Significance of positive tracheal cultures in the 30 days following tracheostomy

Abstract

IntroductionPositive tracheal cultures obtained after tracheostomy are often considered organ/space surgical site infections by the National Surgical Quality Improvement Project. However, the definition of bacterial tracheitis after tracheostomy is not well described. ObjectiveTo determine the relationship of positive tracheal cultures in the 30 days following pediatric tracheostomy, antibiotic treatment of these cultures, and signs/symptoms of respiratory infection. MethodsA retrospective chart review was performed on subjects who underwent tracheostomy from November 2012–September 2017 at a tertiary care pediatric center. The following data was studied: positive tracheal cultures, antibiotic treatment for positive cultures, and other signs/symptoms of infection including fever and elevated white blood cell count. Descriptive data analysis was performed, and relative risk and 95% confidence intervals were calculated. Multivariate logistic regression model was used to assess independent association when applicable. ResultsThere were 173 subjects who met study criteria. Median age at tracheostomy was 4.6 months. Fifty-one percent (89/173) of subjects had at least one positive tracheal culture in the 30 days following tracheostomy. Of those subjects, 38% (34/89) had fever, 71% (32/45) had an elevated white blood cell count, 31% (22/72) had consolidation on chest imaging, 61% (54/89) had increased tracheal secretions, 70% (62/89) had increased ventilation requirements, and 60% (53/89) were treated with antibiotics for a diagnosis of tracheitis. There was no meaningful difference when comparing fever, increased white blood cell count, lung consolidation, increased tracheal secretions, or increased ventilation requirements in those with and without a positive tracheal culture or in those with and without antibiotic treatment for a positive culture. Multivariate logistic regression analysis showed that increased age at time of tracheostomy, more days on the ventilator after tracheostomy, and an increased number of positive cultures in the year after tracheostomy were related to having a positive tracheal culture within 30 days of tracheostomy. ConclusionFor post-operative pediatric tracheostomy subjects, there were no meaningful differences when comparing signs/symptoms of infection between those with and without a positive tracheal culture and between those with and without antibiotic treatment for a positive culture.