Improving surgical wound classification—why it matters

AORN Journal,  August, 2004  by Lynn Devaney,  Katherine S. Rowell

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* SURGICAL WOUND CLASSIFICATION is an important predictor of the risk of postoperative surgical site infections. Wound classification also is used to analyze clinical, economic, and educational outcomes in national reports on quality.

* AS INTEGRAL MEMBERS of the health care team, nurses and physicians need to ensure that their data are correct, consistent, and reliable.

* THIS ARTICLE DELINEATES how one institution developed a multifaceted education program that resulted in a 26% improvement in the rate of correctly classified wounds.

* THE EDUCATION PROGRAM provided regular feedback of results that helped identify opportunities for improvement on a widespread level. AORN J 80 (August 2004) 208-223.

Classification of surgical wounds is considered in many outcomes studies as a predictor of postoperative infections and associated risks. It also affects analyses of surgeries and outcomes. The importance of risk-adjusted outcomes for reporting and improving clinical care is becoming increasingly evident to health care providers. Outcomes risk refers to the probability that a patient may have a poor outcome based on his or her preintervention condition. The higher a patient's preintervention risk status, the greater the chance he or she will experience a poor outcome for that episode of care if all other things are equal.

Risk adjustment can contribute to quality improvement by allowing outcomes to be compared fairly. Comparing outcomes is fair only if the comparison can be defined in risk-adjusted terms. As a result, education of clinical professionals who are responsible for correctly classifying and documenting data used in the calculation of those outcomes efforts must be intensified and formalized.

In a recent study of patient's with appendicitis, logistic models demonstrated that contaminated or infected wound classifications predicted increased morbidity. (1) Eighteen percent of the procedures, however, were classified incorrectly, and data were analyzed before the incorrect information was adjusted so the results of the study were suspect. This underscores the importance of data being consistent and accurate so it can be used by various health care providers. "Classification not only must be unbiased but also as accurate as possible if studies, experiments, and analyses are to be effective." (2)(p189) Nurses are in a unique position to actively collaborate with other health care team members to establish institutional policies for ensuring the accuracy of clinical data.

A retrospective study conducted at Massachusetts General Hospital, Boston, reviewed a random sample of wound class reporting. This article outlines an educational program that was developed based on the study's findings, which can be extrapolated for all surgical procedures, replicated for other educational endeavors, and tested with wound classification data at other institutions.

HISTORY OF SURGICAL WOUND CLASSIFICATION

Since the landmark 1964 National Academy of Sciences' National Research Council study on the use of ultraviolet lights in the OR, wounds have been classified by the level of risk of contamination. The four categories are

* clean,

* clean/contaminated,

* contaminated, and

* dirty/infected (Table 1).

This classification of the degree of infection in the surgical site during surgery has become the traditional system for predicting infection risk in surgical wounds. The classification system is based on the degree of bacterial load or contamination in a surgical wound. (3)

Other studies involving factors such as time of preoperative antibiotic administration, length of anesthesia, length of surgery, and new surgical instruments all take wound classification into account. (4-6) During the Study on the Efficacy of Nosocomial Infection Control (SENIC 1985), researchers developed a multivariate index for wound classification based on both the degree of contamination of the wound and the status of host resistance. (6) They found that the multivariate index, which includes other risk factors, such as length of OR time, whether the abdomen was opened, and wound classification, predicted surgical wound infection risk better than the traditional system alone. The SENIC 1985 risk index for surgical wound infections subsequently has been modified for use by the Centers for Disease Control and Prevention (CDC) as the National Nosocomial Infection Surveillance (NNIS) system. The NNIS system also includes the American Society of Anesthesiologists (ASA) classification of patients immediately before surgery. (7) Although these are modifications to the original system, the four basic classes still are used and are an essential core component to risk stratification.

STANDARDIZED WOUND CLASSIFICATION SYSTEM

Using a standardized system to classify wounds can help clinicians further understand and qualify postoperative surgical site infection rates and gain insight into planning treatment during and after surgery. For example, studies have demonstrated that clean wounds generally have a 1% to 5% risk of developing a superficial or deep postoperative infection, but dirty/infected wounds have a greater than 27% risk of developing one of these infections. (2,3) Timely or more aggressive treatments, such as preoperative and postoperative administration of antibiotics and increased frequency of dressing changes, can be determined in part by the wound class.