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, an d intubated patients can be difficult. The purpose of this study was to det ermine fiberoptically why GTs succeed or fail to enter the esophagus and, b ased on these findings, to determine a mechanism for converting failures in to successes. Methods: Sixty patients under general anesthesia and orotracheally intubate d were studied. The larynx and hypopharynx of each patient were viewed via a fiberscope placed through the left naris. GTs were passed orally (OGT) an d nasally (NGT) in all patients, and the pathway of passage or site of resi stance was visualized. In cases of resistance, medially directed ipsilatera l neck pressure was applied over the lateral thyrohyoid membrane (termed la teral neck pressure) to try to allow passage of the GT. Results: All GO 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 t hese first-pass successes, the GT entered the hypopharynx just lateral to t he 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 site s of impaction were the piriform sinuses (13/28 = 46%), arytenoid cartilage s (7/28 = 25%), and trachea (6/28 = 21%), and two OGTs did not pass the oro pharynx (2/28 = 7%). 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 NG T by the arytenoid cartilage was 13.2 and 16.2 cm, respectively. Conclusion: GTs enter the hypopharynx just lateral to the arytenoid cartila ges. Consequently, the most common sites of resistance at the laryngeal lev el are the arytenoid cartilages and piriform sinuses. Lateral neck pressure compresses the piriform sinuses and moves the arytenoid cartilages mediall y, relieving 85% of these GT impactions.