Finding a method for optimizing risk adjustment when comparing surgical-site infection rates.

OBJECTIVE: To investigate whether stratification of the risk of developing a surgical-site infection (SSI) is improved when a logistic regression model is used to weight the risk factors for each procedure category individually instead of the modified NNIS System risk index. DESIGN AND SETTING: The German Nosocomial Infection Surveillance System, based on NNIS System methodology, has 273 acute care surgical departments participating voluntarily. Data on 9 procedure categories were included (214,271 operations). METHODS: For each of the procedure categories, the significant risk factors from the available data (NNIS System risk index variables of ASA score, wound class, duration of operation, and endoscope use, as well as gender and age) were identified by multiple logistic regression analyses with stepwise variable selection. The area under the receiver operating characteristic (ROC) curve resulting from these analyses was used to evaluate the predictive power of logistic regression models. RESULTS: For most procedures, at least two of the three variables contributing to the NNIS System risk index were shown to be independent risk factors (appendectomy, knee arthroscopy, cholecystectomy, colon surgery, herniorrhaphy, hip prosthesis, knee prosthesis, and vascular surgery). The predictive power of logistic regression models (including age and gender, when appropriate) was low (between 0.55 and 0.71) and for most procedures only slightly better than that of the NNIS System risk index. CONCLUSION: Without the inclusion of additional procedure-specific variables, logistic regression models do not improve the comparison of SSI rates from various hospitals.     

Indices of surgical site infection risk and prediction of other adverse outcomes during hospitalization.

OBJECTIVE: To assess which adverse postsurgical outcomes are best predicted by the Study on the Efficacy of Nosocomial Infection Control (SENIC) index and the National Nosocomial Infection Surveillance system (NNIS) index. DESIGN: Prospective cohort study. SETTING: The service of general surgery at a tertiary care hospital. PATIENTS: A consecutive series of patients hospitalized for more than 1 day (n=2,989). RESULTS: The outcome best predicted by the SENIC and NNIS indices was assessed by estimating the area under the receiver operating characteristic (ROC) curve. The areas under the ROC curves for nosocomial infection and in-hospital death were higher for the NNIS index than they were for the SENIC index (P<.05). The NNIS index predicted in-hospital death better than it predicted surgical site infection (area under the ROC curve+/-SE, 0.836+/-0.022 vs 0.689+/-0.017; P=.001). CONCLUSIONS: The NNIS index is superior to the SENIC index for all adverse postsurgical outcomes. Its ability to predict in-hospital mortality is clearly better than its ability to predict surgical site infection.     

Performance of the national nosocomial infections surveillance risk index in predicting surgical site infection in australia.

BACKGROUND: The Victorian Hospital Acquired Infection Surveillance System (VICNISS) hospital-acquired infection surveillance system was established in 2002 in Victoria, Australia, and collates surgical site infection (SSI) surveillance data from public hospitals in Australia. OBJECTIVE: To evaluate the association between the US National Nosocomial Infections Surveillance (NNIS) system's risk index and SSI rates for 7 surgical procedures. METHODS: SSI surveillance was performed with NNIS definitions and methods for surgical procedures performed between November 2002 and September 2004. Correlations were assessed using the Goodman-Kruskal gamma statistic. RESULTS: Data were submitted for the following numbers of procedures: appendectomy, 545; coronary artery bypass graft (CABG), 4,632; cholecystectomy, 1,001; colon surgery, 623; cesarean section, 4,857; hip arthroplasty, 3,825; and knee arthroplasty, 2,416. NNIS risk index and increasing SSI rate were moderately well correlated for appendectomy ( gamma =0.55), colon surgery ( gamma =0.48), and cesarean section ( gamma =0.42). A fairly positive correlation was found for cholecystectomy ( gamma =0.17), hip arthroplasty ( gamma =0.2), and knee arthroplasty ( gamma =0.16). However, for CABG surgery, a poor association was found ( gamma =0.02). CONCLUSIONS: The NNIS risk index was positively correlated with an increasing SSI rate for all 7 procedures; the strongest correlation was found for appendectomy, cesarean section, and colon surgery, and the poorest correlation was found for CABG surgery. We believe that risk stratification with the NNIS risk index is appropriate for comparison of data for most procedures and superior to use of no risk adjustment. However, for some procedures, particularly CABG, further studies of alternative risk indexes are needed to better stratify patients.     

Applicability of two surgical-site infection risk indices to risk of sepsis in surgical patients.

OBJECTIVE: To compare the ability of the Study of the Efficacy of Nosocomial Infection Control (SENIC) and the National Nosocomial Infection Surveillance (NNIS) indices to predict the development of nosocomial sepsis in subjects undergoing surgery. DESIGN: 1-year prospective case-control study. SETTING: A tertiary-care center in Spain. PATIENTS: Cases were surgical patients with nosocomial sepsis defined using the criteria of the Consensus Conference on Sepsis, identified by daily prospective surveillance. METHODS: Controls were randomly selected from the daily list of surgical inpatients. Data were prospectively collected. To determine whether either index added explanatory information to the other, two methods were used. The first method involved computing a set of residuals for both variables. Residuals and primary variables were introduced in logistic regression models. The second method evaluated both indices with the Goodman-Kruskal (G) nonparametric coefficient. RESULTS: 99 cases and 97 controls were included. After controlling for confounders, both the SENIC index (P<.001) and the NNIS index (P=.04) showed a significant trend. Residuals of the SENIC index added discriminating ability to the NNIS index, whereas residuals of the NNIS index did not improve the prediction ability of the SENIC index. Similar results were yielded by the G statistic: the SENIC index showed higher predictive power than the NNIS index (G=0.56 vs G=0.41). CONCLUSIONS: Both indices performed about equally well for discriminating risk of nosocomial sepsis. The SENIC index had a somewhat better ability than the NNIS index only when the number of discharge diagnoses (not truly a predictive factor) were involved in the calculation of the SENIC index.     

Surgical site infection in patients submitted to orthopedic surgery: the NNIS risk index and risk prediction

The applicability of the risk index for surgical site infection of the National Nosocomial Infection Surveillance (NNIS) has been evaluated for its performance in different surgeries. In some procedures, it is necessary to include other variables to predict. Objective: to evaluate the applicability of the NNIS index for prediction of surgical site infection in orthopedic surgeries and to propose an alternative index. The study involved a historical cohort of 8236 patients who had been submitted to orthopaedic surgery. Statistical analysis was performed using multivariate logistic regression to fit the model. The incidence of infection was 1.41%. Prediction models were evaluated and compared to the NNIS index. The proposed model was not considered a good predictor of infection, despite moderately stratified orthopedic surgical patients in at least three of the four scores. The alternative model scored higher than the NNIS models in the prediction of infection.     

The national nosocomial surveillance network in Hungary: results of two years of surgical site infection surveillance

In 2004, a secure web-based national nosocomial infection surveillance system was established in Hungary. The system, named NNSR (Nemzeti Nosocomiális Surveillance Rendszer), is based on the US National Nosocomial Infection Surveillance System (NNIS). Surgical procedures, definitions, surveillance methodology and patient risk indices are those established by NNIS. In this paper, we present the results of the first two years of the surgical patient component of our system. During this period, 41 hospitals participated and selected 11 surgical procedures for surveillance. Altogether 15812 procedures were surveyed and 360 resulting surgical site infections (SSI) were recorded. The overall SSI rate was 2.27%. The most commonly selected procedures and corresponding SSI rates were caesarean section (1.31%), herniorrhaphy (2.09%), cholecystectomy (1.52%) and hip replacement (2.91%). Standardised infection ratios (SIR) were calculated for chosen surgical procedures in order to compare against NNIS published rates. SSI rates for colonic surgery, caesarean section and mastectomy were lower than expected according to the NNIS data but higher for cholecystectomy, herniorrhaphy and hip prosthesis infection rates. We intend to recruit more participating hospitals, leading to a robust national database that can be used to target infection control interventions for patients in Hungary.     

Increase in the rate of sternal surgical site infection after coronary artery bypass graft: a marker of higher severity of illness.

OBJECTIVE: To evaluate factors related to a gradual rise in sternal surgical site infection (SSI) rates. DESIGN: Retrospective cohort study. SETTING: A 608-bed, tertiary care teaching hospital. PATIENTS: All patients who underwent coronary artery bypass graft (CABG) from January 2000 through September 2004. RESULTS: Of 3,578 patients who underwent CABG, 144 (4%) had sternal SSI. There was an increase in infection rate, with a marked reduction in the number of operations per year. The percentage of patients with peripheral vascular disease increased from 12% to 24.3% (P<.001), and the percentage with congestive heart failure increased from 17% to 22% (P<.001). Between 2002 and 2004, the mean duration of surgery increased from 233 to 290 minutes (P<.001), the percentage of patients with a National Nosocomial Infections Surveillance System (NNIS) risk index of 2 increased from 14.3% to 38% (P<.001), and the percentage of patients with a postoperative stay in the intensive care unit of greater than 72 hours increased from 29% to 40.6% (P<.001). Multivariate analysis showed diabetes mellitus, peripheral vascular disease, obesity, duration of surgery, and postoperative stay in the intensive care unit of greater than 72 hours to be independently associated with infection. CONCLUSIONS: An increase in infection in the CABG population not associated with an outbreak may be a reflection of a change in the severity of illness. Preoperative, intraoperative, and postoperative markers for increased infection risk may be used, in addition to the NNIS risk index, to assess the patient population risk.     

Nosocomial infection, indices of intrinsic infection risk, and in-hospital mortality in general surgery

The objectives of this paper are to assess whether two indices of intrinsic infection risk (the SENIC and the NNIS index) predict in-hospital mortality and the attributable in-hospital mortality due to nosocomial infection in surgical patients. A prospective study on 4714 patients admitted to three hospitals has been carried out. The relative risk and its 95% confidence interval (CI) were estimated. Multiple-risk factors adjusted for odds ratios (OR) were yielded by logistic regression analysis. Overall, 119 patients (2.5%) died before hospital discharge. Both the SENIC and the NNIS indices were related to in-hospital mortality in crude data. After controlling for several variables (age, sex, ASA score, cancer, renal failure, diabetes mellitus, stay at the ICU), the SENIC index did not show any significant trend with mortality (P = 0.252), whereas the trend was significant for the NNIS index (P < 0.001). Risk of death in patients with one nosocomial infection was 7.5%, and in patients developing more than one nosocomial infection was 17.1%. After adjusting for several confounding variables, the development of an organ/space surgical site infection was significantly related to mortality (OR = 4.5, 95% CI 1.5-15.6) as was blood infection (OR = 17.3, 95% CI 3.5-87.0). The association of a surgical site infection and either a respiratory tract infection or a blood infection also increased significantly the risk of in-hospital mortality (OR = 3.3, 95% CI 1.2-8.7). In conclusion, the NNIS index is a good predictor of in-hospital mortality. Patients developing an organ/space surgical site infection and/or a blood infection have an increased risk of in-hospital mortality.     

Duration of operation as a risk factor for surgical site infection: comparison of English and US data

T times are used to categorize surgical procedures into long and short durations. They constitute a part of the US National Nosocomial Infection Surveillance (NNIS) risk index that is widely used internationally in surveillance for surgical site infections (SSIs). The objective of this study was to compare the US NNIS T times with data collected in England. The Surgical Site Infection Surveillance Service in England holds data collected by 168 hospitals in 13 categories of surgical procedures between 1997 and 2002. The 75(th) percentile and corresponding T time were calculated from English data and compared with US times. Differences in rates of SSI above and below the T times were compared. Graphical methods were used to assess the cut points that exhibited an association with risk of SSI. The results show that English and US T times were the same for all surgical categories except coronary artery bypass graft and vascular surgery, where the English T time was 4 h. The 75(th) percentile time for hip hemiarthroplasties was 40 min less than for total hip replacements (THR). Although the incidence of SSI in THR was significantly higher in operations lasting for longer than the T time (P<0.05), no association between risk of SSI and T times set at 1, 1.5 or 2 h was observed for hip hemiarthroplasties. In conclusion, operations lasting for longer than the T time were associated with a higher risk of SSI in most categories. In the hip prosthesis category, this association only applied to THR.     

Outbreak of surgical wound infections associated with total hip arthroplasty.

OBJECTIVES: Describe an outbreak of surgical wound infections associated with total hip arthroplasty; identify risk factors for surgical wound infection during the pre-outbreak and outbreak periods. SETTING: A 100-bed hospital. From May 1 to September 30, 1988, 7 of 15 patients who underwent total hip arthroplasty developed surgical wound infections from Staphylococcus aureus (5), Enterobacter cloacae (1), beta-hemolytic streptococci (1), enterococci (1), coagulase-negative staphylococci (1), and Escherichia coli (1) (attack rate = 46.7%). DESIGN: Retrospective cohort studies comparing surgical wound infection rates by patient- and procedure-related risk factors during the pre-outbreak and outbreak periods were conducted. Drop plate quantitative air culturing was conducted in 10 consecutive total hip arthroplasties in the subsequent 6 months. RESULTS: Rates of surgical wound infection were surgically higher for arthroplasties in which no intraoperative prophylactic antimicrobials were given (44% versus 8%, relative risk [RR] = 5.4, p = .01), or in which the posterior approach (20% versus 3%, RR = 6.7, p = .04) or a specific prosthesis (39% versus 5%, RR = 6.3, p = 0.01) was used. The surgical wound infection rate was highest when one circulating nurse, Nurse A, assisted (47% versus 4%, RR = 12.8, p less than .001). Logistic regression analysis identified use of the posterior approach (RR = 1.8, p = .04) and Nurse A's participation (RR = 5.0, p less than .001) as independent risk factors for surgical wound infection. Interviews of the nursing supervisor indicated that Nurse A had recurrent dermatitis on her hands. During 6 months following Nurse A's reassignment, the rate declined significantly (from 7/15 to 0/10, p = .01). Drop plate culturing yielded 2 to 10 colonies per plate of organisms that did not match outbreak organisms. CONCLUSIONS: Outbreaks associated with personnel generally involve only 1 species. In this outbreak, Nurse A (possibly because of her dermatitis), technique, the posterior approach, and/or other undetermined factors were the primary predictors of surgical wound infection.     

Risk stratification for surgical site infections in Australia: evaluation of the US National Nosocomial Infection Surveillance risk index

This study evaluated the US National Nosocomial Infection Surveillance (NNIS) risk index (RI) in Australia for different surgical site infection (SSI) outcomes (overall, in-hospital, post-discharge, deep-incisional and superficial-incisional infection) and investigated local risk factors for SSI. A SSI surveillance dataset containing 43 611 records for 13 common surgical procedures, conducted in 23 hospitals between February 2001 and June 2005, was used for the analysis. The NNIS RI was evaluated against the observed SSI data using diagnostic test evaluation statistics (sensitivity, specificity, positive predictive value, negative predictive value). Sensitivity was low for all SSI outcomes (ranging from 0.47 to 0.69 and from 0.09 to 0.20 using RI thresholds of 1 and 2 respectively), while specificity varied depending on the RI threshold (0.55 and 0.93 with thresholds of 1 and 2 respectively). Mixed-effects logistic regression models were developed for the five SSI outcomes using a range of available potential risk factors. American Society of Anaesthesiologists (ASA) physical status score >2, duration of surgery, absence of antibiotic prophylaxis and type of surgical procedure were significant risk factors for one or more SSI outcomes, and risk factors varied for different SSI outcomes. The discriminatory ability of the NNIS RI was insufficient for its use as an accurate risk stratification tool for SSI surveillance in Australia and its sensitivity was too low for it to be appropriately used as a prognostic indicator.     

Incidence of surgical-site infections and the validity of the National Nosocomial Infections Surveillance System risk index in a general surgical ward in Santa Cruz, Bolivia.

OBJECTIVES: To estimate the frequency of and risk factors for surgical-site infections (SSIs) in Bolivia, and to study the performance of the National Nosocomial Infections Surveillance (NNIS) System risk index in a developing country. DESIGN: A prospective study with patient follow-up until the 30th postoperative day. SETTING: A general surgical ward of a public hospital in Santa Cruz, Bolivia. PATIENTS: Patients admitted to the ward between July 1998 and June 1999 on whom surgical procedures were performed. RESULTS: Follow-up was complete for 91.5% of 376 surgical procedures. The overall SSI rate was 12%. Thirty-four (75.6%) of the 45 SSIs were culture positive. A logistic regression model retained an American Society of Anesthesiologists score of more than 1 (odds ratio [OR], 1.87), a not-clean wound class (OR, 2.28), a procedure duration of more than 1 hour (OR, 1.81), and drain (OR, 1.98) as independent risk factors for SSI. There was no significant association between the NNIS System risk index and SSI rates. However, a "local" risk index constructed with the above cutoff points showed a linear trend with SSI (P < .001) and a relative risk of 3.18 for risk class 3 versus a class of less than 3. CONCLUSIONS: SSIs cause considerable morbidity in Santa Cruz. Appropriate nosocomial infection surveillance and control should be introduced. The NNIS System risk index did not discriminate between patients at low and high risk for SSI in this hospital setting, but a risk score based on local cutoff points performed substantially better.     

Comparative analysis of 75th percentile durations for neurosurgical procedures in France and in US National Noscomial Infection Surveillance System data

The duration of surgical procedures and the 75th percentiles of those durations are considered in calculation of the US National Nosocomial Infection Surveillance (NNIS) system risk index score. To compare the durations of neurosurgical procedures in a hospital in western France with the durations in the NNIS data, 6,136 neurosurgical patients were followed up to determine surgical site infection rates. The surgical site infection rate was 1.9%, and the 75th percentile durations were lower than those in the NNIS data. The values from the NNIS data are thus inadequate for this neurosurgical center.     

Surveillance for surgical site infection after hospital discharge: a surgical procedure-specific perspective.

OBJECTIVE: To estimate the rate of surgical site infection (SSI) occurring after hospital discharge, to evaluate whether limiting surveillance to inpatients underestimates the true rate of SSI, and to select surgical procedures that should be included in a postdischarge surveillance program. DESIGN: Prospective surveillance study. SETTING: A surgical ward at a university teaching hospital in Italy. PATIENTS: A total of 264 surgical patients were included in the study. RESULTS: The global SSI rate was 10.6% (28 patients); 17 (60.2%) of patients with an SSI developed the infection after hospital discharge. The overall mean length of postoperative stay (+/-SD) for patients who acquired a postdischarge SSI was 4.9+/-3.7 days, and SSI was diagnosed a mean duration (+/-SD) of 11.5+/-4.5 days after surgery. Among procedures with postdischarge SSIs, those classified by the National Nosocomial Infections Surveillance system (NNIS) as herniorrhaphy, mastectomy, other endocrine system, and other integumentary system were associated with a mean postoperative stay that was less than the mean time between the operation and the onset of SSI. Four (36%) of in-hospital SSIs occurred after procedures with an NNIS risk index of 0, and 7 (64%) occurred after procedures with an NNIS risk index of 1 or higher. Of the 17 SSIs diagnosed after discharge, 14 procedures (82%) had an NNIS risk index of 0, compared with 3 procedures (18%) with an NNIS risk index of 1 or higher. CONCLUSIONS: Our results revealed an increased risk of postdischarge SSI after some types of surgical procedures and suggest that there is an important need to change from generalized to NNIS operative category-directed postdischarge surveillance, at least for procedures locally considered to be high-risk.     

Active surveillance of nosocomial infections in heart surgery patients: implementation of the American National Nosocomial Infections Surveillance (NNIS) System in a large hospital in Rome

The authors present the implementation of the American NNIS System method for active surveillance in the heart surgery and its intensive care unit (ICU) of a large hospital in Rome (almost 1.000 beds). This surveillance was based on full time infection control professionals. Device-associated infection rates were calculated for adult ICU surveillance component. For surgical patient surveillance component we used the surgical site infection (SSI) risk index based on wound class, duration of operation and American Society of Anesthesiology score. The NNIS System method allowed us to understand the most relevant problems in heart surgery patients: in comparison with NNIS data, we found high rates of SSIs both in procedures on valves and in coronary artery bypass grafts. The central line-associated bloodstream infection rate was higher than the American median rate. Therefore, we decided to focus on surgical risk factors linked to SSIs and to revise recommendations for intravascular-device use. In conclusion, in our experience the NNIS System method proved to be a very useful and versatile tool for nosocomial infections active surveillance.     

Risk factors for surgical site infection in children.

OBJECTIVES: To assess the appropriateness of using the indices developed by the Study on the Efficacy of Nosocomial Infection Control (SENIC) and the National Nosocomial Infections Surveillance (NNIS) project to determine risk factors for surgical site infection (SSI) in children and, if not appropriate, to explore the factors related to SSI in children so these factors could be used in a risk index for pediatric patients. DESIGN: Cohort study during more than 4 years. SETTING: La Paz University Hospital, a national reference center that serves Health Area 5 of Madrid, Spain, which has approximately 500,000 inhabitants. PATIENTS: Convenience sample consisting of the 3,646 children admitted for surgery who had a postsurgical stay of more than 2 days. RESULTS: A model with 8 predictive factors (degree of surgical contamination; duration of surgery; type of surgery; use of a peripheral venous catheter, central venous catheter, or urinary catheter; number of diagnoses; and SSI exposition time) was created. Its relation to the SSI rate was better than that of the SENIC or NNIS indices. Its sensitivity, specificity, and area under the receiver-operating characteristic curve were higher than that of the SENIC index. CONCLUSIONS: The model that we created seems to be more adequate for predicting SSI and evaluating pediatric patients' intrinsic risk than the SENIC and NNIS indices.     

A new surgical-site infection risk index using risk factors identified by multivariate analysis for patients undergoing coronary artery bypass graft surgery.

OBJECTIVES: To develop a new, simple, and practical risk index for patients undergoing coronary artery bypass graft (CABG) surgery, to develop a preoperative risk index that is predictive of surgical-site infection (SSI), and to compare the new risk indices with the National Nosocomial Infections Surveillance (NNIS) System risk index. DESIGN: Potential risk factor and infection data were collected prospectively and analyzed by multivariate analysis. Two new risk indices were constructed and then compared with the NNIS System risk index for predictive power for SSI. SETTING: Alfred Hospital is a 350-bed, university-affiliated, tertiary-care referral center. The cardiothoracic unit performs approximately 650 CABG procedures per year. PATIENTS: All patients undergoing CABG surgery within the cardiothoracic unit at Alfred Hospital between December 1, 1996, and September 29, 2000, were included. RESULTS: Potential risk factor data were complete for 2,345 patients. There were 199 SSIs. Obesity (odds ratio [OR], 1.78; 95% confidence interval [CI95], 1.24 to 2.55), peripheral or cerebrovascular disease (OR, 1.64; CI95, 1.16 to 2.33), insulin-dependent diabetes mellitus (OR, 2.29; CI95, 1.15 to 4.54), and a procedure lasting longer than 5 hours (OR, 1.75; CI95, 1.18 to 2.58) were identified as independent risk factors for SSI. With the use of a different combination of these risk factors, two risk indices were constructed and compared using the Goodman-Kruskal nonparametric correlation coefficient (G). kisk index B had the highest G value (0.3405; CI95, 0.2245 to 0.4565), compared with the NNIS System risk index G value (0.3142; CI95, 0.1462 to 0.4822). The G value for risk index A, constructed from preoperative variables only, was 0.3299 (CI9,, 0.2039 to 0.4559). CONCLUSION: Two new risk indices have been developed. Both indices are as predictive as the NNIS System risk index. One of the new risk indices can also be applied preoperatively.     

The standardized incidence ratio as a reliable tool for surgical site infection surveillance.

OBJECTIVE: To evaluate whether the standardized incidence ratio (SIR) is a more reliable tool for comparing rates and temporal trends of surgical site infection (SSI) in surgery wards than the incidence rate among patients with an National Nosocomial Infections Surveillance system (NNIS) risk index category of 0. DESIGN: Observational, prospective cohort study in a sequential SSI surveillance system. SETTING: Volunteer surgery wards in a surveillance network in northern France that annually conducted SSI surveillance for 3 months from 1998 to 2000. METHODS: The incidence rate was the number of SSIs divided by the number of patients included, stratified by the NNIS risk index category. SIR was the observed number of SSIs divided by the expected number computed using a multiple regression model. RESULTS: Overall, 26,904 patients in 67 surgery wards were enrolled. Between 1998 and 2000, the SSI incidence rate among patients with NNIS risk index category 0 decreased from 2.1% to 1.4%, which was a 33% reduction (P=.002). The SIR decreased from 1.2 (95% confidence interval [CI], 1.1-1.3) to 0.8 (95% CI, 0.7-0.9), which was a 20% decrease per year and an overall 33% reduction. The number of SSIs was significantly higher than expected in 17 of 201 surveillance periods over the 3 years. The classification of the wards according to the 2 indicators over the 3 years showed that wards with a high SIR did not consistently have the highest SSI incidence rate among patients with NNIS risk index category 0, partly because the type of surgical procedure and the duration of follow-up are not taken into account in the NNIS risk index. CONCLUSION: SIR should be considered a reliable indicator to estimate the reduction in SSI incidence that results from implementation of infection control policies and for comparison of SSI rates between wards.     

择期脑肿瘤切除术患者手术部位感染危险因素

目的探讨择期脑肿瘤切除患者手术部位感染的危险因素,为临床防治提供依据。方法前瞻性监测2013年4—9月及2014年4—9月某院神经外科进行择期脑肿瘤切除术的患者,制定监测方案及个案调查表,收集其基本资料、手术情况、术后感染症状/体征及实验室检查结果、感染有关因素、抗菌药物使用情况等,并分析其感染危险因素。结果共调查205例患者,其中23例发生手术部位感染,发病率为11.22%;单因素分析结果显示,身体质量指数(BMI)、NNIS评分、脑脊液漏与手术部位感染的发生有关(均P0.05);logistic回归分析显示,NNIS评分高、脑脊液漏是择期脑肿瘤切除术患者手术部位感染发生的独立危险因素(均P0.05)。结论择期脑肿瘤切除术患者手术部位感染发病率较高,在临床工作中,应针对包括脑脊液漏在内的不同危险因素采取相应的预防措施。