Microbiological comparison of the disinfecting efficacy of small and large cotton swabs in nasotracheal intubation: a randomized trial.

Background: Nasotracheal intubation (NTI) is necessary during surgeries requiring clear access to the surgical field and in patients with respiratory issues. This study investigates the pre-NTI nasal disinfection efficacy of different cotton swab sizes, hypothesizing that smaller swabs could minimize bleeding while maintaining disinfection efficacy.

Methods: Patients classified as American Society of Anesthesiologists-physical status (ASA-PS) class 1 or 2 scheduled for general anesthesia with NTI were randomly assigned to either a large cotton swabs (LCS) or fine cotton swabs (FCS) group in this randomized controlled trial (RCT)." After anesthesia, a fine cotton swab was inserted into the inferior nasal meatus in both groups to collect bacteria (sample A). Next, the nasal cavity was disinfected with LCS or FCS according to the patient group. Bacteria were collected by inserting a fine cotton swab into the inferior nasal meatus (sample B). After surgery, bacteria were collected from the endotracheal tube tip using a fine cotton swab in both groups (sample C). The samples were cultured for 24 hours, and the colonies from samples A-C were counted. The changes in bacteria count between samples A and B and samples A and C were determined. Nasal bleeding from cotton swab insertion was assessed as a secondary outcome. Student's t-tests, a chi-square independence test, and Mann-Whitney U tests were used for the statistical analysis. The statistical significance level was set at p < 0.05.

Results: Between samples A and B, the change in bacteria count was 7.2% (1.4-26.1%) (median[interquartile range]) in the LCS group and 6.9% (0.9-22%) in the FCS group (p = 0.90). Between samples A and C, the change in bacteria count was 7.5% (0.2-44%) in the LCS group and 8.3% (0.3-39%) in the FCS group (p = 0.55). We examined 62 subjects in each group (LCS and FCS), and samples A, B, and C were collected from all participants in both groups. Nasal bleeding occurred in 42/62 in the LCS group and 22/62 in the FCS group (p < 0.01).

Conclusion: Cotton swab thickness did not impact disinfection efficacy, but large swabs increased the risk of nasal bleeding. We recommend FCS for nasal disinfection prior to NTI in ASA 1-2 patients, as they reduce bleeding risk without compromising disinfection.

Trial registration: UMIN-CTR (registration no. UMIN000051495), June 30, 2023.