BackgroundNasal bleeding is the most common complication during nasotracheal intubation (NTI). To reduce nasal bleeding, the nasal mucosa is treated with vasoconstrictors (epinephrine [E] or tramazoline [T]) prior to NTI. This study aimed to determine whether E or T is more effective and safe for reducing nasal bleeding during NTI.MethodsThis study was preregistered on UMIN-CTR after being approved by the IRB of the School of Dentistry at Aichi Gakuin University. Written consent was received from all the patients. Total 206 patients aged 20–70 years and classified as 1–2 on American Society of Anesthesiologists-physical status were scheduled to undergo general anesthesia with NTI. At last, 197 patients were randomly divided into two groups and treated with either E (n = 99; 3 patients were discontinued) or T (n = 98; 2 patient were discontinued). After induction of general anesthesia, each patient’s nasal mucosa was treated using either E or T. The E used in this study was BOSMIN® SOLUTION 0.1% (Daiichi-Sankyo Co., Ltd., Tokyo), and the T used in this study was TRAMAZOLIN Nasal Solution 0.118% AFP, (Alfresa Pharma Corporation, Osaka). E was diluted five times according to the package insert (final concentration of E = 0.02%), and T was used in its original solution. After 2 min, NTI was performed via the right nostril. Primary outcome were the presence of nasal bleeding (if bleeding was recognized at the posterior pharyngeal wall via nasal cavity during intubation, it was defined as bleeding) and the degree of bleeding (classified as none, mild, moderate, or severe). Secondary outcomes were arrhythmia, and hemodynamic (mean atrial pressure and heart rate) changes associated with vasoconstrictors.ResultsThe presence of bleeding was comparable in both groups (12.5%, E; 14.5%, T; P = 0.63). No significant difference between the groups regarding the degree of bleeding (P = 0.78) was observed, with most patients having no bleeding (n = 84, E; n = 82, T). No severe bleeding and no arrhythmias induced by vasoconstrictor were observed in the two groups.ConclusionsNasal treatment with E or T shows no difference in nasal bleeding during NTI. Although no arrhythmia associated with E was observed in this study, it has been reported in literature. Therefore, as frequency and degree of nasal bleeding were comparable, nasal treatment with T could reduce the risk of NTI.Trial registrationUMIN-CTR (Registration No. UMIN000037907). Registered (05/09/2019).