Is Tube Thermosoftening Helpful for Videolaryngoscope-Guided Nasotracheal Intubation?: A Randomized Controlled Trial

Thermosoftening of the endotracheal tube (ETT) and telescoping the ETT into a rubber catheter have been suggested as a method for reducing epistaxis during nasotracheal intubation (NTI). However, thermosoftening technique is known to make it difficult to navigate the ETT into trachea without the use of Magill forceps during NTI. The cuff inflation technique has been suggested as an effective alternative to the use of Magill forceps to improve the oropharyngeal navigation of the ETT, irrespective of their stiffness, during direct laryngoscope-guided NTI. We evaluated whether thermosoftening of the ETT telescoped into rubber catheters has an additional benefit in reducing nasal injury. Simultaneously, we also evaluated whether thermosoftening of the ETT worsened orotracheal navigability during cuff inflation-supplemented videolaryngoscope-guided NTI. One hundred forty patients were randomly assigned to 1 of the 2 groups depending on whether the ETT was softened by warming or not. The primary outcome was the incidence of epistaxis during NTI. The secondary outcome was nasotracheal navigability of the ETT, assessed by navigation grade and time required for insertion of ETT in each phase (from nose to oropharynx, from oropharynx to glottic inlet aided by cuff inflation if needed, and from glottic inlet to trachea). The ETTs were successfully inserted through the selected nostril of all 140 patients. In the thermosoftening group, the incidence and severity of epistaxis was significantly lower (7% vs 51%; difference of 44.2%; 95% confidence interval, 29.9%-56.2%; P < .001), and the ETT passed through the nasal cavity with lower resistance (P = .001) and less time (P < .001) when compared to the control group. No difference was found in the ease of ETT insertion (navigation grade and time required) from the oropharynx to the glottic inlet (P > .99 and P = .054, respectively) and from the glottic inlet to the trachea (P > .99 and P = .750, respectively) between the 2 groups. In both groups, all ETTs could be navigated into the trachea without the use of Magill forceps. Supplemented with cuff inflation during videolaryngoscope-guided NTI, thermosoftening of the ETT telescoped into rubber catheters has a substantial benefit because it significantly reduces the incidence of epistaxis without worsening the oropharyngeal navigability of the ETT.