Effects of differences in perioperative mouthwash on oral bacteria and postoperative complications: Sub-analysis of a mouthwash intervention study

Background Perioperative oral management (POM) reduces the risk of postoperative complications. We previously conducted a randomized controlled feasibility study of POM using povidone iodine (PVP-I) or 0.05% cetylpyridinium chloride (CPC) and found that perioperative self-care with CPC mouthwash may support antibiotic-induced changes in the oral flora. In this sub-analysis, we investigated how use of PVP-I and CPC products in the perioperative period affects postoperative systemic inflammation. Methods The subjects were 78 patients scheduled to undergo surgery under general anesthesia who received POM with random assignment of mouthwash containing PVP-I (n = 38) or CPC (n = 40). White blood cell (WBC) count, serum CRP level, and fever were used as postoperative inflammatory markers for comparison between the groups. Bacteria were collected from the dorsal surface of the tongue, and the total bacterial count, operational taxonomic unit (OTU) count, and Shannon Index were analyzed. Results Perioperative inflammatory indices such as WBC, CRP, and body temperature were compared between groups, and only mean CRP was significantly lower in the CPC group than PVP-I group (7.0 (range: 0-19.2) mg/dL vs. 5.3 (range: 0.1–21.0) mg/dL). A significant difference was found in the CRP level between the two groups. The incidence of high CRP (≥ 5 mg/dL) was significantly lower in the CPC group (16/40, 40%) compared to the PVP-I group (24/38, 63.2%). In multivariate analysis, the intervention product was a significant independent factor related to high CRP. The lower CRP in the CPC group was associated with a lower OTU count and lower Shannon Index. Conclusion The results suggest that use of CPC in POM is associated with a lower CRP level. Use of mouthwash containing CPC may decrease bacterial diversity on the dorsal surface of the tongue, and this may reduce postoperative complications such as pneumonia. Trial registration: University Hospitals Medical Information Network Clinical Trials Registry (UMIN-CTR), UMIN000030919. Registered January 21, 2018.