A Comparative Study of the Effect of Mouthwashes (Cetylpyridinium Chloride vs. Povidone Iodine) on Postoperative Inflammatory Reactions in Surgical Patients: Subanalysis of a Mouthwash Intervention Study

ABSTRACT Aim Perioperative oral management (POM) reduces the risk of postoperative complications. We previously conducted a randomized controlled feasibility study using povidone iodine (PVP‐I) or cetylpyridinium chloride (CPC) and found that perioperative self‐care with CPC mouthwash may support antibiotic‐induced changes in the oral flora. In this subanalysis, the effects of mouthwashes on postoperative systemic inflammatory reactions were analyzed. Methods This subanalysis was conducted on 78 patients undergoing general anesthesia (38 with PVP‐I group and 40 with CPC group). White blood cell (WBC) counts, serum CRP levels, and postoperative fever were employed as postoperative inflammatory markers, and a comparison was made between the groups. We collected bacteria from the dorsal surface of the tongue, and the total bacterial count, operational taxonomic unit (OTU) counts, and Shannon Index were analyzed. Results In comparing postoperative inflammatory indices between PVP‐I and CPC groups, median CRP was significantly lower in the CPC group than in the PVP‐I group (3.7 mg/dL vs. 6.3 mg/dL, p = 0.038). Univariate analysis identified significant associations between high CRP levels (≥ 5 mg/dL) and surgical site (OR = 0.62, 95% CI: 0.44–0.88, p = 0.008), surgical time (OR = 1.00, CI: 1.00–1.01, p = 0.047), and intervention product (OR = 0.39, 95% CI: 0.16–0.97, p = 0.043). In the multiple logistic regression analysis, the intervention product remained significantly associated with high CRP (OR = 0.30, 95% CI: 0.10–0.91, p = 0.034). In addition, the low CRP in the CPC group was associated with lower OTU and Shannon Index. Conclusion CPC rather than PVP‐I in POM has a significant positive effect on systemic inflammation (CRP level) and on the richness and evenness of the bacterial community on the surface of the tongue. These findings suggest that CPC rather than PVP‐I might be useful in POM. Trial Registration: UMIN000030919. Registered January 21, 2018.