Validação da procalcitonina como marcador precoce de infecção do sítio cirúrgico em pacientes submetidos à artroplastia

LIMA, Paulo Rogerio Gomes, VALIDATING PROCALCITONIN AS AN EARLY MARKER FOR INFECTION DIAGNOSIS OF ON SURGICAL SITES AFTER ARTHROPLASTY. 145s. Tese (PhD), Federal University of Pernambuco, Center of Medical Sciences. Postgraduate Program in Tropical Medicine, Recife, Pernambuco. Abstract: Infections in orthopedic surgeries remain an uncommon complication. However, when they occur, their effects may be devastating, with the loss of function and an increase in patient morbidity and mortality, and bringing about high hospital costs (Luessenhop, 1996). Infection rates in closed elective orthopedic surgery vary from 0.5% to 4%, and may reach 30% in open surgeries in referral centers (MacGraw, 1988; Perren, 2002). The definition of surgical site infection (SSI) is very variable, and covers a period of postoperative follow-up ranging from 02 months to 01 years depending of system used, if score ASESPSIS or CDC criteria. The relevance of this issue has motivated several researchers to investigate the factors that predispose patients to SSI as well as the development of more accurate test for diagnosis of SSI. Several markers have been proposed for early diagnosis of bacterial infections in surgical wound, but with little satisfactory results. Recently it has been proposed the use of procalcitonin. The aim of this study was to estimate the incidence of SSI in general and identify factors associated with it and sets out to assess the diagnostic value of PCT as an early marker for distinguishing an infectious process from a noninfectious process at the surgical site. The score ASEPSIS was used as the gold standard for presence of infection. The study consisted of two steps: case-control and a phase III validation study. Patients were placed into 03 groups (infected, noninfected and normal) determined by score ASEPSIS. In case-control study conducted univariate and multivariate analysis, calculating odds ratio and their confidence intervals and p values. In the phase III validation study comparing the mean PCT pre-operative and post-operative and estimate parameters related to test accuracy. The total of 590 patients were selected for the case-control study. The incidence of SSI was 11.5%. Factors that presented an independent association with SSI were: in the pre-operative period, the daily use of corticosteroids (OR=6.43), bronchitis (OR=5.55) and hemoglobin<12g/dl (OR=3.98); in the per-operative an ASA score>2(OR=5.03); and in the post-operative period, a surgical wound hematoma (OR=20.41). In the validation study cutoff point corresponding to the best accuracy was 0.065ng/ml. When comparing just the Infected and Noninfected groups, an area of 0.76 (95% CI, 0.683-0.833) under the ROC was encountered. Sensitivity of 60.3% (95% CI, 47.0-72.0), specificity of 85.1% (95% CI, 74.3-92.6), LR+ of 4.04 (95% CI, 3.3-5.0) and LRof 0.47 (95% CI, 0.2-0.9), were obtained. In a comparison of the Infected Group with the Noninfected and Normal considered jointly, the area under the ROC curve was 0.78 (95% CI, 0.737-0.832), sensitivity of 60.3% (95%CI 4, 47.7-72.0), specificity of 90.5% (95% CI, 86.0-94.0), LR+ of 6.36 (95% CI, 5.2-7.7), LRof 0.44 (95% CI, 0.3-0.7). For the positive test, the post-test probability was 65% and the post-test odds was 1.9 and for the negative test the post-test probability was 11% and the post-test odds was 0.1. We conclude, based on data from study that some of the independent risk factors identified can be minimized with proper procedures. Concerning the value of postoperative PCT above 0.065ng/ml in the first 24 hours after surgical procedure may help to distinguish, reasonably an infectious process from a noninfectious process on a postarthroplasty surgical wound. And even if the result test is above cutoff point determined, one should think starting antibiotic therapy, especially when that is accompanied by risk factor associated with SSI (bronchitis, use continuous steroids, anemia, ASA>2 or hematoma).