Through the Nasal Route for Nasal Intubation Tube

Within the nasal cannula, tracheal intubation can be done through the two main passages in the nostrils. The lower pathway is located at the bottom of the inferior nasal concha. The upper pathway is located above the inferior nasal concha and below the middle nasal concha. The lower pathway may be considered a safer route as it is away from the middle nasal concha and ethmoid bone.

92 ASA I and II adult patients undergoing elective maxillofacial surgery requiring nasal intubation tube as a part of anesthesia management were recruited. Exclusion criteria included morbid obesity, nasal trauma, history of surgery or obstruction, gastroesophageal reflux, bleeding diathesis, and anticipated difficulty in tracheal intubation. All patients were asked if they had any difficulty in nasal breathing and only asymptomatic patients able to breathe comfortably through both nostrils were invited to participate in the study.

Nasal cannula endoscopy examination

The endoscopy examination and intubation were randomly assigned among three investigators. Each nostril was inspected in sequence, with a fiber-optic laryngoscope (diameter, 4 mm) connected to a camera system and video recorder. A videotape of the endoscopic examination was made for review. Guidelines for making and using patient visual and audio recordings as specified by the Institutional Review Board were followed. Following nasal inspection, the lower pathway below the inferior nasal concha, upper pathway above the inferior nasal concha and below the middle nasal concha were systematically inspected in both nostrils using the fiberoptic scope. Any presence of nasal internal anomalies was recorded, and the most patent nostril was selected for intubation. If the nostrils were considered equally patent, random selection was made.

Nasal intubation tube laryngoscopy examination

Standardized traditional nasal intubation tube placement was then performed using a laryngoscope. A 7-mm tube was used for male patients and a 6-mm tube for female patients. The pre-formed tubes were warmed and softened by immersion in sterile 0.9% saline maintained at 37℃. All tubes were lubricated with sterile, water-soluble gel and inserted with the aid of forceps, as necessary. All tubes were directed in a standard manner, with the concave aspect of the tube downward, the tip of the tube to the right and the slanted portion to the left. The selected tube was introduced into the selected nostril, with the near end of the tube pulled toward the head side and the tip guided along the nasal floor in an attempt to advance it along the lower pathway. If inappropriate resistance was encountered, the tube was slightly re-directed at the end of the nasal cavity. If resistance persisted, the tube was turned slightly toward the head side in an attempt to intubate through the path offering the least resistance, and the number of attempts required was recorded. The resistance offered by the passage to the tube was characterized as mild or moderate resistance.

If a clear path was not found, an attempt was made to intubate the other nostril in the same manner. Ventilation was re-established with oxygen, air, and isoflurane, and an independent anesthetist who did not witness the intubation examined the pharynx with a laryngoscope and recorded any nasal bleeding. Blood staining, pooling, clotting, or dripping into the oral pharynx was deemed evidence of nasal bleeding. The path of the tube was identified and recorded by passing the fiberoptic scope through the tube from above and below, a distance of 2-3 cm into the nostril. A videotape of the endoscopy following tube placement was made for review.