Surgical site infections in patients undergoing major operations in a university hospital: using standardized infection ratio as a benchmarking tool.

BACKGROUND Because patterns of infection acquired in patients undergoing operation are ever changing, it is an essential part of nosocomial infection surveillance programs to periodically document the epidemiologic features of infection in these patients. This study was conducted with the primary intention of describing the incidence and risk factors of the surgical site infection (SSI). METHODS We performed a prospective study in patients undergoing certain major operations at a 750-bed university hospital in Thailand. The National Nosocomial Infection Surveillance (NNIS) system method and criteria were used for identifying and diagnosing infection. The infection rates were benchmarked with the NNIS report by means of indirect standardization and reported in terms of standardized infection ratio. Risk factors for SSI were evaluated using the multiple logistic regression model. RESULTS From September 1998 to March 2000, the study included 4193 patients with 4437 major operations. The study identified 192 SSIs, 76 urinary catheter-related urinary tract infections, 26 central line-related bloodstream infections, and 39 instances of ventilator-associated pneumonia (VAP), yielding an infection rate of 4.3 SSIs/100 operations, 11.0 catheter-related urinary tract infections/1000 urinary catheter-days, 6.1 central line-related bloodstream infections/1000 central line-days, and 11.0 VAPs/1000 ventilator-days. When compared with data from NNIS, the standardized infection ratio of SSI, catheter-related urinary tract infection, central line-related bloodstream infection, and VAP were 2.3, 2.1, 1.1, and 0.8, respectively. The factors that significantly associated with SSI were duration of operation in minutes, American Society of Anesthesiologists (ASA) class, and degree of wound contamination. CONCLUSION All of the infection rates identified, except VAP, were higher than the average NNIS rates. The risk factors for SSI were prolonged duration of operation, poor physical status according to ASA classification, and higher degree of wound contamination.

[1]  R. Haley,et al.  Identifying patients at high risk of surgical wound infection. A simple multivariate index of patient susceptibility and wound contamination. , 1985, American journal of epidemiology.

[2]  P. Gastmeier,et al.  Surveillance of Hospital-Acquired Infection in England, Germany, and The Netherlands Will International Comparison of Rates Be Possible? , 2001, Infection Control & Hospital Epidemiology.

[3]  R. Gaynes,et al.  Surgical site infection (SSI) rates in the United States, 1992-1998: the National Nosocomial Infections Surveillance System basic SSI risk index. , 2001, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[4]  R. Gaynes,et al.  Nosocomial infections in surgical patients in the United States, January 1986-June 1992. National Nosocomial Infections Surveillance (NNIS) System. , 1993 .

[5]  P. F. Freitas,et al.  Suitability of the NNIS Index for Estimating Surgical-Site Infection Risk at a Small University Hospital in Brazil , 2001, Infection Control & Hospital Epidemiology.

[6]  N. Breslow,et al.  Statistical methods in cancer research. Volume II--The design and analysis of cohort studies. , 1987, IARC scientific publications.

[7]  W J Martone,et al.  CDC definitions of nosocomial surgical site infections, 1992: a modification of CDC definitions of surgical wound infections. , 1992, American journal of infection control.

[8]  Nnis System.  National Nosocomial Infections Surveillance (NNIS) System Report, data summary from January 1992 through June 2003, issued August 2003. , 2003, American journal of infection control.

[9]  R. Gaynes,et al.  Nosocomial Infections in Surgical Patients in the United States, January 1986-June 1992 , 1993, Infection Control & Hospital Epidemiology.

[10]  CDC definitions for nosocomial infections, 1988. , 1989, The American review of respiratory disease.

[11]  M. Delgado-Rodríguez,et al.  Nosocomial Infections in Surgical Patients: Comparison of Two Measures of Intrinsic Patient Risk , 1997, Infection Control & Hospital Epidemiology.

[12]  A. Hall,et al.  Hospital-acquired infections among surgical patients in a Brazilian hospital. , 1997, The Journal of hospital infection.

[13]  V. H. Nguyen,et al.  Incidence and Predictors of Surgical-Site Infections in Vietnam , 2001, Infection Control & Hospital Epidemiology.

[14]  T. L. Gustafson,et al.  Practical risk-adjusted quality control charts for infection control. , 2000, American journal of infection control.

[15]  Curtis P. McLaughlin,et al.  Continuous Quality Improvement in Health Care: Theory, Implementation, and Applications , 1994 .

[16]  D. Goldmann,et al.  Risk-adjusted infection rates in surgery: a model for outcome measurement in hospitals developing new quality improvement programmes. , 2000, The Journal of hospital infection.

[17]  M. Decker,et al.  An Epidemiologic Approach to Quality Improvement, Quality Assurance, and Clinical Research , 1992, Infection Control & Hospital Epidemiology.

[18]  E. Spitznagel,et al.  ASA Physical Status Classifications: A Study of Consistency of Ratings , 1978, Anesthesiology.

[19]  J M Hughes,et al.  CDC definitions for nosocomial infections, 1988. , 1988, American journal of infection control.

[20]  Plsek Pe,et al.  Techniques for managing quality. , 1995 .

[21]  Sankey V. Williams,et al.  Mortality and complications associated with laparoscopic cholecystectomy. A meta-analysis. , 1996, Annals of surgery.