The impact of COVID-19 prevention measures on surgical wound infection rates post-cardiac surgery

Abstract

The COVID-19 pandemic had a huge impact on medical services. Several measures have been implemented to reduce the risk of viral transmission. In this paper, we assessed the impact of these measures on surgical wound infection rates in patients post-cardiac surgery. Hypothesis testing was used to compare post-cardiac operation infection rates between the year prior to the COVID-19 pandemic being declared and the first 13 months of the pandemic. The infection rates in 969 patients with operations between 01/03/2019 and 29/02/2020 were compared to those of 925 patients with cardiac surgery between 01/03/2020 and 31/03/2021. Infection rates for various operative urgencies and infection types were analysed. To compare infection rates, a two-tailed pooled z-test using the difference in infection proportions was performed. A 5% significance level was used and only categories with at least 10 patients in both the pre-covid and covid populations were tested. For leg infections, only operations involving coronary artery bypass grafting were included. To ensure that any differences in outcomes were not due to differences in patient demographics resulting in unequal operative risks, Euroscore II values, a measure of cardiac operative risk, were compared between the pre-covid and post-covid cohorts. The Mann-Whitney U-test was used to determine whether the distributions of Euroscore II values were likely to be drawn from the same population. A significance level of 5% was used. A total of 1901 patients (932 during the COVID-19 pandemic) were included in this study. Significant reduction in post-operative infections for all patients undergoing cardiac surgery from 4.3% of patients before COVID to 1.5% during the pandemic. During the pandemic, fewer elective and more urgent operations were performed. This study suggests a significant role of iatrogenic causes in wound infections prior to the pandemic. The implementation of COVID-19 prevention measures in healthcare providers can reduce surgical infection rates. As COVID-19-related restrictions have been eased, we suggest maintaining them in healthcare providers to reduce the incidence of surgical wound infections.