Effects of Wet Versus Dry Warming Techniques on the Hardness of Nasotracheal Tubes

Background and aim Nasotracheal intubation is widely used in oral and maxillofacial surgery but is frequently associated with epistaxis. To reduce mucosal trauma, pre-warming the tube with warm water is commonly used; however, time-dependent changes in tube hardness and limitations of warming methods remain concerns. This study aimed to evaluate the softening effect of dry warming with heated gloves compared with conventional warm-water-based warming. Methods Nasotracheal tubes (NT) were cut into 1 cm² sections and measured at room temperature. They were then warmed for 10 min in either 40°C warm water or with 55°C heated gloves. Hardness was measured at 5 s after warming ended and every 30 s for 5 min. Data were analyzed using repeated-measures ANOVA and Mann-Whitney U tests. Results The heated-glove group showed significantly greater softening than the warm-water group at 5 s after warming ended and at 30, 60, 120, and 150 s after warming (p < 0.05). By 240 s, both groups had recovered to approximately 90% of baseline hardness. Measurement reliability was good (intraclass correlation coefficient {ICC} = 0.78). Discussion Dry warming offers advantages over wet warming, including ease of preparation, reduced risk of burns or contamination, and consistent temperature control. Warming to 55°C was considered acceptable for short-term use with respect to tube material tolerance. Conclusion Dry warming with heated gloves provides greater early softening than warm water-based warming and may serve as a practical method for NT tube preparation. This study focused on physical properties; clinical outcomes such as pain, mucosal injury, or airway patency were not assessed. Further clinical studies are warranted.