Ozer S, Benumof J L
Department of Anesthesia, UCSD Medical Center, San Diego, California 92103-8812, USA.
Anesthesiology. 1999 Jul;91(1):137-43. doi: 10.1097/00000542-199907000-00022.
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.
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.
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.
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.
在麻醉、瘫痪且已插管的患者中插入胃管（GT）可能会很困难。本研究的目的是通过纤维光学手段确定胃管成功或未能进入食管的原因，并基于这些发现确定将失败转化为成功的机制。
对60例接受全身麻醉并经口气管插管的患者进行研究。通过经左鼻孔插入的纤维镜观察每位患者的喉部和下咽。所有患者均经口（OGT）和经鼻（NGT）插入胃管，并观察其通过路径或阻力部位。在出现阻力的情况下，在同侧甲状舌骨膜外侧施加向内侧的颈部压力（称为侧颈压力），以尝试使胃管通过。
60例患者均进行了OGT和NGT插入，共尝试120次。120次插入中有92次（77%）在首次尝试时胃管顺利通过（OGT为51/60 = 85%，NGT为41/60 = 68%，P < 0.05）。在这些首次通过成功的病例中，92%的胃管进入下咽时位于杓状软骨外侧。120次插入中有28次（23%）胃管遇到阻力未能通过（OGT为9/60 = 15%，NGT为19/60 = 32%）。受阻部位为梨状窦（13/28 = 46%）、杓状软骨（7/28 = 25%）和气管（6/28 = 21%），2根OGT未通过口咽（2/28 = 7%）。对梨状窦和杓状软骨受阻情况尝试侧颈压力20次，17次成功（85%），3次失败（15%）。OGT和NGT通过杓状软骨的平均距离分别为13.2 cm和16.2 cm。
胃管进入下咽时位于杓状软骨外侧。因此，喉部水平最常见的阻力部位是杓状软骨和梨状窦。侧颈压力可压缩梨状窦并使杓状软骨向内侧移动，解除85%的胃管受阻情况。
