Oro- and nasogastric tube passage in intubated patients: fiberoptic description of where they go at the laryngeal level and how to make them enter the esophagus.

BACKGROUND

Insertion of a gastric tube (GT) in anesthetized, paralyzed, and intubated patients can be difficult The purpose of this study was to determine fiberoptically why GTs succeed or fail to enter the esophagus and, based on these findings, to determine a mechanism for converting failures into successes.

METHODS

Sixty patients under general anesthesia and orotracheally intubated were studied. The larynx and hypopharynx of each patient were viewed via a fiberscope placed through the left naris. GTs were passed orally (OGT) and nasally (NGT) in all patients, and the pathway of passage or site of resistance was visualized. In cases of resistance, medially directed ipsilateral neck pressure was applied over the lateral thyrohyoid membrane (termed lateral neck pressure) to try to allow passage of the GT.

RESULTS

All 60 patients had both an OGT and NGT passed for a total of 120 attempts. The GT passed easily on the first attempt in 92 of 120 insertions (77%) (for OGT 51/60 = 85% and for NGT 41/60 = 68%, P < 0.05). In 92% of these first-pass successes, the GT entered the hypopharynx just lateral to the arytenoid cartilages. The GT met resistance and failed to pass in 28 of 120 insertions (23%) (for OGT 9/60 = 15% and for NGT 19/60 = 32%). The sites of impaction were the piriform sinuses (13/28 = 46%), arytenoid cartilages (7/28 = 25%), and trachea (6/28 = 21%), and two OGTs did not pass the oropharynx (2/28 = 70%). Lateral neck pressure was attempted 20 times (for the piriform sinus and arytenoid cartilage impactions) with 17 successes (85%) and three failures (15%). The average distance to passage of the OGT and NGT by the arytenoid cartilage was 13.2 and 16.2 cm, respectively.

CONCLUSION

GTs enter the hypopharynx just lateral to the arytenoid cartilages. Consequently, the most common sites of resistance at the laryngeal level are the arytenoid cartilages and piriform sinuses. Lateral neck pressure compresses the piriform sinuses and moves the arytenoid cartilages medially, relieving 85% of these GT impactions.