Standardized Approach to Wound Class and Impact on Surgical Site Infection Rate

Abstract

<h3>Background</h3> Surgical wound classification is an important factor for surgical site infection (SSI) surveillance and reporting. Intended to be a surgeon's decision, use of electronic medical records (EMRs) may instead enter a default value. During SSI review, Infection Preventionists (IPs) will change a wound class if the entered value does not match the operative note's description but may not adjust the EMR-generated denominator. We assessed SSI rates when adjusting both numerator and denominator based on IP review. <h3>Methods</h3> We performed a retrospective review of all National Health Safety Network (NHSN) SSIs at our institution between 1/1/2019–10/31/2021. A meaningful change was one made by an IP that would change a wound class from I or II to III or IV. We calculated rate using class I and II procedures only. We used percent meaningful of all changes to estimate IP-derived denominators. We compared rates generated by different numerators and denominators (EMR and IP) using Fisher's exact test. <h3>Results</h3> We identified 176 SSIs during the study period. Of the 82 changes made by IPs, 37 (45%) were meaningful. The proportion of meaningful changes ranged from 0-60% across all months. Out of 34 months, 21 (62%) showed a higher rate when using EMR class vs. IP class with the largest difference of 2.33 vs. 0.47 (p = 0.22). When comparing the alternative rate to IP class rate across all months, the rate was 1.14 vs. 0.91 (p=0.17). For both comparisons, September 2019 showed the largest monthly rate difference. <h3>Conclusions</h3> This study found that using EMR wound class for numerator and denominator increases the SSI rate, although not significantly different from IP class rate, even when adjusting the denominator for meaningful changes. Rates using IP class numerator and EMR class denominators are likely accurate.