(n=206);Group D: infection group(n=21)which were diagnosised by bacteria positive or pus in re-operation.Inflammation-related hematological parameters during perioperative period were recorded.ResultHematological parameters before operation had no significant difference between all groups.First day after operation,leucocyte and nutrophils(10.60n/?L?7.96 n/?L)of group A were significantly lower than that of group B,C and D.2~3 days after operation,the CRP of group D(17.22mg/d L)were significantly higher than that of group A and B(11.74mg/dL,P<0.05;13.80mg/d L,P<0.05),but there were no significant difference between group C and D(16.30mg/dL,P>0.05).4~6 days after operation,leucocyte of group D(13.39n/?L)were higher than that of group A and B(9.05n/?L,P<0.05;11.91n/?L,P<0.05),leucocyte of group C were significantly higher than that of group A(9.05n/?L,P<0.05).Lymphocyte of group D(1.22n/?L)were significantly lower than that of group A,B and C(1.57 n/?L,P<0.05;1.66 n/?L,P<0.05;1.92 n/?L,P<0.05).CRP of group D were higher than that of group A and B(7.61 mg/dL,P<0.05;10.63 mg/d L,P<0.05).7~9 days after operation,CRP of group D were significantly higher than that of group A,B and C(5.10 mg/dL,P<0.05;8.93 mg/d L,P<0.05;10.04 mg/dL,P<0.05).CRP of group B and C were significantly higher than that of group A(P<0.05).Leucocyte and nutrophils of non-infection groups(A,B,C)increased significantly on the first day after operation.Then,these two parameters began to decrease except group A.7~9 days after operation,leucocyte and nutrophils were normalized to preoperative level.Tha maximum descent range of group A and B were between 4 to 6 days after operation,and that of group C was between 7 to 9 days after operation.Leucocyte and nutrophils of infection group(D)also increased significantly,and there was no evidence to decrease as it was always on a high level between 2 to 9 days after operation.CRP of all groups increased significantly on the first day after operation.2~3 days after operation,the CRP keeps rising and reaches its peak.4~6 days after operation,CRP of non-infection groups began to decrease.However,the CRP of infection group increased again on 7~9 days after operation.There were a significant decrease in Lymphocyte of group B and C on the first day after operation.2~9 days after operation,Lymphocyte of group B and C gradually increase to normal level.Lymphocyte of group D keeps to remain a low level between 4 to 9 days after operation.ROC for Neutrophils as a indicater to SSI was 0.705(P=0.015,95%CI 0.552~0.858),and for CRP,the value was 0.966(P=0.000,95%CI 0.924~1.000).ConclusionCRP maybe a reliable parameter for us to infer surgical site infection.When re-crease of CRP occurs,infection must be considered.The peak of CRP 2~3 days after operation was due to tissue damage,and the degree of increase was proportional to the degree of tissue damage.3 days after operation,CRP of non-infection patients began to decrease.It's hard to distinguish whether infection or re-crease of CRP when the tissue damage was serious,but if there was a decrease Lymphocyte at the same time,infection should be considered.Neutrophils is also a tool for us to infer surgical site infection,but the sensitive of Neutrophils was poor.The increase degree of Neutrophils was mainly related to internal fixation,and its normalized time was earlier than CRP.