The EndoFlex® Tube Enhances Navigability Through the Nasal Cavity During Nasotracheal Intubation

Abstract

To the Editor: During nasotracheal intubation, the distal tip of the endotracheal tube (ETT) is inserted from the naris into the oropharynx and can impinge on the posterior wall of the nasopharynx, where the nasal passage curves perpendicularly. If excess force is applied, the ETT tip may perforate the retropharyngeal mucosa and, in rare cases, be inserted into the retropharyngeal space. Retropharyngeal laceration is a serious complication of nasotracheal intubation.1 Therefore, a number of methods have been reported to enhance the navigability of ETTs.2–4 The EndoFlex® tube (Merlyn Associates, Tustin, CA) is equipped with a distal-tip flexing mechanism.5 By pulling the friction lock upward, the distal tip of the tube is flexed anteriorly. Conceivably, anterior flexion of the distal tip can be easily adjusted to follow the anatomical curve of the nasopharynx. We compared the EndoFlex tube and the standard ETT (Portex® Blue Line Tracheal Tube) with regard to navigability through the nasal passage. The Clinical Ethical Committee at our hospital approved the study protocol, and informed consent was obtained from all patients. Sixty patients, aged 17–77 yr, scheduled to undergo elective oral surgery, were enrolled in the study. Patients with a history of nasal surgery, trauma, or recurrent epistaxis were excluded. Anesthesia was induced with thiopental (4–5 mg · kg−1) or propofol (1–2 mg · kg−1) and vecuronium (0.1 mg · kg−1) was IV administered. After the nasal cavity was examined using cotton swabs soaked with a vasoconstrictor,6 either the Portex tube (Portex tube group; n = 30) or the EndoFlex tube (EndoFlex tube group; n = 30) was randomly chosen and then gently inserted into the nasal cavity. The navigability of the tube on the first attempt was defined as either smooth or impinged.3,4 Data were analyzed by the χ2 test. A P value <0.05 was considered statistically significant. The ETT was judged to have impinged navigability in 13 of 30 patients in the Portex tube group. In these patients, the ETT was rotated counterclockwise and a bent stylet was used on the second or third attempt. Severe epistaxis impeding intubation was observed in one patient. In contrast, in all 30 patients in the EndoFlex tube group, ETT navigability was smooth, no repeated attempts were required, and no severe epistaxis occurred. The incidence of impingement was significantly different between these two groups (P < 0.001). These results suggest that the anteriorly flexed tip of the EndoFlex tube can improve navigability through the nasal passage without impinging on the posterior wall of the nasopharynx (Figure 1). Manipulating the friction lock of the EndoFlex tube facilitates reliable advancement of the ETT tip through the nasal cavity into the oropharynx and may reduce the incidence of retropharyngeal injuries.Figure 1.: Placement of the EndoFlex® tube in the nasopharynx. The distal tip of the tube can be adjusted to follow the anatomical curve of the nasopharynx by pulling the friction lock upward.Kazuna Sugiyama, DDS, PhD Naoki Takahashi, DDS, PhD Atsushi Kohjitani, DDS, PhD Department of Dental Anesthesiology Kagoshima University Graduate School of Medical and Dental Sciences Sakuragaoka, Kagoshima Japan [email protected]